Commit Graph

14147 Commits

Author SHA1 Message Date
Mel Gorman 68265390f9 mm, pcpu: make zone pcp updates and reset internal to the mm
Memory hotplug needs to be able to reset and reinit the pcpu allocator
batch and high limits but this action is internal to the VM.  Move the
declaration to internal.h

Link: http://lkml.kernel.org/r/20191021094808.28824-4-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Qian Cai <cai@lca.pw>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01 12:59:06 -08:00
Mel Gorman cb1ef534ce mm, pcp: share common code between memory hotplug and percpu sysctl handler
Both the percpu_pagelist_fraction sysctl handler and memory hotplug have
a common requirement of updating the pcpu page allocation batch and high
values.  Split the relevant helper to share common code.

No functional change.

Link: http://lkml.kernel.org/r/20191021094808.28824-3-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Qian Cai <cai@lca.pw>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01 12:59:06 -08:00
Anshuman Khandual 5e27a2df03 mm/page_alloc: add alloc_contig_pages()
HugeTLB helper alloc_gigantic_page() implements fairly generic
allocation method where it scans over various zones looking for a large
contiguous pfn range before trying to allocate it with
alloc_contig_range().

Other than deriving the requested order from 'struct hstate', there is
nothing HugeTLB specific in there.  This can be made available for
general use to allocate contiguous memory which could not have been
allocated through the buddy allocator.

alloc_gigantic_page() has been split carving out actual allocation
method which is then made available via new alloc_contig_pages() helper
wrapped under CONFIG_CONTIG_ALLOC.  All references to 'gigantic' have
been replaced with more generic term 'contig'.  Allocated pages here
should be freed with free_contig_range() or by calling __free_page() on
each allocated page.

Link: http://lkml.kernel.org/r/1571300646-32240-1-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Michal Hocko <mhocko@suse.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Pavel Tatashin <pavel.tatashin@microsoft.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01 12:59:06 -08:00
Daniel Axtens 3c5c3cfb9e kasan: support backing vmalloc space with real shadow memory
Patch series "kasan: support backing vmalloc space with real shadow
memory", v11.

Currently, vmalloc space is backed by the early shadow page.  This means
that kasan is incompatible with VMAP_STACK.

This series provides a mechanism to back vmalloc space with real,
dynamically allocated memory.  I have only wired up x86, because that's
the only currently supported arch I can work with easily, but it's very
easy to wire up other architectures, and it appears that there is some
work-in-progress code to do this on arm64 and s390.

This has been discussed before in the context of VMAP_STACK:
 - https://bugzilla.kernel.org/show_bug.cgi?id=202009
 - https://lkml.org/lkml/2018/7/22/198
 - https://lkml.org/lkml/2019/7/19/822

In terms of implementation details:

Most mappings in vmalloc space are small, requiring less than a full
page of shadow space.  Allocating a full shadow page per mapping would
therefore be wasteful.  Furthermore, to ensure that different mappings
use different shadow pages, mappings would have to be aligned to
KASAN_SHADOW_SCALE_SIZE * PAGE_SIZE.

Instead, share backing space across multiple mappings.  Allocate a
backing page when a mapping in vmalloc space uses a particular page of
the shadow region.  This page can be shared by other vmalloc mappings
later on.

We hook in to the vmap infrastructure to lazily clean up unused shadow
memory.

Testing with test_vmalloc.sh on an x86 VM with 2 vCPUs shows that:

 - Turning on KASAN, inline instrumentation, without vmalloc, introuduces
   a 4.1x-4.2x slowdown in vmalloc operations.

 - Turning this on introduces the following slowdowns over KASAN:
     * ~1.76x slower single-threaded (test_vmalloc.sh performance)
     * ~2.18x slower when both cpus are performing operations
       simultaneously (test_vmalloc.sh sequential_test_order=1)

This is unfortunate but given that this is a debug feature only, not the
end of the world.  The benchmarks are also a stress-test for the vmalloc
subsystem: they're not indicative of an overall 2x slowdown!

This patch (of 4):

Hook into vmalloc and vmap, and dynamically allocate real shadow memory
to back the mappings.

Most mappings in vmalloc space are small, requiring less than a full
page of shadow space.  Allocating a full shadow page per mapping would
therefore be wasteful.  Furthermore, to ensure that different mappings
use different shadow pages, mappings would have to be aligned to
KASAN_SHADOW_SCALE_SIZE * PAGE_SIZE.

Instead, share backing space across multiple mappings.  Allocate a
backing page when a mapping in vmalloc space uses a particular page of
the shadow region.  This page can be shared by other vmalloc mappings
later on.

We hook in to the vmap infrastructure to lazily clean up unused shadow
memory.

To avoid the difficulties around swapping mappings around, this code
expects that the part of the shadow region that covers the vmalloc space
will not be covered by the early shadow page, but will be left unmapped.
This will require changes in arch-specific code.

