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Author SHA1 Message Date
Miaohe Lin d70cec8983 mm: mmap: merge vma after call_mmap() if possible 
The vm_flags may be changed after call_mmap() because drivers may set some
flags for their own purpose.  As a result, we failed to merge the adjacent
vma due to the different vm_flags as userspace can't pass in the same one.
Try to merge vma after call_mmap() to fix this issue.

Signed-off-by: Hongxiang Lou <louhongxiang@huawei.com>
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/1594954065-23733-1-git-send-email-linmiaohe@huawei.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:27 -07:00
Anshuman Khandual 56993b4e14 mm/sparsemem: enable vmem_altmap support in vmemmap_alloc_block_buf() 
There are many instances where vmemap allocation is often switched between
regular memory and device memory just based on whether altmap is available
or not.  vmemmap_alloc_block_buf() is used in various platforms to
allocate vmemmap mappings.  Lets also enable it to handle altmap based
device memory allocation along with existing regular memory allocations.
This will help in avoiding the altmap based allocation switch in many
places.  To summarize there are two different methods to call
vmemmap_alloc_block_buf().

vmemmap_alloc_block_buf(size, node, NULL)   /* Allocate from system RAM */
vmemmap_alloc_block_buf(size, node, altmap) /* Allocate from altmap */

This converts altmap_alloc_block_buf() into a static function, drops it's
entry from the header and updates Documentation/vm/memory-model.rst.

Suggested-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Jia He <justin.he@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Will Deacon <will@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Hsin-Yi Wang <hsinyi@chromium.org>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Steve Capper <steve.capper@arm.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Yu Zhao <yuzhao@google.com>
Link: http://lkml.kernel.org/r/1594004178-8861-3-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:27 -07:00
Anshuman Khandual 1d9cfee753 mm/sparsemem: enable vmem_altmap support in vmemmap_populate_basepages() 
Patch series "arm64: Enable vmemmap mapping from device memory", v4.

This series enables vmemmap backing memory allocation from device memory
ranges on arm64.  But before that, it enables vmemmap_populate_basepages()
and vmemmap_alloc_block_buf() to accommodate struct vmem_altmap based
alocation requests.

This patch (of 3):

vmemmap_populate_basepages() is used across platforms to allocate backing
memory for vmemmap mapping.  This is used as a standard default choice or
as a fallback when intended huge pages allocation fails.  This just
creates entire vmemmap mapping with base pages (PAGE_SIZE).

On arm64 platforms, vmemmap_populate_basepages() is called instead of the
platform specific vmemmap_populate() when ARM64_SWAPPER_USES_SECTION_MAPS
is not enabled as in case for ARM64_16K_PAGES and ARM64_64K_PAGES configs.

At present vmemmap_populate_basepages() does not support allocating from
driver defined struct vmem_altmap while trying to create vmemmap mapping
for a device memory range.  It prevents ARM64_16K_PAGES and
ARM64_64K_PAGES configs on arm64 from supporting device memory with
vmemap_altmap request.

This enables vmem_altmap support in vmemmap_populate_basepages() unlocking
device memory allocation for vmemap mapping on arm64 platforms with 16K or
64K base page configs.

Each architecture should evaluate and decide on subscribing device memory
based base page allocation through vmemmap_populate_basepages().  Hence
lets keep it disabled on all archs in order to preserve the existing
semantics.  A subsequent patch enables it on arm64.

Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Jia He <justin.he@arm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Will Deacon <will@kernel.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Hsin-Yi Wang <hsinyi@chromium.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Steve Capper <steve.capper@arm.com>
Cc: Yu Zhao <yuzhao@google.com>
Link: http://lkml.kernel.org/r/1594004178-8861-1-git-send-email-anshuman.khandual@arm.com
Link: http://lkml.kernel.org/r/1594004178-8861-2-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:27 -07:00
Feng Tang 56f3547bfa mm: adjust vm_committed_as_batch according to vm overcommit policy 
When checking a performance change for will-it-scale scalability mmap test
[1], we found very high lock contention for spinlock of percpu counter
'vm_committed_as':

    94.14%     0.35%  [kernel.kallsyms]         [k] _raw_spin_lock_irqsave
    48.21% _raw_spin_lock_irqsave;percpu_counter_add_batch;__vm_enough_memory;mmap_region;do_mmap;
    45.91% _raw_spin_lock_irqsave;percpu_counter_add_batch;__do_munmap;

Actually this heavy lock contention is not always necessary.  The
'vm_committed_as' needs to be very precise when the strict
OVERCOMMIT_NEVER policy is set, which requires a rather small batch number
for the percpu counter.

So keep 'batch' number unchanged for strict OVERCOMMIT_NEVER policy, and
lift it to 64X for OVERCOMMIT_ALWAYS and OVERCOMMIT_GUESS policies.  Also
add a sysctl handler to adjust it when the policy is reconfigured.

Benchmark with the same testcase in [1] shows 53% improvement on a 8C/16T
desktop, and 2097%(20X) on a 4S/72C/144T server.  We tested with test
platforms in 0day (server, desktop and laptop), and 80%+ platforms shows
improvements with that test.  And whether it shows improvements depends on
if the test mmap size is bigger than the batch number computed.

And if the lift is 16X, 1/3 of the platforms will show improvements,
though it should help the mmap/unmap usage generally, as Michal Hocko
mentioned:

: I believe that there are non-synthetic worklaods which would benefit from
: a larger batch.  E.g.  large in memory databases which do large mmaps
: during startups from multiple threads.

[1] https://lore.kernel.org/lkml/20200305062138.GI5972@shao2-debian/

Signed-off-by: Feng Tang <feng.tang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Qian Cai <cai@lca.pw>
Cc: Kees Cook <keescook@chromium.org>
Cc: Andi Kleen <andi.kleen@intel.com>
Cc: Tim Chen <tim.c.chen@intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: kernel test robot <rong.a.chen@intel.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Tejun Heo <tj@kernel.org>
Link: http://lkml.kernel.org/r/1589611660-89854-4-git-send-email-feng.tang@intel.com
Link: http://lkml.kernel.org/r/1592725000-73486-4-git-send-email-feng.tang@intel.com
Link: http://lkml.kernel.org/r/1594389708-60781-5-git-send-email-feng.tang@intel.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:26 -07:00
Feng Tang 4e2ee51e82 mm/util.c: make vm_memory_committed() more accurate 
percpu_counter_sum_positive() will provide more accurate info.

As with percpu_counter_read_positive(), in worst case the deviation could
be 'batch * nr_cpus', which is totalram_pages/256 for now, and will be
more when the batch gets enlarged.

Its time cost is about 800 nanoseconds on a 2C/4T platform and 2~3
microseconds on a 2S/36C/72T Skylake server in normal case, and in worst
case where vm_committed_as's spinlock is under severe contention, it costs
30~40 microseconds for the 2S/36C/72T Skylake sever, which should be fine
for its only two users: /proc/meminfo and HyperV balloon driver's status
trace per second.

Signed-off-by: Feng Tang <feng.tang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Michal Hocko <mhocko@suse.com> # for /proc/meminfo
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Qian Cai <cai@lca.pw>
Cc: Andi Kleen <andi.kleen@intel.com>
Cc: Tim Chen <tim.c.chen@intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: kernel test robot <rong.a.chen@intel.com>
Cc: Tejun Heo <tj@kernel.org>
Link: http://lkml.kernel.org/r/1592725000-73486-3-git-send-email-feng.tang@intel.com
Link: http://lkml.kernel.org/r/1594389708-60781-3-git-send-email-feng.tang@intel.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:26 -07:00
Zhen Lei 7bba8f0ea4 mm/mmap: optimize a branch judgment in ksys_mmap_pgoff() 
Look at the pseudo code below.  It's very clear that, the judgement
"!is_file_hugepages(file)" at 3) is duplicated to the one at 1), we can
use "else if" to avoid it.  And the assignment "retval = -EINVAL" at 2) is
only needed by the branch 3), because "retval" will be overwritten at 4).

No functional change, but it can reduce the code size. Maybe more clearer?
Before:
text    data     bss     dec     hex filename
28733    1590       1   30324    7674 mm/mmap.o

After:
text    data     bss     dec     hex filename
28701    1590       1   30292    7654 mm/mmap.o

====pseudo code====:
	if (!(flags & MAP_ANONYMOUS)) {
		...
1)		if (is_file_hugepages(file))
			len = ALIGN(len, huge_page_size(hstate_file(file)));
2)		retval = -EINVAL;
3)		if (unlikely(flags & MAP_HUGETLB && !is_file_hugepages(file)))
			goto out_fput;
	} else if (flags & MAP_HUGETLB) {
		...
	}
	...

4)	retval = vm_mmap_pgoff(file, addr, len, prot, flags, pgoff);
out_fput:
	...
	return retval;

Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20200705080112.1405-1-thunder.leizhen@huawei.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:26 -07:00
Joerg Roedel 2a681cfa5b mm: move p?d_alloc_track to separate header file 
The functions are only used in two source files, so there is no need for
them to be in the global <linux/mm.h> header.  Move them to the new
<linux/pgalloc-track.h> header and include it only where needed.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Pekka Enberg <penberg@kernel.org>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Abdul Haleem <abdhalee@linux.vnet.ibm.com>
Cc: Satheesh Rajendran <sathnaga@linux.vnet.ibm.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Matthew Wilcox <willy@infradead.org>
Link: http://lkml.kernel.org/r/20200609120533.25867-1-joro@8bytes.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:26 -07:00
Mike Rapoport ab05eabfa1 mm: move lib/ioremap.c to mm/ 
The functionality in lib/ioremap.c deals with pagetables, vmalloc and
caches, so it naturally belongs to mm/ Moving it there will also allow
declaring p?d_alloc_track functions in an header file inside mm/ rather
than having those declarations in include/linux/mm.h

Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Pekka Enberg <penberg@kernel.org>
Cc: Abdul Haleem <abdhalee@linux.vnet.ibm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Joerg Roedel <jroedel@suse.de>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Satheesh Rajendran <sathnaga@linux.vnet.ibm.com>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Matthew Wilcox <willy@infradead.org>
Link: http://lkml.kernel.org/r/20200627143453.31835-8-rppt@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:26 -07:00
Mike Rapoport ca15ca406f mm: remove unneeded includes of <asm/pgalloc.h> 
Patch series "mm: cleanup usage of <asm/pgalloc.h>"

Most architectures have very similar versions of pXd_alloc_one() and
pXd_free_one() for intermediate levels of page table.  These patches add
generic versions of these functions in <asm-generic/pgalloc.h> and enable
use of the generic functions where appropriate.

In addition, functions declared and defined in <asm/pgalloc.h> headers are
used mostly by core mm and early mm initialization in arch and there is no
actual reason to have the <asm/pgalloc.h> included all over the place.
The first patch in this series removes unneeded includes of
<asm/pgalloc.h>

In the end it didn't work out as neatly as I hoped and moving
pXd_alloc_track() definitions to <asm-generic/pgalloc.h> would require
unnecessary changes to arches that have custom page table allocations, so
I've decided to move lib/ioremap.c to mm/ and make pgalloc-track.h local
to mm/.

This patch (of 8):

In most cases <asm/pgalloc.h> header is required only for allocations of
page table memory.  Most of the .c files that include that header do not
use symbols declared in <asm/pgalloc.h> and do not require that header.

As for the other header files that used to include <asm/pgalloc.h>, it is
possible to move that include into the .c file that actually uses symbols
from <asm/pgalloc.h> and drop the include from the header file.

The process was somewhat automated using

	sed -i -E '/[<"]asm\/pgalloc\.h/d' \
                $(grep -L -w -f /tmp/xx \
                        $(git grep -E -l '[<"]asm/pgalloc\.h'))

where /tmp/xx contains all the symbols defined in
arch/*/include/asm/pgalloc.h.

[rppt@linux.ibm.com: fix powerpc warning]

Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Pekka Enberg <penberg@kernel.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>	[m68k]
Cc: Abdul Haleem <abdhalee@linux.vnet.ibm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Satheesh Rajendran <sathnaga@linux.vnet.ibm.com>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Joerg Roedel <jroedel@suse.de>
Cc: Matthew Wilcox <willy@infradead.org>
Link: http://lkml.kernel.org/r/20200627143453.31835-1-rppt@kernel.org
Link: http://lkml.kernel.org/r/20200627143453.31835-2-rppt@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:26 -07:00
Alex Zhang 0c4123e3fb mm/memory.c: make remap_pfn_range() reject unaligned addr 
This function implicitly assumes that the addr passed in is page aligned.
A non page aligned addr could ultimately cause a kernel bug in
remap_pte_range as the exit condition in the logic loop may never be
satisfied.  This patch documents the need for the requirement, as well as
explicitly adds a check for it.

Signed-off-by: Alex Zhang <zhangalex@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20200617233512.177519-1-zhangalex@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:26 -07:00
Ralph Campbell 463b7a173d mm: remove redundant check non_swap_entry() 
In zap_pte_range(), the check for non_swap_entry() and
is_device_private_entry() is unnecessary since the latter is sufficient to
determine if the page is a device private page.  Remove the test for
non_swap_entry() to simplify the code and for clarity.

Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Jason Gunthorpe <jgg@mellanox.com>
Acked-by: David Hildenbrand <david@redhat.com>
Link: http://lkml.kernel.org/r/20200615175405.4613-1-rcampbell@nvidia.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:26 -07:00
Michal Koutný a6f23d14ec mm/page_counter.c: fix protection usage propagation 
When workload runs in cgroups that aren't directly below root cgroup and
their parent specifies reclaim protection, it may end up ineffective.

The reason is that propagate_protected_usage() is not called in all
hierarchy up.  All the protected usage is incorrectly accumulated in the
workload's parent.  This means that siblings_low_usage is overestimated
and effective protection underestimated.  Even though it is transitional
phenomenon (uncharge path does correct propagation and fixes the wrong
children_low_usage), it can undermine the intended protection
unexpectedly.

We have noticed this problem while seeing a swap out in a descendant of a
protected memcg (intermediate node) while the parent was conveniently
under its protection limit and the memory pressure was external to that
hierarchy.  Michal has pinpointed this down to the wrong
siblings_low_usage which led to the unwanted reclaim.

The fix is simply updating children_low_usage in respective ancestors also
in the charging path.

Fixes: 230671533d ("mm: memory.low hierarchical behavior")
Signed-off-by: Michal Koutný <mkoutny@suse.com>
Signed-off-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Roman Gushchin <guro@fb.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: <stable@vger.kernel.org>	[4.18+]
Link: http://lkml.kernel.org/r/20200803153231.15477-1-mhocko@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:26 -07:00
Johannes Weiner e22c6ed90a mm: memcontrol: don't count limit-setting reclaim as memory pressure 
When an outside process lowers one of the memory limits of a cgroup (or
uses the force_empty knob in cgroup1), direct reclaim is performed in the
context of the write(), in order to directly enforce the new limit and
have it being met by the time the write() returns.

Currently, this reclaim activity is accounted as memory pressure in the
cgroup that the writer(!) belongs to.  This is unexpected.  It
specifically causes problems for senpai
(https://github.com/facebookincubator/senpai), which is an agent that
routinely adjusts the memory limits and performs associated reclaim work
in tens or even hundreds of cgroups running on the host.  The cgroup that
senpai is running in itself will report elevated levels of memory
pressure, even though it itself is under no memory shortage or any sort of
distress.

Move the psi annotation from the central cgroup reclaim function to
callsites in the allocation context, and thereby no longer count any
limit-setting reclaim as memory pressure.  If the newly set limit causes
the workload inside the cgroup into direct reclaim, that of course will
continue to count as memory pressure.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Reviewed-by: Roman Gushchin <guro@fb.com>
Acked-by: Chris Down <chris@chrisdown.name>
Acked-by: Michal Hocko <mhocko@suse.com>
Link: http://lkml.kernel.org/r/20200728135210.379885-2-hannes@cmpxchg.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:26 -07:00
Johannes Weiner 19ce33acbb mm: memcontrol: restore proper dirty throttling when memory.high changes 
Commit 8c8c383c04 ("mm: memcontrol: try harder to set a new
memory.high") inadvertently removed a callback to recalculate the
writeback cache size in light of a newly configured memory.high limit.

Without letting the writeback cache know about a potentially heavily
reduced limit, it may permit too many dirty pages, which can cause
unnecessary reclaim latencies or even avoidable OOM situations.

This was spotted while reading the code, it hasn't knowingly caused any
problems in practice so far.

Fixes: 8c8c383c04 ("mm: memcontrol: try harder to set a new memory.high")
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Chris Down <chris@chrisdown.name>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <guro@fb.com>
Link: http://lkml.kernel.org/r/20200728135210.379885-1-hannes@cmpxchg.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:26 -07:00
Yafang Shao 1378b37d03 memcg, oom: check memcg margin for parallel oom 
Memcg oom killer invocation is synchronized by the global oom_lock and
tasks are sleeping on the lock while somebody is selecting the victim or
potentially race with the oom_reaper is releasing the victim's memory.
This can result in a pointless oom killer invocation because a waiter
might be racing with the oom_reaper

        P1              oom_reaper              P2
                        oom_reap_task           mutex_lock(oom_lock)
                                                out_of_memory # no victim because we have one already
                        __oom_reap_task_mm      mute_unlock(oom_lock)
 mutex_lock(oom_lock)
                        set MMF_OOM_SKIP
 select_bad_process
 # finds a new victim

The page allocator prevents from this race by trying to allocate after the
lock can be acquired (in __alloc_pages_may_oom) which acts as a last
minute check.  Moreover page allocator simply doesn't block on the
oom_lock and simply retries the whole reclaim process.

Memcg oom killer should do the last minute check as well.  Call
mem_cgroup_margin to do that.  Trylock on the oom_lock could be done as
well but this doesn't seem to be necessary at this stage.

[mhocko@kernel.org: commit log]

Suggested-by: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Chris Down <chris@chrisdown.name>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: David Rientjes <rientjes@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Link: http://lkml.kernel.org/r/1594735034-19190-1-git-send-email-laoar.shao@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:25 -07:00
Chris Down 45c7f7e1ef mm, memcg: decouple e{low,min} state mutations from protection checks 
mem_cgroup_protected currently is both used to set effective low and min
and return a mem_cgroup_protection based on the result.  As a user, this
can be a little unexpected: it appears to be a simple predicate function,
if not for the big warning in the comment above about the order in which
it must be executed.

This change makes it so that we separate the state mutations from the
actual protection checks, which makes it more obvious where we need to be
careful mutating internal state, and where we are simply checking and
don't need to worry about that.

[mhocko@suse.com - don't check protection on root memcgs]

Suggested-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Chris Down <chris@chrisdown.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Yafang Shao <laoar.shao@gmail.com>
Link: http://lkml.kernel.org/r/ff3f915097fcee9f6d7041c084ef92d16aaeb56a.1594638158.git.chris@chrisdown.name
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:25 -07:00
Yafang Shao 22f7496f0b mm, memcg: avoid stale protection values when cgroup is above protection 
Patch series "mm, memcg: memory.{low,min} reclaim fix & cleanup", v4.

This series contains a fix for a edge case in my earlier protection
calculation patches, and a patch to make the area overall a little more
robust to hopefully help avoid this in future.

This patch (of 2):

A cgroup can have both memory protection and a memory limit to isolate it
from its siblings in both directions - for example, to prevent it from
being shrunk below 2G under high pressure from outside, but also from
growing beyond 4G under low pressure.

Commit 9783aa9917 ("mm, memcg: proportional memory.{low,min} reclaim")
implemented proportional scan pressure so that multiple siblings in excess
of their protection settings don't get reclaimed equally but instead in
accordance to their unprotected portion.

During limit reclaim, this proportionality shouldn't apply of course:
there is no competition, all pressure is from within the cgroup and should
be applied as such.  Reclaim should operate at full efficiency.

However, mem_cgroup_protected() never expected anybody to look at the
effective protection values when it indicated that the cgroup is above its
protection.  As a result, a query during limit reclaim may return stale
protection values that were calculated by a previous reclaim cycle in
which the cgroup did have siblings.

When this happens, reclaim is unnecessarily hesitant and potentially slow
to meet the desired limit.  In theory this could lead to premature OOM
kills, although it's not obvious this has occurred in practice.

Workaround the problem by special casing reclaim roots in
mem_cgroup_protection.  These memcgs are never participating in the
reclaim protection because the reclaim is internal.

We have to ignore effective protection values for reclaim roots because
mem_cgroup_protected might be called from racing reclaim contexts with
different roots.  Calculation is relying on root -> leaf tree traversal
therefore top-down reclaim protection invariants should hold.  The only
exception is the reclaim root which should have effective protection set
to 0 but that would be problematic for the following setup:

 Let's have global and A's reclaim in parallel:
  |
  A (low=2G, usage = 3G, max = 3G, children_low_usage = 1.5G)
  |\
  | C (low = 1G, usage = 2.5G)
  B (low = 1G, usage = 0.5G)

 for A reclaim we have
 B.elow = B.low
 C.elow = C.low

 For the global reclaim
 A.elow = A.low
 B.elow = min(B.usage, B.low) because children_low_usage <= A.elow
 C.elow = min(C.usage, C.low)

 With the effective values resetting we have A reclaim
 A.elow = 0
 B.elow = B.low
 C.elow = C.low

 and global reclaim could see the above and then
 B.elow = C.elow = 0 because children_low_usage > A.elow

Which means that protected memcgs would get reclaimed.

In future we would like to make mem_cgroup_protected more robust against
racing reclaim contexts but that is likely more complex solution than this
simple workaround.

[hannes@cmpxchg.org - large part of the changelog]
[mhocko@suse.com - workaround explanation]
[chris@chrisdown.name - retitle]

Fixes: 9783aa9917 ("mm, memcg: proportional memory.{low,min} reclaim")
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Chris Down <chris@chrisdown.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Chris Down <chris@chrisdown.name>
Acked-by: Roman Gushchin <guro@fb.com>
Link: http://lkml.kernel.org/r/cover.1594638158.git.chris@chrisdown.name
Link: http://lkml.kernel.org/r/044fb8ecffd001c7905d27c0c2ad998069fdc396.1594638158.git.chris@chrisdown.name
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:25 -07:00
Chris Down d977aa939f mm, memcg: unify reclaim retry limits with page allocator 
Reclaim retries have been set to 5 since the beginning of time in
commit 66e1707bc3 ("Memory controller: add per cgroup LRU and
reclaim").  However, we now have a generally agreed-upon standard for
page reclaim: MAX_RECLAIM_RETRIES (currently 16), added many years later
in commit 0a0337e0d1 ("mm, oom: rework oom detection").

In the absence of a compelling reason to declare an OOM earlier in memcg
context than page allocator context, it seems reasonable to supplant
MEM_CGROUP_RECLAIM_RETRIES with MAX_RECLAIM_RETRIES, making the page
allocator and memcg internals more similar in semantics when reclaim
fails to produce results, avoiding premature OOMs or throttling.

Signed-off-by: Chris Down <chris@chrisdown.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Roman Gushchin <guro@fb.com>
Link: http://lkml.kernel.org/r/da557856c9c7654308eaff4eedc1952a95e8df5f.1594640214.git.chris@chrisdown.name
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:25 -07:00
Chris Down b3ff92916a mm, memcg: reclaim more aggressively before high allocator throttling 
Patch series "mm, memcg: reclaim harder before high throttling", v2.

This patch (of 2):

In Facebook production, we've seen cases where cgroups have been put into
allocator throttling even when they appear to have a lot of slack file
caches which should be trivially reclaimable.

Looking more closely, the problem is that we only try a single cgroup
reclaim walk for each return to usermode before calculating whether or not
we should throttle.  This single attempt doesn't produce enough pressure
to shrink for cgroups with a rapidly growing amount of file caches prior
to entering allocator throttling.

As an example, we see that threads in an affected cgroup are stuck in
allocator throttling:

    # for i in $(cat cgroup.threads); do
    >     grep over_high "/proc/$i/stack"
    > done
    [<0>] mem_cgroup_handle_over_high+0x10b/0x150
    [<0>] mem_cgroup_handle_over_high+0x10b/0x150
    [<0>] mem_cgroup_handle_over_high+0x10b/0x150

...however, there is no I/O pressure reported by PSI, despite a lot of
slack file pages:

    # cat memory.pressure
    some avg10=78.50 avg60=84.99 avg300=84.53 total=5702440903
    full avg10=78.50 avg60=84.99 avg300=84.53 total=5702116959
    # cat io.pressure
    some avg10=0.00 avg60=0.00 avg300=0.00 total=78051391
    full avg10=0.00 avg60=0.00 avg300=0.00 total=78049640
    # grep _file memory.stat
    inactive_file 1370939392
    active_file 661635072

This patch changes the behaviour to retry reclaim either until the current
task goes below the 10ms grace period, or we are making no reclaim
progress at all.  In the latter case, we enter reclaim throttling as
before.

To a user, there's no intuitive reason for the reclaim behaviour to differ
from hitting memory.high as part of a new allocation, as opposed to
hitting memory.high because someone lowered its value.  As such this also
brings an added benefit: it unifies the reclaim behaviour between the two.

There's precedent for this behaviour: we already do reclaim retries when
writing to memory.{high,max}, in max reclaim, and in the page allocator
itself.

Signed-off-by: Chris Down <chris@chrisdown.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Roman Gushchin <guro@fb.com>
Link: http://lkml.kernel.org/r/cover.1594640214.git.chris@chrisdown.name
Link: http://lkml.kernel.org/r/a4e23b59e9ef499b575ae73a8120ee089b7d3373.1594640214.git.chris@chrisdown.name
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:25 -07:00
Roman Gushchin 536d3bf261 mm: memcontrol: avoid workload stalls when lowering memory.high 
Memory.high limit is implemented in a way such that the kernel penalizes
all threads which are allocating a memory over the limit.  Forcing all
threads into the synchronous reclaim and adding some artificial delays
allows to slow down the memory consumption and potentially give some time
for userspace oom handlers/resource control agents to react.

It works nicely if the memory usage is hitting the limit from below,
however it works sub-optimal if a user adjusts memory.high to a value way
below the current memory usage.  It basically forces all workload threads
(doing any memory allocations) into the synchronous reclaim and sleep.
This makes the workload completely unresponsive for a long period of time
and can also lead to a system-wide contention on lru locks.  It can happen
even if the workload is not actually tight on memory and has, for example,
a ton of cold pagecache.

In the current implementation writing to memory.high causes an atomic
update of page counter's high value followed by an attempt to reclaim
enough memory to fit into the new limit.  To fix the problem described
above, all we need is to change the order of execution: try to push the
memory usage under the limit first, and only then set the new high limit.

Reported-by: Domas Mituzas <domas@fb.com>
Signed-off-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Chris Down <chris@chrisdown.name>
Link: http://lkml.kernel.org/r/20200709194718.189231-1-guro@fb.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:25 -07:00
Roman Gushchin 74d555bed5 mm: slab: rename (un)charge_slab_page() to (un)account_slab_page() 
charge_slab_page() and uncharge_slab_page() are not related anymore to
memcg charging and uncharging.  In order to make their names less
confusing, let's rename them to account_slab_page() and
unaccount_slab_page() respectively.

Signed-off-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Pekka Enberg <penberg@kernel.org>
Link: http://lkml.kernel.org/r/20200707173612.124425-2-guro@fb.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:25 -07:00
Roman Gushchin 849504809f mm: memcg/slab: remove unused argument by charge_slab_page() 
charge_slab_page() is not using the gfp argument anymore,
remove it.

Signed-off-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Link: http://lkml.kernel.org/r/20200707173612.124425-1-guro@fb.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:25 -07:00
Shakeel Butt 991e767385 mm: memcontrol: account kernel stack per node 
Currently the kernel stack is being accounted per-zone.  There is no need
to do that.  In addition due to being per-zone, memcg has to keep a
separate MEMCG_KERNEL_STACK_KB.  Make the stat per-node and deprecate
MEMCG_KERNEL_STACK_KB as memcg_stat_item is an extension of
node_stat_item.  In addition localize the kernel stack stats updates to
account_kernel_stack().

Signed-off-by: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Roman Gushchin <guro@fb.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Link: http://lkml.kernel.org/r/20200630161539.1759185-1-shakeelb@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:25 -07:00
Roman Gushchin 10befea91b mm: memcg/slab: use a single set of kmem_caches for all allocations 
Instead of having two sets of kmem_caches: one for system-wide and
non-accounted allocations and the second one shared by all accounted
allocations, we can use just one.

The idea is simple: space for obj_cgroup metadata can be allocated on
demand and filled only for accounted allocations.

It allows to remove a bunch of code which is required to handle kmem_cache
clones for accounted allocations.  There is no more need to create them,
accumulate statistics, propagate attributes, etc.  It's a quite
significant simplification.

Also, because the total number of slab_caches is reduced almost twice (not
all kmem_caches have a memcg clone), some additional memory savings are
expected.  On my devvm it additionally saves about 3.5% of slab memory.