This allows KASAN with VMAP_STACK, and may be helpful for architectures
that do not have a separate module space (e.g.  powerpc64, which I am
currently working on).  It also allows relaxing the module alignment
back to PAGE_SIZE.

Testing with test_vmalloc.sh on an x86 VM with 2 vCPUs shows that:

 - Turning on KASAN, inline instrumentation, without vmalloc, introuduces
   a 4.1x-4.2x slowdown in vmalloc operations.

 - Turning this on introduces the following slowdowns over KASAN:
     * ~1.76x slower single-threaded (test_vmalloc.sh performance)
     * ~2.18x slower when both cpus are performing operations
       simultaneously (test_vmalloc.sh sequential_test_order=3D1)

This is unfortunate but given that this is a debug feature only, not the
end of the world.

The full benchmark results are:

Performance

                              No KASAN      KASAN original x baseline  KASAN vmalloc x baseline    x KASAN

fix_size_alloc_test             662004            11404956      17.23       19144610      28.92       1.68
full_fit_alloc_test             710950            12029752      16.92       13184651      18.55       1.10
long_busy_list_alloc_test      9431875            43990172       4.66       82970178       8.80       1.89
random_size_alloc_test         5033626            23061762       4.58       47158834       9.37       2.04
fix_align_alloc_test           1252514            15276910      12.20       31266116      24.96       2.05
random_size_align_alloc_te     1648501            14578321       8.84       25560052      15.51       1.75
align_shift_alloc_test             147                 830       5.65           5692      38.72       6.86
pcpu_alloc_test                  80732              125520       1.55         140864       1.74       1.12
Total Cycles              119240774314        763211341128       6.40  1390338696894      11.66       1.82

Sequential, 2 cpus

                              No KASAN      KASAN original x baseline  KASAN vmalloc x baseline    x KASAN

fix_size_alloc_test            1423150            14276550      10.03       27733022      19.49       1.94
full_fit_alloc_test            1754219            14722640       8.39       15030786       8.57       1.02
long_busy_list_alloc_test     11451858            52154973       4.55      107016027       9.34       2.05
random_size_alloc_test         5989020            26735276       4.46       68885923      11.50       2.58
fix_align_alloc_test           2050976            20166900       9.83       50491675      24.62       2.50
random_size_align_alloc_te     2858229            17971700       6.29       38730225      13.55       2.16
align_shift_alloc_test             405                6428      15.87          26253      64.82       4.08
pcpu_alloc_test                 127183              151464       1.19         216263       1.70       1.43
Total Cycles               54181269392        308723699764       5.70   650772566394      12.01       2.11
fix_size_alloc_test            1420404            14289308      10.06       27790035      19.56       1.94
full_fit_alloc_test            1736145            14806234       8.53       15274301       8.80       1.03
long_busy_list_alloc_test     11404638            52270785       4.58      107550254       9.43       2.06
random_size_alloc_test         6017006            26650625       4.43       68696127      11.42       2.58
fix_align_alloc_test           2045504            20280985       9.91       50414862      24.65       2.49
random_size_align_alloc_te     2845338            17931018       6.30       38510276      13.53       2.15
align_shift_alloc_test             472                3760       7.97           9656      20.46       2.57
pcpu_alloc_test                 118643              132732       1.12         146504       1.23       1.10
Total Cycles               54040011688        309102805492       5.72   651325675652      12.05       2.11

[dja@axtens.net: fixups]
  Link: http://lkml.kernel.org/r/20191120052719.7201-1-dja@axtens.net
Link: https://bugzilla.kernel.org/show_bug.cgi?id=3D202009
Link: http://lkml.kernel.org/r/20191031093909.9228-2-dja@axtens.net
Signed-off-by: Mark Rutland <mark.rutland@arm.com> [shadow rework]
Signed-off-by: Daniel Axtens <dja@axtens.net>
Co-developed-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Vasily Gorbik <gor@linux.ibm.com>
Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Qian Cai <cai@lca.pw>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01 12:59:05 -08:00
Uladzislau Rezki (Sony) e36176be1c mm/vmalloc: rework vmap_area_lock
With the new allocation approach introduced in the 5.2 kernel, it
becomes possible to get rid of one global spinlock.  By doing that we
can further improve the KVA from the performance point of view.

Basically we can have two independent locks, one for allocation part and
another one for deallocation, because of two different entities: "free
data structures" and "busy data structures".

As a result, allocation/deallocation operations can still interfere
between each other in case of running simultaneously on different CPUs,
it means there is still dependency, but with two locks it becomes lower.

Summarizing:
  - it reduces the high lock contention
  - it allows to perform operations on "free" and "busy"
    trees in parallel on different CPUs. Please note it
    does not solve scalability issue.

Test results:

In order to evaluate this patch, we can run "vmalloc test driver" to see
how many CPU cycles it takes to complete all test cases running
sequentially.  All online CPUs run it so it will cause a high lock
contention.

HiKey 960, ARM64, 8xCPUs, big.LITTLE:

<snip>
    sudo ./test_vmalloc.sh sequential_test_order=1
<snip>

<default>
[  390.950557] All test took CPU0=457126382 cycles
[  391.046690] All test took CPU1=454763452 cycles
[  391.128586] All test took CPU2=454539334 cycles
[  391.222669] All test took CPU3=455649517 cycles
[  391.313946] All test took CPU4=388272196 cycles
[  391.410425] All test took CPU5=384036264 cycles
[  391.492219] All test took CPU6=387432964 cycles
[  391.578433] All test took CPU7=387201996 cycles
<default>

<patched>
[  304.721224] All test took CPU0=391521310 cycles
[  304.821219] All test took CPU1=393533002 cycles
[  304.917120] All test took CPU2=392243032 cycles
[  305.008986] All test took CPU3=392353853 cycles
[  305.108944] All test took CPU4=297630721 cycles
[  305.196406] All test took CPU5=297548736 cycles
[  305.288602] All test took CPU6=297092392 cycles
[  305.381088] All test took CPU7=297293597 cycles
<patched>

~14%-23% patched variant is better.

Link: http://lkml.kernel.org/r/20191022155800.20468-1-urezki@gmail.com
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Oleksiy Avramchenko <oleksiy.avramchenko@sonymobile.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01 12:59:05 -08:00
Uladzislau Rezki (Sony) 060650a2a0 mm/vmalloc: add more comments to the adjust_va_to_fit_type()
When fit type is NE_FIT_TYPE there is a need in one extra object.
Usually the "ne_fit_preload_node" per-CPU variable has it and there is
no need in GFP_NOWAIT allocation, but there are exceptions.

This commit just adds more explanations, as a result giving answers on
questions like when it can occur, how often, under which conditions and
what happens if GFP_NOWAIT gets failed.

Link: http://lkml.kernel.org/r/20191016095438.12391-3-urezki@gmail.com
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Daniel Wagner <dwagner@suse.de>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Uladzislau Rezki <urezki@gmail.com>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Oleksiy Avramchenko <oleksiy.avramchenko@sonymobile.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01 12:59:05 -08:00
Uladzislau Rezki (Sony) f07116d77b mm/vmalloc: respect passed gfp_mask when doing preloading
Allocation functions should comply with the given gfp_mask as much as
possible.  The preallocation code in alloc_vmap_area doesn't follow that
pattern and it is using a hardcoded GFP_KERNEL.  Although this doesn't
really make much difference because vmalloc is not GFP_NOWAIT compliant
in general (e.g.  page table allocations are GFP_KERNEL) there is no
reason to spread that bad habit and it is good to fix the antipattern.

[mhocko@suse.com: rewrite changelog]
Link: http://lkml.kernel.org/r/20191016095438.12391-2-urezki@gmail.com
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Daniel Wagner <dwagner@suse.de>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Oleksiy Avramchenko <oleksiy.avramchenko@sonymobile.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01 12:59:05 -08:00
Uladzislau Rezki (Sony) 81f1ba586e mm/vmalloc: remove preempt_disable/enable when doing preloading
Some background.  The preemption was disabled before to guarantee that a
preloaded object is available for a CPU, it was stored for.  That was
achieved by combining the disabling the preemption and taking the spin
lock while the ne_fit_preload_node is checked.

The aim was to not allocate in atomic context when spinlock is taken
later, for regular vmap allocations.  But that approach conflicts with
CONFIG_PREEMPT_RT philosophy.  It means that calling spin_lock() with
disabled preemption is forbidden in the CONFIG_PREEMPT_RT kernel.

Therefore, get rid of preempt_disable() and preempt_enable() when the
preload is done for splitting purpose.  As a result we do not guarantee
now that a CPU is preloaded, instead we minimize the case when it is
not, with this change, by populating the per cpu preload pointer under
the vmap_area_lock.

This implies that at least each caller that has done the preallocation
will not fallback to an atomic allocation later.  It is possible that
the preallocation would be pointless or that no preallocation is done
because of the race but the data shows that this is really rare.

For example i run the special test case that follows the preload pattern
and path.  20 "unbind" threads run it and each does 1000000 allocations.
Only 3.5 times among 1000000 a CPU was not preloaded.  So it can happen
but the number is negligible.

[mhocko@suse.com: changelog additions]
Link: http://lkml.kernel.org/r/20191016095438.12391-1-urezki@gmail.com
Fixes: 82dd23e84b ("mm/vmalloc.c: preload a CPU with one object for split purpose")
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Acked-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Daniel Wagner <dwagner@suse.de>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Oleksiy Avramchenko <oleksiy.avramchenko@sonymobile.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01 12:59:05 -08:00
Liu Xiang dcf61ff06d mm/vmalloc.c: remove unnecessary highmem_mask from parameter of gfpflags_allow_blocking()
gfpflags_allow_blocking() does not care about __GFP_HIGHMEM, so
highmem_mask can be removed.