[guro@fb.com: fix build on MIPS]
  Link: http://lkml.kernel.org/r/20200717214810.3733082-1-guro@fb.com

Suggested-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Naresh Kamboju <naresh.kamboju@linaro.org>
Link: http://lkml.kernel.org/r/20200623174037.3951353-18-guro@fb.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:25 -07:00
Roman Gushchin 15999eef7f mm: memcg/slab: remove redundant check in memcg_accumulate_slabinfo() 
memcg_accumulate_slabinfo() is never called with a non-root kmem_cache as
a first argument, so the is_root_cache(s) check is redundant and can be
removed without any functional change.

Signed-off-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Link: http://lkml.kernel.org/r/20200623174037.3951353-17-guro@fb.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:25 -07:00
Roman Gushchin c7094406fc mm: memcg/slab: deprecate slab_root_caches 
Currently there are two lists of kmem_caches:
1) slab_caches, which contains all kmem_caches,
2) slab_root_caches, which contains only root kmem_caches.

And there is some preprocessor magic to have a single list if
CONFIG_MEMCG_KMEM isn't enabled.

It was required earlier because the number of non-root kmem_caches was
proportional to the number of memory cgroups and could reach really big
values.  Now, when it cannot exceed the number of root kmem_caches, there
is really no reason to maintain two lists.

We never iterate over the slab_root_caches list on any hot paths, so it's
perfectly fine to iterate over slab_caches and filter out non-root
kmem_caches.

It allows to remove a lot of config-dependent code and two pointers from
the kmem_cache structure.

Signed-off-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Link: http://lkml.kernel.org/r/20200623174037.3951353-16-guro@fb.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:25 -07:00
Roman Gushchin 272911a4ad mm: memcg/slab: remove memcg_kmem_get_cache() 
The memcg_kmem_get_cache() function became really trivial, so let's just
inline it into the single call point: memcg_slab_pre_alloc_hook().

It will make the code less bulky and can also help the compiler to
generate a better code.

Signed-off-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Link: http://lkml.kernel.org/r/20200623174037.3951353-15-guro@fb.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:25 -07:00
Roman Gushchin d797b7d054 mm: memcg/slab: simplify memcg cache creation 
Because the number of non-root kmem_caches doesn't depend on the number of
memory cgroups anymore and is generally not very big, there is no more
need for a dedicated workqueue.

Also, as there is no more need to pass any arguments to the
memcg_create_kmem_cache() except the root kmem_cache, it's possible to
just embed the work structure into the kmem_cache and avoid the dynamic
allocation of the work structure.

This will also simplify the synchronization: for each root kmem_cache
there is only one work.  So there will be no more concurrent attempts to
create a non-root kmem_cache for a root kmem_cache: the second and all
following attempts to queue the work will fail.

On the kmem_cache destruction path there is no more need to call the
expensive flush_workqueue() and wait for all pending works to be finished.
Instead, cancel_work_sync() can be used to cancel/wait for only one work.

Signed-off-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Link: http://lkml.kernel.org/r/20200623174037.3951353-14-guro@fb.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:25 -07:00
Roman Gushchin 9855609bde mm: memcg/slab: use a single set of kmem_caches for all accounted allocations 
This is fairly big but mostly red patch, which makes all accounted slab
allocations use a single set of kmem_caches instead of creating a separate
set for each memory cgroup.

Because the number of non-root kmem_caches is now capped by the number of
root kmem_caches, there is no need to shrink or destroy them prematurely.
They can be perfectly destroyed together with their root counterparts.
This allows to dramatically simplify the management of non-root
kmem_caches and delete a ton of code.

This patch performs the following changes:
1) introduces memcg_params.memcg_cache pointer to represent the
   kmem_cache which will be used for all non-root allocations
2) reuses the existing memcg kmem_cache creation mechanism
   to create memcg kmem_cache on the first allocation attempt
3) memcg kmem_caches are named <kmemcache_name>-memcg,
   e.g. dentry-memcg
4) simplifies memcg_kmem_get_cache() to just return memcg kmem_cache
   or schedule it's creation and return the root cache
5) removes almost all non-root kmem_cache management code
   (separate refcounter, reparenting, shrinking, etc)
6) makes slab debugfs to display root_mem_cgroup css id and never
   show :dead and :deact flags in the memcg_slabinfo attribute.

Following patches in the series will simplify the kmem_cache creation.

Signed-off-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Link: http://lkml.kernel.org/r/20200623174037.3951353-13-guro@fb.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:25 -07:00
Roman Gushchin 0f876e4dc5 mm: memcg/slab: move memcg_kmem_bypass() to memcontrol.h 
To make the memcg_kmem_bypass() function available outside of the
memcontrol.c, let's move it to memcontrol.h.  The function is small and
nicely fits into static inline sort of functions.

It will be used from the slab code.

Signed-off-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Link: http://lkml.kernel.org/r/20200623174037.3951353-12-guro@fb.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:24 -07:00
Roman Gushchin 4330a26bc4 mm: memcg/slab: deprecate memory.kmem.slabinfo 
Deprecate memory.kmem.slabinfo.

An empty file will be presented if corresponding config options are
enabled.

The interface is implementation dependent, isn't present in cgroup v2, and
is generally useful only for core mm debugging purposes.  In other words,
it doesn't provide any value for the absolute majority of users.

A drgn-based replacement can be found in
tools/cgroup/memcg_slabinfo.py.  It does support cgroup v1 and v2,
mimics memory.kmem.slabinfo output and also allows to get any
additional information without a need to recompile the kernel.

If a drgn-based solution is too slow for a task, a bpf-based tracing tool
can be used, which can easily keep track of all slab allocations belonging
to a memory cgroup.

Signed-off-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Link: http://lkml.kernel.org/r/20200623174037.3951353-11-guro@fb.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:24 -07:00
Roman Gushchin f2fe7b09a5 mm: memcg/slab: charge individual slab objects instead of pages 
Switch to per-object accounting of non-root slab objects.

Charging is performed using obj_cgroup API in the pre_alloc hook.
Obj_cgroup is charged with the size of the object and the size of
metadata: as now it's the size of an obj_cgroup pointer.  If the amount of
memory has been charged successfully, the actual allocation code is
executed.  Otherwise, -ENOMEM is returned.

In the post_alloc hook if the actual allocation succeeded, corresponding
vmstats are bumped and the obj_cgroup pointer is saved.  Otherwise, the
charge is canceled.

On the free path obj_cgroup pointer is obtained and used to uncharge the
size of the releasing object.

Memcg and lruvec counters are now representing only memory used by active
slab objects and do not include the free space.  The free space is shared
and doesn't belong to any specific cgroup.

Global per-node slab vmstats are still modified from
(un)charge_slab_page() functions.  The idea is to keep all slab pages
accounted as slab pages on system level.

Signed-off-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Link: http://lkml.kernel.org/r/20200623174037.3951353-10-guro@fb.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:24 -07:00
Roman Gushchin 964d4bd370 mm: memcg/slab: save obj_cgroup for non-root slab objects 
Store the obj_cgroup pointer in the corresponding place of
page->obj_cgroups for each allocated non-root slab object.  Make sure that
each allocated object holds a reference to obj_cgroup.

Objcg pointer is obtained from the memcg->objcg dereferencing in
memcg_kmem_get_cache() and passed from pre_alloc_hook to post_alloc_hook.
Then in case of successful allocation(s) it's getting stored in the
page->obj_cgroups vector.

The objcg obtaining part look a bit bulky now, but it will be simplified
by next commits in the series.

Signed-off-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Link: http://lkml.kernel.org/r/20200623174037.3951353-9-guro@fb.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:24 -07:00
Roman Gushchin 286e04b8ed mm: memcg/slab: allocate obj_cgroups for non-root slab pages 
Allocate and release memory to store obj_cgroup pointers for each non-root
slab page. Reuse page->mem_cgroup pointer to store a pointer to the
allocated space.

This commit temporarily increases the memory footprint of the kernel memory
accounting. To store obj_cgroup pointers we'll need a place for an
objcg_pointer for each allocated object. However, the following patches
in the series will enable sharing of slab pages between memory cgroups,
which will dramatically increase the total slab utilization. And the final
memory footprint will be significantly smaller than before.

To distinguish between obj_cgroups and memcg pointers in case when it's
not obvious which one is used (as in page_cgroup_ino()), let's always set
the lowest bit in the obj_cgroup case. The original obj_cgroups
pointer is marked to be ignored by kmemleak, which otherwise would
report a memory leak for each allocated vector.

Signed-off-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Link: http://lkml.kernel.org/r/20200623174037.3951353-8-guro@fb.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:24 -07:00
Roman Gushchin bf4f059954 mm: memcg/slab: obj_cgroup API 
Obj_cgroup API provides an ability to account sub-page sized kernel
objects, which potentially outlive the original memory cgroup.

The top-level API consists of the following functions:
  bool obj_cgroup_tryget(struct obj_cgroup *objcg);
  void obj_cgroup_get(struct obj_cgroup *objcg);
  void obj_cgroup_put(struct obj_cgroup *objcg);

  int obj_cgroup_charge(struct obj_cgroup *objcg, gfp_t gfp, size_t size);
  void obj_cgroup_uncharge(struct obj_cgroup *objcg, size_t size);

  struct mem_cgroup *obj_cgroup_memcg(struct obj_cgroup *objcg);
  struct obj_cgroup *get_obj_cgroup_from_current(void);

Object cgroup is basically a pointer to a memory cgroup with a per-cpu
reference counter.  It substitutes a memory cgroup in places where it's
necessary to charge a custom amount of bytes instead of pages.

All charged memory rounded down to pages is charged to the corresponding
memory cgroup using __memcg_kmem_charge().

It implements reparenting: on memcg offlining it's getting reattached to
the parent memory cgroup.  Each online memory cgroup has an associated
active object cgroup to handle new allocations and the list of all
attached object cgroups.  On offlining of a cgroup this list is reparented
and for each object cgroup in the list the memcg pointer is swapped to the
parent memory cgroup.  It prevents long-living objects from pinning the
original memory cgroup in the memory.

The implementation is based on byte-sized per-cpu stocks.  A sub-page
sized leftover is stored in an atomic field, which is a part of obj_cgroup
object.  So on cgroup offlining the leftover is automatically reparented.

memcg->objcg is rcu protected.  objcg->memcg is a raw pointer, which is
always pointing at a memory cgroup, but can be atomically swapped to the
parent memory cgroup.  So a user must ensure the lifetime of the
cgroup, e.g.  grab rcu_read_lock or css_set_lock.

Suggested-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Link: http://lkml.kernel.org/r/20200623174037.3951353-7-guro@fb.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:24 -07:00
Johannes Weiner 1a3e1f4096 mm: memcontrol: decouple reference counting from page accounting 
The reference counting of a memcg is currently coupled directly to how
many 4k pages are charged to it.  This doesn't work well with Roman's new
slab controller, which maintains pools of objects and doesn't want to keep
an extra balance sheet for the pages backing those objects.

This unusual refcounting design (reference counts usually track pointers
to an object) is only for historical reasons: memcg used to not take any
css references and simply stalled offlining until all charges had been
reparented and the page counters had dropped to zero.  When we got rid of
the reparenting requirement, the simple mechanical translation was to take
a reference for every charge.

More historical context can be found in commit e8ea14cc6e ("mm:
memcontrol: take a css reference for each charged page"), commit
64f2199389 ("mm: memcontrol: remove obsolete kmemcg pinning tricks") and
commit b2052564e6 ("mm: memcontrol: continue cache reclaim from offlined
groups").

The new slab controller exposes the limitations in this scheme, so let's
switch it to a more idiomatic reference counting model based on actual
kernel pointers to the memcg:

- The per-cpu stock holds a reference to the memcg its caching

- User pages hold a reference for their page->mem_cgroup. Transparent
  huge pages will no longer acquire tail references in advance, we'll
  get them if needed during the split.

- Kernel pages hold a reference for their page->mem_cgroup

- Pages allocated in the root cgroup will acquire and release css
  references for simplicity. css_get() and css_put() optimize that.

- The current memcg_charge_slab() already hacked around the per-charge
  references; this change gets rid of that as well.

- tcp accounting will handle reference in mem_cgroup_sk_{alloc,free}

Roman:
1) Rebased on top of the current mm tree: added css_get() in
   mem_cgroup_charge(), dropped mem_cgroup_try_charge() part
2) I've reformatted commit references in the commit log to make
   checkpatch.pl happy.

[hughd@google.com: remove css_put_many() from __mem_cgroup_clear_mc()]
  Link: http://lkml.kernel.org/r/alpine.LSU.2.11.2007302011450.2347@eggly.anvils

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Roman Gushchin <guro@fb.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Link: http://lkml.kernel.org/r/20200623174037.3951353-6-guro@fb.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:24 -07:00
Roman Gushchin 4138fdfc8b mm: slub: implement SLUB version of obj_to_index() 
This commit implements SLUB version of the obj_to_index() function, which
will be required to calculate the offset of obj_cgroup in the obj_cgroups
vector to store/obtain the objcg ownership data.

To make it faster, let's repeat the SLAB's trick introduced by commit
6a2d7a955d ("SLAB: use a multiply instead of a divide in
obj_to_index()") and avoid an expensive division.

Vlastimil Babka noticed, that SLUB does have already a similar function
called slab_index(), which is defined only if SLUB_DEBUG is enabled.  The
function does a similar math, but with a division, and it also takes a
page address instead of a page pointer.

Let's remove slab_index() and replace it with the new helper
__obj_to_index(), which takes a page address.  obj_to_index() will be a
simple wrapper taking a page pointer and passing page_address(page) into
__obj_to_index().

Signed-off-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Link: http://lkml.kernel.org/r/20200623174037.3951353-5-guro@fb.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:24 -07:00
Roman Gushchin d42f3245c7 mm: memcg: convert vmstat slab counters to bytes 
In order to prepare for per-object slab memory accounting, convert
NR_SLAB_RECLAIMABLE and NR_SLAB_UNRECLAIMABLE vmstat items to bytes.

To make it obvious, rename them to NR_SLAB_RECLAIMABLE_B and
NR_SLAB_UNRECLAIMABLE_B (similar to NR_KERNEL_STACK_KB).

Internally global and per-node counters are stored in pages, however memcg
and lruvec counters are stored in bytes.  This scheme may look weird, but
only for now.  As soon as slab pages will be shared between multiple
cgroups, global and node counters will reflect the total number of slab
pages.  However memcg and lruvec counters will be used for per-memcg slab
memory tracking, which will take separate kernel objects in the account.
Keeping global and node counters in pages helps to avoid additional
overhead.

The size of slab memory shouldn't exceed 4Gb on 32-bit machines, so it
will fit into atomic_long_t we use for vmstats.

Signed-off-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Link: http://lkml.kernel.org/r/20200623174037.3951353-4-guro@fb.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:24 -07:00
Roman Gushchin ea426c2a7d mm: memcg: prepare for byte-sized vmstat items 
To implement per-object slab memory accounting, we need to convert slab
vmstat counters to bytes.  Actually, out of 4 levels of counters: global,
per-node, per-memcg and per-lruvec only two last levels will require
byte-sized counters.  It's because global and per-node counters will be
counting the number of slab pages, and per-memcg and per-lruvec will be
counting the amount of memory taken by charged slab objects.

Converting all vmstat counters to bytes or even all slab counters to bytes
would introduce an additional overhead.  So instead let's store global and
per-node counters in pages, and memcg and lruvec counters in bytes.

To make the API clean all access helpers (both on the read and write
sides) are dealing with bytes.

To avoid back-and-forth conversions a new flavor of read-side helpers is
introduced, which always returns values in pages: node_page_state_pages()
and global_node_page_state_pages().

Actually new helpers are just reading raw values.  Old helpers are simple
wrappers, which will complain on an attempt to read byte value, because at
the moment no one actually needs bytes.

Thanks to Johannes Weiner for the idea of having the byte-sized API on top
of the page-sized internal storage.

Signed-off-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Link: http://lkml.kernel.org/r/20200623174037.3951353-3-guro@fb.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:24 -07:00
Roman Gushchin eedc4e5a14 mm: memcg: factor out memcg- and lruvec-level changes out of __mod_lruvec_state() 
Patch series "The new cgroup slab memory controller", v7.

The patchset moves the accounting from the page level to the object level.
It allows to share slab pages between memory cgroups.  This leads to a
significant win in the slab utilization (up to 45%) and the corresponding
drop in the total kernel memory footprint.  The reduced number of
unmovable slab pages should also have a positive effect on the memory
fragmentation.

The patchset makes the slab accounting code simpler: there is no more need
in the complicated dynamic creation and destruction of per-cgroup slab
caches, all memory cgroups use a global set of shared slab caches.  The
lifetime of slab caches is not more connected to the lifetime of memory
cgroups.

The more precise accounting does require more CPU, however in practice the
difference seems to be negligible.  We've been using the new slab
controller in Facebook production for several months with different
workloads and haven't seen any noticeable regressions.  What we've seen
were memory savings in order of 1 GB per host (it varied heavily depending
on the actual workload, size of RAM, number of CPUs, memory pressure,
etc).

The third version of the patchset added yet another step towards the
simplification of the code: sharing of slab caches between accounted and
non-accounted allocations.  It comes with significant upsides (most
noticeable, a complete elimination of dynamic slab caches creation) but
not without some regression risks, so this change sits on top of the
patchset and is not completely merged in.  So in the unlikely event of a
noticeable performance regression it can be reverted separately.

The slab memory accounting works in exactly the same way for SLAB and
SLUB.  With both allocators the new controller shows significant memory
savings, with SLUB the difference is bigger.  On my 16-core desktop
machine running Fedora 32 the size of the slab memory measured after the
start of the system was lower by 58% and 38% with SLUB and SLAB
correspondingly.

As an estimation of a potential CPU overhead, below are results of
slab_bulk_test01 test, kindly provided by Jesper D.  Brouer.  He also
helped with the evaluation of results.

The test can be found here: https://github.com/netoptimizer/prototype-kernel/
The smallest number in each row should be picked for a comparison.

SLUB-patched - bulk-API
 - SLUB-patched : bulk_quick_reuse objects=1 : 187 -  90 - 224  cycles(tsc)
 - SLUB-patched : bulk_quick_reuse objects=2 : 110 -  53 - 133  cycles(tsc)
 - SLUB-patched : bulk_quick_reuse objects=3 :  88 -  95 -  42  cycles(tsc)
 - SLUB-patched : bulk_quick_reuse objects=4 :  91 -  85 -  36  cycles(tsc)
 - SLUB-patched : bulk_quick_reuse objects=8 :  32 -  66 -  32  cycles(tsc)

SLUB-original -  bulk-API
 - SLUB-original: bulk_quick_reuse objects=1 :  87 -  87 - 142  cycles(tsc)
 - SLUB-original: bulk_quick_reuse objects=2 :  52 -  53 -  53  cycles(tsc)
 - SLUB-original: bulk_quick_reuse objects=3 :  42 -  42 -  91  cycles(tsc)
 - SLUB-original: bulk_quick_reuse objects=4 :  91 -  37 -  37  cycles(tsc)
 - SLUB-original: bulk_quick_reuse objects=8 :  31 -  79 -  76  cycles(tsc)

SLAB-patched -  bulk-API
 - SLAB-patched : bulk_quick_reuse objects=1 :  67 -  67 - 140  cycles(tsc)
 - SLAB-patched : bulk_quick_reuse objects=2 :  55 -  46 -  46  cycles(tsc)
 - SLAB-patched : bulk_quick_reuse objects=3 :  93 -  94 -  39  cycles(tsc)
 - SLAB-patched : bulk_quick_reuse objects=4 :  35 -  88 -  85  cycles(tsc)
 - SLAB-patched : bulk_quick_reuse objects=8 :  30 -  30 -  30  cycles(tsc)

SLAB-original-  bulk-API
 - SLAB-original: bulk_quick_reuse objects=1 : 143 - 136 -  67  cycles(tsc)
 - SLAB-original: bulk_quick_reuse objects=2 :  45 -  46 -  46  cycles(tsc)
 - SLAB-original: bulk_quick_reuse objects=3 :  38 -  39 -  39  cycles(tsc)
 - SLAB-original: bulk_quick_reuse objects=4 :  35 -  87 -  87  cycles(tsc)
 - SLAB-original: bulk_quick_reuse objects=8 :  29 -  66 -  30  cycles(tsc)

This patch (of 19):

To convert memcg and lruvec slab counters to bytes there must be a way to
change these counters without touching node counters.  Factor out
__mod_memcg_lruvec_state() out of __mod_lruvec_state().

Signed-off-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Link: http://lkml.kernel.org/r/20200623174037.3951353-1-guro@fb.com
Link: http://lkml.kernel.org/r/20200623174037.3951353-2-guro@fb.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:24 -07:00
Roman Gushchin d648bcc7fe mm: kmem: make memcg_kmem_enabled() irreversible 
Historically the kernel memory accounting was an opt-in feature, which
could be enabled for individual cgroups.  But now it's not true, and it's
on by default both on cgroup v1 and cgroup v2.  And as long as a user has
at least one non-root memory cgroup, the kernel memory accounting is on.
So in most setups it's either always on (if memory cgroups are in use and
kmem accounting is not disabled), either always off (otherwise).

memcg_kmem_enabled() is used in many places to guard the kernel memory
accounting code.  If memcg_kmem_enabled() can reverse from returning true
to returning false (as now), we can't rely on it on release paths and have
to check if it was on before.

If we'll make memcg_kmem_enabled() irreversible (always returning true
after returning it for the first time), it'll make the general logic more
simple and robust.  It also will allow to guard some checks which
otherwise would stay unguarded.

Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Signed-off-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Link: http://lkml.kernel.org/r/20200702180926.1330769-1-guro@fb.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:24 -07:00
Chris Down ea3271f719 tmpfs: support 64-bit inums per-sb 
The default is still set to inode32 for backwards compatibility, but
system administrators can opt in to the new 64-bit inode numbers by
either:

1. Passing inode64 on the command line when mounting, or
2. Configuring the kernel with CONFIG_TMPFS_INODE64=y

The inode64 and inode32 names are used based on existing precedent from
XFS.

[hughd@google.com: Kconfig fixes]
  Link: http://lkml.kernel.org/r/alpine.LSU.2.11.2008011928010.13320@eggly.anvils

Signed-off-by: Chris Down <chris@chrisdown.name>
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tejun Heo <tj@kernel.org>
Link: http://lkml.kernel.org/r/8b23758d0c66b5e2263e08baf9c4b6a7565cbd8f.1594661218.git.chris@chrisdown.name
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:24 -07:00
Chris Down e809d5f0b5 tmpfs: per-superblock i_ino support 
Patch series "tmpfs: inode: Reduce risk of inum overflow", v7.

In Facebook production we are seeing heavy i_ino wraparounds on tmpfs.  On
affected tiers, in excess of 10% of hosts show multiple files with
different content and the same inode number, with some servers even having
as many as 150 duplicated inode numbers with differing file content.

This causes actual, tangible problems in production.  For example, we have
complaints from those working on remote caches that their application is
reporting cache corruptions because it uses (device, inodenum) to
establish the identity of a particular cache object, but because it's not
unique any more, the application refuses to continue and reports cache
corruption.  Even worse, sometimes applications may not even detect the
corruption but may continue anyway, causing phantom and hard to debug
behaviour.

In general, userspace applications expect that (device, inodenum) should
be enough to be uniquely point to one inode, which seems fair enough.  One
might also need to check the generation, but in this case:

1. That's not currently exposed to userspace
   (ioctl(...FS_IOC_GETVERSION...) returns ENOTTY on tmpfs);
2. Even with generation, there shouldn't be two live inodes with the
   same inode number on one device.

In order to mitigate this, we take a two-pronged approach:

1. Moving inum generation from being global to per-sb for tmpfs. This
   itself allows some reduction in i_ino churn. This works on both 64-
   and 32- bit machines.
2. Adding inode{64,32} for tmpfs. This fix is supported on machines with
   64-bit ino_t only: we allow users to mount tmpfs with a new inode64
   option that uses the full width of ino_t, or CONFIG_TMPFS_INODE64.

You can see how this compares to previous related patches which didn't
implement this per-superblock:

- https://patchwork.kernel.org/patch/11254001/
- https://patchwork.kernel.org/patch/11023915/

This patch (of 2):

get_next_ino has a number of problems:

- It uses and returns a uint, which is susceptible to become overflowed
  if a lot of volatile inodes that use get_next_ino are created.
- It's global, with no specificity per-sb or even per-filesystem. This
  means it's not that difficult to cause inode number wraparounds on a
  single device, which can result in having multiple distinct inodes
  with the same inode number.

This patch adds a per-superblock counter that mitigates the second case.
This design also allows us to later have a specific i_ino size per-device,
for example, allowing users to choose whether to use 32- or 64-bit inodes
for each tmpfs mount.  This is implemented in the next commit.

For internal shmem mounts which may be less tolerant to spinlock delays,
we implement a percpu batching scheme which only takes the stat_lock at
each batch boundary.

Signed-off-by: Chris Down <chris@chrisdown.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: Amir Goldstein <amir73il@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tejun Heo <tj@kernel.org>
Link: http://lkml.kernel.org/r/cover.1594661218.git.chris@chrisdown.name
Link: http://lkml.kernel.org/r/1986b9d63b986f08ec07a4aa4b2275e718e47d8a.1594661218.git.chris@chrisdown.name
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:24 -07:00
Xianting Tian 0f190a7ab7 mm/page_io.c: use blk_io_schedule() for avoiding task hung in sync io 
swap_readpage() does the sync io for one page, the io is not big,
normally, the io can be finished quickly, but it may take long time or
wait forever in case of io failure or discard.

This patch uses blk_io_schedule() instead of io_schedule() to avoid task
hung and crash (when set /proc/sys/kernel/hung_task_panic) when the above
exception occurs.

This is similar to the hung task avoidance in submit_bio_wait(),
blk_execute_rq() and __blkdev_direct_IO().

Signed-off-by: Xianting Tian <xianting_tian@126.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Bart Van Assche <bvanassche@acm.org>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Hugh Dickins <hughd@google.com>
Link: http://lkml.kernel.org/r/1596461807-21087-1-git-send-email-xianting_tian@126.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:24 -07:00
Krzysztof Kozlowski 27ec4878df mm: swap: fix kerneldoc of swap_vma_readahead() 
Fix W=1 compile warnings (invalid kerneldoc):

    mm/swap_state.c:742: warning: Function parameter or member 'fentry' not described in 'swap_vma_readahead'
    mm/swap_state.c:742: warning: Excess function parameter 'entry' description in 'swap_vma_readahead'

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20200728171109.28687-2-krzk@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:24 -07:00
Zhen Lei e0f3ebba97 mm/swap_slots.c: remove redundant check for swap_slot_cache_initialized 
Because enable_swap_slots_cache can only become true in
enable_swap_slots_cache(), and depends on swap_slot_cache_initialized is
true before.  That means, when enable_swap_slots_cache is true,
swap_slot_cache_initialized is true also.

So the condition:
"swap_slot_cache_enabled && swap_slot_cache_initialized"
can be reduced to "swap_slot_cache_enabled"

And in mathematics:
"!swap_slot_cache_enabled || !swap_slot_cache_initialized"
is equal to "!(swap_slot_cache_enabled && swap_slot_cache_initialized)"

So no functional change.

Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Tim Chen <tim.c.chen@linux.intel.com>
Link: http://lkml.kernel.org/r/20200430061143.450-4-thunder.leizhen@huawei.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:24 -07:00
Zhen Lei d69a9575f5 mm/swap_slots.c: simplify enable_swap_slots_cache() 
Whether swap_slot_cache_initialized is true or false,
__reenable_swap_slots_cache() is always called.  To make this meaning
clear, leave only one call to __reenable_swap_slots_cache().  This also
make it clearer what extra needs be done when swap_slot_cache_initialized
is false.

No functional change.

Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Tim Chen <tim.c.chen@linux.intel.com>
Link: http://lkml.kernel.org/r/20200430061143.450-3-thunder.leizhen@huawei.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:23 -07:00
Zhen Lei f90eae2a0f mm/swap_slots.c: simplify alloc_swap_slot_cache() 
Patch series "clean up some functions in mm/swap_slots.c".

When I studied the code of mm/swap_slots.c, I found some places can be
improved.

This patch (of 3):

Both "slots" and "slots_ret" are only need to be freed when cache already
allocated.  Make them closer, seems more clear.

No functional change.

Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Tim Chen <tim.c.chen@linux.intel.com>
Link: http://lkml.kernel.org/r/20200430061143.450-1-thunder.leizhen@huawei.com
Link: http://lkml.kernel.org/r/20200430061143.450-2-thunder.leizhen@huawei.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:23 -07:00
Tang Yizhou 0a36f7f85e mm/gup.c: fix the comment of return value for populate_vma_page_range() 
The return value of populate_vma_page_range() is consistent with
__get_user_pages(), and so is the function comment of return value.

Signed-off-by: Tang Yizhou <tangyizhou@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Link: http://lkml.kernel.org/r/20200720034303.29920-1-tangyizhou@huawei.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:23 -07:00
Yang Shi 605cad8343 mm: filemap: add missing FGP_ flags in kerneldoc comment for pagecache_get_page 
FGP_{WRITE|NOFS|NOWAIT} were missed in pagecache_get_page's kerneldoc
comment.

Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Gang Deng <gavin.dg@linux.alibaba.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Rik van Riel <riel@surriel.com>
Link: http://lkml.kernel.org/r/1593031747-4249-1-git-send-email-yang.shi@linux.alibaba.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:23 -07:00
Yang Shi b9306a796c mm: filemap: clear idle flag for writes 
Since commit bbddabe2e4 ("mm: filemap: only do access activations on
reads"), mark_page_accessed() is called for reads only.  But the idle flag
is cleared by mark_page_accessed() so the idle flag won't get cleared if
the page is write accessed only.

Basically idle page tracking is used to estimate workingset size of
workload, noticeable size of workingset might be missed if the idle flag
is not maintained correctly.

It seems good enough to just clear idle flag for write operations.

Fixes: bbddabe2e4 ("mm: filemap: only do access activations on reads")
Reported-by: Gang Deng <gavin.dg@linux.alibaba.com>
Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Rik van Riel <riel@surriel.com>
Link: http://lkml.kernel.org/r/1593020612-13051-1-git-send-email-yang.shi@linux.alibaba.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:23 -07:00
John Hubbard 6dc5ea16c8 mm, dump_page: do not crash with bad compound_mapcount() 
If a compound page is being split while dump_page() is being run on that
page, we can end up calling compound_mapcount() on a page that is no
longer compound.  This leads to a crash (already seen at least once in the
field), due to the VM_BUG_ON_PAGE() assertion inside compound_mapcount().

(The above is from Matthew Wilcox's analysis of Qian Cai's bug report.)

A similar problem is possible, via compound_pincount() instead of
compound_mapcount().

In order to avoid this kind of crash, make dump_page() slightly more
robust, by providing a pair of simpler routines that don't contain
assertions: head_mapcount() and head_pincount().

For debug tools, we don't want to go *too* far in this direction, but this
is a simple small fix, and the crash has already been seen, so it's a good
trade-off.

Reported-by: Qian Cai <cai@lca.pw>
Suggested-by: Matthew Wilcox <willy@infradead.org>
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: William Kucharski <william.kucharski@oracle.com>
Link: http://lkml.kernel.org/r/20200804214807.169256-1-jhubbard@nvidia.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:23 -07:00
Matthew Wilcox (Oracle) 54a75157d9 mm/debug: print hashed address of struct page 
The actual address of the struct page isn't particularly helpful, while
the hashed address helps match with other messages elsewhere.  Add the PFN
that the page refers to in order to help diagnose problems where the page
is improperly aligned for the purpose.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: William Kucharski <william.kucharski@oracle.com>
Link: http://lkml.kernel.org/r/20200709202117.7216-7-willy@infradead.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:23 -07:00
Matthew Wilcox (Oracle) 9bdaf2cc5e mm/debug: print the inode number in dump_page 
The inode number helps correlate this page with debug messages elsewhere
in the kernel.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: William Kucharski <william.kucharski@oracle.com>
Link: http://lkml.kernel.org/r/20200709202117.7216-6-willy@infradead.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:23 -07:00
Matthew Wilcox (Oracle) 9ad3826575 mm/debug: switch dump_page to get_kernel_nofault 
This is simpler to use than copy_from_kernel_nofault().  Also make some of
the related error messages less verbose.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: William Kucharski <william.kucharski@oracle.com>
Link: http://lkml.kernel.org/r/20200709202117.7216-5-willy@infradead.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:23 -07:00
Matthew Wilcox (Oracle) 0b93d59e90 mm/debug: print head flags in dump_page 
Tail page flags contain very little useful information.  Print the head
page's flags instead.  While the flags will contain "head" for tail pages,
this should not be too confusing as the previous line starts with the word
"head:" and so the flags should be interpreted as belonging to the head
page.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: William Kucharski <william.kucharski@oracle.com>
Link: http://lkml.kernel.org/r/20200709202117.7216-4-willy@infradead.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:23 -07:00
Matthew Wilcox (Oracle) 452b557c95 mm/debug: dump compound page information on a second line 
Simplify both the implementation and the output by splitting all the
compound page information onto a second line.

Reported-by: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: William Kucharski <william.kucharski@oracle.com>
Link: http://lkml.kernel.org/r/20200709202117.7216-3-willy@infradead.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:23 -07:00
Matthew Wilcox (Oracle) e1ab96f8cc mm/debug: handle page->mapping better in dump_page 
Patch series "Improvements for dump_page()", v2.

Here's a sample dump of a pagecache tail page with all of the patches
applied:

page:000000006d1c49ca refcount:6 mapcount:0 mapping:00000000136b8d90 index:0x109 pfn:0x6c645
head:000000008bd38076 order:2 compound_mapcount:0 compound_pincount:0
aops:xfs_address_space_operations ino:800042 dentry name:"fd"
flags: 0x4000000000012014(uptodate|lru|private|head)
raw: 4000000000000000 ffffd46ac1b19101 ffffffff00000202 dead000000000004
raw: 0000000000000001 0000000000000000 00000000ffffffff 0000000000000000
head: 4000000000012014 ffffd46ac1b1bbc8 ffffd46ac1b1bc08 ffff91976f659560
head: 0000000000000108 ffff919773220680 00000006ffffffff 0000000000000000
page dumped because: testing

This patch (of 6):

If we can't call page_mapping() to get the page mapping, handle the
anon/ksm/movable bits correctly.

[akpm@linux-foundation.org: augmented code comment from John]
  Link: http://lkml.kernel.org/r/15cff11a-6762-8a6a-3f0e-dd227280cd6f@nvidia.com

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: William Kucharski <william.kucharski@oracle.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Link: http://lkml.kernel.org/r/20200709202117.7216-1-willy@infradead.org
Link: http://lkml.kernel.org/r/20200709202117.7216-2-willy@infradead.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:23 -07:00
Anshuman Khandual b1d00007f2 Documentation/mm: add descriptions for arch page table helpers 
This adds a specific description file for all arch page table helpers which
is in sync with the semantics being tested via CONFIG_DEBUG_VM_PGTABLE. All
future changes either to these descriptions here or the debug test should
always remain in sync.

[anshuman.khandual@arm.com: fold in Mike's patch for the rst document, fix typos in the rst document]
  Link: http://lkml.kernel.org/r/1594610587-4172-5-git-send-email-anshuman.khandual@arm.com

Suggested-by: Mike Rapoport <rppt@kernel.org>
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Zi Yan <ziy@nvidia.com>
Link: http://lkml.kernel.org/r/1593996516-7186-5-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:23 -07:00
Anshuman Khandual 6315df41af mm/debug_vm_pgtable: add debug prints for individual tests 
This adds debug print information that enlists all tests getting executed
on a given platform.  With dynamic debug enabled, the following
information will be splashed during boot.  For compactness purpose,
dropped both time stamp and prefix (i.e debug_vm_pgtable) from this sample
output.

[debug_vm_pgtable      ]: Validating architecture page table helpers
[pte_basic_tests       ]: Validating PTE basic
[pmd_basic_tests       ]: Validating PMD basic
[p4d_basic_tests       ]: Validating P4D basic
[pgd_basic_tests       ]: Validating PGD basic
[pte_clear_tests       ]: Validating PTE clear
[pmd_clear_tests       ]: Validating PMD clear
[pte_advanced_tests    ]: Validating PTE advanced
[pmd_advanced_tests    ]: Validating PMD advanced
[hugetlb_advanced_tests]: Validating HugeTLB advanced
[pmd_leaf_tests        ]: Validating PMD leaf
[pmd_huge_tests        ]: Validating PMD huge
[pte_savedwrite_tests  ]: Validating PTE saved write
[pmd_savedwrite_tests  ]: Validating PMD saved write
[pmd_populate_tests    ]: Validating PMD populate
[pte_special_tests     ]: Validating PTE special
[pte_protnone_tests    ]: Validating PTE protnone
[pmd_protnone_tests    ]: Validating PMD protnone
[pte_devmap_tests      ]: Validating PTE devmap
[pmd_devmap_tests      ]: Validating PMD devmap
[pte_swap_tests        ]: Validating PTE swap
[swap_migration_tests  ]: Validating swap migration
[hugetlb_basic_tests   ]: Validating HugeTLB basic
[pmd_thp_tests         ]: Validating PMD based THP

Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Vineet Gupta <vgupta@synopsys.com>	[arc]
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Will Deacon <will@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Mike Rapoport <rppt@kernel.org>
Link: http://lkml.kernel.org/r/1593996516-7186-4-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:23 -07:00
Anshuman Khandual a5c3b9ffb0 mm/debug_vm_pgtable: add tests validating advanced arch page table helpers 
This adds new tests validating for these following arch advanced page
table helpers.  These tests create and test specific mapping types at
various page table levels.

1. pxxp_set_wrprotect()
2. pxxp_get_and_clear()
3. pxxp_set_access_flags()
4. pxxp_get_and_clear_full()
5. pxxp_test_and_clear_young()
6. pxx_leaf()
7. pxx_set_huge()
8. pxx_(clear|mk)_savedwrite()
9. huge_pxxp_xxx()

[anshuman.khandual@arm.com: drop RANDOM_ORVALUE from hugetlb_advanced_tests()]
  Link: http://lkml.kernel.org/r/1594610587-4172-3-git-send-email-anshuman.khandual@arm.com

Suggested-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Vineet Gupta <vgupta@synopsys.com>	[arc]
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Steven Price <steven.price@arm.com>
Link: http://lkml.kernel.org/r/1593996516-7186-3-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:23 -07:00
Anshuman Khandual 05289402d7 mm/debug_vm_pgtable: add tests validating arch helpers for core MM features 
Patch series "mm/debug_vm_pgtable: Add some more tests", v5.

This series adds some more arch page table helper validation tests which
are related to core and advanced memory functions.  This also creates a
documentation, enlisting expected semantics for all page table helpers as
suggested by Mike Rapoport previously
(https://lkml.org/lkml/2020/1/30/40).

There are many TRANSPARENT_HUGEPAGE and ARCH_HAS_TRANSPARENT_HUGEPAGE_PUD
ifdefs scattered across the test.  But consolidating all the fallback
stubs is not very straight forward because
ARCH_HAS_TRANSPARENT_HUGEPAGE_PUD is not explicitly dependent on
ARCH_HAS_TRANSPARENT_HUGEPAGE.

Tested on arm64, x86 platforms but only build tested on all other enabled
platforms through ARCH_HAS_DEBUG_VM_PGTABLE i.e powerpc, arc, s390.  The
following failure on arm64 still exists which was mentioned previously.
It will be fixed with the upcoming THP migration on arm64 enablement
series.

WARNING .... mm/debug_vm_pgtable.c:860 debug_vm_pgtable+0x940/0xa54
WARN_ON(!pmd_present(pmd_mkinvalid(pmd_mkhuge(pmd))))

This patch (of 4):

This adds new tests validating arch page table helpers for these following
core memory features.  These tests create and test specific mapping types
at various page table levels.

1. SPECIAL mapping
2. PROTNONE mapping
3. DEVMAP mapping
4. SOFTDIRTY mapping
5. SWAP mapping
6. MIGRATION mapping
7. HUGETLB mapping
8. THP mapping

Suggested-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Vineet Gupta <vgupta@synopsys.com>	[arc]
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Steven Price <steven.price@arm.com>
Link: http://lkml.kernel.org/r/1594610587-4172-1-git-send-email-anshuman.khandual@arm.com
Link: http://lkml.kernel.org/r/1593996516-7186-1-git-send-email-anshuman.khandual@arm.com
Link: http://lkml.kernel.org/r/1593996516-7186-2-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:23 -07:00
Marco Elver cfbe1636c3 mm, kcsan: instrument SLAB/SLUB free with "ASSERT_EXCLUSIVE_ACCESS" 
Provide the necessary KCSAN checks to assist with debugging racy
use-after-frees.  While KASAN is more reliable at generally catching such
use-after-frees (due to its use of a quarantine), it can be difficult to
debug racy use-after-frees.  If a reliable reproducer exists, KCSAN can
assist in debugging such issues.

Note: ASSERT_EXCLUSIVE_ACCESS is a convenience wrapper if the size is
simply sizeof(var).  Instead, here we just use __kcsan_check_access()
explicitly to pass the correct size.

Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Link: http://lkml.kernel.org/r/20200623072653.114563-1-elver@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:23 -07:00
Sebastian Andrzej Siewior b3cb9fc3ae mm/slub.c: drop lockdep_assert_held() from put_map() 
There is no point in using lockdep_assert_held() unlock that is about to
be unlocked.  It works only with lockdep and lockdep will complain if
spin_unlock() is used on a lock that has not been locked.

Remove superfluous lockdep_assert_held().

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Christopher Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20200618201234.795692-2-bigeasy@linutronix.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:23 -07:00
Vlastimil Babka e42f174e43 mm, slab/slub: improve error reporting and overhead of cache_from_obj() 
cache_from_obj() was added by commit b9ce5ef49f ("sl[au]b: always get
the cache from its page in kmem_cache_free()") to support kmemcg, where
per-memcg cache can be different from the root one, so we can't use the
kmem_cache pointer given to kmem_cache_free().

Prior to that commit, SLUB already had debugging check+warning that could
be enabled to compare the given kmem_cache pointer to one referenced by
the slab page where the object-to-be-freed resides.  This check was moved
to cache_from_obj().  Later the check was also enabled for
SLAB_FREELIST_HARDENED configs by commit 598a0717a8 ("mm/slab: validate
cache membership under freelist hardening").

These checks and warnings can be useful especially for the debugging,
which can be improved.  Commit 598a0717a8 changed the pr_err() with
WARN_ON_ONCE() to WARN_ONCE() so only the first hit is now reported,
others are silent.  This patch changes it to WARN() so that all errors are
reported.

It's also useful to print SLUB allocation/free tracking info for the
offending object, if tracking is enabled.  Thus, export the SLUB
print_tracking() function and provide an empty one for SLAB.

For SLUB we can also benefit from the static key check in
kmem_cache_debug_flags(), but we need to move this function to slab.h and
declare the static key there.

[1] https://lore.kernel.org/r/20200608230654.828134-18-guro@fb.com

[vbabka@suse.cz: avoid bogus WARN()]
  Link: https://lore.kernel.org/r/20200623090213.GW5535@shao2-debian
  Link: http://lkml.kernel.org/r/b33e0fa7-cd28-4788-9e54-5927846329ef@suse.cz

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Kees Cook <keescook@chromium.org>
Acked-by: Roman Gushchin <guro@fb.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Matthew Garrett <mjg59@google.com>
Cc: Jann Horn <jannh@google.com>
Cc: Vijayanand Jitta <vjitta@codeaurora.org>
Cc: Vinayak Menon <vinmenon@codeaurora.org>
Link: http://lkml.kernel.org/r/afeda7ac-748b-33d8-a905-56b708148ad5@suse.cz
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:23 -07:00
Vlastimil Babka d3c58f24be mm, slab/slub: move and improve cache_from_obj() 
The function cache_from_obj() was added by commit b9ce5ef49f ("sl[au]b:
always get the cache from its page in kmem_cache_free()") to support
kmemcg, where per-memcg cache can be different from the root one, so we
can't use the kmem_cache pointer given to kmem_cache_free().

Prior to that commit, SLUB already had debugging check+warning that could
be enabled to compare the given kmem_cache pointer to one referenced by
the slab page where the object-to-be-freed resides.  This check was moved
to cache_from_obj().  Later the check was also enabled for
SLAB_FREELIST_HARDENED configs by commit 598a0717a8 ("mm/slab: validate
cache membership under freelist hardening").

These checks and warnings can be useful especially for the debugging,
which can be improved.  Commit 598a0717a8 changed the pr_err() with
WARN_ON_ONCE() to WARN_ONCE() so only the first hit is now reported,
others are silent.  This patch changes it to WARN() so that all errors are
reported.

It's also useful to print SLUB allocation/free tracking info for the
offending object, if tracking is enabled.  We could export the SLUB
print_tracking() function and provide an empty one for SLAB, or realize
that both the debugging and hardening cases in cache_from_obj() are only
supported by SLUB anyway.  So this patch moves cache_from_obj() from
slab.h to separate instances in slab.c and slub.c, where the SLAB version
only does the kmemcg lookup and even could be completely removed once the
kmemcg rework [1] is merged.  The SLUB version can thus easily use the
print_tracking() function.  It can also use the kmem_cache_debug_flags()
static key check for improved performance in kernels without the hardening
and with debugging not enabled on boot.

[1] https://lore.kernel.org/r/20200608230654.828134-18-guro@fb.com

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Jann Horn <jannh@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Vijayanand Jitta <vjitta@codeaurora.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Pekka Enberg <penberg@kernel.org>
Link: http://lkml.kernel.org/r/20200610163135.17364-10-vbabka@suse.cz
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:22 -07:00
Vlastimil Babka 8fc8d66642 mm, slub: extend checks guarded by slub_debug static key 
There are few more places in SLUB that could benefit from reduced overhead
of the static key introduced by a previous patch:

- setup_object_debug() called on each object in newly allocated slab page
- setup_page_debug() called on newly allocated slab page
- __free_slab() called on freed slab page

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Roman Gushchin <guro@fb.com>
Acked-by: Christoph Lameter <cl@linux.com>
Cc: Jann Horn <jannh@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Vijayanand Jitta <vjitta@codeaurora.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Pekka Enberg <penberg@kernel.org>
Link: http://lkml.kernel.org/r/20200610163135.17364-9-vbabka@suse.cz
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:22 -07:00
Vlastimil Babka 59052e89fc mm, slub: introduce kmem_cache_debug_flags() 
There are few places that call kmem_cache_debug(s) (which tests if any of
debug flags are enabled for a cache) immediately followed by a test for a
specific flag.  The compiler can probably eliminate the extra check, but
we can make the code nicer by introducing kmem_cache_debug_flags() that
works like kmem_cache_debug() (including the static key check) but tests
for specific flag(s).  The next patches will add more users.

[vbabka@suse.cz: change return from int to bool, per Kees.  Add VM_WARN_ON_ONCE() for invalid flags, per Roman]
  Link: http://lkml.kernel.org/r/949b90ed-e0f0-07d7-4d21-e30ec0958a7c@suse.cz

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Roman Gushchin <guro@fb.com>
Acked-by: Christoph Lameter <cl@linux.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Jann Horn <jannh@google.com>
Cc: Vijayanand Jitta <vjitta@codeaurora.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Pekka Enberg <penberg@kernel.org>
Link: http://lkml.kernel.org/r/20200610163135.17364-8-vbabka@suse.cz
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:22 -07:00
Vlastimil Babka ca0cab65ea mm, slub: introduce static key for slub_debug() 
One advantage of CONFIG_SLUB_DEBUG is that a generic distro kernel can be
built with the option enabled, but it's inactive until simply enabled on
boot, without rebuilding the kernel.  With a static key, we can further
eliminate the overhead of checking whether a cache has a particular debug
flag enabled if we know that there are no such caches (slub_debug was not
enabled during boot).  We use the same mechanism also for e.g.
page_owner, debug_pagealloc or kmemcg functionality.

This patch introduces the static key and makes the general check for
per-cache debug flags kmem_cache_debug() use it.  This benefits several
call sites, including (slow path but still rather frequent) __slab_free().
The next patches will add more uses.

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Roman Gushchin <guro@fb.com>
Acked-by: Christoph Lameter <cl@linux.com>
Cc: Jann Horn <jannh@google.com>
Cc: Vijayanand Jitta <vjitta@codeaurora.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Pekka Enberg <penberg@kernel.org>
Link: http://lkml.kernel.org/r/20200610163135.17364-7-vbabka@suse.cz
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:22 -07:00
Vlastimil Babka 8f58119ac4 mm, slub: make reclaim_account attribute read-only 
The attribute reflects the SLAB_RECLAIM_ACCOUNT cache flag.  It's not
clear why this attribute was writable in the first place, as it's tied to
how the cache is used by its creator, it's not a user tunable.
Furthermore:

- it affects slab merging, but that's not being checked while toggled
- if affects whether __GFP_RECLAIMABLE flag is used to allocate page, but
  the runtime toggle doesn't update allocflags
- it affects cache_vmstat_idx() so runtime toggling might lead to incosistency
  of NR_SLAB_RECLAIMABLE and NR_SLAB_UNRECLAIMABLE

Thus make it read-only.

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Roman Gushchin <guro@fb.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Jann Horn <jannh@google.com>
Cc: Vijayanand Jitta <vjitta@codeaurora.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Pekka Enberg <penberg@kernel.org>
Link: http://lkml.kernel.org/r/20200610163135.17364-6-vbabka@suse.cz
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:22 -07:00
Vlastimil Babka 060807f841 mm, slub: make remaining slub_debug related attributes read-only 
SLUB_DEBUG creates several files under /sys/kernel/slab/<cache>/ that can
be read to check if the respective debugging options are enabled for given
cache.  Some options, namely sanity_checks, trace, and failslab can be
also enabled and disabled at runtime by writing into the files.

The runtime toggling is racy.  Some options disable __CMPXCHG_DOUBLE when
enabled, which means that in case of concurrent allocations, some can
still use __CMPXCHG_DOUBLE and some not, leading to potential corruption.
The s->flags field is also not updated or checked atomically.  The
simplest solution is to remove the runtime toggling.  The extended
slub_debug boot parameter syntax introduced by earlier patch should allow
to fine-tune the debugging configuration during boot with same
granularity.

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Roman Gushchin <guro@fb.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Jann Horn <jannh@google.com>
Cc: Vijayanand Jitta <vjitta@codeaurora.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Pekka Enberg <penberg@kernel.org>
Link: http://lkml.kernel.org/r/20200610163135.17364-5-vbabka@suse.cz
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:22 -07:00
Vlastimil Babka 32a6f409b6 mm, slub: remove runtime allocation order changes 
SLUB allows runtime changing of page allocation order by writing into the
/sys/kernel/slab/<cache>/order file.  Jann has reported [1] that this
interface allows the order to be set too small, leading to crashes.

While it's possible to fix the immediate issue, closer inspection reveals
potential races.  Storing the new order calls calculate_sizes() which
non-atomically updates a lot of kmem_cache fields while the cache is still
in use.  Unexpected behavior might occur even if the fields are set to the
same value as they were.

This could be fixed by splitting out the part of calculate_sizes() that
depends on forced_order, so that we only update kmem_cache.oo field.  This
could still race with init_cache_random_seq(), shuffle_freelist(),
allocate_slab().  Perhaps it's possible to audit and e.g.  add some
READ_ONCE/WRITE_ONCE accesses, it might be easier just to remove the
runtime order changes, which is what this patch does.  If there are valid
usecases for per-cache order setting, we could e.g.  extend the boot
parameters to do that.

[1] https://lore.kernel.org/r/CAG48ez31PP--h6_FzVyfJ4H86QYczAFPdxtJHUEEan+7VJETAQ@mail.gmail.com

Reported-by: Jann Horn <jannh@google.com>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Christoph Lameter <cl@linux.com>
Acked-by: Roman Gushchin <guro@fb.com>
Cc: Vijayanand Jitta <vjitta@codeaurora.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Pekka Enberg <penberg@kernel.org>
Link: http://lkml.kernel.org/r/20200610163135.17364-4-vbabka@suse.cz
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:22 -07:00
Vlastimil Babka ad38b5b113 mm, slub: make some slub_debug related attributes read-only 
SLUB_DEBUG creates several files under /sys/kernel/slab/<cache>/ that can
be read to check if the respective debugging options are enabled for given
cache.  The options can be also toggled at runtime by writing into the
files.  Some of those, namely red_zone, poison, and store_user can be
toggled only when no objects yet exist in the cache.

Vijayanand reports [1] that there is a problem with freelist randomization
if changing the debugging option's state results in different number of
objects per page, and the random sequence cache needs thus needs to be
recomputed.

However, another problem is that the check for "no objects yet exist in
the cache" is racy, as noted by Jann [2] and fixing that would add
overhead or otherwise complicate the allocation/freeing paths.  Thus it
would be much simpler just to remove the runtime toggling support.  The
documentation describes it's "In case you forgot to enable debugging on
the kernel command line", but the neccessity of having no objects limits
its usefulness anyway for many caches.

Vijayanand describes an use case [3] where debugging is enabled for all
but zram caches for memory overhead reasons, and using the runtime toggles
was the only way to achieve such configuration.  After the previous patch
it's now possible to do that directly from the kernel boot option, so we
can remove the dangerous runtime toggles by making the /sys attribute
files read-only.

While updating it, also improve the documentation of the debugging /sys files.

[1] https://lkml.kernel.org/r/1580379523-32272-1-git-send-email-vjitta@codeaurora.org
[2] https://lore.kernel.org/r/CAG48ez31PP--h6_FzVyfJ4H86QYczAFPdxtJHUEEan+7VJETAQ@mail.gmail.com
[3] https://lore.kernel.org/r/1383cd32-1ddc-4dac-b5f8-9c42282fa81c@codeaurora.org

Reported-by: Vijayanand Jitta <vjitta@codeaurora.org>
Reported-by: Jann Horn <jannh@google.com>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Roman Gushchin <guro@fb.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Pekka Enberg <penberg@kernel.org>
Link: http://lkml.kernel.org/r/20200610163135.17364-3-vbabka@suse.cz
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:22 -07:00
Vlastimil Babka e17f1dfba3 mm, slub: extend slub_debug syntax for multiple blocks 
Patch series "slub_debug fixes and improvements".

The slub_debug kernel boot parameter can either apply a single set of
options to all caches or a list of caches.  There is a use case where
debugging is applied for all caches and then disabled at runtime for
specific caches, for performance and memory consumption reasons [1].  As
runtime changes are dangerous, extend the boot parameter syntax so that
multiple blocks of either global or slab-specific options can be
specified, with blocks delimited by ';'.  This will also support the use
case of [1] without runtime changes.

For details see the updated Documentation/vm/slub.rst

[1] https://lore.kernel.org/r/1383cd32-1ddc-4dac-b5f8-9c42282fa81c@codeaurora.org

[weiyongjun1@huawei.com: make parse_slub_debug_flags() static]
  Link: http://lkml.kernel.org/r/20200702150522.4940-1-weiyongjun1@huawei.com

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: Jann Horn <jannh@google.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Vijayanand Jitta <vjitta@codeaurora.org>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Link: http://lkml.kernel.org/r/20200610163135.17364-2-vbabka@suse.cz
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:22 -07:00
Xiao Yang 221503e128 mm/slab.c: update outdated kmem_list3 in a comment 
kmem_list3 has been renamed to kmem_cache_node long long ago so update it.

References:
6744f087ba ("slab: Common name for the per node structures")
ce8eb6c424 ("slab: Rename list3/l3 to node")

Signed-off-by: Xiao Yang <yangx.jy@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Pekka Enberg <penberg@kernel.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Link: http://lkml.kernel.org/r/20200722033355.26908-1-yangx.jy@cn.fujitsu.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:22 -07:00
Long Li 444050990d mm, slab: check GFP_SLAB_BUG_MASK before alloc_pages in kmalloc_order 
kmalloc cannot allocate memory from HIGHMEM.  Allocating large amounts of
memory currently bypasses the check and will simply leak the memory when
page_address() returns NULL.  To fix this, factor the GFP_SLAB_BUG_MASK
check out of slab & slub, and call it from kmalloc_order() as well.  In
order to make the code clear, the warning message is put in one place.

Signed-off-by: Long Li <lonuxli.64@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Pekka Enberg <penberg@kernel.org>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Link: http://lkml.kernel.org/r/20200704035027.GA62481@lilong
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:22 -07:00
Kees Cook dabc3e291d mm/slab: add naive detection of double free 
Similar to commit ce6fa91b93 ("mm/slub.c: add a naive detection of
double free or corruption"), add a very cheap double-free check for SLAB
under CONFIG_SLAB_FREELIST_HARDENED.  With this added, the
"SLAB_FREE_DOUBLE" LKDTM test passes under SLAB:

  lkdtm: Performing direct entry SLAB_FREE_DOUBLE
  lkdtm: Attempting double slab free ...
  ------------[ cut here ]------------
  WARNING: CPU: 2 PID: 2193 at mm/slab.c:757 ___cache _free+0x325/0x390

[keescook@chromium.org: fix misplaced __free_one()]
  Link: http://lkml.kernel.org/r/202006261306.0D82A2B@keescook
  Link: https://lore.kernel.org/lkml/7ff248c7-d447-340c-a8e2-8c02972aca70@infradead.org

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Randy Dunlap <rdunlap@infradead.org>	[build tested]
Cc: Roman Gushchin <guro@fb.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Alexander Popov <alex.popov@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Vinayak Menon <vinmenon@codeaurora.org>
Cc: Matthew Garrett <mjg59@google.com>
Cc: Jann Horn <jannh@google.com>
Cc: Vijayanand Jitta <vjitta@codeaurora.org>
Link: http://lkml.kernel.org/r/20200625215548.389774-3-keescook@chromium.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:22 -07:00
William Kucharski fa9ba3aa89 mm: ksize() should silently accept a NULL pointer 
Other mm routines such as kfree() and kzfree() silently do the right thing
if passed a NULL pointer, so ksize() should do the same.