Link: http://lkml.kernel.org/r/1568812319-3467-1-git-send-email-liuxiang_1999@126.com
Signed-off-by: Liu Xiang <liuxiang_1999@126.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>
2019-12-01 12:59:05 -08:00
Michal Hocko 09dbcf422e mm/sparse.c: do not waste pre allocated memmap space
Vincent has noticed [1] that there is something unusual with the memmap
allocations going on on his platform

: I noticed this because on my ARM64 platform, with 1 GiB of memory the
: first [and only] section is allocated from the zeroing path while with
: 2 GiB of memory the first 1 GiB section is allocated from the
: non-zeroing path.

The underlying problem is that although sparse_buffer_init allocates
enough memory for all sections on the node sparse_buffer_alloc is not
able to consume them due to mismatch in the expected allocation
alignement.  While sparse_buffer_init preallocation uses the PAGE_SIZE
alignment the real memmap has to be aligned to section_map_size() this
results in a wasted initial chunk of the preallocated memmap and
unnecessary fallback allocation for a section.

While we are at it also change __populate_section_memmap to align to the
requested size because at least VMEMMAP has constrains to have memmap
properly aligned.

[1] http://lkml.kernel.org/r/20191030131122.8256-1-vincent.whitchurch@axis.com

[akpm@linux-foundation.org: tweak layout, per David]
Link: http://lkml.kernel.org/r/20191119092642.31799-1-mhocko@kernel.org
Fixes: 35fd1eb1e8 ("mm/sparse: abstract sparse buffer allocations")
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reported-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
Debugged-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Oscar Salvador <OSalvador@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01 12:59:05 -08:00
Ilya Leoshkevich 030eab4f9f mm/sparse.c: mark populate_section_memmap as __meminit
Building the kernel on s390 with -Og produces the following warning:

  WARNING: vmlinux.o(.text+0x28dabe): Section mismatch in reference from the function populate_section_memmap() to the function .meminit.text:__populate_section_memmap()
  The function populate_section_memmap() references
  the function __meminit __populate_section_memmap().
  This is often because populate_section_memmap lacks a __meminit
  annotation or the annotation of __populate_section_memmap is wrong.

While -Og is not supported, in theory this might still happen with
another compiler or on another architecture.  So fix this by using the
correct section annotations.

[iii@linux.ibm.com: v2]
  Link: http://lkml.kernel.org/r/20191030151639.41486-1-iii@linux.ibm.com
Link: http://lkml.kernel.org/r/20191028165549.14478-1-iii@linux.ibm.com
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Oscar Salvador <OSalvador@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01 12:59:05 -08:00
Vincent Whitchurch 4c29700ed9 mm/sparse: consistently do not zero memmap
sparsemem without VMEMMAP has two allocation paths to allocate the
memory needed for its memmap (done in sparse_mem_map_populate()).

In one allocation path (sparse_buffer_alloc() succeeds), the memory is
not zeroed (since it was previously allocated with
memblock_alloc_try_nid_raw()).

In the other allocation path (sparse_buffer_alloc() fails and
sparse_mem_map_populate() falls back to memblock_alloc_try_nid()), the
memory is zeroed.

AFAICS this difference does not appear to be on purpose.  If the code is
supposed to work with non-initialized memory (__init_single_page() takes
care of zeroing the struct pages which are actually used), we should
consistently not zero the memory, to avoid masking bugs.

( I noticed this because on my ARM64 platform, with 1 GiB of memory the
  first [and only] section is allocated from the zeroing path while with
  2 GiB of memory the first 1 GiB section is allocated from the
  non-zeroing path. )

Michal:
 "the main user visible problem is a memory wastage. The overal amount
  of memory should be small. I wouldn't call it stable material."

Link: http://lkml.kernel.org/r/20191030131122.8256-1-vincent.whitchurch@axis.com
Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Pavel Tatashin <pasha.tatashin@soleen.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01 12:59:05 -08:00
David Hildenbrand c5e79ef561 mm/memory_hotplug.c: don't allow to online/offline memory blocks with holes
Our onlining/offlining code is unnecessarily complicated.  Only memory
blocks added during boot can have holes (a range that is not
IORESOURCE_SYSTEM_RAM).  Hotplugged memory never has holes (e.g., see
add_memory_resource()).  All memory blocks that belong to boot memory
are already online.

Note that boot memory can have holes and the memmap of the holes is
marked PG_reserved.  However, also memory allocated early during boot is
PG_reserved - basically every page of boot memory that is not given to
the buddy is PG_reserved.

Therefore, when we stop allowing to offline memory blocks with holes, we
implicitly no longer have to deal with onlining memory blocks with
holes.  E.g., online_pages() will do a walk_system_ram_range(...,
online_pages_range), whereby online_pages_range() will effectively only
free the memory holes not falling into a hole to the buddy.  The other
pages (holes) are kept PG_reserved (via
move_pfn_range_to_zone()->memmap_init_zone()).