Signed-off-by: William Kucharski <william.kucharski@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Link: http://lkml.kernel.org/r/20200616225409.4670-1-william.kucharski@oracle.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:22 -07:00
Waiman Long 453431a549 mm, treewide: rename kzfree() to kfree_sensitive() 
As said by Linus:

  A symmetric naming is only helpful if it implies symmetries in use.
  Otherwise it's actively misleading.

  In "kzalloc()", the z is meaningful and an important part of what the
  caller wants.

  In "kzfree()", the z is actively detrimental, because maybe in the
  future we really _might_ want to use that "memfill(0xdeadbeef)" or
  something. The "zero" part of the interface isn't even _relevant_.

The main reason that kzfree() exists is to clear sensitive information
that should not be leaked to other future users of the same memory
objects.

Rename kzfree() to kfree_sensitive() to follow the example of the recently
added kvfree_sensitive() and make the intention of the API more explicit.
In addition, memzero_explicit() is used to clear the memory to make sure
that it won't get optimized away by the compiler.

The renaming is done by using the command sequence:

  git grep -w --name-only kzfree |\
  xargs sed -i 's/kzfree/kfree_sensitive/'

followed by some editing of the kfree_sensitive() kerneldoc and adding
a kzfree backward compatibility macro in slab.h.

[akpm@linux-foundation.org: fs/crypto/inline_crypt.c needs linux/slab.h]
[akpm@linux-foundation.org: fix fs/crypto/inline_crypt.c some more]

Suggested-by: Joe Perches <joe@perches.com>
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: David Howells <dhowells@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Cc: James Morris <jmorris@namei.org>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: Joe Perches <joe@perches.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: "Jason A . Donenfeld" <Jason@zx2c4.com>
Link: http://lkml.kernel.org/r/20200616154311.12314-3-longman@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:22 -07:00
David Hildenbrand 4a93025cbe mm/shuffle: don't move pages between zones and don't read garbage memmaps 
Especially with memory hotplug, we can have offline sections (with a
garbage memmap) and overlapping zones.  We have to make sure to only touch
initialized memmaps (online sections managed by the buddy) and that the
zone matches, to not move pages between zones.

To test if this can actually happen, I added a simple

	BUG_ON(page_zone(page_i) != page_zone(page_j));

right before the swap.  When hotplugging a 256M DIMM to a 4G x86-64 VM and
onlining the first memory block "online_movable" and the second memory
block "online_kernel", it will trigger the BUG, as both zones (NORMAL and
MOVABLE) overlap.

This might result in all kinds of weird situations (e.g., double
allocations, list corruptions, unmovable allocations ending up in the
movable zone).

Fixes: e900a918b0 ("mm: shuffle initial free memory to improve memory-side-cache utilization")
Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Wei Yang <richard.weiyang@linux.alibaba.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: <stable@vger.kernel.org>	[5.2+]
Link: http://lkml.kernel.org/r/20200624094741.9918-2-david@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:21 -07:00
Ralph Campbell c1a06df6eb mm/migrate: fix migrate_pgmap_owner w/o CONFIG_MMU_NOTIFIER 
On x86_64, when CONFIG_MMU_NOTIFIER is not set/enabled, there is a
compiler error:

   mm/migrate.c: In function 'migrate_vma_collect':
   mm/migrate.c:2481:7: error: 'struct mmu_notifier_range' has no member named 'migrate_pgmap_owner'
     range.migrate_pgmap_owner = migrate->pgmap_owner;
          ^

Fixes: 998427b3ad ("mm/notifier: add migration invalidation type")
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: "Jason Gunthorpe" <jgg@mellanox.com>
Link: http://lkml.kernel.org/r/20200806193353.7124-1-rcampbell@nvidia.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:21 -07:00
Linus Torvalds 25d8d4eeca powerpc updates for 5.9 
- Add support for (optionally) using queued spinlocks & rwlocks.
 
  - Support for a new faster system call ABI using the scv instruction on Power9
    or later.
 
  - Drop support for the PROT_SAO mmap/mprotect flag as it will be unsupported on
    Power10 and future processors, leaving us with no way to implement the
    functionality it requests. This risks breaking userspace, though we believe
    it is unused in practice.
 
  - A bug fix for, and then the removal of, our custom stack expansion checking.
    We now allow stack expansion up to the rlimit, like other architectures.
 
  - Remove the remnants of our (previously disabled) topology update code, which
    tried to react to NUMA layout changes on virtualised systems, but was prone
    to crashes and other problems.
 
  - Add PMU support for Power10 CPUs.
 
  - A change to our signal trampoline so that we don't unbalance the link stack
    (branch return predictor) in the signal delivery path.
 
  - Lots of other cleanups, refactorings, smaller features and so on as usual.
 
 Thanks to:
   Abhishek Goel, Alastair D'Silva, Alexander A. Klimov, Alexey Kardashevskiy,
   Alistair Popple, Andrew Donnellan, Aneesh Kumar K.V, Anju T Sudhakar, Anton
   Blanchard, Arnd Bergmann, Athira Rajeev, Balamuruhan S, Bharata B Rao, Bill
   Wendling, Bin Meng, Cédric Le Goater, Chris Packham, Christophe Leroy,
   Christoph Hellwig, Daniel Axtens, Dan Williams, David Lamparter, Desnes A.
   Nunes do Rosario, Erhard F., Finn Thain, Frederic Barrat, Ganesh Goudar,
   Gautham R. Shenoy, Geoff Levand, Greg Kurz, Gustavo A. R. Silva, Hari Bathini,
   Harish, Imre Kaloz, Joel Stanley, Joe Perches, John Crispin, Jordan Niethe,
   Kajol Jain, Kamalesh Babulal, Kees Cook, Laurent Dufour, Leonardo Bras, Li
   RongQing, Madhavan Srinivasan, Mahesh Salgaonkar, Mark Cave-Ayland, Michal
   Suchanek, Milton Miller, Mimi Zohar, Murilo Opsfelder Araujo, Nathan
   Chancellor, Nathan Lynch, Naveen N. Rao, Nayna Jain, Nicholas Piggin, Oliver
   O'Halloran, Palmer Dabbelt, Pedro Miraglia Franco de Carvalho, Philippe
   Bergheaud, Pingfan Liu, Pratik Rajesh Sampat, Qian Cai, Qinglang Miao, Randy
   Dunlap, Ravi Bangoria, Sachin Sant, Sam Bobroff, Sandipan Das, Santosh
   Sivaraj, Satheesh Rajendran, Shirisha Ganta, Sourabh Jain, Srikar Dronamraju,
   Stan Johnson, Stephen Rothwell, Thadeu Lima de Souza Cascardo, Thiago Jung
   Bauermann, Tom Lane, Vaibhav Jain, Vladis Dronov, Wei Yongjun, Wen Xiong,
   YueHaibing.
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Merge tag 'powerpc-5.9-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

Pull powerpc updates from Michael Ellerman:

 - Add support for (optionally) using queued spinlocks & rwlocks.

 - Support for a new faster system call ABI using the scv instruction on
   Power9 or later.

 - Drop support for the PROT_SAO mmap/mprotect flag as it will be
   unsupported on Power10 and future processors, leaving us with no way
   to implement the functionality it requests. This risks breaking
   userspace, though we believe it is unused in practice.

 - A bug fix for, and then the removal of, our custom stack expansion
   checking. We now allow stack expansion up to the rlimit, like other
   architectures.

 - Remove the remnants of our (previously disabled) topology update
   code, which tried to react to NUMA layout changes on virtualised
   systems, but was prone to crashes and other problems.

 - Add PMU support for Power10 CPUs.

 - A change to our signal trampoline so that we don't unbalance the link
   stack (branch return predictor) in the signal delivery path.

 - Lots of other cleanups, refactorings, smaller features and so on as
   usual.

Thanks to: Abhishek Goel, Alastair D'Silva, Alexander A. Klimov, Alexey
Kardashevskiy, Alistair Popple, Andrew Donnellan, Aneesh Kumar K.V, Anju
T Sudhakar, Anton Blanchard, Arnd Bergmann, Athira Rajeev, Balamuruhan
S, Bharata B Rao, Bill Wendling, Bin Meng, Cédric Le Goater, Chris
Packham, Christophe Leroy, Christoph Hellwig, Daniel Axtens, Dan
Williams, David Lamparter, Desnes A. Nunes do Rosario, Erhard F., Finn
Thain, Frederic Barrat, Ganesh Goudar, Gautham R. Shenoy, Geoff Levand,
Greg Kurz, Gustavo A. R. Silva, Hari Bathini, Harish, Imre Kaloz, Joel
Stanley, Joe Perches, John Crispin, Jordan Niethe, Kajol Jain, Kamalesh
Babulal, Kees Cook, Laurent Dufour, Leonardo Bras, Li RongQing, Madhavan
Srinivasan, Mahesh Salgaonkar, Mark Cave-Ayland, Michal Suchanek, Milton
Miller, Mimi Zohar, Murilo Opsfelder Araujo, Nathan Chancellor, Nathan
Lynch, Naveen N. Rao, Nayna Jain, Nicholas Piggin, Oliver O'Halloran,
Palmer Dabbelt, Pedro Miraglia Franco de Carvalho, Philippe Bergheaud,
Pingfan Liu, Pratik Rajesh Sampat, Qian Cai, Qinglang Miao, Randy
Dunlap, Ravi Bangoria, Sachin Sant, Sam Bobroff, Sandipan Das, Santosh
Sivaraj, Satheesh Rajendran, Shirisha Ganta, Sourabh Jain, Srikar
Dronamraju, Stan Johnson, Stephen Rothwell, Thadeu Lima de Souza
Cascardo, Thiago Jung Bauermann, Tom Lane, Vaibhav Jain, Vladis Dronov,
Wei Yongjun, Wen Xiong, YueHaibing.

* tag 'powerpc-5.9-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (337 commits)
  selftests/powerpc: Fix pkey syscall redefinitions
  powerpc: Fix circular dependency between percpu.h and mmu.h
  powerpc/powernv/sriov: Fix use of uninitialised variable
  selftests/powerpc: Skip vmx/vsx/tar/etc tests on older CPUs
  powerpc/40x: Fix assembler warning about r0
  powerpc/papr_scm: Add support for fetching nvdimm 'fuel-gauge' metric
  powerpc/papr_scm: Fetch nvdimm performance stats from PHYP
  cpuidle: pseries: Fixup exit latency for CEDE(0)
  cpuidle: pseries: Add function to parse extended CEDE records
  cpuidle: pseries: Set the latency-hint before entering CEDE
  selftests/powerpc: Fix online CPU selection
  powerpc/perf: Consolidate perf_callchain_user_[64|32]()
  powerpc/pseries/hotplug-cpu: Remove double free in error path
  powerpc/pseries/mobility: Add pr_debug() for device tree changes
  powerpc/pseries/mobility: Set pr_fmt()
  powerpc/cacheinfo: Warn if cache object chain becomes unordered
  powerpc/cacheinfo: Improve diagnostics about malformed cache lists
  powerpc/cacheinfo: Use name@unit instead of full DT path in debug messages
  powerpc/cacheinfo: Set pr_fmt()
  powerpc: fix function annotations to avoid section mismatch warnings with gcc-10
  ...
 2020-08-07 10:33:50 -07:00
Linus Torvalds 47ec5303d7 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next 
Pull networking updates from David Miller:

 1) Support 6Ghz band in ath11k driver, from Rajkumar Manoharan.

 2) Support UDP segmentation in code TSO code, from Eric Dumazet.

 3) Allow flashing different flash images in cxgb4 driver, from Vishal
    Kulkarni.

 4) Add drop frames counter and flow status to tc flower offloading,
    from Po Liu.

 5) Support n-tuple filters in cxgb4, from Vishal Kulkarni.

 6) Various new indirect call avoidance, from Eric Dumazet and Brian
    Vazquez.

 7) Fix BPF verifier failures on 32-bit pointer arithmetic, from
    Yonghong Song.

 8) Support querying and setting hardware address of a port function via
    devlink, use this in mlx5, from Parav Pandit.

 9) Support hw ipsec offload on bonding slaves, from Jarod Wilson.

10) Switch qca8k driver over to phylink, from Jonathan McDowell.

11) In bpftool, show list of processes holding BPF FD references to
    maps, programs, links, and btf objects. From Andrii Nakryiko.

12) Several conversions over to generic power management, from Vaibhav
    Gupta.

13) Add support for SO_KEEPALIVE et al. to bpf_setsockopt(), from Dmitry
    Yakunin.

14) Various https url conversions, from Alexander A. Klimov.

15) Timestamping and PHC support for mscc PHY driver, from Antoine
    Tenart.

16) Support bpf iterating over tcp and udp sockets, from Yonghong Song.

17) Support 5GBASE-T i40e NICs, from Aleksandr Loktionov.

18) Add kTLS RX HW offload support to mlx5e, from Tariq Toukan.

19) Fix the ->ndo_start_xmit() return type to be netdev_tx_t in several
    drivers. From Luc Van Oostenryck.

20) XDP support for xen-netfront, from Denis Kirjanov.

21) Support receive buffer autotuning in MPTCP, from Florian Westphal.

22) Support EF100 chip in sfc driver, from Edward Cree.

23) Add XDP support to mvpp2 driver, from Matteo Croce.

24) Support MPTCP in sock_diag, from Paolo Abeni.

25) Commonize UDP tunnel offloading code by creating udp_tunnel_nic
    infrastructure, from Jakub Kicinski.

26) Several pci_ --> dma_ API conversions, from Christophe JAILLET.

27) Add FLOW_ACTION_POLICE support to mlxsw, from Ido Schimmel.

28) Add SK_LOOKUP bpf program type, from Jakub Sitnicki.

29) Refactor a lot of networking socket option handling code in order to
    avoid set_fs() calls, from Christoph Hellwig.

30) Add rfc4884 support to icmp code, from Willem de Bruijn.

31) Support TBF offload in dpaa2-eth driver, from Ioana Ciornei.

32) Support XDP_REDIRECT in qede driver, from Alexander Lobakin.

33) Support PCI relaxed ordering in mlx5 driver, from Aya Levin.

34) Support TCP syncookies in MPTCP, from Flowian Westphal.

35) Fix several tricky cases of PMTU handling wrt. briding, from Stefano
    Brivio.

* git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (2056 commits)
  net: thunderx: initialize VF's mailbox mutex before first usage
  usb: hso: remove bogus check for EINPROGRESS
  usb: hso: no complaint about kmalloc failure
  hso: fix bailout in error case of probe
  ip_tunnel_core: Fix build for archs without _HAVE_ARCH_IPV6_CSUM
  selftests/net: relax cpu affinity requirement in msg_zerocopy test
  mptcp: be careful on subflow creation
  selftests: rtnetlink: make kci_test_encap() return sub-test result
  selftests: rtnetlink: correct the final return value for the test
  net: dsa: sja1105: use detected device id instead of DT one on mismatch
  tipc: set ub->ifindex for local ipv6 address
  ipv6: add ipv6_dev_find()
  net: openvswitch: silence suspicious RCU usage warning
  Revert "vxlan: fix tos value before xmit"
  ptp: only allow phase values lower than 1 period
  farsync: switch from 'pci_' to 'dma_' API
  wan: wanxl: switch from 'pci_' to 'dma_' API
  hv_netvsc: do not use VF device if link is down
  dpaa2-eth: Fix passing zero to 'PTR_ERR' warning
  net: macb: Properly handle phylink on at91sam9x
  ...
 2020-08-05 20:13:21 -07:00
Linus Torvalds fffe3ae0ee hmm related patches for 5.9 
This series adds reporting of the page table order from hmm_range_fault()
 and some optimization of migrate_vma():
 
 - Report the size of the page table mapping out of hmm_range_fault(). This
   makes it easier to establish a large/huge/etc mapping in the device's
   page table.
 
 - Allow devices to ignore the invalidations during migration in cases
   where the migration is not going to change pages. For instance migrating
   pages to a device does not require the device to invalidate pages
   already in the device.
 
 - Update nouveau and hmm_tests to use the above
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Merge tag 'for-linus-hmm' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma

Pull hmm updates from Jason Gunthorpe:
 "Ralph has been working on nouveau's use of hmm_range_fault() and
  migrate_vma() which resulted in this small series. It adds reporting
  of the page table order from hmm_range_fault() and some optimization
  of migrate_vma():

   - Report the size of the page table mapping out of hmm_range_fault().

     This makes it easier to establish a large/huge/etc mapping in the
     device's page table.

   - Allow devices to ignore the invalidations during migration in cases
     where the migration is not going to change pages.

     For instance migrating pages to a device does not require the
     device to invalidate pages already in the device.

   - Update nouveau and hmm_tests to use the above"

* tag 'for-linus-hmm' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma:
  mm/hmm/test: use the new migration invalidation
  nouveau/svm: use the new migration invalidation
  mm/notifier: add migration invalidation type
  mm/migrate: add a flags parameter to migrate_vma
  nouveau: fix storing invalid ptes
  nouveau/hmm: support mapping large sysmem pages
  nouveau: fix mapping 2MB sysmem pages
  nouveau/hmm: fault one page at a time
  mm/hmm: add tests for hmm_pfn_to_map_order()
  mm/hmm: provide the page mapping order in hmm_range_fault()
 2020-08-05 13:28:50 -07:00
Linus Torvalds 2324d50d05 It's been a busy cycle for documentation - hopefully the busiest for a 
while to come.  Changes include:
 
  - Some new Chinese translations
 
  - Progress on the battle against double words words and non-HTTPS URLs
 
  - Some block-mq documentation
 
  - More RST conversions from Mauro.  At this point, that task is
    essentially complete, so we shouldn't see this kind of churn again for a
    while.  Unless we decide to switch to asciidoc or something...:)
 
  - Lots of typo fixes, warning fixes, and more.
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Merge tag 'docs-5.9' of git://git.lwn.net/linux

Pull documentation updates from Jonathan Corbet:
 "It's been a busy cycle for documentation - hopefully the busiest for a
  while to come. Changes include:

   - Some new Chinese translations

   - Progress on the battle against double words words and non-HTTPS
     URLs

   - Some block-mq documentation

   - More RST conversions from Mauro. At this point, that task is
     essentially complete, so we shouldn't see this kind of churn again
     for a while. Unless we decide to switch to asciidoc or
     something...:)

   - Lots of typo fixes, warning fixes, and more"

* tag 'docs-5.9' of git://git.lwn.net/linux: (195 commits)
  scripts/kernel-doc: optionally treat warnings as errors
  docs: ia64: correct typo
  mailmap: add entry for <alobakin@marvell.com>
  doc/zh_CN: add cpu-load Chinese version
  Documentation/admin-guide: tainted-kernels: fix spelling mistake
  MAINTAINERS: adjust kprobes.rst entry to new location
  devices.txt: document rfkill allocation
  PCI: correct flag name
  docs: filesystems: vfs: correct flag name
  docs: filesystems: vfs: correct sync_mode flag names
  docs: path-lookup: markup fixes for emphasis
  docs: path-lookup: more markup fixes
  docs: path-lookup: fix HTML entity mojibake
  CREDITS: Replace HTTP links with HTTPS ones
  docs: process: Add an example for creating a fixes tag
  doc/zh_CN: add Chinese translation prefer section
  doc/zh_CN: add clearing-warn-once Chinese version
  doc/zh_CN: add admin-guide index
  doc:it_IT: process: coding-style.rst: Correct __maybe_unused compiler label
  futex: MAINTAINERS: Re-add selftests directory
  ...
 2020-08-04 22:47:54 -07:00
Linus Torvalds 99ea1521a0 Remove uninitialized_var() macro for v5.9-rc1 
- Clean up non-trivial uses of uninitialized_var()
 - Update documentation and checkpatch for uninitialized_var() removal
 - Treewide removal of uninitialized_var()
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Merge tag 'uninit-macro-v5.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull uninitialized_var() macro removal from Kees Cook:
 "This is long overdue, and has hidden too many bugs over the years. The
  series has several "by hand" fixes, and then a trivial treewide
  replacement.

   - Clean up non-trivial uses of uninitialized_var()

   - Update documentation and checkpatch for uninitialized_var() removal

   - Treewide removal of uninitialized_var()"

* tag 'uninit-macro-v5.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  compiler: Remove uninitialized_var() macro
  treewide: Remove uninitialized_var() usage
  checkpatch: Remove awareness of uninitialized_var() macro
  mm/debug_vm_pgtable: Remove uninitialized_var() usage
  f2fs: Eliminate usage of uninitialized_var() macro
  media: sur40: Remove uninitialized_var() usage
  KVM: PPC: Book3S PR: Remove uninitialized_var() usage
  clk: spear: Remove uninitialized_var() usage
  clk: st: Remove uninitialized_var() usage
  spi: davinci: Remove uninitialized_var() usage
  ide: Remove uninitialized_var() usage
  rtlwifi: rtl8192cu: Remove uninitialized_var() usage
  b43: Remove uninitialized_var() usage
  drbd: Remove uninitialized_var() usage
  x86/mm/numa: Remove uninitialized_var() usage
  docs: deprecated.rst: Add uninitialized_var()
 2020-08-04 13:49:43 -07:00
Linus Torvalds 8f0cb6660a These are the latest RCU bits for v5.9: 
- kfree_rcu updates
   - RCU tasks updates
   - Read-side scalability tests
   - SRCU updates
   - Torture-test updates
   - Documentation updates
   - Miscellaneous fixes
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'core-rcu-2020-08-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull RCU updates from Ingo Molnar:

 - kfree_rcu updates

 - RCU tasks updates

 - Read-side scalability tests

 - SRCU updates

 - Torture-test updates

 - Documentation updates

 - Miscellaneous fixes

* tag 'core-rcu-2020-08-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (109 commits)
  torture: Remove obsolete "cd $KVM"
  torture: Avoid duplicate specification of qemu command
  torture: Dump ftrace at shutdown only if requested
  torture: Add kvm-tranform.sh script for qemu-cmd files
  torture: Add more tracing crib notes to kvm.sh
  torture: Improve diagnostic for KCSAN-incapable compilers
  torture: Correctly summarize build-only runs
  torture: Pass --kmake-arg to all make invocations
  rcutorture: Check for unwatched readers
  torture: Abstract out console-log error detection
  torture: Add a stop-run capability
  torture: Create qemu-cmd in --buildonly runs
  rcu/rcutorture: Replace 0 with false
  torture: Add --allcpus argument to the kvm.sh script
  torture: Remove whitespace from identify_qemu_vcpus output
  rcutorture: NULL rcu_torture_current earlier in cleanup code
  rcutorture: Handle non-statistic bang-string error messages
  torture: Set configfile variable to current scenario
  rcutorture: Add races with task-exit processing
  locktorture: Use true and false to assign to bool variables
  ...
 2020-08-03 14:31:33 -07:00
Linus Torvalds 145ff1ec09 arm64 and cross-arch updates for 5.9: 
- Removal of the tremendously unpopular read_barrier_depends() barrier,
   which is a NOP on all architectures apart from Alpha, in favour of
   allowing architectures to override READ_ONCE() and do whatever dance
   they need to do to ensure address dependencies provide LOAD ->
   LOAD/STORE ordering. This work also offers a potential solution if
   compilers are shown to convert LOAD -> LOAD address dependencies into
   control dependencies (e.g. under LTO), as weakly ordered architectures
   will effectively be able to upgrade READ_ONCE() to smp_load_acquire().
   The latter case is not used yet, but will be discussed further at LPC.
 
 - Make the MSI/IOMMU input/output ID translation PCI agnostic, augment
   the MSI/IOMMU ACPI/OF ID mapping APIs to accept an input ID
   bus-specific parameter and apply the resulting changes to the device
   ID space provided by the Freescale FSL bus.
 
 - arm64 support for TLBI range operations and translation table level
   hints (part of the ARMv8.4 architecture version).
 
 - Time namespace support for arm64.
 
 - Export the virtual and physical address sizes in vmcoreinfo for
   makedumpfile and crash utilities.
 
 - CPU feature handling cleanups and checks for programmer errors
   (overlapping bit-fields).
 
 - ACPI updates for arm64: disallow AML accesses to EFI code regions and
   kernel memory.
 
 - perf updates for arm64.
 
 - Miscellaneous fixes and cleanups, most notably PLT counting
   optimisation for module loading, recordmcount fix to ignore
   relocations other than R_AARCH64_CALL26, CMA areas reserved for
   gigantic pages on 16K and 64K configurations.
 
 - Trivial typos, duplicate words.
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Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

Pull arm64 and cross-arch updates from Catalin Marinas:
 "Here's a slightly wider-spread set of updates for 5.9.

  Going outside the usual arch/arm64/ area is the removal of
  read_barrier_depends() series from Will and the MSI/IOMMU ID
  translation series from Lorenzo.

  The notable arm64 updates include ARMv8.4 TLBI range operations and
  translation level hint, time namespace support, and perf.

  Summary:

   - Removal of the tremendously unpopular read_barrier_depends()
     barrier, which is a NOP on all architectures apart from Alpha, in
     favour of allowing architectures to override READ_ONCE() and do
     whatever dance they need to do to ensure address dependencies
     provide LOAD -> LOAD/STORE ordering.

     This work also offers a potential solution if compilers are shown
     to convert LOAD -> LOAD address dependencies into control
     dependencies (e.g. under LTO), as weakly ordered architectures will
     effectively be able to upgrade READ_ONCE() to smp_load_acquire().
     The latter case is not used yet, but will be discussed further at
     LPC.

   - Make the MSI/IOMMU input/output ID translation PCI agnostic,
     augment the MSI/IOMMU ACPI/OF ID mapping APIs to accept an input ID
     bus-specific parameter and apply the resulting changes to the
     device ID space provided by the Freescale FSL bus.

   - arm64 support for TLBI range operations and translation table level
     hints (part of the ARMv8.4 architecture version).

   - Time namespace support for arm64.

   - Export the virtual and physical address sizes in vmcoreinfo for
     makedumpfile and crash utilities.

   - CPU feature handling cleanups and checks for programmer errors
     (overlapping bit-fields).

   - ACPI updates for arm64: disallow AML accesses to EFI code regions
     and kernel memory.

   - perf updates for arm64.

   - Miscellaneous fixes and cleanups, most notably PLT counting
     optimisation for module loading, recordmcount fix to ignore
     relocations other than R_AARCH64_CALL26, CMA areas reserved for
     gigantic pages on 16K and 64K configurations.

   - Trivial typos, duplicate words"

Link: http://lkml.kernel.org/r/20200710165203.31284-1-will@kernel.org
Link: http://lkml.kernel.org/r/20200619082013.13661-1-lorenzo.pieralisi@arm.com

* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (82 commits)
  arm64: use IRQ_STACK_SIZE instead of THREAD_SIZE for irq stack
  arm64/mm: save memory access in check_and_switch_context() fast switch path
  arm64: sigcontext.h: delete duplicated word
  arm64: ptrace.h: delete duplicated word
  arm64: pgtable-hwdef.h: delete duplicated words
  bus: fsl-mc: Add ACPI support for fsl-mc
  bus/fsl-mc: Refactor the MSI domain creation in the DPRC driver
  of/irq: Make of_msi_map_rid() PCI bus agnostic
  of/irq: make of_msi_map_get_device_domain() bus agnostic
  dt-bindings: arm: fsl: Add msi-map device-tree binding for fsl-mc bus
  of/device: Add input id to of_dma_configure()
  of/iommu: Make of_map_rid() PCI agnostic
  ACPI/IORT: Add an input ID to acpi_dma_configure()
  ACPI/IORT: Remove useless PCI bus walk
  ACPI/IORT: Make iort_msi_map_rid() PCI agnostic
  ACPI/IORT: Make iort_get_device_domain IRQ domain agnostic
  ACPI/IORT: Make iort_match_node_callback walk the ACPI namespace for NC
  arm64: enable time namespace support
  arm64/vdso: Restrict splitting VVAR VMA
  arm64/vdso: Handle faults on timens page
  ...
 2020-08-03 14:11:08 -07:00
Linus Torvalds 45365a06aa - Add support for function error injection. 
- Add support for custom exception handlers, as required by BPF_PROBE_MEM.
 
 - Add support for BPF_PROBE_MEM.
 
 - Add trace events for idle enter / exit for the s390 specific idle
   implementation.
 
 - Remove unused zcore memmmap device.
 
 - Remove unused "raw view" from s390 debug feature.
 
 - AP bus + zcrypt device driver code refactoring.
 
 - Provide cex4 cca sysfs attributes for cex3 for zcrypt device driver.
 
 - Expose only minimal interface to walk physmem for mm/memblock. This
   is a common code change and it has been agreed on with Mike Rapoport
   and Andrew Morton that this can go upstream via the s390 tree.
 
 - Rework of the s390 vmem/vmmemap code to allow for future memory hot
   remove.
 
 - Get rid of FORCE_MAX_ZONEORDER to finally allow for order-10
   allocations again, instead of only order-8 allocations.
 