This allows to simplify the code.  For example, we no longer have to
worry about marking pages that fall into memory holes PG_reserved when
onlining memory.  We can stop setting pages PG_reserved completely in
memmap_init_zone().

Offlining memory blocks added during boot is usually not guaranteed to
work either way (unmovable data might have easily ended up on that
memory during boot).  So stopping to do that should not really hurt.
Also, people are not even aware of a setup where onlining/offlining of
memory blocks with holes used to work reliably (see [1] and [2]
especially regarding the hotplug path) - I doubt it worked reliably.

For the use case of offlining memory to unplug DIMMs, we should see no
change.  (holes on DIMMs would be weird).

Please note that hardware errors (PG_hwpoison) are not memory holes and
are not affected by this change when offlining.

[1] https://lkml.org/lkml/2019/10/22/135
[2] https://lkml.org/lkml/2019/8/14/1365

Link: http://lkml.kernel.org/r/20191119115237.6662-1-david@redhat.com
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01 12:59:05 -08:00
David Hildenbrand 756d25be45 mm/page_isolation.c: convert SKIP_HWPOISON to MEMORY_OFFLINE
We have two types of users of page isolation:

 1. Memory offlining:  Offline memory so it can be unplugged. Memory
                       won't be touched.

 2. Memory allocation: Allocate memory (e.g., alloc_contig_range()) to
                       become the owner of the memory and make use of
                       it.

For example, in case we want to offline memory, we can ignore (skip
over) PageHWPoison() pages, as the memory won't get used.  We can allow
to offline memory.  In contrast, we don't want to allow to allocate such
memory.

Let's generalize the approach so we can special case other types of
pages we want to skip over in case we offline memory.  While at it, also
pass the same flags to test_pages_isolated().

Link: http://lkml.kernel.org/r/20191021172353.3056-3-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Suggested-by: Michal Hocko <mhocko@suse.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Pingfan Liu <kernelfans@gmail.com>
Cc: Qian Cai <cai@lca.pw>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Pavel Tatashin <pavel.tatashin@microsoft.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01 12:59:04 -08:00
David Hildenbrand 0ee5f4f31d mm/page_alloc.c: don't set pages PageReserved() when offlining
Patch series "mm: Memory offlining + page isolation cleanups", v2.

This patch (of 2):

We call __offline_isolated_pages() from __offline_pages() after all
pages were isolated and are either free (PageBuddy()) or PageHWPoison.
Nothing can stop us from offlining memory at this point.

In __offline_isolated_pages() we first set all affected memory sections
offline (offline_mem_sections(pfn, end_pfn)), to mark the memmap as
invalid (pfn_to_online_page() will no longer succeed), and then walk
over all pages to pull the free pages from the free lists (to the
isolated free lists, to be precise).

Note that re-onlining a memory block will result in the whole memmap
getting reinitialized, overwriting any old state.  We already poision
the memmap when offlining is complete to find any access to
stale/uninitialized memmaps.

So, setting the pages PageReserved() is not helpful.  The memap is
marked offline and all pageblocks are isolated.  As soon as offline, the
memmap is stale either way.

This looks like a leftover from ancient times where we initialized the
memmap when adding memory and not when onlining it (the pages were set
PageReserved so re-onling would work as expected).

Link: http://lkml.kernel.org/r/20191021172353.3056-2-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Pavel Tatashin <pavel.tatashin@microsoft.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Pingfan Liu <kernelfans@gmail.com>
Cc: Qian Cai <cai@lca.pw>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01 12:59:04 -08:00
David Hildenbrand 0ec4709743 mm/memory_hotplug: remove __online_page_free() and __online_page_increment_counters()
Let's drop the now unused functions.

Link: http://lkml.kernel.org/r/20190909114830.662-4-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Oscar Salvador <osalvador@suse.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Qian Cai <cai@lca.pw>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Sasha Levin <sashal@kernel.org>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01 12:59:04 -08:00
David Hildenbrand 18db149120 mm/memory_hotplug: export generic_online_page()
Patch series "mm/memory_hotplug: Export generic_online_page()".

Let's replace the __online_page...() functions by generic_online_page().
Hyper-V only wants to delay the actual onlining of un-backed pages, so
we can simpy re-use the generic function.

This patch (of 3):

Let's expose generic_online_page() so online_page_callback users can
simply fall back to the generic implementation when actually deciding to
online the pages.

Link: http://lkml.kernel.org/r/20190909114830.662-2-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Oscar Salvador <osalvador@suse.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Qian Cai <cai@lca.pw>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Sasha Levin <sashal@kernel.org>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01 12:59:04 -08:00
Alastair D'Silva dca4436d1c mm/memory_hotplug.c: add a bounds check to __add_pages()
On PowerPC, the address ranges allocated to OpenCAPI LPC memory are
allocated from firmware.  These address ranges may be higher than what
older kernels permit, as we increased the maximum permissable address in
commit 4ffe713b75 ("powerpc/mm: Increase the max addressable memory to
2PB").  It is possible that the addressable range may change again in
the future.

In this scenario, we end up with a bogus section returned from
__section_nr (see the discussion on the thread "mm: Trigger bug on if a
section is not found in __section_nr").

Adding a check here means that we fail early and have an opportunity to
handle the error gracefully, rather than rumbling on and potentially
accessing an incorrect section.

Further discussion is also on the thread ("powerpc: Perform a bounds
check in arch_add_memory")
  http://lkml.kernel.org/r/20190827052047.31547-1-alastair@au1.ibm.com

Link: http://lkml.kernel.org/r/20191001004617.7536-2-alastair@au1.ibm.com
Signed-off-by: Alastair D'Silva <alastair@d-silva.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01 12:59:04 -08:00
Anshuman Khandual 32d1fe8fcb mm/hotplug: reorder memblock_[free|remove]() calls in try_remove_memory()
Currently during memory hot add procedure, memory gets into memblock
before calling arch_add_memory() which creates its linear mapping.

  add_memory_resource() {
	..................
	memblock_add_node()
	..................
	arch_add_memory()
	..................
  }

But during memory hot remove procedure, removal from memblock happens
first before its linear mapping gets teared down with
arch_remove_memory() which is not consistent.  Resource removal should
happen in reverse order as they were added.  However this does not pose
any problem for now, unless there is an assumption regarding linear
mapping.  One example was a subtle failure on arm64 platform [1].
Though this has now found a different solution.

  try_remove_memory() {
	..................
	memblock_free()
	memblock_remove()
	..................
	arch_remove_memory()
	..................
  }

This changes the sequence of resource removal including memblock and
linear mapping tear down during memory hot remove which will now be the
reverse order in which they were added during memory hot add.  The
changed removal order looks like the following.

  try_remove_memory() {
	..................
	arch_remove_memory()
	..................
	memblock_free()
	memblock_remove()
	..................
  }

[1] https://patchwork.kernel.org/patch/11127623/

Memory hot remove now works on arm64 without this because a recent
commit 60bb462fc7ad ("drivers/base/node.c: simplify
unregister_memory_block_under_nodes()").

This does not fix a serious problem.  It just removes an inconsistency
while freeing resources during memory hot remove which for now does not
pose a real problem.

David mentioned that re-ordering should still make sense for consistency
purpose (removing stuff in the reverse order they were added).  This
patch is now detached from arm64 hot-remove series.

Michal:

: I would just a note that the inconsistency doesn't pose any problem now
: but if somebody makes any assumptions about linear mappings then it could
: get subtly broken like your example for arm64 which has found a different
: solution in the meantime.

Link: http://lkml.kernel.org/r/1569380273-7708-1-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01 12:59:04 -08:00
Yunfeng Ye 7506851837 mm/memory-failure.c: use page_shift() in add_to_kill()
page_shift() is supported after the commit 94ad933810 ("mm: introduce
page_shift()").

So replace with page_shift() in add_to_kill() for readability.

Link: http://lkml.kernel.org/r/543d8bc9-f2e7-3023-7c35-2e7ed67c0e82@huawei.com
Signed-off-by: Yunfeng Ye <yeyunfeng@huawei.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01 12:59:04 -08:00
Naoya Horiguchi feec24a613 mm, soft-offline: convert parameter to pfn
Currently soft_offline_page() receives struct page, and its sibling
memory_failure() receives pfn.  This discrepancy looks weird and makes
precheck on pfn validity tricky.  So let's align them.

Link: http://lkml.kernel.org/r/20191016234706.GA5493@www9186uo.sakura.ne.jp
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01 12:59:04 -08:00
Jane Chu 996ff7a08d mm/memory-failure.c clean up around tk pre-allocation
add_to_kill() expects the first 'tk' to be pre-allocated, it makes
subsequent allocations on need basis, this makes the code a bit
difficult to read.

Move all the allocation internal to add_to_kill() and drop the **tk
argument.

Link: http://lkml.kernel.org/r/1565112345-28754-2-git-send-email-jane.chu@oracle.com
Signed-off-by: Jane Chu <jane.chu@oracle.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01 12:59:04 -08:00
Nicolas Geoffray 05d351102d mm, memfd: fix COW issue on MAP_PRIVATE and F_SEAL_FUTURE_WRITE mappings
F_SEAL_FUTURE_WRITE has unexpected behavior when used with MAP_PRIVATE:
A private mapping created after the memfd file that gets sealed with
F_SEAL_FUTURE_WRITE loses the copy-on-write at fork behavior, meaning
children and parent share the same memory, even though the mapping is
private.