 - Various small improvements and fixes.
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Merge tag 's390-5.9-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

Pull s390 updates from Heiko Carstens:

 - Add support for function error injection.

 - Add support for custom exception handlers, as required by
   BPF_PROBE_MEM.

 - Add support for BPF_PROBE_MEM.

 - Add trace events for idle enter / exit for the s390 specific idle
   implementation.

 - Remove unused zcore memmmap device.

 - Remove unused "raw view" from s390 debug feature.

 - AP bus + zcrypt device driver code refactoring.

 - Provide cex4 cca sysfs attributes for cex3 for zcrypt device driver.

 - Expose only minimal interface to walk physmem for mm/memblock. This
   is a common code change and it has been agreed on with Mike Rapoport
   and Andrew Morton that this can go upstream via the s390 tree.

 - Rework of the s390 vmem/vmmemap code to allow for future memory hot
   remove.

 - Get rid of FORCE_MAX_ZONEORDER to finally allow for order-10
   allocations again, instead of only order-8 allocations.

 - Various small improvements and fixes.

* tag 's390-5.9-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (48 commits)
  s390/vmemmap: coding style updates
  s390/vmemmap: avoid memset(PAGE_UNUSED) when adding consecutive sections
  s390/vmemmap: remember unused sub-pmd ranges
  s390/vmemmap: fallback to PTEs if mapping large PMD fails
  s390/vmem: cleanup empty page tables
  s390/vmemmap: take the vmem_mutex when populating/freeing
  s390/vmemmap: cleanup when vmemmap_populate() fails
  s390/vmemmap: extend modify_pagetable() to handle vmemmap
  s390/vmem: consolidate vmem_add_range() and vmem_remove_range()
  s390/vmem: rename vmem_add_mem() to vmem_add_range()
  s390: enable HAVE_FUNCTION_ERROR_INJECTION
  s390/pci: clarify comment in s390_mmio_read/write
  s390/time: improve comparison for tod steering
  s390/time: select CLOCKSOURCE_VALIDATE_LAST_CYCLE
  s390/time: use CLOCKSOURCE_MASK
  s390/bpf: implement BPF_PROBE_MEM
  s390/kernel: expand exception table logic to allow new handling options
  s390/kernel: unify EX_TABLE* implementations
  s390/mm: allow order 10 allocations
  s390/mm: avoid trimming to MAX_ORDER
  ...
 2020-08-03 13:58:10 -07:00
Linus Torvalds cdc8fcb499 for-5.9/io_uring-20200802 
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Merge tag 'for-5.9/io_uring-20200802' of git://git.kernel.dk/linux-block

Pull io_uring updates from Jens Axboe:
 "Lots of cleanups in here, hardening the code and/or making it easier
  to read and fixing bugs, but a core feature/change too adding support
  for real async buffered reads. With the latter in place, we just need
  buffered write async support and we're done relying on kthreads for
  the fast path. In detail:

   - Cleanup how memory accounting is done on ring setup/free (Bijan)

   - sq array offset calculation fixup (Dmitry)

   - Consistently handle blocking off O_DIRECT submission path (me)

   - Support proper async buffered reads, instead of relying on kthread
     offload for that. This uses the page waitqueue to drive retries
     from task_work, like we handle poll based retry. (me)

   - IO completion optimizations (me)

   - Fix race with accounting and ring fd install (me)

   - Support EPOLLEXCLUSIVE (Jiufei)

   - Get rid of the io_kiocb unionizing, made possible by shrinking
     other bits (Pavel)

   - Completion side cleanups (Pavel)

   - Cleanup REQ_F_ flags handling, and kill off many of them (Pavel)

   - Request environment grabbing cleanups (Pavel)

   - File and socket read/write cleanups (Pavel)

   - Improve kiocb_set_rw_flags() (Pavel)

   - Tons of fixes and cleanups (Pavel)

   - IORING_SQ_NEED_WAKEUP clear fix (Xiaoguang)"

* tag 'for-5.9/io_uring-20200802' of git://git.kernel.dk/linux-block: (127 commits)
  io_uring: flip if handling after io_setup_async_rw
  fs: optimise kiocb_set_rw_flags()
  io_uring: don't touch 'ctx' after installing file descriptor
  io_uring: get rid of atomic FAA for cq_timeouts
  io_uring: consolidate *_check_overflow accounting
  io_uring: fix stalled deferred requests
  io_uring: fix racy overflow count reporting
  io_uring: deduplicate __io_complete_rw()
  io_uring: de-unionise io_kiocb
  io-wq: update hash bits
  io_uring: fix missing io_queue_linked_timeout()
  io_uring: mark ->work uninitialised after cleanup
  io_uring: deduplicate io_grab_files() calls
  io_uring: don't do opcode prep twice
  io_uring: clear IORING_SQ_NEED_WAKEUP after executing task works
  io_uring: batch put_task_struct()
  tasks: add put_task_struct_many()
  io_uring: return locked and pinned page accounting
  io_uring: don't miscount pinned memory
  io_uring: don't open-code recv kbuf managment
  ...
 2020-08-03 13:01:22 -07:00
Linus Torvalds 382625d0d4 for-5.9/block-20200802 
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Merge tag 'for-5.9/block-20200802' of git://git.kernel.dk/linux-block

Pull core block updates from Jens Axboe:
 "Good amount of cleanups and tech debt removals in here, and as a
  result, the diffstat shows a nice net reduction in code.

   - Softirq completion cleanups (Christoph)

   - Stop using ->queuedata (Christoph)

   - Cleanup bd claiming (Christoph)

   - Use check_events, moving away from the legacy media change
     (Christoph)

   - Use inode i_blkbits consistently (Christoph)

   - Remove old unused writeback congestion bits (Christoph)

   - Cleanup/unify submission path (Christoph)

   - Use bio_uninit consistently, instead of bio_disassociate_blkg
     (Christoph)

   - sbitmap cleared bits handling (John)

   - Request merging blktrace event addition (Jan)

   - sysfs add/remove race fixes (Luis)

   - blk-mq tag fixes/optimizations (Ming)

   - Duplicate words in comments (Randy)

   - Flush deferral cleanup (Yufen)

   - IO context locking/retry fixes (John)

   - struct_size() usage (Gustavo)

   - blk-iocost fixes (Chengming)

   - blk-cgroup IO stats fixes (Boris)

   - Various little fixes"

* tag 'for-5.9/block-20200802' of git://git.kernel.dk/linux-block: (135 commits)
  block: blk-timeout: delete duplicated word
  block: blk-mq-sched: delete duplicated word
  block: blk-mq: delete duplicated word
  block: genhd: delete duplicated words
  block: elevator: delete duplicated word and fix typos
  block: bio: delete duplicated words
  block: bfq-iosched: fix duplicated word
  iocost_monitor: start from the oldest usage index
  iocost: Fix check condition of iocg abs_vdebt
  block: Remove callback typedefs for blk_mq_ops
  block: Use non _rcu version of list functions for tag_set_list
  blk-cgroup: show global disk stats in root cgroup io.stat
  blk-cgroup: make iostat functions visible to stat printing
  block: improve discard bio alignment in __blkdev_issue_discard()
  block: change REQ_OP_ZONE_RESET and REQ_OP_ZONE_RESET_ALL to be odd numbers
  block: defer flush request no matter whether we have elevator
  block: make blk_timeout_init() static
  block: remove retry loop in ioc_release_fn()
  block: remove unnecessary ioc nested locking
  block: integrate bd_start_claiming into __blkdev_get
  ...
 2020-08-03 11:57:03 -07:00
Linus Torvalds c6fe44d96f list: add "list_del_init_careful()" to go with "list_empty_careful()" 
That gives us ordering guarantees around the pair.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-02 20:39:44 -07:00
Linus Torvalds 2a9127fcf2 mm: rewrite wait_on_page_bit_common() logic 
It turns out that wait_on_page_bit_common() had several problems,
ranging from just unfair behavioe due to re-queueing at the end of the
wait queue when re-trying, and an outright bug that could result in
missed wakeups (but probably never happened in practice).

This rewrites the whole logic to avoid both issues, by simply moving the
logic to check (and possibly take) the bit lock into the wakeup path
instead.

That makes everything much more straightforward, and means that we never
need to re-queue the wait entry: if we get woken up, we'll be notified
through WQ_FLAG_WOKEN, and the wait queue entry will have been removed,
and everything will have been done for us.

Link: https://lore.kernel.org/lkml/CAHk-=wjJA2Z3kUFb-5s=6+n0qbTs8ELqKFt9B3pH85a8fGD73w@mail.gmail.com/
Link: https://lore.kernel.org/lkml/alpine.LSU.2.11.2007221359450.1017@eggly.anvils/
Reported-by: Oleg Nesterov <oleg@redhat.com>
Reported-by: Hugh Dickins <hughd@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-02 20:39:44 -07:00
Ingo Molnar c1cc4784ce Merge branch 'for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu 
Pull the v5.9 RCU bits from Paul E. McKenney:

 - Documentation updates
 - Miscellaneous fixes
 - kfree_rcu updates
 - RCU tasks updates
 - Read-side scalability tests
 - SRCU updates
 - Torture-test updates

Signed-off-by: Ingo Molnar <mingo@kernel.org>
 2020-07-31 00:15:53 +02:00
Ralph Campbell 998427b3ad mm/notifier: add migration invalidation type 
Currently migrate_vma_setup() calls mmu_notifier_invalidate_range_start()
which flushes all device private page mappings whether or not a page is
being migrated to/from device private memory.

In order to not disrupt device mappings that are not being migrated, shift
the responsibility for clearing device private mappings to the device
driver and leave CPU page table unmapping handled by
migrate_vma_setup().

To support this, the caller of migrate_vma_setup() should always set
struct migrate_vma::pgmap_owner to a non NULL value that matches the
device private page->pgmap->owner. This value is then passed to the struct
mmu_notifier_range with a new event type which the driver's invalidation
function can use to avoid device MMU invalidations.

Link: https://lore.kernel.org/r/20200723223004.9586-4-rcampbell@nvidia.com
Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
 2020-07-28 16:20:33 -03:00
Ralph Campbell 5143192cd4 mm/migrate: add a flags parameter to migrate_vma 
The src_owner field in struct migrate_vma is being used for two purposes,
it acts as a selection filter for which types of pages are to be migrated
and it identifies device private pages owned by the caller.

Split this into separate parameters so the src_owner field can be used
just to identify device private pages owned by the caller of
migrate_vma_setup().

Rename the src_owner field to pgmap_owner to reflect it is now used only
to identify which device private pages to migrate.

Link: https://lore.kernel.org/r/20200723223004.9586-3-rcampbell@nvidia.com
Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
Reviewed-by: Bharata B Rao <bharata@linux.ibm.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
 2020-07-28 16:20:33 -03:00
David S. Miller a57066b1a0 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 
The UDP reuseport conflict was a little bit tricky.

The net-next code, via bpf-next, extracted the reuseport handling
into a helper so that the BPF sk lookup code could invoke it.

At the same time, the logic for reuseport handling of unconnected
sockets changed via commit efc6b6f6c3
which changed the logic to carry on the reuseport result into the
rest of the lookup loop if we do not return immediately.

This requires moving the reuseport_has_conns() logic into the callers.

While we are here, get rid of inline directives as they do not belong
in foo.c files.

The other changes were cases of more straightforward overlapping
modifications.

Signed-off-by: David S. Miller <davem@davemloft.net>
 2020-07-25 17:49:04 -07:00
Kirill A. Shutemov 594cced14a khugepaged: fix null-pointer dereference due to race 
khugepaged has to drop mmap lock several times while collapsing a page.
The situation can change while the lock is dropped and we need to
re-validate that the VMA is still in place and the PMD is still subject
for collapse.

But we miss one corner case: while collapsing an anonymous pages the VMA
could be replaced with file VMA.  If the file VMA doesn't have any
private pages we get NULL pointer dereference:

	general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN
	KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
	anon_vma_lock_write include/linux/rmap.h:120 [inline]
	collapse_huge_page mm/khugepaged.c:1110 [inline]
	khugepaged_scan_pmd mm/khugepaged.c:1349 [inline]
	khugepaged_scan_mm_slot mm/khugepaged.c:2110 [inline]
	khugepaged_do_scan mm/khugepaged.c:2193 [inline]
	khugepaged+0x3bba/0x5a10 mm/khugepaged.c:2238

The fix is to make sure that the VMA is anonymous in
hugepage_vma_revalidate().  The helper is only used for collapsing
anonymous pages.

Fixes: 99cb0dbd47 ("mm,thp: add read-only THP support for (non-shmem) FS")
Reported-by: syzbot+ed318e8b790ca72c5ad0@syzkaller.appspotmail.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Yang Shi <yang.shi@linux.alibaba.com>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/20200722121439.44328-1-kirill.shutemov@linux.intel.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-07-24 12:42:41 -07:00
Barry Song dbda8feadf mm/hugetlb: avoid hardcoding while checking if cma is enabled 
hugetlb_cma[0] can be NULL due to various reasons, for example, node0
has no memory.  so NULL hugetlb_cma[0] doesn't necessarily mean cma is
not enabled.  gigantic pages might have been reserved on other nodes.
This patch fixes possible double reservation and CMA leak.

[akpm@linux-foundation.org: fix CONFIG_CMA=n warning]
[sfr@canb.auug.org.au: better checks before using hugetlb_cma]
  Link: http://lkml.kernel.org/r/20200721205716.6dbaa56b@canb.auug.org.au

Fixes: cf11e85fc0 ("mm: hugetlb: optionally allocate gigantic hugepages using cma")
Signed-off-by: Barry Song <song.bao.hua@hisilicon.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: Roman Gushchin <guro@fb.com>
Cc: Jonathan Cameron <jonathan.cameron@huawei.com>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/20200710005726.36068-1-song.bao.hua@hisilicon.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-07-24 12:42:41 -07:00
Muchun Song d38a2b7a9c mm: memcg/slab: fix memory leak at non-root kmem_cache destroy 
If the kmem_cache refcount is greater than one, we should not mark the
root kmem_cache as dying.  If we mark the root kmem_cache dying
incorrectly, the non-root kmem_cache can never be destroyed.  It
resulted in memory leak when memcg was destroyed.  We can use the
following steps to reproduce.

  1) Use kmem_cache_create() to create a new kmem_cache named A.
  2) Coincidentally, the kmem_cache A is an alias for kmem_cache B,
     so the refcount of B is just increased.
  3) Use kmem_cache_destroy() to destroy the kmem_cache A, just
     decrease the B's refcount but mark the B as dying.
  4) Create a new memory cgroup and alloc memory from the kmem_cache
     B. It leads to create a non-root kmem_cache for allocating memory.
  5) When destroy the memory cgroup created in the step 4), the
     non-root kmem_cache can never be destroyed.

If we repeat steps 4) and 5), this will cause a lot of memory leak.  So
only when refcount reach zero, we mark the root kmem_cache as dying.

Fixes: 92ee383f6d ("mm: fix race between kmem_cache destroy, create and deactivate")
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Roman Gushchin <guro@fb.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/20200716165103.83462-1-songmuchun@bytedance.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-07-24 12:42:41 -07:00
Hugh Dickins 8d22a93510 mm/memcg: fix refcount error while moving and swapping 
It was hard to keep a test running, moving tasks between memcgs with
move_charge_at_immigrate, while swapping: mem_cgroup_id_get_many()'s
refcount is discovered to be 0 (supposedly impossible), so it is then
forced to REFCOUNT_SATURATED, and after thousands of warnings in quick
succession, the test is at last put out of misery by being OOM killed.

This is because of the way moved_swap accounting was saved up until the
task move gets completed in __mem_cgroup_clear_mc(), deferred from when
mem_cgroup_move_swap_account() actually exchanged old and new ids.
Concurrent activity can free up swap quicker than the task is scanned,
bringing id refcount down 0 (which should only be possible when
offlining).

Just skip that optimization: do that part of the accounting immediately.

Fixes: 615d66c37c ("mm: memcontrol: fix memcg id ref counter on swap charge move")
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/alpine.LSU.2.11.2007071431050.4726@eggly.anvils
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-07-24 12:42:41 -07:00
Bhupesh Sharma 82ff165cd3 mm/memcontrol: fix OOPS inside mem_cgroup_get_nr_swap_pages() 
Prabhakar reported an OOPS inside mem_cgroup_get_nr_swap_pages()
function in a corner case seen on some arm64 boards when kdump kernel
runs with "cgroup_disable=memory" passed to the kdump kernel via
bootargs.

The root-cause behind the same is that currently mem_cgroup_swap_init()
function is implemented as a subsys_initcall() call instead of a
core_initcall(), this means 'cgroup_memory_noswap' still remains set to
the default value (false) even when memcg is disabled via
"cgroup_disable=memory" boot parameter.

This may result in premature OOPS inside mem_cgroup_get_nr_swap_pages()
function in corner cases:

  Unable to handle kernel NULL pointer dereference at virtual address 0000000000000188
  Mem abort info:
    ESR = 0x96000006
    EC = 0x25: DABT (current EL), IL = 32 bits
    SET = 0, FnV = 0
    EA = 0, S1PTW = 0
  Data abort info:
    ISV = 0, ISS = 0x00000006
    CM = 0, WnR = 0
  [0000000000000188] user address but active_mm is swapper
  Internal error: Oops: 96000006 [#1] SMP
  Modules linked in:
  <..snip..>
  Call trace:
    mem_cgroup_get_nr_swap_pages+0x9c/0xf4
    shrink_lruvec+0x404/0x4f8
    shrink_node+0x1a8/0x688
    do_try_to_free_pages+0xe8/0x448
    try_to_free_pages+0x110/0x230
    __alloc_pages_slowpath.constprop.106+0x2b8/0xb48
    __alloc_pages_nodemask+0x2ac/0x2f8
    alloc_page_interleave+0x20/0x90
    alloc_pages_current+0xdc/0xf8
    atomic_pool_expand+0x60/0x210
    __dma_atomic_pool_init+0x50/0xa4
    dma_atomic_pool_init+0xac/0x158
    do_one_initcall+0x50/0x218
    kernel_init_freeable+0x22c/0x2d0
    kernel_init+0x18/0x110
    ret_from_fork+0x10/0x18
  Code: aa1403e3 91106000 97f82a27 14000011 (f940c663)
  ---[ end trace 9795948475817de4 ]---
  Kernel panic - not syncing: Fatal exception
  Rebooting in 10 seconds..

Fixes: eccb52e788 ("mm: memcontrol: prepare swap controller setup for integration")
Reported-by: Prabhakar Kushwaha <pkushwaha@marvell.com>
Signed-off-by: Bhupesh Sharma <bhsharma@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: James Morse <james.morse@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Link: http://lkml.kernel.org/r/1593641660-13254-2-git-send-email-bhsharma@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-07-24 12:42:41 -07:00
Tom Rix 45779b036d mm: initialize return of vm_insert_pages 
clang static analysis reports a garbage return

  In file included from mm/memory.c:84:
  mm/memory.c:1612:2: warning: Undefined or garbage value returned to caller [core.uninitialized.UndefReturn]
          return err;
          ^~~~~~~~~~

The setting of err depends on a loop executing.  So initialize err.

Signed-off-by: Tom Rix <trix@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20200703155354.29132-1-trix@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-07-24 12:42:41 -07:00
Chengguang Xu 3bef735ad7 vfs/xattr: mm/shmem: kernfs: release simple xattr entry in a right way 
After commit fdc85222d5 ("kernfs: kvmalloc xattr value instead of
kmalloc"), simple xattr entry is allocated with kvmalloc() instead of
kmalloc(), so we should release it with kvfree() instead of kfree().

Fixes: fdc85222d5 ("kernfs: kvmalloc xattr value instead of kmalloc")
Signed-off-by: Chengguang Xu <cgxu519@mykernel.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Hugh Dickins <hughd@google.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Daniel Xu <dxu@dxuuu.xyz>
Cc: Chris Down <chris@chrisdown.name>
Cc: Andreas Dilger <adilger@dilger.ca>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: <stable@vger.kernel.org>	[5.7]
Link: http://lkml.kernel.org/r/20200704051608.15043-1-cgxu519@mykernel.net
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-07-24 12:42:41 -07:00
Kirill A. Shutemov 246c320a8c mm/mmap.c: close race between munmap() and expand_upwards()/downwards() 
VMA with VM_GROWSDOWN or VM_GROWSUP flag set can change their size under
mmap_read_lock().  It can lead to race with __do_munmap():

	Thread A			Thread B
__do_munmap()
  detach_vmas_to_be_unmapped()
  mmap_write_downgrade()
				expand_downwards()
				  vma->vm_start = address;
				  // The VMA now overlaps with
				  // VMAs detached by the Thread A
				// page fault populates expanded part
				// of the VMA
  unmap_region()
    // Zaps pagetables partly
    // populated by Thread B

Similar race exists for expand_upwards().

The fix is to avoid downgrading mmap_lock in __do_munmap() if detached
VMAs are next to VM_GROWSDOWN or VM_GROWSUP VMA.

[akpm@linux-foundation.org: s/mmap_sem/mmap_lock/ in comment]

Fixes: dd2283f260 ("mm: mmap: zap pages with read mmap_sem in munmap")
Reported-by: Jann Horn <jannh@google.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Yang Shi <yang.shi@linux.alibaba.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: <stable@vger.kernel.org>	[4.20+]
Link: http://lkml.kernel.org/r/20200709105309.42495-1-kirill.shutemov@linux.intel.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-07-24 12:42:41 -07:00
Nicholas Piggin 5c9fa16e8a powerpc/64s: Remove PROT_SAO support 
ISA v3.1 does not support the SAO storage control attribute required to
implement PROT_SAO. PROT_SAO was used by specialised system software
(Lx86) that has been discontinued for about 7 years, and is not thought
to be used elsewhere, so removal should not cause problems.

We rather remove it than keep support for older processors, because
live migrating guest partitions to newer processors may not be possible
if SAO is in use (or worse allowed with silent races).

- PROT_SAO stays in the uapi header so code using it would still build.
- arch_validate_prot() is removed, the generic version rejects PROT_SAO
  so applications would get a failure at mmap() time.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Drop KVM change for the time being]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200703011958.1166620-3-npiggin@gmail.com
 2020-07-22 00:01:25 +10:00
Will Deacon bb7cdd3818 alpha: Replace smp_read_barrier_depends() usage with smp_[r]mb() 
In preparation for removing smp_read_barrier_depends() altogether,
move the Alpha code over to using smp_rmb() and smp_mb() directly.

Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>
 2020-07-21 10:50:36 +01:00
Kees Cook 3f649ab728 treewide: Remove uninitialized_var() usage 
Using uninitialized_var() is dangerous as it papers over real bugs[1]
(or can in the future), and suppresses unrelated compiler warnings
(e.g. "unused variable"). If the compiler thinks it is uninitialized,
either simply initialize the variable or make compiler changes.

In preparation for removing[2] the[3] macro[4], remove all remaining
needless uses with the following script:

git grep '\buninitialized_var\b' | cut -d: -f1 | sort -u | \
	xargs perl -pi -e \
		's/\buninitialized_var\(([^\)]+)\)/\1/g;
		 s:\s*/\* (GCC be quiet|to make compiler happy) \*/$::g;'

drivers/video/fbdev/riva/riva_hw.c was manually tweaked to avoid
pathological white-space.

No outstanding warnings were found building allmodconfig with GCC 9.3.0
for x86_64, i386, arm64, arm, powerpc, powerpc64le, s390x, mips, sparc64,
alpha, and m68k.

[1] https://lore.kernel.org/lkml/20200603174714.192027-1-glider@google.com/
[2] https://lore.kernel.org/lkml/CA+55aFw+Vbj0i=1TGqCR5vQkCzWJ0QxK6CernOU6eedsudAixw@mail.gmail.com/
[3] https://lore.kernel.org/lkml/CA+55aFwgbgqhbp1fkxvRKEpzyR5J8n1vKT1VZdz9knmPuXhOeg@mail.gmail.com/
[4] https://lore.kernel.org/lkml/CA+55aFz2500WfbKXAx8s67wrm9=yVJu65TpLgN_ybYNv0VEOKA@mail.gmail.com/

Reviewed-by: Leon Romanovsky <leonro@mellanox.com> # drivers/infiniband and mlx4/mlx5
Acked-by: Jason Gunthorpe <jgg@mellanox.com> # IB
Acked-by: Kalle Valo <kvalo@codeaurora.org> # wireless drivers
Reviewed-by: Chao Yu <yuchao0@huawei.com> # erofs
Signed-off-by: Kees Cook <keescook@chromium.org>
 2020-07-16 12:35:15 -07:00
Kees Cook fea1120c56 mm/debug_vm_pgtable: Remove uninitialized_var() usage 
Using uninitialized_var() is dangerous as it papers over real bugs[1]
(or can in the future), and suppresses unrelated compiler warnings (e.g.
"unused variable"). If the compiler thinks it is uninitialized, either
simply initialize the variable or make compiler changes. As a precursor
to removing[2] this[3] macro[4], just initialize this variable to NULL.

[1] https://lore.kernel.org/lkml/20200603174714.192027-1-glider@google.com/
[2] https://lore.kernel.org/lkml/CA+55aFw+Vbj0i=1TGqCR5vQkCzWJ0QxK6CernOU6eedsudAixw@mail.gmail.com/
[3] https://lore.kernel.org/lkml/CA+55aFwgbgqhbp1fkxvRKEpzyR5J8n1vKT1VZdz9knmPuXhOeg@mail.gmail.com/
[4] https://lore.kernel.org/lkml/CA+55aFz2500WfbKXAx8s67wrm9=yVJu65TpLgN_ybYNv0VEOKA@mail.gmail.com/

Fixes: 399145f9eb ("mm/debug: add tests validating architecture page table helpers")
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
 2020-07-16 12:32:26 -07:00
Linus Torvalds f81fdd0c4a mm: document warning in move_normal_pmd() and make it warn only once 
Naresh Kamboju reported that the LTP tests can cause warnings on i386
going back all the way to v5.0, and bisected it to commit 2c91bd4a4e
("mm: speed up mremap by 20x on large regions").

The warning in move_normal_pmd() is actually mostly correct, but we have
a very unusual special case at process creation time, when we may move
the stack down with an overlapping mode (kind of like a "memmove()"
except using the page tables).

And when you have just the right condition of "move a large initial
stack by the right alignment in the end, but with the early part of the
move being only page-aligned", we'll be in a situation where we're
trying to move a normal PMD entry on top of an already existing - but
now empty - PMD entry.

The warning is still worth having, in case it ever triggers other cases,
and perhaps as a reminder that we could do the stack move case more
efficiently (although it's clearly rare enough that it probably doesn't
matter).

But make it do WARN_ON_ONCE(), so that you can't flood the logs with it.

And add a *big* comment above it to explain and remind us what's going
on, because it took some figuring out to see how this could trigger.
Kudos to Joel Fernandes for debugging this.

Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Debugged-and-acked-by: Joel Fernandes <joel@joelfernandes.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-07-13 11:37:39 -07:00
David S. Miller 71930d6102 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 
All conflicts seemed rather trivial, with some guidance from
Saeed Mameed on the tc_ct.c one.

Signed-off-by: David S. Miller <davem@davemloft.net>
 2020-07-11 00:46:00 -07:00
Jakub Kicinski a2b992c828 debugfs: make sure we can remove u32_array files cleanly 
debugfs_create_u32_array() allocates a small structure to wrap
the data and size information about the array. If users ever
try to remove the file this leads to a leak since nothing ever
frees this wrapper.

That said there are no upstream users of debugfs_create_u32_array()
that'd remove a u32 array file (we only have one u32 array user in
CMA), so there is no real bug here.

Make callers pass a wrapper they allocated. This way the lifetime
management of the wrapper is on the caller, and we can avoid the
potential leak in debugfs.

CC: Chucheng Luo <luochucheng@vivo.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
 2020-07-10 13:54:00 -07:00
Ralph Campbell 3b50a6e536 mm/hmm: provide the page mapping order in hmm_range_fault() 
hmm_range_fault() returns an array of page frame numbers and flags for how
the pages are mapped in the requested process' page tables. The PFN can be
used to get the struct page with hmm_pfn_to_page() and the page size order
can be determined with compound_order(page).

However, if the page is larger than order 0 (PAGE_SIZE), there is no
indication that a compound page is mapped by the CPU using a larger page
size. Without this information, the caller can't safely use a large device
PTE to map the compound page because the CPU might be using smaller PTEs
with different read/write permissions.

Add a new function hmm_pfn_to_map_order() to return the mapping size order
so that callers know the pages are being mapped with consistent
permissions and a large device page table mapping can be used if one is
available.

This will allow devices to optimize mapping the page into HW by avoiding
or batching work for huge pages. For instance the dma_map can be done with
a high order directly.

Link: https://lore.kernel.org/r/20200701225352.9649-3-rcampbell@nvidia.com
Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
 2020-07-10 16:24:28 -03:00
Linus Torvalds d02b0478c1 Fix gfs2 readahead deadlocks 
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Merge tag 'gfs2-v5.8-rc4.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2

Pull gfs2 fixes from Andreas Gruenbacher:
 "Fix gfs2 readahead deadlocks by adding a IOCB_NOIO flag that allows
  gfs2 to use the generic fiel read iterator functions without having to
  worry about being called back while holding locks".