The reason for this is due to the code below:

  static int shmem_mmap(struct file *file, struct vm_area_struct *vma)
  {
        struct shmem_inode_info *info = SHMEM_I(file_inode(file));

        if (info->seals & F_SEAL_FUTURE_WRITE) {
                /*
                 * New PROT_WRITE and MAP_SHARED mmaps are not allowed when
                 * "future write" seal active.
                 */
                if ((vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_WRITE))
                        return -EPERM;

                /*
                 * Since the F_SEAL_FUTURE_WRITE seals allow for a MAP_SHARED
                 * read-only mapping, take care to not allow mprotect to revert
                 * protections.
                 */
                vma->vm_flags &= ~(VM_MAYWRITE);
        }
        ...
  }

And for the mm to know if a mapping is copy-on-write:

  static inline bool is_cow_mapping(vm_flags_t flags)
  {
        return (flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
  }

The patch fixes the issue by making the mprotect revert protection
happen only for shared mappings.  For private mappings, using mprotect
will have no effect on the seal behavior.

The F_SEAL_FUTURE_WRITE feature was introduced in v5.1 so v5.3.x stable
kernels would need a backport.

[akpm@linux-foundation.org: reflow comment, per Christoph]
Link: http://lkml.kernel.org/r/20191107195355.80608-1-joel@joelfernandes.org
Fixes: ab3948f58f ("mm/memfd: add an F_SEAL_FUTURE_WRITE seal to memfd")
Signed-off-by: Nicolas Geoffray <ngeoffray@google.com>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01 12:59:03 -08:00
Thomas Hellstrom 625110b5e9 mm/memory.c: fix a huge pud insertion race during faulting
A huge pud page can theoretically be faulted in racing with pmd_alloc()
in __handle_mm_fault().  That will lead to pmd_alloc() returning an
invalid pmd pointer.

Fix this by adding a pud_trans_unstable() function similar to
pmd_trans_unstable() and check whether the pud is really stable before
using the pmd pointer.

Race:
  Thread 1:             Thread 2:                 Comment
  create_huge_pud()                               Fallback - not taken.
                        create_huge_pud()         Taken.
  pmd_alloc()                                     Returns an invalid pointer.

This will result in user-visible huge page data corruption.

Note that this was caught during a code audit rather than a real
experienced problem.  It looks to me like the only implementation that
currently creates huge pud pagetable entries is dev_dax_huge_fault()
which doesn't appear to care much about private (COW) mappings or
write-tracking which is, I believe, a prerequisite for create_huge_pud()
falling back on thread 1, but not in thread 2.

Link: http://lkml.kernel.org/r/20191115115808.21181-2-thomas_os@shipmail.org
Fixes: a00cc7d9dd ("mm, x86: add support for PUD-sized transparent hugepages")
Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01 06:29:19 -08:00
Yang Shi 30c4638285 mm/rmap.c: use VM_BUG_ON_PAGE() in __page_check_anon_rmap()
The __page_check_anon_rmap() just calls two BUG_ON()s protected by
CONFIG_DEBUG_VM, the #ifdef could be eliminated by using VM_BUG_ON_PAGE().

Link: http://lkml.kernel.org/r/1573157346-111316-1-git-send-email-yang.shi@linux.alibaba.com
Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01 06:29:19 -08:00
Miles Chen 091e429954 mm/rmap.c: fix outdated comment in page_get_anon_vma()
Replace DESTROY_BY_RCU with SLAB_TYPESAFE_BY_RCU because
SLAB_DESTROY_BY_RCU has been renamed to SLAB_TYPESAFE_BY_RCU by commit
5f0d5a3ae7 ("mm: Rename SLAB_DESTROY_BY_RCU to SLAB_TYPESAFE_BY_RCU")

Link: http://lkml.kernel.org/r/20191017093554.22562-1-miles.chen@mediatek.com
Signed-off-by: Miles Chen <miles.chen@mediatek.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01 06:29:19 -08:00
Vineet Gupta f2400abc78 asm-generic/mm: stub out p{4,u}d_clear_bad() if __PAGETABLE_P{4,U}D_FOLDED
This came up when removing __ARCH_HAS_5LEVEL_HACK for ARC as code bloat.
With this patch we see the following code reduction.

| bloat-o-meter2 vmlinux-D-elide-p4d_free_tlb vmlinux-E-elide-p?d_clear_bad
| add/remove: 0/2 grow/shrink: 0/0 up/down: 0/-40 (-40)
| function                                     old     new   delta
| pud_clear_bad                                 20       -     -20
| p4d_clear_bad                                 20       -     -20
| Total: Before=4136930, After=4136890, chg -1.000000%

Link: http://lkml.kernel.org/r/20191016162400.14796-6-vgupta@synopsys.com
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Will Deacon <will@kernel.org>
Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>
Cc: Nick Piggin <npiggin@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01 06:29:19 -08:00
Gaowei Pu ff68dac6d6 mm/mmap.c: use IS_ERR_VALUE to check return value of get_unmapped_area
get_unmapped_area() returns an address or -errno on failure.  Historically
we have checked for the failure by offset_in_page() which is correct but
quite hard to read.  Newer code started using IS_ERR_VALUE which is much
easier to read.  Convert remaining users of offset_in_page as well.