* tag 'gfs2-v5.8-rc4.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2:
  gfs2: Rework read and page fault locking
  fs: Add IOCB_NOIO flag for generic_file_read_iter
 2020-07-10 08:53:21 -07:00
David Hildenbrand 7764990581 mm/memblock: expose only miminal interface to add/walk physmem 
"physmem" in the memblock allocator is somewhat weird: it's not actually
used for allocation, it's simply information collected during boot, which
describes the unmodified physical memory map at boot time, without any
standby/hotplugged memory. It's only used on s390 and is currently the
only reason s390 keeps using CONFIG_ARCH_KEEP_MEMBLOCK.

Physmem isn't numa aware and current users don't specify any flags. Let's
hide it from the user, exposing only for_each_physmem(), and simplify. The
interface for physmem is now really minimalistic:
- memblock_physmem_add() to add ranges
- for_each_physmem() / __next_physmem_range() to walk physmem ranges

Don't place it into an __init section and don't discard it without
CONFIG_ARCH_KEEP_MEMBLOCK. As we're reusing __next_mem_range(), remove
the __meminit notifier to avoid section mismatch warnings once
CONFIG_ARCH_KEEP_MEMBLOCK is no longer used with
CONFIG_HAVE_MEMBLOCK_PHYS_MAP.

While fixing up the documentation, sneak in some related cleanups. We can
stop setting CONFIG_ARCH_KEEP_MEMBLOCK for s390 next.

Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
Message-Id: <20200701141830.18749-2-david@redhat.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
 2020-07-10 15:08:09 +02:00
Christoph Hellwig 8c911f3d4c writeback: remove struct bdi_writeback_congested 
We never set any congested bits in the group writeback instances of it.
And for the simpler bdi-wide case a simple scalar field is all that
that is needed.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
 2020-07-08 17:05:53 -06:00
Christoph Hellwig 492d76b215 writeback: remove {set,clear}_wb_congested 
Just merge them into their only callers.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
 2020-07-08 17:05:53 -06:00
Linus Torvalds 6ec4476ac8 Raise gcc version requirement to 4.9 
I realize that we fairly recently raised it to 4.8, but the fact is, 4.9
is a much better minimum version to target.

We have a number of workarounds for actual bugs in pre-4.9 gcc versions
(including things like internal compiler errors on ARM), but we also
have some syntactic workarounds for lacking features.

In particular, raising the minimum to 4.9 means that we can now just
assume _Generic() exists, which is likely the much better replacement
for a lot of very convoluted built-time magic with conditionals on
sizeof and/or __builtin_choose_expr() with same_type() etc.

Using _Generic also means that you will need to have a very recent
version of 'sparse', but thats easy to build yourself, and much less of
a hassle than some old gcc version can be.

The latest (in a long string) of reasons for minimum compiler version
upgrades was commit 5435f73d5c ("efi/x86: Fix build with gcc 4").

Ard points out that RHEL 7 uses gcc-4.8, but the people who stay back on
old RHEL versions persumably also don't build their own kernels anyway.
And maybe they should cross-built or just have a little side affair with
a newer compiler?

Acked-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-07-08 10:48:35 -07:00
Andreas Gruenbacher 41da51bce3 fs: Add IOCB_NOIO flag for generic_file_read_iter 
Add an IOCB_NOIO flag that indicates to generic_file_read_iter that it
shouldn't trigger any filesystem I/O for the actual request or for
readahead.  This allows to do tentative reads out of the page cache as
some filesystems allow, and to take the appropriate locks and retry the
reads only if the requested pages are not cached.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
 2020-07-07 23:40:08 +02:00
Masahiro Yamada 893ab00439 kbuild: remove cc-option test of -fno-stack-protector 
Some Makefiles already pass -fno-stack-protector unconditionally.
For example, arch/arm64/kernel/vdso/Makefile, arch/x86/xen/Makefile.

No problem report so far about hard-coding this option. So, we can
assume all supported compilers know -fno-stack-protector.

GCC 4.8 and Clang support this option (https://godbolt.org/z/_HDGzN)

Get rid of cc-option from -fno-stack-protector.

Remove CONFIG_CC_HAS_STACKPROTECTOR_NONE, which is always 'y'.

Note:
arch/mips/vdso/Makefile adds -fno-stack-protector twice, first
unconditionally, and second conditionally. I removed the second one.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
 2020-07-07 11:13:10 +09:00
Joel Savitz 8beeae86b8 mm/page_alloc: fix documentation error 
When I increased the upper bound of the min_free_kbytes value in
ee8eb9a5fe ("mm/page_alloc: increase default min_free_kbytes bound") I
forgot to tweak the above comment to reflect the new value.  This patch
fixes that mistake.

Signed-off-by: Joel Savitz <jsavitz@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Rafael Aquini <aquini@redhat.com>
Cc: Fabrizio D'Angelo <fdangelo@redhat.com>
Link: http://lkml.kernel.org/r/20200624221236.29560-1-jsavitz@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-07-03 16:15:25 -07:00
Barry Song 40366bd70b mm/cma.c: use exact_nid true to fix possible per-numa cma leak 
Calling cma_declare_contiguous_nid() with false exact_nid for per-numa
reservation can easily cause cma leak and various confusion.  For example,
mm/hugetlb.c is trying to reserve per-numa cma for gigantic pages.  But it
can easily leak cma and make users confused when system has memoryless
nodes.

In case the system has 4 numa nodes, and only numa node0 has memory.  if
we set hugetlb_cma=4G in bootargs, mm/hugetlb.c will get 4 cma areas for 4
different numa nodes.  since exact_nid=false in current code, all 4 numa
nodes will get cma successfully from node0, but hugetlb_cma[1 to 3] will
never be available to hugepage will only allocate memory from
hugetlb_cma[0].

In case the system has 4 numa nodes, both numa node0&2 has memory, other
nodes have no memory.  if we set hugetlb_cma=4G in bootargs, mm/hugetlb.c
will get 4 cma areas for 4 different numa nodes.  since exact_nid=false in
current code, all 4 numa nodes will get cma successfully from node0 or 2,
but hugetlb_cma[1] and [3] will never be available to hugepage as
mm/hugetlb.c will only allocate memory from hugetlb_cma[0] and
hugetlb_cma[2].  This causes permanent leak of the cma areas which are
supposed to be used by memoryless node.

Of cource we can workaround the issue by letting mm/hugetlb.c scan all cma
areas in alloc_gigantic_page() even node_mask includes node0 only.  that
means when node_mask includes node0 only, we can get page from
hugetlb_cma[1] to hugetlb_cma[3].  But this will cause kernel crash in
free_gigantic_page() while it wants to free page by:
cma_release(hugetlb_cma[page_to_nid(page)], page, 1 << order)

On the other hand, exact_nid=false won't consider numa distance, it might
be not that useful to leverage cma areas on remote nodes.  I feel it is
much simpler to make exact_nid true to make everything clear.  After that,
memoryless nodes won't be able to reserve per-numa CMA from other nodes
which have memory.

Fixes: cf11e85fc0 ("mm: hugetlb: optionally allocate gigantic hugepages using cma")
Signed-off-by: Barry Song <song.bao.hua@hisilicon.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Roman Gushchin <guro@fb.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Aslan Bakirov <aslan@fb.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Andreas Schaufler <andreas.schaufler@gmx.de>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/20200628074345.27228-1-song.bao.hua@hisilicon.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-07-03 16:15:25 -07:00
Mike Kravetz 1139d336ff mm/hugetlb.c: fix pages per hugetlb calculation 
The routine hpage_nr_pages() was incorrectly used to calculate the number
of base pages in a hugetlb page.  hpage_nr_pages is designed to be called
for THP pages and will return HPAGE_PMD_NR for hugetlb pages of any size.

Due to the context in which hpage_nr_pages was called, it is unlikely to
produce a user visible error.  The routine with the incorrect call is only
exercised in the case of hugetlb memory error or migration.  In addition,
this would need to be on an architecture which supports huge page sizes
less than PMD_SIZE.  And, the vma containing the huge page would also need
to smaller than PMD_SIZE.

Fixes: c0d0381ade ("hugetlbfs: use i_mmap_rwsem for more pmd sharing synchronization")
Reported-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/20200629185003.97202-1-mike.kravetz@oracle.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-07-03 16:15:25 -07:00
Christoph Hellwig e556f6ba10 block: remove the bd_queue field from struct block_device 
Just use bd_disk->queue instead.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
 2020-07-01 08:08:20 -06:00
Paul E. McKenney 13625c0a40 Merge branches 'doc.2020.06.29a', 'fixes.2020.06.29a', 'kfree_rcu.2020.06.29a', 'rcu-tasks.2020.06.29a', 'scale.2020.06.29a', 'srcu.2020.06.29a' and 'torture.2020.06.29a' into HEAD 
doc.2020.06.29a:  Documentation updates.
fixes.2020.06.29a:  Miscellaneous fixes.
kfree_rcu.2020.06.29a:  kfree_rcu() updates.
rcu-tasks.2020.06.29a:  RCU Tasks updates.
scale.2020.06.29a:  Read-side scalability tests.
srcu.2020.06.29a:  SRCU updates.
torture.2020.06.29a:  Torture-test updates.
 2020-06-29 12:03:15 -07:00
Uladzislau Rezki (Sony) e0feed08ab mm/list_lru.c: Rename kvfree_rcu() to local variant 
Rename kvfree_rcu() function to the kvfree_rcu_local() one.
The purpose is to prevent a conflict of two same function
declarations. The kvfree_rcu() will be globally visible
what would lead to a build error. No functional change.

Cc: linux-mm@kvack.org
Cc: rcu@vger.kernel.org
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
 2020-06-29 11:59:25 -07:00
Paul E. McKenney 0a3b3c253a mm/mmap.c: Add cond_resched() for exit_mmap() CPU stalls 
A large process running on a heavily loaded system can encounter the
following RCU CPU stall warning:

  rcu: INFO: rcu_sched self-detected stall on CPU
  rcu: 	3-....: (20998 ticks this GP) idle=4ea/1/0x4000000000000002 softirq=556558/556558 fqs=5190
  	(t=21013 jiffies g=1005461 q=132576)
  NMI backtrace for cpu 3
  CPU: 3 PID: 501900 Comm: aio-free-ring-w Kdump: loaded Not tainted 5.2.9-108_fbk12_rc3_3858_gb83b75af7909 #1
  Hardware name: Wiwynn   HoneyBadger/PantherPlus, BIOS HBM6.71 02/03/2016
  Call Trace:
   <IRQ>
   dump_stack+0x46/0x60
   nmi_cpu_backtrace.cold.3+0x13/0x50
   ? lapic_can_unplug_cpu.cold.27+0x34/0x34
   nmi_trigger_cpumask_backtrace+0xba/0xca
   rcu_dump_cpu_stacks+0x99/0xc7
   rcu_sched_clock_irq.cold.87+0x1aa/0x397
   ? tick_sched_do_timer+0x60/0x60
   update_process_times+0x28/0x60
   tick_sched_timer+0x37/0x70
   __hrtimer_run_queues+0xfe/0x270
   hrtimer_interrupt+0xf4/0x210
   smp_apic_timer_interrupt+0x5e/0x120
   apic_timer_interrupt+0xf/0x20
   </IRQ>
  RIP: 0010:kmem_cache_free+0x223/0x300
  Code: 88 00 00 00 0f 85 ca 00 00 00 41 8b 55 18 31 f6 f7 da 41 f6 45 0a 02 40 0f 94 c6 83 c6 05 9c 41 5e fa e8 a0 a7 01 00 41 56 9d <49> 8b 47 08 a8 03 0f 85 87 00 00 00 65 48 ff 08 e9 3d fe ff ff 65
  RSP: 0018:ffffc9000e8e3da8 EFLAGS: 00000206 ORIG_RAX: ffffffffffffff13
  RAX: 0000000000020000 RBX: ffff88861b9de960 RCX: 0000000000000030
  RDX: fffffffffffe41e8 RSI: 000060777fe3a100 RDI: 000000000001be18
  RBP: ffffea00186e7780 R08: ffffffffffffffff R09: ffffffffffffffff
  R10: ffff88861b9dea28 R11: ffff88887ffde000 R12: ffffffff81230a1f
  R13: ffff888854684dc0 R14: 0000000000000206 R15: ffff8888547dbc00
   ? remove_vma+0x4f/0x60
   remove_vma+0x4f/0x60
   exit_mmap+0xd6/0x160
   mmput+0x4a/0x110
   do_exit+0x278/0xae0
   ? syscall_trace_enter+0x1d3/0x2b0
   ? handle_mm_fault+0xaa/0x1c0
   do_group_exit+0x3a/0xa0
   __x64_sys_exit_group+0x14/0x20
   do_syscall_64+0x42/0x100
   entry_SYSCALL_64_after_hwframe+0x44/0xa9

And on a PREEMPT=n kernel, the "while (vma)" loop in exit_mmap() can run
for a very long time given a large process.  This commit therefore adds
a cond_resched() to this loop, providing RCU any needed quiescent states.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: <linux-mm@kvack.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
 2020-06-29 11:58:49 -07:00
Christoph Hellwig a18b9b1590 block: move bio_associate_blkg_from_page to mm/page_io.c 
bio_associate_blkg_from_page is a special purpose helper for swap bios
that doesn't need access to bio internals.  Move it to the swap code
instead of having it in bio.c.

Acked-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
 2020-06-29 09:09:08 -06:00
Mauro Carvalho Chehab 800c02f5d0 docs: move nommu-mmap.txt to admin-guide and rename to ReST 
The nommu-mmap.txt file provides description of user visible
behaviuour. So, move it to the admin-guide.

As it is already at the ReST, also rename it.

Suggested-by: Mike Rapoport <rppt@linux.ibm.com>
Suggested-by: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/3a63d1833b513700755c85bf3bda0a6c4ab56986.1592918949.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
 2020-06-26 11:33:35 -06:00
Ben Widawsky b7e3debdd0 mm/memory_hotplug.c: fix false softlockup during pfn range removal 
When working with very large nodes, poisoning the struct pages (for which
there will be very many) can take a very long time.  If the system is
using voluntary preemptions, the software watchdog will not be able to
detect forward progress.  This patch addresses this issue by offering to
give up time like __remove_pages() does.  This behavior was introduced in
v5.6 with: commit d33695b16a ("mm/memory_hotplug: poison memmap in
remove_pfn_range_from_zone()")

Alternately, init_page_poison could do this cond_resched(), but it seems
to me that the caller of init_page_poison() is what actually knows whether
or not it should relax its own priority.

Based on Dan's notes, I think this is perfectly safe: commit f931ab479d
("mm: fix devm_memremap_pages crash, use mem_hotplug_{begin, done}")

Aside from fixing the lockup, it is also a friendlier thing to do on lower
core systems that might wipe out large chunks of hotplug memory (probably
not a very common case).

Fixes this kind of splat:

  watchdog: BUG: soft lockup - CPU#46 stuck for 22s! [daxctl:9922]
  irq event stamp: 138450
  hardirqs last  enabled at (138449): [<ffffffffa1001f26>] trace_hardirqs_on_thunk+0x1a/0x1c
  hardirqs last disabled at (138450): [<ffffffffa1001f42>] trace_hardirqs_off_thunk+0x1a/0x1c
  softirqs last  enabled at (138448): [<ffffffffa1e00347>] __do_softirq+0x347/0x456
  softirqs last disabled at (138443): [<ffffffffa10c416d>] irq_exit+0x7d/0xb0
  CPU: 46 PID: 9922 Comm: daxctl Not tainted 5.7.0-BEN-14238-g373c6049b336 #30
  Hardware name: Intel Corporation PURLEY/PURLEY, BIOS PLYXCRB1.86B.0578.D07.1902280810 02/28/2019
  RIP: 0010:memset_erms+0x9/0x10
  Code: c1 e9 03 40 0f b6 f6 48 b8 01 01 01 01 01 01 01 01 48 0f af c6 f3 48 ab 89 d1 f3 aa 4c 89 c8 c3 90 49 89 f9 40 88 f0 48 89 d1 <f3> aa 4c 89 c8 c3 90 49 89 fa 40 0f b6 ce 48 b8 01 01 01 01 01 01
  Call Trace:
   remove_pfn_range_from_zone+0x3a/0x380
   memunmap_pages+0x17f/0x280
   release_nodes+0x22a/0x260
   __device_release_driver+0x172/0x220
   device_driver_detach+0x3e/0xa0
   unbind_store+0x113/0x130
   kernfs_fop_write+0xdc/0x1c0
   vfs_write+0xde/0x1d0
   ksys_write+0x58/0xd0
   do_syscall_64+0x5a/0x120
   entry_SYSCALL_64_after_hwframe+0x49/0xb3
  Built 2 zonelists, mobility grouping on.  Total pages: 49050381
  Policy zone: Normal
  Built 3 zonelists, mobility grouping on.  Total pages: 49312525
  Policy zone: Normal

David said: "It really only is an issue for devmem.  Ordinary
hotplugged system memory is not affected (onlined/offlined in memory
block granularity)."

Link: http://lkml.kernel.org/r/20200619231213.1160351-1-ben.widawsky@intel.com
Fixes: commit d33695b16a ("mm/memory_hotplug: poison memmap in remove_pfn_range_from_zone()")
Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
Reported-by: "Scargall, Steve" <steve.scargall@intel.com>
Reported-by: Ben Widawsky <ben.widawsky@intel.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-06-26 00:27:38 -07:00
Christoph Hellwig 7a0e27b2a0 mm: remove vmalloc_exec 
Merge vmalloc_exec into its only caller.  Note that for !CONFIG_MMU
__vmalloc_node_range maps to __vmalloc, which directly clears the
__GFP_HIGHMEM added by the vmalloc_exec stub anyway.

Link: http://lkml.kernel.org/r/20200618064307.32739-4-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dexuan Cui <decui@microsoft.com>
Cc: Jessica Yu <jeyu@kernel.org>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Wei Liu <wei.liu@kernel.org>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-06-26 00:27:38 -07:00
Joonsoo Kim 0076f029cb mm/memory: fix IO cost for anonymous page 
With synchronous IO swap device, swap-in is directly handled in fault
code.  Since IO cost notation isn't added there, with synchronous IO
swap device, LRU balancing could be wrongly biased.  Fix it to count it
in fault code.

Link: http://lkml.kernel.org/r/1592288204-27734-4-git-send-email-iamjoonsoo.kim@lge.com
Fixes: 314b57fb04 ("mm: balance LRU lists based on relative thrashing cache sizing")
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: Rik van Riel <riel@surriel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-06-26 00:27:38 -07:00
Joonsoo Kim cb6868832e mm/swap: fix for "mm: workingset: age nonresident information alongside anonymous pages" 
Non-file-lru page could also be activated in mark_page_accessed() and we
need to count this activation for nonresident_age.

Note that it's better for this patch to be squashed into the patch "mm:
workingset: age nonresident information alongside anonymous pages".

Link: http://lkml.kernel.org/r/1592288204-27734-3-git-send-email-iamjoonsoo.kim@lge.com
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: Rik van Riel <riel@surriel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-06-26 00:27:38 -07:00
Johannes Weiner 31d8fcac00 mm: workingset: age nonresident information alongside anonymous pages 
Patch series "fix for "mm: balance LRU lists based on relative
thrashing" patchset"

This patchset fixes some problems of the patchset, "mm: balance LRU
lists based on relative thrashing", which is now merged on the mainline.

Patch "mm: workingset: let cache workingset challenge anon fix" is the
result of discussion with Johannes.  See following link.

  http://lkml.kernel.org/r/20200520232525.798933-6-hannes@cmpxchg.org

And, the other two are minor things which are found when I try to rebase
my patchset.

This patch (of 3):

After ("mm: workingset: let cache workingset challenge anon fix"), we
compare refault distances to active_file + anon.  But age of the
non-resident information is only driven by the file LRU.  As a result,
we may overestimate the recency of any incoming refaults and activate
them too eagerly, causing unnecessary LRU churn in certain situations.

Make anon aging drive nonresident age as well to address that.

Link: http://lkml.kernel.org/r/1592288204-27734-1-git-send-email-iamjoonsoo.kim@lge.com
Link: http://lkml.kernel.org/r/1592288204-27734-2-git-send-email-iamjoonsoo.kim@lge.com
Fixes: 34e58cac6d ("mm: workingset: let cache workingset challenge anon")
Reported-by: Joonsoo Kim <js1304@gmail.com>
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-06-26 00:27:37 -07:00
Chris Down 03960e3318 mm/memcontrol.c: prevent missed memory.low load tears 
Looks like one of these got missed when massaging in f86b810c26 ("mm,
memcg: prevent memory.low load/store tearing") with other linux-mm
changes.

Link: http://lkml.kernel.org/r/20200612174437.GA391453@chrisdown.name
Signed-off-by: Chris Down <chris@chrisdown.name>
Reported-by: Michal Koutny <mkoutny@suse.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-06-26 00:27:37 -07:00
Muchun Song 3a98990ae2 mm/memcontrol.c: add missed css_put() 
We should put the css reference when memory allocation failed.

Link: http://lkml.kernel.org/r/20200614122653.98829-1-songmuchun@bytedance.com
Fixes: f0a3a24b53 ("mm: memcg/slab: rework non-root kmem_cache lifecycle management")
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Roman Gushchin <guro@fb.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Qian Cai <cai@lca.pw>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-06-26 00:27:37 -07:00
Johannes Weiner cd324edce5 mm: memcontrol: handle div0 crash race condition in memory.low 
Tejun reports seeing rare div0 crashes in memory.low stress testing:

  RIP: 0010:mem_cgroup_calculate_protection+0xed/0x150
  Code: 0f 46 d1 4c 39 d8 72 57 f6 05 16 d6 42 01 40 74 1f 4c 39 d8 76 1a 4c 39 d1 76 15 4c 29 d1 4c 29 d8 4d 29 d9 31 d2 48 0f af c1 <49> f7 f1 49 01 c2 4c 89 96 38 01 00 00 5d c3 48 0f af c7 31 d2 49
  RSP: 0018:ffffa14e01d6fcd0 EFLAGS: 00010246
  RAX: 000000000243e384 RBX: 0000000000000000 RCX: 0000000000008f4b
  RDX: 0000000000000000 RSI: ffff8b89bee84000 RDI: 0000000000000000
  RBP: ffffa14e01d6fcd0 R08: ffff8b89ca7d40f8 R09: 0000000000000000
  R10: 0000000000000000 R11: 00000000006422f7 R12: 0000000000000000
  R13: ffff8b89d9617000 R14: ffff8b89bee84000 R15: ffffa14e01d6fdb8
  FS:  0000000000000000(0000) GS:ffff8b8a1f1c0000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 00007f93b1fc175b CR3: 000000016100a000 CR4: 0000000000340ea0
  Call Trace:
    shrink_node+0x1e5/0x6c0
    balance_pgdat+0x32d/0x5f0
    kswapd+0x1d7/0x3d0
    kthread+0x11c/0x160
    ret_from_fork+0x1f/0x30

This happens when parent_usage == siblings_protected.

We check that usage is bigger than protected, which should imply
parent_usage being bigger than siblings_protected.  However, we don't
read (or even update) these values atomically, and they can be out of
sync as the memory state changes under us.  A bit of fluctuation around
the target protection isn't a big deal, but we need to handle the div0
case.

Check the parent state explicitly to make sure we have a reasonable
positive value for the divisor.

Link: http://lkml.kernel.org/r/20200615140658.601684-1-hannes@cmpxchg.org
Fixes: 8a931f8013 ("mm: memcontrol: recursive memory.low protection")
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reported-by: Tejun Heo <tj@kernel.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Chris Down <chris@chrisdown.name>
Cc: Roman Gushchin <guro@fb.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-06-26 00:27:37 -07:00
Masanari Iida 8eab7035b2 mm/vmalloc.c: fix a warning while make xmldocs 
This patch fixes following warning while "make xmldocs"

  mm/vmalloc.c:1877: warning: Excess function parameter 'prot' description in 'vm_map_ram'

This warning started since commit d4efd79a81 ("mm: remove the prot
argument from vm_map_ram").

Link: http://lkml.kernel.org/r/20200622152850.140871-1-standby24x7@gmail.com
Fixes: d4efd79a81 ("mm: remove the prot argument from vm_map_ram")
Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-06-26 00:27:37 -07:00
Christophe Leroy 9449c9cb42 mm/debug_vm_pgtable: fix build failure with powerpc 8xx 
Since commit 9e343b467c ("READ_ONCE: Enforce atomicity for
{READ,WRITE}_ONCE() memory accesses"), READ_ONCE() cannot be used
anymore to read complex page table entries.

This leads to:

      CC      mm/debug_vm_pgtable.o
    In file included from ./include/asm-generic/bug.h:5,
                     from ./arch/powerpc/include/asm/bug.h:109,
                     from ./include/linux/bug.h:5,
                     from ./include/linux/mmdebug.h:5,
                     from ./include/linux/gfp.h:5,
                     from mm/debug_vm_pgtable.c:13:
    In function 'pte_clear_tests',
        inlined from 'debug_vm_pgtable' at mm/debug_vm_pgtable.c:363:2:
    ./include/linux/compiler.h:392:38: error: Unsupported access size for {READ,WRITE}_ONCE().
    mm/debug_vm_pgtable.c:249:14: note: in expansion of macro 'READ_ONCE'
      249 |  pte_t pte = READ_ONCE(*ptep);
          |              ^~~~~~~~~
    make[2]: *** [mm/debug_vm_pgtable.o] Error 1

Fix it by using the recently added ptep_get() helper.

Link: http://lkml.kernel.org/r/6ca8c972e6c920dc4ae0d4affbed9703afa4d010.1592490570.git.christophe.leroy@csgroup.eu
Fixes: 9e343b467c ("READ_ONCE: Enforce atomicity for {READ,WRITE}_ONCE() memory accesses")
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Acked-by: Will Deacon <will@kernel.org>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-06-26 00:27:37 -07:00
Arjun Roy 7f70c2a68a mm/memory.c: properly pte_offset_map_lock/unlock in vm_insert_pages() 
Calls to pte_offset_map() in vm_insert_pages() are erroneously not
matched with a call to pte_unmap().  This would cause problems on
architectures where that is not a no-op.

This patch does away with the non-traditional locking in the existing
code, and instead uses pte_offset_map_lock/unlock() as usual,
incrementing PTE as necessary.  The PTE pointer is kept within bounds
since we clamp it with PTRS_PER_PTE.

Link: http://lkml.kernel.org/r/20200618220446.20284-1-arjunroy.kdev@gmail.com
Fixes: 8cd3984d81 ("mm/memory.c: add vm_insert_pages()")
Signed-off-by: Arjun Roy <arjunroy@google.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Soheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-06-26 00:27:37 -07:00
Hugh Dickins 243bce09c9 mm: fix swap cache node allocation mask 
Chris Murphy reports that a slightly overcommitted load, testing swap
and zram along with i915, splats and keeps on splatting, when it had
better fail less noisily:

  gnome-shell: page allocation failure: order:0,
  mode:0x400d0(__GFP_IO|__GFP_FS|__GFP_COMP|__GFP_RECLAIMABLE),
  nodemask=(null),cpuset=/,mems_allowed=0
  CPU: 2 PID: 1155 Comm: gnome-shell Not tainted 5.7.0-1.fc33.x86_64 #1
  Call Trace:
    dump_stack+0x64/0x88
    warn_alloc.cold+0x75/0xd9
    __alloc_pages_slowpath.constprop.0+0xcfa/0xd30
    __alloc_pages_nodemask+0x2df/0x320
    alloc_slab_page+0x195/0x310
    allocate_slab+0x3c5/0x440
    ___slab_alloc+0x40c/0x5f0
    __slab_alloc+0x1c/0x30
    kmem_cache_alloc+0x20e/0x220
    xas_nomem+0x28/0x70
    add_to_swap_cache+0x321/0x400
    __read_swap_cache_async+0x105/0x240
    swap_cluster_readahead+0x22c/0x2e0
    shmem_swapin+0x8e/0xc0
    shmem_swapin_page+0x196/0x740
    shmem_getpage_gfp+0x3a2/0xa60
    shmem_read_mapping_page_gfp+0x32/0x60
    shmem_get_pages+0x155/0x5e0 [i915]
    __i915_gem_object_get_pages+0x68/0xa0 [i915]
    i915_vma_pin+0x3fe/0x6c0 [i915]
    eb_add_vma+0x10b/0x2c0 [i915]
    i915_gem_do_execbuffer+0x704/0x3430 [i915]
    i915_gem_execbuffer2_ioctl+0x1ea/0x3e0 [i915]
    drm_ioctl_kernel+0x86/0xd0 [drm]
    drm_ioctl+0x206/0x390 [drm]
    ksys_ioctl+0x82/0xc0
    __x64_sys_ioctl+0x16/0x20
    do_syscall_64+0x5b/0xf0
    entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported on 5.7, but it goes back really to 3.1: when
shmem_read_mapping_page_gfp() was implemented for use by i915, and
allowed for __GFP_NORETRY and __GFP_NOWARN flags in most places, but
missed swapin's "& GFP_KERNEL" mask for page tree node allocation in
__read_swap_cache_async() - that was to mask off HIGHUSER_MOVABLE bits
from what page cache uses, but GFP_RECLAIM_MASK is now what's needed.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=208085
Link: http://lkml.kernel.org/r/alpine.LSU.2.11.2006151330070.11064@eggly.anvils
Fixes: 68da9f0557 ("tmpfs: pass gfp to shmem_getpage_gfp")
Signed-off-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reported-by: Chris Murphy <lists@colorremedies.com>
Analyzed-by: Vlastimil Babka <vbabka@suse.cz>
Analyzed-by: Matthew Wilcox <willy@infradead.org>
Tested-by: Chris Murphy <lists@colorremedies.com>
Cc: <stable@vger.kernel.org>	[3.1+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-06-26 00:27:37 -07:00
Sebastian Andrzej Siewior 55860d96ca slub: cure list_slab_objects() from double fix 
According to Christopher Lameter two fixes have been merged for the same
problem.  As far as I can tell, the code does not acquire the list_lock
and invoke kmalloc().  list_slab_objects() misses an unlock (the
counterpart to get_map()) and the memory allocated in free_partial()
isn't used.

Revert the mentioned commit.

Link: http://lkml.kernel.org/r/20200618201234.795692-1-bigeasy@linutronix.de
Fixes: aa456c7aeb ("slub: remove kmalloc under list_lock from list_slab_objects() V2")
Link: https://lkml.kernel.org/r/alpine.DEB.2.22.394.2006181501480.12014@www.lameter.com
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-06-26 00:27:37 -07:00
Waiman Long 8982ae527f mm/slab: use memzero_explicit() in kzfree() 
The kzfree() function is normally used to clear some sensitive
information, like encryption keys, in the buffer before freeing it back to
the pool.  Memset() is currently used for buffer clearing.  However
unlikely, there is still a non-zero probability that the compiler may
choose to optimize away the memory clearing especially if LTO is being
used in the future.

To make sure that this optimization will never happen,
memzero_explicit(), which is introduced in v3.18, is now used in
kzfree() to future-proof it.

Link: http://lkml.kernel.org/r/20200616154311.12314-2-longman@redhat.com
Fixes: 3ef0e5ba46 ("slab: introduce kzfree()")
Signed-off-by: Waiman Long <longman@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Cc: James Morris <jmorris@namei.org>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: Joe Perches <joe@perches.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: "Jason A . Donenfeld" <Jason@zx2c4.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-06-26 00:27:37 -07:00
Waiman Long d7670879c5 mm, slab: fix sign conversion problem in memcg_uncharge_slab() 
It was found that running the LTP test on a PowerPC system could produce
erroneous values in /proc/meminfo, like:

  MemTotal:       531915072 kB
  MemFree:        507962176 kB
  MemAvailable:   1100020596352 kB

Using bisection, the problem is tracked down to commit 9c315e4d7d ("mm:
memcg/slab: cache page number in memcg_(un)charge_slab()").

In memcg_uncharge_slab() with a "int order" argument:

  unsigned int nr_pages = 1 << order;
    :
  mod_lruvec_state(lruvec, cache_vmstat_idx(s), -nr_pages);

The mod_lruvec_state() function will eventually call the
__mod_zone_page_state() which accepts a long argument.  Depending on the
compiler and how inlining is done, "-nr_pages" may be treated as a
negative number or a very large positive number.  Apparently, it was
treated as a large positive number in that PowerPC system leading to
incorrect stat counts.  This problem hasn't been seen in x86-64 yet,
perhaps the gcc compiler there has some slight difference in behavior.

It is fixed by making nr_pages a signed value.  For consistency, a similar
change is applied to memcg_charge_slab() as well.

Link: http://lkml.kernel.org/r/20200620184719.10994-1-longman@redhat.com
Fixes: 9c315e4d7d ("mm: memcg/slab: cache page number in memcg_(un)charge_slab()").
Signed-off-by: Waiman Long <longman@redhat.com>
Acked-by: Roman Gushchin <guro@fb.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-06-26 00:27:37 -07:00
Vlastimil Babka b9e20f0da1 mm, compaction: make capture control handling safe wrt interrupts 
Hugh reports:

 "While stressing compaction, one run oopsed on NULL capc->cc in
  __free_one_page()'s task_capc(zone): compact_zone_order() had been
  interrupted, and a page was being freed in the return from interrupt.

  Though you would not expect it from the source, both gccs I was using
  (4.8.1 and 7.5.0) had chosen to compile compact_zone_order() with the
  ".cc = &cc" implemented by mov %rbx,-0xb0(%rbp) immediately before
  callq compact_zone - long after the "current->capture_control =
  &capc". An interrupt in between those finds capc->cc NULL (zeroed by
  an earlier rep stos).

  This could presumably be fixed by a barrier() before setting
  current->capture_control in compact_zone_order(); but would also need
  more care on return from compact_zone(), in order not to risk leaking
  a page captured by interrupt just before capture_control is reset.

  Maybe that is the preferable fix, but I felt safer for task_capc() to
  exclude the rather surprising possibility of capture at interrupt
  time"

I have checked that gcc10 also behaves the same.

The advantage of fix in compact_zone_order() is that we don't add
another test in the page freeing hot path, and that it might prevent
future problems if we stop exposing pointers to uninitialized structures
in current task.

So this patch implements the suggestion for compact_zone_order() with
barrier() (and WRITE_ONCE() to prevent store tearing) for setting
current->capture_control, and prevents page leaking with
WRITE_ONCE/READ_ONCE in the proper order.

Link: http://lkml.kernel.org/r/20200616082649.27173-1-vbabka@suse.cz
Fixes: 5e1f0f098b ("mm, compaction: capture a page under direct compaction")
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reported-by: Hugh Dickins <hughd@google.com>
Suggested-by: Hugh Dickins <hughd@google.com>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Li Wang <liwang@redhat.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: <stable@vger.kernel.org>	[5.1+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-06-26 00:27:36 -07:00
Michal Hocko 545b1b077c mm: do_swap_page(): fix up the error code 
do_swap_page() returns error codes from the VM_FAULT* space.  try_charge()
might return -ENOMEM, though, and then do_swap_page() simply returns 0
which means a success.

We almost never return ENOMEM for GFP_KERNEL single page charge.  Except
for async OOM handling (oom_disabled v1).  So this needs translation to
VM_FAULT_OOM otherwise the the page fault path will not notify the
userspace and wait for an action.

Link: http://lkml.kernel.org/r/20200617090238.GL9499@dhcp22.suse.cz
Fixes: 4c6355b25e ("mm: memcontrol: charge swapin pages on instantiation")
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Roman Gushchin <guro@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-06-26 00:27:36 -07:00
Jens Axboe 1a0a7853b9 mm: support async buffered reads in generic_file_buffered_read() 
Use the async page locking infrastructure, if IOCB_WAITQ is set in the
passed in iocb. The caller must expect an -EIOCBQUEUED return value,
which means that IO is started but not done yet. This is similar to how
O_DIRECT signals the same operation. Once the callback is received by
the caller for IO completion, the caller must retry the operation.

Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
 2020-06-21 20:44:25 -06:00
Jens Axboe dd3e6d5039 mm: add support for async page locking 
Normally waiting for a page to become unlocked, or locking the page,
requires waiting for IO to complete. Add support for lock_page_async()
and wait_on_page_locked_async(), which are callback based instead. This
allows a caller to get notified when a page becomes unlocked, rather
than wait for it.

We add a new iocb field, ki_waitq, to pass in the necessary data for this
to happen. We can unionize this with ki_cookie, since that is only used
for polled IO. Polled IO can never co-exist with async callbacks, as it is
(by definition) polled completions. struct wait_page_key is made public,
and we define struct wait_page_async as the interface between the caller
and the core.

Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
 2020-06-21 20:44:25 -06:00
Jens Axboe c7510ab2cf mm: abstract out wake_page_match() from wake_page_function() 
No functional changes in this patch, just in preparation for allowing
more callers.

Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
 2020-06-21 20:44:25 -06:00
Jens Axboe 2e85abf053 mm: allow read-ahead with IOCB_NOWAIT set 
The read-ahead shouldn't block, so allow it to be done even if
IOCB_NOWAIT is set in the kiocb.

Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
 2020-06-21 20:44:25 -06:00
Linus Torvalds 7561393908 powerpc fixes for 5.8 #3 
One fix for the interrupt rework we did last release which broke KVM-PR.
 
 Three commits fixing some fallout from the READ_ONCE() changes interacting badly
 with our 8xx 16K pages support, which uses a pte_t that is a structure of 4
 actual PTEs.
 
 A cleanup of the 8xx pte_update() to use the newly added pmd_off().
 
 A fix for a crash when handling an oops if CONFIG_DEBUG_VIRTUAL is enabled.
 
 A minor fix for the SPU syscall generation.
 
 Thanks to:
   Aneesh Kumar K.V, Christian Zigotzky, Christophe Leroy, Mike Rapoport,
   Nicholas Piggin.
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Merge tag 'powerpc-5.8-3' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

Pull powerpc fixes from Michael Ellerman:

 - One fix for the interrupt rework we did last release which broke
   KVM-PR

 - Three commits fixing some fallout from the READ_ONCE() changes
   interacting badly with our 8xx 16K pages support, which uses a pte_t
   that is a structure of 4 actual PTEs

 - A cleanup of the 8xx pte_update() to use the newly added pmd_off()

 - A fix for a crash when handling an oops if CONFIG_DEBUG_VIRTUAL is
   enabled

 - A minor fix for the SPU syscall generation

Thanks to Aneesh Kumar K.V, Christian Zigotzky, Christophe Leroy, Mike
Rapoport, Nicholas Piggin.

* tag 'powerpc-5.8-3' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc/8xx: Provide ptep_get() with 16k pages
  mm: Allow arches to provide ptep_get()
  mm/gup: Use huge_ptep_get() in gup_hugepte()
  powerpc/syscalls: Use the number when building SPU syscall table
  powerpc/8xx: use pmd_off() to access a PMD entry in pte_update()
  powerpc/64s: Fix KVM interrupt using wrong save area
  powerpc: Fix kernel crash in show_instructions() w/DEBUG_VIRTUAL
 2020-06-21 10:02:53 -07:00
Christophe Leroy 481e980a7c mm: Allow arches to provide ptep_get() 
Since commit 9e343b467c ("READ_ONCE: Enforce atomicity for
{READ,WRITE}_ONCE() memory accesses") it is not possible anymore to
use READ_ONCE() to access complex page table entries like the one
defined for powerpc 8xx with 16k size pages.

Define a ptep_get() helper that architectures can override instead
of performing a READ_ONCE() on the page table entry pointer.

Fixes: 9e343b467c ("READ_ONCE: Enforce atomicity for {READ,WRITE}_ONCE() memory accesses")
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Acked-by: Will Deacon <will@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/087fa12b6e920e32315136b998aa834f99242695.1592225558.git.christophe.leroy@csgroup.eu
 2020-06-20 22:14:53 +10:00
Christophe Leroy 55ca22633a mm/gup: Use huge_ptep_get() in gup_hugepte() 
gup_hugepte() reads hugepage table entries, it can't read
them directly, huge_ptep_get() must be used.

Fixes: 9e343b467c ("READ_ONCE: Enforce atomicity for {READ,WRITE}_ONCE() memory accesses")
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Acked-by: Will Deacon <will@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/ffc3714334c3bfaca6f13788ad039e8759ae413f.1592225558.git.christophe.leroy@csgroup.eu
 2020-06-20 22:14:53 +10:00
Christoph Hellwig c0ee37e85e maccess: rename probe_user_{read,write} to copy_{from,to}_user_nofault 
Better describe what these functions do.

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-06-17 10:57:41 -07:00
Christoph Hellwig fe557319aa maccess: rename probe_kernel_{read,write} to copy_{from,to}_kernel_nofault 
Better describe what these functions do.

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-06-17 10:57:41 -07:00
Linus Torvalds 6adc19fd13 Kbuild updates for v5.8 (2nd) 
- fix build rules in binderfs sample
 
  - fix build errors when Kbuild recurses to the top Makefile
 
  - covert '---help---' in Kconfig to 'help'
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Merge tag 'kbuild-v5.8-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull more Kbuild updates from Masahiro Yamada:

 - fix build rules in binderfs sample

 - fix build errors when Kbuild recurses to the top Makefile

 - covert '---help---' in Kconfig to 'help'

* tag 'kbuild-v5.8-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
  treewide: replace '---help---' in Kconfig files with 'help'
  kbuild: fix broken builds because of GZIP,BZIP2,LZOP variables
  samples: binderfs: really compile this sample and fix build issues
 2020-06-13 13:29:16 -07:00
Masahiro Yamada a7f7f6248d treewide: replace '---help---' in Kconfig files with 'help' 
Since commit 84af7a6194 ("checkpatch: kconfig: prefer 'help' over
'---help---'"), the number of '---help---' has been gradually
decreasing, but there are still more than 2400 instances.

This commit finishes the conversion. While I touched the lines,
I also fixed the indentation.

There are a variety of indentation styles found.

  a) 4 spaces + '---help---'
  b) 7 spaces + '---help---'
  c) 8 spaces + '---help---'
  d) 1 space + 1 tab + '---help---'
  e) 1 tab + '---help---'    (correct indentation)
  f) 1 tab + 1 space + '---help---'
  g) 1 tab + 2 spaces + '---help---'

In order to convert all of them to 1 tab + 'help', I ran the
following commend:

  $ find . -name 'Kconfig*' | xargs sed -i 's/^[[:space:]]*---help---/\thelp/'

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
 2020-06-14 01:57:21 +09:00
Linus Torvalds b791d1bdf9 The Kernel Concurrency Sanitizer (KCSAN) 
KCSAN is a dynamic race detector, which relies on compile-time
 instrumentation, and uses a watchpoint-based sampling approach to detect
 races.
 
 The feature was under development for quite some time and has already found
 legitimate bugs.
 
 Unfortunately it comes with a limitation, which was only understood late in
 the development cycle:
 
   It requires an up to date CLANG-11 compiler
 
 CLANG-11 is not yet released (scheduled for June), but it's the only
 compiler today which handles the kernel requirements and especially the
 annotations of functions to exclude them from KCSAN instrumentation
 correctly.
 
 These annotations really need to work so that low level entry code and
 especially int3 text poke handling can be completely isolated.
 
 A detailed discussion of the requirements and compiler issues can be found
 here:
 
   https://lore.kernel.org/lkml/CANpmjNMTsY_8241bS7=XAfqvZHFLrVEkv_uM4aDUWE_kh3Rvbw@mail.gmail.com/
 
 We came to the conclusion that trying to work around compiler limitations
 and bugs again would end up in a major trainwreck, so requiring a working
 compiler seemed to be the best choice.
 
 For Continous Integration purposes the compiler restriction is manageable
 and that's where most xxSAN reports come from.
 
 For a change this limitation might make GCC people actually look at their
 bugs. Some issues with CSAN in GCC are 7 years old and one has been 'fixed'
 3 years ago with a half baken solution which 'solved' the reported issue
 but not the underlying problem.
 
 The KCSAN developers also ponder to use a GCC plugin to become independent,
 but that's not something which will show up in a few days.
 
 Blocking KCSAN until wide spread compiler support is available is not a
 really good alternative because the continuous growth of lockless
 optimizations in the kernel demands proper tooling support.
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Merge tag 'locking-kcsan-2020-06-11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull the Kernel Concurrency Sanitizer from Thomas Gleixner:
 "The Kernel Concurrency Sanitizer (KCSAN) is a dynamic race detector,
  which relies on compile-time instrumentation, and uses a
  watchpoint-based sampling approach to detect races.

  The feature was under development for quite some time and has already
  found legitimate bugs.

  Unfortunately it comes with a limitation, which was only understood
  late in the development cycle:

     It requires an up to date CLANG-11 compiler

  CLANG-11 is not yet released (scheduled for June), but it's the only
  compiler today which handles the kernel requirements and especially
  the annotations of functions to exclude them from KCSAN
  instrumentation correctly.

  These annotations really need to work so that low level entry code and
  especially int3 text poke handling can be completely isolated.

  A detailed discussion of the requirements and compiler issues can be
  found here:

    https://lore.kernel.org/lkml/CANpmjNMTsY_8241bS7=XAfqvZHFLrVEkv_uM4aDUWE_kh3Rvbw@mail.gmail.com/

  We came to the conclusion that trying to work around compiler
  limitations and bugs again would end up in a major trainwreck, so
  requiring a working compiler seemed to be the best choice.

  For Continous Integration purposes the compiler restriction is
  manageable and that's where most xxSAN reports come from.

  For a change this limitation might make GCC people actually look at
  their bugs. Some issues with CSAN in GCC are 7 years old and one has
  been 'fixed' 3 years ago with a half baken solution which 'solved' the
  reported issue but not the underlying problem.

  The KCSAN developers also ponder to use a GCC plugin to become
  independent, but that's not something which will show up in a few
  days.

  Blocking KCSAN until wide spread compiler support is available is not
  a really good alternative because the continuous growth of lockless
  optimizations in the kernel demands proper tooling support"

* tag 'locking-kcsan-2020-06-11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (76 commits)
  compiler_types.h, kasan: Use __SANITIZE_ADDRESS__ instead of CONFIG_KASAN to decide inlining
  compiler.h: Move function attributes to compiler_types.h
  compiler.h: Avoid nested statement expression in data_race()
  compiler.h: Remove data_race() and unnecessary checks from {READ,WRITE}_ONCE()
  kcsan: Update Documentation to change supported compilers
  kcsan: Remove 'noinline' from __no_kcsan_or_inline
  kcsan: Pass option tsan-instrument-read-before-write to Clang
  kcsan: Support distinguishing volatile accesses
  kcsan: Restrict supported compilers
  kcsan: Avoid inserting __tsan_func_entry/exit if possible
  ubsan, kcsan: Don't combine sanitizer with kcov on clang
  objtool, kcsan: Add kcsan_disable_current() and kcsan_enable_current_nowarn()
  kcsan: Add __kcsan_{enable,disable}_current() variants
  checkpatch: Warn about data_race() without comment
  kcsan: Use GFP_ATOMIC under spin lock
  Improve KCSAN documentation a bit
  kcsan: Make reporting aware of KCSAN tests
  kcsan: Fix function matching in report
  kcsan: Change data_race() to no longer require marking racing accesses
  kcsan: Move kcsan_{disable,enable}_current() to kcsan-checks.h
  ...
 2020-06-11 18:55:43 -07:00
Naoya Horiguchi 03151c6e0b mm/memory-failure: send SIGBUS(BUS_MCEERR_AR) only to current thread 
Action Required memory error should happen only when a processor is
about to access to a corrupted memory, so it's synchronous and only
affects current process/thread.

Recently commit 872e9a205c ("mm, memory_failure: don't send
BUS_MCEERR_AO for action required error") fixed the issue that Action
Required memory could unnecessarily send SIGBUS to the processes which
share the error memory.  But we still have another issue that we could
send SIGBUS to a wrong thread.

This is because collect_procs() and task_early_kill() fails to add the
current process to "to-kill" list.  So this patch is suggesting to fix
it.  With this fix, SIGBUS(BUS_MCEERR_AR) is never sent to non-current
process/thread.

Signed-off-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Tony Luck <tony.luck@intel.com>
Acked-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Link: http://lkml.kernel.org/r/1591321039-22141-3-git-send-email-naoya.horiguchi@nec.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-06-11 18:17:47 -07:00
Naoya Horiguchi 4e018b450a mm/memory-failure: prioritize prctl(PR_MCE_KILL) over vm.memory_failure_early_kill 
Patch series "hwpoison: fixes signaling on memory error"

This is a small patchset to solve issues in memory error handler to send
SIGBUS to proper process/thread as expected in configuration.  Please
see descriptions in individual patches for more details.

This patch (of 2):

Early-kill policy is controlled from two types of settings, one is
per-process setting prctl(PR_MCE_KILL) and the other is system-wide
setting vm.memory_failure_early_kill.  Users expect per-process setting
to override system-wide setting as many other settings do, but
early-kill setting doesn't work as such.

For example, if a system configures vm.memory_failure_early_kill to 1
(enabled), a process receives SIGBUS even if it's configured to
explicitly disable PF_MCE_KILL by prctl().  That's not desirable for
applications with their own policies.

This patch is suggesting to change the priority of these two types of
settings, by checking sysctl_memory_failure_early_kill only when a given
process has the default kill policy.

Note that this patch is solving a thread choice issue too.

Originally, collect_procs() always chooses the main thread when
vm.memory_failure_early_kill is 1, even if the process has a dedicated
thread for memory error handling.  SIGBUS should be sent to the
dedicated thread if early-kill is enabled via
vm.memory_failure_early_kill as we are doing for PR_MCE_KILL_EARLY
processes.

Signed-off-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Link: http://lkml.kernel.org/r/1591321039-22141-1-git-send-email-naoya.horiguchi@nec.com
Link: http://lkml.kernel.org/r/1591321039-22141-2-git-send-email-naoya.horiguchi@nec.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-06-11 18:17:47 -07:00
Linus Torvalds 623f6dc593 Merge branch 'akpm' (patches from Andrew) 
Merge some more updates from Andrew Morton:

 - various hotfixes and minor things

 - hch's use_mm/unuse_mm clearnups

Subsystems affected by this patch series: mm/hugetlb, scripts, kcov,
lib, nilfs, checkpatch, lib, mm/debug, ocfs2, lib, misc.

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  kernel: set USER_DS in kthread_use_mm
  kernel: better document the use_mm/unuse_mm API contract
  kernel: move use_mm/unuse_mm to kthread.c
  kernel: move use_mm/unuse_mm to kthread.c
  stacktrace: cleanup inconsistent variable type
  lib: test get_count_order/long in test_bitops.c
  mm: add comments on pglist_data zones
  ocfs2: fix spelling mistake and grammar
  mm/debug_vm_pgtable: fix kernel crash by checking for THP support
  lib: fix bitmap_parse() on 64-bit big endian archs
  checkpatch: correct check for kernel parameters doc
  nilfs2: fix null pointer dereference at nilfs_segctor_do_construct()
  lib/lz4/lz4_decompress.c: document deliberate use of `&'
  kcov: check kcov_softirq in kcov_remote_stop()
  scripts/spelling: add a few more typos
  khugepaged: selftests: fix timeout condition in wait_for_scan()
 2020-06-11 13:25:53 -07:00
Thomas Gleixner 37d1a04b13 Rebase locking/kcsan to locking/urgent 
Merge the state of the locking kcsan branch before the read/write_once()
and the atomics modifications got merged.

Squash the fallout of the rebase on top of the read/write once and atomic
fallback work into the merge. The history of the original branch is
preserved in tag locking-kcsan-2020-06-02.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
 2020-06-11 20:02:46 +02:00
Christoph Hellwig f5678e7f2a kernel: better document the use_mm/unuse_mm API contract 
Switch the function documentation to kerneldoc comments, and add
WARN_ON_ONCE asserts that the calling thread is a kernel thread and does
not have ->mm set (or has ->mm set in the case of unuse_mm).

Also give the functions a kthread_ prefix to better document the use case.

[hch@lst.de: fix a comment typo, cover the newly merged use_mm/unuse_mm caller in vfio]
  Link: http://lkml.kernel.org/r/20200416053158.586887-3-hch@lst.de
[sfr@canb.auug.org.au: powerpc/vas: fix up for {un}use_mm() rename]
  Link: http://lkml.kernel.org/r/20200422163935.5aa93ba5@canb.auug.org.au

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Acked-by: Felix Kuehling <Felix.Kuehling@amd.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> [usb]
Acked-by: Haren Myneni <haren@linux.ibm.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Felipe Balbi <balbi@kernel.org>
Cc: Jason Wang <jasowang@redhat.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Zhenyu Wang <zhenyuw@linux.intel.com>
Cc: Zhi Wang <zhi.a.wang@intel.com>
Link: http://lkml.kernel.org/r/20200404094101.672954-6-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-06-10 19:14:18 -07:00
Christoph Hellwig 9bf5b9eb23 kernel: move use_mm/unuse_mm to kthread.c 
Patch series "improve use_mm / unuse_mm", v2.

This series improves the use_mm / unuse_mm interface by better documenting
the assumptions, and my taking the set_fs manipulations spread over the
callers into the core API.

This patch (of 3):

Use the proper API instead.

Link: http://lkml.kernel.org/r/20200404094101.672954-1-hch@lst.de

These helpers are only for use with kernel threads, and I will tie them
more into the kthread infrastructure going forward.  Also move the
prototypes to kthread.h - mmu_context.h was a little weird to start with
as it otherwise contains very low-level MM bits.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Acked-by: Felix Kuehling <Felix.Kuehling@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Felipe Balbi <balbi@kernel.org>
Cc: Jason Wang <jasowang@redhat.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Zhenyu Wang <zhenyuw@linux.intel.com>
Cc: Zhi Wang <zhi.a.wang@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: http://lkml.kernel.org/r/20200404094101.672954-1-hch@lst.de
Link: http://lkml.kernel.org/r/20200416053158.586887-1-hch@lst.de
Link: http://lkml.kernel.org/r/20200404094101.672954-5-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-06-10 19:14:18 -07:00
Aneesh Kumar K.V 787d563b86 mm/debug_vm_pgtable: fix kernel crash by checking for THP support 
Architectures can have CONFIG_TRANSPARENT_HUGEPAGE enabled but no THP
support enabled based on platforms.  For ex: with 4K PAGE_SIZE ppc64
supports THP only with radix translation.

This results in below crash when running with hash translation and 4K
PAGE_SIZE.

    kernel BUG at arch/powerpc/include/asm/book3s/64/hash-4k.h:140!
    cpu 0x61: Vector: 700 (Program Check) at [c000000ff948f860]
        pc: debug_vm_pgtable+0x480/0x8b0
        lr: debug_vm_pgtable+0x474/0x8b0
    ...
        debug_vm_pgtable+0x374/0x8b0 (unreliable)
        do_one_initcall+0x98/0x4f0
        kernel_init_freeable+0x330/0x3fc
        kernel_init+0x24/0x148

Check for THP support correctly

Link: http://lkml.kernel.org/r/20200608125252.407659-1-aneesh.kumar@linux.ibm.com
Fixes: 399145f9eb ("mm/debug: add tests validating architecture page table helpers")
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-06-10 19:14:18 -07:00
Linus Torvalds 09102704c6 virtio: features, fixes 
virtio-mem
 doorbell mapping for vdpa
 config interrupt support in ifc
 fixes all over the place
 
 Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost

Pull virtio updates from Michael Tsirkin:

 - virtio-mem: paravirtualized memory hotplug

 - support doorbell mapping for vdpa

 - config interrupt support in ifc

 - fixes all over the place

* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost: (40 commits)
  vhost/test: fix up after API change
  virtio_mem: convert device block size into 64bit
  virtio-mem: drop unnecessary initialization
  ifcvf: implement config interrupt in IFCVF
  vhost: replace -1 with VHOST_FILE_UNBIND in ioctls
  vhost_vdpa: Support config interrupt in vdpa
  ifcvf: ignore continuous setting same status value
  virtio-mem: Don't rely on implicit compiler padding for requests
  virtio-mem: Try to unplug the complete online memory block first
  virtio-mem: Use -ETXTBSY as error code if the device is busy
  virtio-mem: Unplug subblocks right-to-left
  virtio-mem: Drop manual check for already present memory
  virtio-mem: Add parent resource for all added "System RAM"
  virtio-mem: Better retry handling
  virtio-mem: Offline and remove completely unplugged memory blocks
  mm/memory_hotplug: Introduce offline_and_remove_memory()
  virtio-mem: Allow to offline partially unplugged memory blocks
  mm: Allow to offline unmovable PageOffline() pages via MEM_GOING_OFFLINE
  virtio-mem: Paravirtualized memory hotunplug part 2
  virtio-mem: Paravirtualized memory hotunplug part 1
  ...
 2020-06-10 13:42:09 -07:00
Christoph Hellwig 2a71e81d32 maccess: return -ERANGE when probe_kernel_read() fails 
Allow the callers to distinguish a real unmapped address vs a range
that can't be probed.

Suggested-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20200521152301.2587579-24-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-06-09 09:39:16 -07:00
Christoph Hellwig b58294ead1 maccess: allow architectures to provide kernel probing directly 
Provide alternative versions of probe_kernel_read, probe_kernel_write
and strncpy_from_kernel_unsafe that don't need set_fs magic, but instead
use arch hooks that are modelled after unsafe_{get,put}_user to access
kernel memory in an exception safe way.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20200521152301.2587579-19-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-06-09 09:39:15 -07:00
Christoph Hellwig fc3562d794 maccess: move user access routines together 
Move kernel access vs user access routines together to ease upcoming
ifdefs.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20200521152301.2587579-18-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-06-09 09:39:15 -07:00
Christoph Hellwig 98a23609b1 maccess: always use strict semantics for probe_kernel_read 
Except for historical confusion in the kprobes/uprobes and bpf tracers,
which has been fixed now, there is no good reason to ever allow user
memory accesses from probe_kernel_read.  Switch probe_kernel_read to only
read from kernel memory.

[akpm@linux-foundation.org: update it for "mm, dump_page(): do not crash with invalid mapping pointer"]

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20200521152301.2587579-17-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-06-09 09:39:15 -07:00
Christoph Hellwig 7676fbf21b maccess: remove strncpy_from_unsafe 
All users are gone now.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20200521152301.2587579-16-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-06-09 09:39:15 -07:00
Christoph Hellwig eab0c6089b maccess: unify the probe kernel arch hooks 
Currently architectures have to override every routine that probes
kernel memory, which includes a pure read and strcpy, both in strict
and not strict variants.  Just provide a single arch hooks instead to
make sure all architectures cover all the cases.

[akpm@linux-foundation.org: fix !CONFIG_X86_64 build]

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20200521152301.2587579-11-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-06-09 09:39:15 -07:00
Christoph Hellwig cd0309058f maccess: remove probe_read_common and probe_write_common 
Each of the helpers has just two callers, which also different in
dealing with kernel or userspace pointers.  Just open code the logic
in the callers.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20200521152301.2587579-10-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-06-09 09:39:15 -07:00
Christoph Hellwig 02dddb160e maccess: rename strnlen_unsafe_user to strnlen_user_nofault 
This matches the naming of strnlen_user, and also makes it more clear
what the function is supposed to do.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20200521152301.2587579-9-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-06-09 09:39:15 -07:00
Christoph Hellwig c4cb164426 maccess: rename strncpy_from_unsafe_strict to strncpy_from_kernel_nofault 
This matches the naming of strncpy_from_user_nofault, and also makes it
more clear what the function is supposed to do.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20200521152301.2587579-8-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-06-09 09:39:15 -07:00
Christoph Hellwig bd88bb5d40 maccess: rename strncpy_from_unsafe_user to strncpy_from_user_nofault 
This matches the naming of strncpy_from_user, and also makes it more
clear what the function is supposed to do.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20200521152301.2587579-7-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-06-09 09:39:15 -07:00
Christoph Hellwig 3f0acb1eb3 maccess: update the top of file comment 
This file now also contains several helpers for accessing user memory.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20200521152301.2587579-6-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-06-09 09:39:15 -07:00
Christoph Hellwig 4f6de12b37 maccess: clarify kerneldoc comments 
Add proper kerneldoc comments for probe_kernel_read_strict and
probe_kernel_read strncpy_from_unsafe_strict and explain the different
versus the non-strict version.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20200521152301.2587579-5-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-06-09 09:39:15 -07:00
Christoph Hellwig 48c49c0e5f maccess: remove various unused weak aliases 
maccess tends to define lots of underscore prefixed symbols that then
have other weak aliases.  But except for two cases they are never
actually used, so remove them.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20200521152301.2587579-3-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-06-09 09:39:15 -07:00
Christoph Hellwig 0493cb0863 maccess: unexport probe_kernel_write() 
Patch series "clean up and streamline probe_kernel_* and friends", v4.

This series start cleaning up the safe kernel and user memory probing
helpers in mm/maccess.c, and then allows architectures to implement the
kernel probing without overriding the address space limit and temporarily
allowing access to user memory.  It then switches x86 over to this new
mechanism by reusing the unsafe_* uaccess logic.

This version also switches to the saner copy_{from,to}_kernel_nofault
naming suggested by Linus.

I kept the x86 helpers as-is without calling unsage_{get,put}_user as that
avoids a number of hard to trace casts, and it will still work with the
asm-goto based version easily.

This patch (of 20):

probe_kernel_write() is not used by any modular code.

[sfr@canb.auug.org.au: turns out that probe_user_write is used in modular code]
  Link: http://lkml.kernel.org/r/20200602195741.4faaa348@canb.auug.org.au

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20200521152301.2587579-1-hch@lst.de
Link: http://lkml.kernel.org/r/20200521152301.2587579-2-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-06-09 09:39:15 -07:00
Michel Lespinasse c1e8d7c6a7 mmap locking API: convert mmap_sem comments 
Convert comments that reference mmap_sem to reference mmap_lock instead.

[akpm@linux-foundation.org: fix up linux-next leftovers]
[akpm@linux-foundation.org: s/lockaphore/lock/, per Vlastimil]
[akpm@linux-foundation.org: more linux-next fixups, per Michel]

Signed-off-by: Michel Lespinasse <walken@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Laurent Dufour <ldufour@linux.ibm.com>
Cc: Liam Howlett <Liam.Howlett@oracle.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ying Han <yinghan@google.com>
Link: http://lkml.kernel.org/r/20200520052908.204642-13-walken@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-06-09 09:39:14 -07:00
Michel Lespinasse 3e4e28c5a8 mmap locking API: convert mmap_sem API comments 
Convert comments that reference old mmap_sem APIs to reference
corresponding new mmap locking APIs instead.

Signed-off-by: Michel Lespinasse <walken@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Davidlohr Bueso <dbueso@suse.de>
Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Laurent Dufour <ldufour@linux.ibm.com>
Cc: Liam Howlett <Liam.Howlett@oracle.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ying Han <yinghan@google.com>
Link: http://lkml.kernel.org/r/20200520052908.204642-12-walken@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-06-09 09:39:14 -07:00
Michel Lespinasse da1c55f1b2 mmap locking API: rename mmap_sem to mmap_lock 
Rename the mmap_sem field to mmap_lock.  Any new uses of this lock should
now go through the new mmap locking api.  The mmap_lock is still
implemented as a rwsem, though this could change in the future.

[akpm@linux-foundation.org: fix it for mm-gup-might_lock_readmmap_sem-in-get_user_pages_fast.patch]

Signed-off-by: Michel Lespinasse <walken@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Davidlohr Bueso <dbueso@suse.de>
Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Laurent Dufour <ldufour@linux.ibm.com>
Cc: Liam Howlett <Liam.Howlett@oracle.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ying Han <yinghan@google.com>
Link: http://lkml.kernel.org/r/20200520052908.204642-11-walken@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-06-09 09:39:14 -07:00
Michel Lespinasse 42fc541404 mmap locking API: add mmap_assert_locked() and mmap_assert_write_locked() 
Add new APIs to assert that mmap_sem is held.

Using this instead of rwsem_is_locked and lockdep_assert_held[_write]
makes the assertions more tolerant of future changes to the lock type.

Signed-off-by: Michel Lespinasse <walken@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Laurent Dufour <ldufour@linux.ibm.com>
Cc: Liam Howlett <Liam.Howlett@oracle.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ying Han <yinghan@google.com>
Link: http://lkml.kernel.org/r/20200520052908.204642-10-walken@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-06-09 09:39:14 -07:00
Michel Lespinasse 14c3656b72 mmap locking API: add MMAP_LOCK_INITIALIZER 
Define a new initializer for the mmap locking api.  Initially this just
evaluates to __RWSEM_INITIALIZER as the API is defined as wrappers around
rwsem.

Signed-off-by: Michel Lespinasse <walken@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Laurent Dufour <ldufour@linux.ibm.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Liam Howlett <Liam.Howlett@oracle.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ying Han <yinghan@google.com>
Link: http://lkml.kernel.org/r/20200520052908.204642-9-walken@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-06-09 09:39:14 -07:00
Michel Lespinasse d8ed45c5dc mmap locking API: use coccinelle to convert mmap_sem rwsem call sites 
This change converts the existing mmap_sem rwsem calls to use the new mmap
locking API instead.

The change is generated using coccinelle with the following rule:

// spatch --sp-file mmap_lock_api.cocci --in-place --include-headers --dir .

@@
expression mm;
@@
(
-init_rwsem
+mmap_init_lock
|
-down_write
+mmap_write_lock
|
-down_write_killable
+mmap_write_lock_killable
|
-down_write_trylock
+mmap_write_trylock
|
-up_write
+mmap_write_unlock
|
-downgrade_write
+mmap_write_downgrade
|
-down_read
+mmap_read_lock
|
-down_read_killable
+mmap_read_lock_killable
|
-down_read_trylock
+mmap_read_trylock
|
-up_read
+mmap_read_unlock
)
-(&mm->mmap_sem)
+(mm)

Signed-off-by: Michel Lespinasse <walken@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Reviewed-by: Laurent Dufour <ldufour@linux.ibm.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Liam Howlett <Liam.Howlett@oracle.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ying Han <yinghan@google.com>
Link: http://lkml.kernel.org/r/20200520052908.204642-5-walken@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-06-09 09:39:14 -07:00
Mike Rapoport 65fddcfca8 mm: reorder includes after introduction of linux/pgtable.h 
The replacement of <asm/pgrable.h> with <linux/pgtable.h> made the include
of the latter in the middle of asm includes.  Fix this up with the aid of
the below script and manual adjustments here and there.

	import sys
	import re

	if len(sys.argv) is not 3:
	    print "USAGE: %s <file> <header>" % (sys.argv[0])
	    sys.exit(1)

	hdr_to_move="#include <linux/%s>" % sys.argv[2]
	moved = False
	in_hdrs = False

	with open(sys.argv[1], "r") as f:
	    lines = f.readlines()
	    for _line in lines:
		line = _line.rstrip('
')
		if line == hdr_to_move:
		    continue
		if line.startswith("#include <linux/"):
		    in_hdrs = True
		elif not moved and in_hdrs:
		    moved = True
		    print hdr_to_move
		print line

Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Cain <bcain@codeaurora.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Greg Ungerer <gerg@linux-m68k.org>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: Guo Ren <guoren@kernel.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Ley Foon Tan <ley.foon.tan@intel.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Nick Hu <nickhu@andestech.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vincent Chen <deanbo422@gmail.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: http://lkml.kernel.org/r/20200514170327.31389-4-rppt@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-06-09 09:39:13 -07:00
Mike Rapoport ca5999fde0 mm: introduce include/linux/pgtable.h 
The include/linux/pgtable.h is going to be the home of generic page table
manipulation functions.

Start with moving asm-generic/pgtable.h to include/linux/pgtable.h and
make the latter include asm/pgtable.h.

Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Cain <bcain@codeaurora.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Greg Ungerer <gerg@linux-m68k.org>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: Guo Ren <guoren@kernel.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Ley Foon Tan <ley.foon.tan@intel.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Nick Hu <nickhu@andestech.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vincent Chen <deanbo422@gmail.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: http://lkml.kernel.org/r/20200514170327.31389-3-rppt@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-06-09 09:39:13 -07:00
Mike Rapoport e31cf2f4ca mm: don't include asm/pgtable.h if linux/mm.h is already included 
Patch series "mm: consolidate definitions of page table accessors", v2.

The low level page table accessors (pXY_index(), pXY_offset()) are
duplicated across all architectures and sometimes more than once.  For
instance, we have 31 definition of pgd_offset() for 25 supported
architectures.

Most of these definitions are actually identical and typically it boils
down to, e.g.

static inline unsigned long pmd_index(unsigned long address)
{
        return (address >> PMD_SHIFT) & (PTRS_PER_PMD - 1);
}

static inline pmd_t *pmd_offset(pud_t *pud, unsigned long address)
{
        return (pmd_t *)pud_page_vaddr(*pud) + pmd_index(address);
}

These definitions can be shared among 90% of the arches provided
XYZ_SHIFT, PTRS_PER_XYZ and xyz_page_vaddr() are defined.

For architectures that really need a custom version there is always
possibility to override the generic version with the usual ifdefs magic.

These patches introduce include/linux/pgtable.h that replaces
include/asm-generic/pgtable.h and add the definitions of the page table
accessors to the new header.

This patch (of 12):

The linux/mm.h header includes <asm/pgtable.h> to allow inlining of the
functions involving page table manipulations, e.g.  pte_alloc() and
pmd_alloc().  So, there is no point to explicitly include <asm/pgtable.h>
in the files that include <linux/mm.h>.

The include statements in such cases are remove with a simple loop:

	for f in $(git grep -l "include <linux/mm.h>") ; do
		sed -i -e '/include <asm\/pgtable.h>/ d' $f
	done

Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Cain <bcain@codeaurora.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Greg Ungerer <gerg@linux-m68k.org>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: Guo Ren <guoren@kernel.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Ley Foon Tan <ley.foon.tan@intel.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nick Hu <nickhu@andestech.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vincent Chen <deanbo422@gmail.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: http://lkml.kernel.org/r/20200514170327.31389-1-rppt@kernel.org
Link: http://lkml.kernel.org/r/20200514170327.31389-2-rppt@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-06-09 09:39:13 -07:00
Linus Torvalds 20b0d06722 Merge branch 'akpm' (patches from Andrew) 
Merge still more updates from Andrew Morton:
 "Various trees. Mainly those parts of MM whose linux-next dependents
  are now merged. I'm still sitting on ~160 patches which await merges
  from -next.

  Subsystems affected by this patch series: mm/proc, ipc, dynamic-debug,
  panic, lib, sysctl, mm/gup, mm/pagemap"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (52 commits)
  doc: cgroup: update note about conditions when oom killer is invoked
  module: move the set_fs hack for flush_icache_range to m68k
  nommu: use flush_icache_user_range in brk and mmap
  binfmt_flat: use flush_icache_user_range
  exec: use flush_icache_user_range in read_code
  exec: only build read_code when needed
  m68k: implement flush_icache_user_range
  arm: rename flush_cache_user_range to flush_icache_user_range
  xtensa: implement flush_icache_user_range
  sh: implement flush_icache_user_range
  asm-generic: add a flush_icache_user_range stub
  mm: rename flush_icache_user_range to flush_icache_user_page
  arm,sparc,unicore32: remove flush_icache_user_range
  riscv: use asm-generic/cacheflush.h
  powerpc: use asm-generic/cacheflush.h
  openrisc: use asm-generic/cacheflush.h
  m68knommu: use asm-generic/cacheflush.h
  microblaze: use asm-generic/cacheflush.h
  ia64: use asm-generic/cacheflush.h
  hexagon: use asm-generic/cacheflush.h
  ...
 2020-06-08 11:11:38 -07:00
Christoph Hellwig a75a2df68f nommu: use flush_icache_user_range in brk and mmap 
These obviously operate on user addresses.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Greg Ungerer <gerg@linux-m68k.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Link: http://lkml.kernel.org/r/20200515143646.3857579-29-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-06-08 11:05:58 -07:00
John Hubbard 6a005645ed mm/gup: documentation fix for pin_user_pages*() APIs 
All of the pin_user_pages*() API calls will cause pages to be
dma-pinned.  As such, they are all suitable for either DMA, RDMA, and/or
Direct IO.

The documentation should say so, but it was instead saying that three of
the API calls were only suitable for Direct IO.  This was discovered
when a reviewer wondered why an API call that specifically recommended
against Case 2 (DMA/RDMA) was being used in a DMA situation [1].

Fix this by simply deleting those claims.  The gup.c comments already
refer to the more extensive Documentation/core-api/pin_user_pages.rst,
which does have the correct guidance.  So let's just write it once,
there.

[1] https://lore.kernel.org/r/20200529074658.GM30374@kadam

Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Acked-by: Souptick Joarder <jrdr.linux@gmail.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Vlastimil Babka <vbabka@suse.cz>
Link: http://lkml.kernel.org/r/20200529084515.46259-1-jhubbard@nvidia.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-06-08 11:05:56 -07:00
John Hubbard 55a650c35f mm/gup: frame_vector: convert get_user_pages() --> pin_user_pages() 
This code was using get_user_pages*(), and all of the callers so far
were in a "Case 2" scenario (DMA/RDMA), using the categorization from [1].

That means that it's time to convert the get_user_pages*() + put_page()
calls to pin_user_pages*() + unpin_user_pages() calls.

There is some helpful background in [2]: basically, this is a small part
of fixing a long-standing disconnect between pinning pages, and file
systems' use of those pages.

[1] Documentation/core-api/pin_user_pages.rst

[2] "Explicit pinning of user-space pages":
    https://lwn.net/Articles/807108/

Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Jan Kara <jack@suse.cz>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Cc: Souptick Joarder <jrdr.linux@gmail.com>
Link: http://lkml.kernel.org/r/20200527223243.884385-3-jhubbard@nvidia.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-06-08 11:05:56 -07:00
John Hubbard 420c2091b6 mm/gup: introduce pin_user_pages_locked() 
Patch series "mm/gup: introduce pin_user_pages_locked(), use it in frame_vector.c", v2.

This adds yet one more pin_user_pages*() variant, and uses that to
convert mm/frame_vector.c.

With this, along with maybe 20 or 30 other recent patches in various
trees, we are close to having the relevant gup call sites
converted--with the notable exception of the bio/block layer.

This patch (of 2):

Introduce pin_user_pages_locked(), which is nearly identical to
get_user_pages_locked() except that it sets FOLL_PIN and rejects
FOLL_GET.

As with other pairs of get_user_pages*() and pin_user_pages() API calls,
it's prudent to assert that FOLL_PIN is *not* set in the
get_user_pages*() call, so add that as part of this.

[jhubbard@nvidia.com: v2]
  Link: http://lkml.kernel.org/r/20200531234131.770697-2-jhubbard@nvidia.com

Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Jan Kara <jack@suse.cz>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Souptick Joarder <jrdr.linux@gmail.com>
Link: http://lkml.kernel.org/r/20200531234131.770697-1-jhubbard@nvidia.com
Link: http://lkml.kernel.org/r/20200527223243.884385-1-jhubbard@nvidia.com
Link: http://lkml.kernel.org/r/20200527223243.884385-2-jhubbard@nvidia.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-06-08 11:05:56 -07:00
Souptick Joarder dadbb612f6 mm/gup.c: convert to use get_user_{page|pages}_fast_only() 
API __get_user_pages_fast() renamed to get_user_pages_fast_only() to
align with pin_user_pages_fast_only().

As part of this we will get rid of write parameter.  Instead caller will
pass FOLL_WRITE to get_user_pages_fast_only().  This will not change any
existing functionality of the API.

All the callers are changed to pass FOLL_WRITE.

Also introduce get_user_page_fast_only(), and use it in a few places
that hard-code nr_pages to 1.

Updated the documentation of the API.

Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: Paul Mackerras <paulus@ozlabs.org>		[arch/powerpc/kvm]
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Michal Suchanek <msuchanek@suse.de>
Link: http://lkml.kernel.org/r/1590396812-31277-1-git-send-email-jrdr.linux@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-06-08 11:05:56 -07:00
Vlastimil Babka 0a477e1ae2 kernel/sysctl: support handling command line aliases 
We can now handle sysctl parameters on kernel command line, but
historically some parameters introduced their own command line
equivalent, which we don't want to remove for compatibility reasons.

We can, however, convert them to the generic infrastructure with a table
translating the legacy command line parameters to their sysctl names,
and removing the one-off param handlers.

This patch adds the support and makes the first conversion to
demonstrate it, on the (deprecated) numa_zonelist_order parameter.

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Acked-by: Kees Cook <keescook@chromium.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Christian Brauner <christian.brauner@ubuntu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: "Eric W . Biederman" <ebiederm@xmission.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Guilherme G . Piccoli" <gpiccoli@canonical.com>
Cc: Iurii Zaikin <yzaikin@google.com>
Cc: Ivan Teterevkov <ivan.teterevkov@nutanix.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20200427180433.7029-3-vbabka@suse.cz
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-06-08 11:05:56 -07:00
SeongJae Park 92fb1db26e mm/page_idle.c: skip offline pages 
'Idle page tracking' users can pass random pfn that might be mapped to an
offline page.  To avoid accessing such pages, this commit modifies the
'page_idle_get_page()' to use 'pfn_to_online_page()' instead of
'pfn_valid()' and 'pfn_to_page()' combination, so that the pfn mapped to
an offline page can be skipped.

Reported-by: David Hildenbrand <david@redhat.com>
Signed-off-by: SeongJae Park <sjpark@amazon.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Link: http://lkml.kernel.org/r/20200605092502.18018-2-sjpark@amazon.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-06-08 11:05:55 -07:00
Linus Torvalds 52e0ad262c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-next 
Pull sparc updates from David Miller:

 - Rework the sparc32 page tables so that READ_ONCE(*pmd), as done by
   generic code, operates on a word sized element. From Will Deacon.

 - Some scnprintf() conversions, from Chen Zhou.

 - A pin_user_pages() conversion from John Hubbard.

 - Several 32-bit ptrace register handling fixes and such from Al Viro.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-next:
  fix a braino in "sparc32: fix register window handling in genregs32_[gs]et()"
  sparc32: mm: Only call ctor()/dtor() functions for first and last user
  sparc32: mm: Disable SPLIT_PTLOCK_CPUS
  sparc32: mm: Don't try to free page-table pages if ctor() fails
  sparc32: register memory occupied by kernel as memblock.memory
  sparc: remove unused header file nfs_fs.h
  sparc32: fix register window handling in genregs32_[gs]et()
  sparc64: fix misuses of access_process_vm() in genregs32_[sg]et()
  oradax: convert get_user_pages() --> pin_user_pages()
  sparc: use scnprintf() in show_pciobppath_attr() in vio.c
  sparc: use scnprintf() in show_pciobppath_attr() in pci.c
  tty: vcc: Fix error return code in vcc_probe()
  sparc32: mm: Reduce allocation size for PMD and PTE tables
  sparc32: mm: Change pgtable_t type to pte_t * instead of struct page *
  sparc32: mm: Restructure sparc32 MMU page-table layout
  sparc32: mm: Fix argument checking in __srmmu_get_nocache()
  sparc64: Replace zero-length array with flexible-array
  sparc: mm: return true,false in kern_addr_valid()
 2020-06-07 17:25:29 -07:00
Linus Torvalds 7ae77150d9 powerpc updates for 5.8 
- Support for userspace to send requests directly to the on-chip GZIP
    accelerator on Power9.
 
  - Rework of our lockless page table walking (__find_linux_pte()) to make it
    safe against parallel page table manipulations without relying on an IPI for
    serialisation.
 
  - A series of fixes & enhancements to make our machine check handling more
    robust.
 
  - Lots of plumbing to add support for "prefixed" (64-bit) instructions on
    Power10.
 
  - Support for using huge pages for the linear mapping on 8xx (32-bit).
 
  - Remove obsolete Xilinx PPC405/PPC440 support, and an associated sound driver.
 
  - Removal of some obsolete 40x platforms and associated cruft.
 
  - Initial support for booting on Power10.
 
  - Lots of other small features, cleanups & fixes.
 
 Thanks to:
   Alexey Kardashevskiy, Alistair Popple, Andrew Donnellan, Andrey Abramov,
   Aneesh Kumar K.V, Balamuruhan S, Bharata B Rao, Bulent Abali, Cédric Le
   Goater, Chen Zhou, Christian Zigotzky, Christophe JAILLET, Christophe Leroy,
   Dmitry Torokhov, Emmanuel Nicolet, Erhard F., Gautham R. Shenoy, Geoff Levand,
   George Spelvin, Greg Kurz, Gustavo A. R. Silva, Gustavo Walbon, Haren Myneni,
   Hari Bathini, Joel Stanley, Jordan Niethe, Kajol Jain, Kees Cook, Leonardo
   Bras, Madhavan Srinivasan., Mahesh Salgaonkar, Markus Elfring, Michael
   Neuling, Michal Simek, Nathan Chancellor, Nathan Lynch, Naveen N. Rao,
   Nicholas Piggin, Oliver O'Halloran, Paul Mackerras, Pingfan Liu, Qian Cai, Ram
   Pai, Raphael Moreira Zinsly, Ravi Bangoria, Sam Bobroff, Sandipan Das, Segher
   Boessenkool, Stephen Rothwell, Sukadev Bhattiprolu, Tyrel Datwyler, Wolfram
   Sang, Xiongfeng Wang.
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Merge tag 'powerpc-5.8-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

Pull powerpc updates from Michael Ellerman:

 - Support for userspace to send requests directly to the on-chip GZIP
   accelerator on Power9.

 - Rework of our lockless page table walking (__find_linux_pte()) to
   make it safe against parallel page table manipulations without
   relying on an IPI for serialisation.

 - A series of fixes & enhancements to make our machine check handling
   more robust.

 - Lots of plumbing to add support for "prefixed" (64-bit) instructions
   on Power10.

 - Support for using huge pages for the linear mapping on 8xx (32-bit).

 - Remove obsolete Xilinx PPC405/PPC440 support, and an associated sound
   driver.

 - Removal of some obsolete 40x platforms and associated cruft.

 - Initial support for booting on Power10.

 - Lots of other small features, cleanups & fixes.

Thanks to: Alexey Kardashevskiy, Alistair Popple, Andrew Donnellan,
Andrey Abramov, Aneesh Kumar K.V, Balamuruhan S, Bharata B Rao, Bulent
Abali, Cédric Le Goater, Chen Zhou, Christian Zigotzky, Christophe
JAILLET, Christophe Leroy, Dmitry Torokhov, Emmanuel Nicolet, Erhard F.,
Gautham R. Shenoy, Geoff Levand, George Spelvin, Greg Kurz, Gustavo A.
R. Silva, Gustavo Walbon, Haren Myneni, Hari Bathini, Joel Stanley,
Jordan Niethe, Kajol Jain, Kees Cook, Leonardo Bras, Madhavan
Srinivasan., Mahesh Salgaonkar, Markus Elfring, Michael Neuling, Michal
Simek, Nathan Chancellor, Nathan Lynch, Naveen N. Rao, Nicholas Piggin,
Oliver O'Halloran, Paul Mackerras, Pingfan Liu, Qian Cai, Ram Pai,
Raphael Moreira Zinsly, Ravi Bangoria, Sam Bobroff, Sandipan Das, Segher
Boessenkool, Stephen Rothwell, Sukadev Bhattiprolu, Tyrel Datwyler,
Wolfram Sang, Xiongfeng Wang.

* tag 'powerpc-5.8-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (299 commits)
  powerpc/pseries: Make vio and ibmebus initcalls pseries specific
  cxl: Remove dead Kconfig options
  powerpc: Add POWER10 architected mode
  powerpc/dt_cpu_ftrs: Add MMA feature
  powerpc/dt_cpu_ftrs: Enable Prefixed Instructions
  powerpc/dt_cpu_ftrs: Advertise support for ISA v3.1 if selected
  powerpc: Add support for ISA v3.1
  powerpc: Add new HWCAP bits
  powerpc/64s: Don't set FSCR bits in INIT_THREAD
  powerpc/64s: Save FSCR to init_task.thread.fscr after feature init
  powerpc/64s: Don't let DT CPU features set FSCR_DSCR
  powerpc/64s: Don't init FSCR_DSCR in __init_FSCR()
  powerpc/32s: Fix another build failure with CONFIG_PPC_KUAP_DEBUG
  powerpc/module_64: Use special stub for _mcount() with -mprofile-kernel
  powerpc/module_64: Simplify check for -mprofile-kernel ftrace relocations
  powerpc/module_64: Consolidate ftrace code
  powerpc/32: Disable KASAN with pages bigger than 16k
  powerpc/uaccess: Don't set KUEP by default on book3s/32
  powerpc/uaccess: Don't set KUAP by default on book3s/32
  powerpc/8xx: Reduce time spent in allow_user_access() and friends
  ...
 2020-06-05 12:39:30 -07:00
Linus Torvalds 886d7de631 Merge branch 'akpm' (patches from Andrew) 
Merge yet more updates from Andrew Morton:

 - More MM work. 100ish more to go. Mike Rapoport's "mm: remove
   __ARCH_HAS_5LEVEL_HACK" series should fix the current ppc issue

 - Various other little subsystems

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (127 commits)
  lib/ubsan.c: fix gcc-10 warnings
  tools/testing/selftests/vm: remove duplicate headers
  selftests: vm: pkeys: fix multilib builds for x86
  selftests: vm: pkeys: use the correct page size on powerpc
  selftests/vm/pkeys: override access right definitions on powerpc
  selftests/vm/pkeys: test correct behaviour of pkey-0
  selftests/vm/pkeys: introduce a sub-page allocator
  selftests/vm/pkeys: detect write violation on a mapped access-denied-key page
  selftests/vm/pkeys: associate key on a mapped page and detect write violation
  selftests/vm/pkeys: associate key on a mapped page and detect access violation
  selftests/vm/pkeys: improve checks to determine pkey support
  selftests/vm/pkeys: fix assertion in test_pkey_alloc_exhaust()
  selftests/vm/pkeys: fix number of reserved powerpc pkeys
  selftests/vm/pkeys: introduce powerpc support
  selftests/vm/pkeys: introduce generic pkey abstractions
  selftests: vm: pkeys: use the correct huge page size
  selftests/vm/pkeys: fix alloc_random_pkey() to make it really random
  selftests/vm/pkeys: fix assertion in pkey_disable_set/clear()
  selftests/vm/pkeys: fix pkey_disable_clear()
  selftests: vm: pkeys: add helpers for pkey bits
  ...
 2020-06-04 19:18:29 -07:00