[mhocko@suse.com: rewrite changelog]
[mhocko@kernel.org: fix mremap.c and uprobes.c sites also]
Link: http://lkml.kernel.org/r/20191012102512.28051-1-pugaowei@gmail.com
Signed-off-by: Gaowei Pu <pugaowei@gmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Yang <richardw.yang@linux.intel.com>
Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: "Jérôme Glisse" <jglisse@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Qian Cai <cai@lca.pw>
Cc: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01 06:29:19 -08:00
Wei Yang 4e4a9eb921 mm/rmap.c: reuse mergeable anon_vma as parent when fork
In __anon_vma_prepare(), we will try to find anon_vma if it is possible to
reuse it.  While on fork, the logic is different.

Since commit 5beb493052 ("mm: change anon_vma linking to fix
multi-process server scalability issue"), function anon_vma_clone() tries
to allocate new anon_vma for child process.  But the logic here will
allocate a new anon_vma for each vma, even in parent this vma is mergeable
and share the same anon_vma with its sibling.  This may do better for
scalability issue, while it is not necessary to do so especially after
interval tree is used.

Commit 7a3ef208e6 ("mm: prevent endless growth of anon_vma hierarchy")
tries to reuse some anon_vma by counting child anon_vma and attached vmas.
While for those mergeable anon_vmas, we can just reuse it and not
necessary to go through the logic.

After this change, kernel build test reduces 20% anon_vma allocation.

Do the same kernel build test, it shows run time in sys reduced 11.6%.

Origin:

real    2m50.467s
user    17m52.002s
sys     1m51.953s

real    2m48.662s
user    17m55.464s
sys     1m50.553s

real    2m51.143s
user    17m59.687s
sys     1m53.600s

Patched:

real	2m39.933s
user	17m1.835s
sys	1m38.802s

real	2m39.321s
user	17m1.634s
sys	1m39.206s

real	2m39.575s
user	17m1.420s
sys	1m38.845s

Link: http://lkml.kernel.org/r/20191011072256.16275-2-richardw.yang@linux.intel.com
Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>
Acked-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: "Jérôme Glisse" <jglisse@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Qian Cai <cai@lca.pw>
Cc: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01 06:29:19 -08:00
Wei Yang 47b390d23b mm/rmap.c: don't reuse anon_vma if we just want a copy
Before commit 7a3ef208e6 ("mm: prevent endless growth of anon_vma
hierarchy"), anon_vma_clone() doesn't change dst->anon_vma.  While after
this commit, anon_vma_clone() will try to reuse an exist one on forking.

But this commit go a little bit further for the case not forking.
anon_vma_clone() is called from __vma_split(), __split_vma(), copy_vma()
and anon_vma_fork().  For the first three places, the purpose here is
get a copy of src and we don't expect to touch dst->anon_vma even it is
NULL.

While after that commit, it is possible to reuse an anon_vma when
dst->anon_vma is NULL.  This is not we intend to have.

This patch stops reuse of anon_vma for non-fork cases.

Link: http://lkml.kernel.org/r/20191011072256.16275-1-richardw.yang@linux.intel.com
Fixes: 7a3ef208e6 ("mm: prevent endless growth of anon_vma hierarchy")
Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>
Acked-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: "Jérôme Glisse" <jglisse@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Qian Cai <cai@lca.pw>
Cc: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01 06:29:19 -08:00
Wei Yang aba6dfb75f mm/mmap.c: rb_parent is not necessary in __vma_link_list()
Now we use rb_parent to get next, while this is not necessary.

When prev is NULL, this means vma should be the first element in the list.
Then next should be current first one (mm->mmap), no matter whether we
have parent or not.

After removing it, the code shows the beauty of symmetry.

Link: http://lkml.kernel.org/r/20190813032656.16625-1-richardw.yang@linux.intel.com
Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01 06:29:19 -08:00
Wei Yang 1b9fc5b24f mm/mmap.c: extract __vma_unlink_list() as counterpart for __vma_link_list()
Just make the code a little easier to read.

Link: http://lkml.kernel.org/r/20191006012636.31521-3-richardw.yang@linux.intel.com
Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01 06:29:19 -08:00
Wei Yang 9d81fbe09a mm/mmap.c: __vma_unlink_prev() is not necessary now
The third parameter of __vma_unlink_common() could differentiate these two
types.  __vma_unlink_prev() is not necessary now.

Link: http://lkml.kernel.org/r/20191006012636.31521-2-richardw.yang@linux.intel.com
Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>

Cc: Christoph Hellwig <hch@infradead.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01 06:29:19 -08:00
Wei Yang 93b343ab2d mm/mmap.c: prev could be retrieved from vma->vm_prev
Currently __vma_unlink_common handles two cases:

  * has_prev
  * or not

When has_prev is false, it is obvious prev is calculated from
vma->vm_prev in __vma_unlink_common.

When has_prev is true, the prev is passed through from __vma_unlink_prev
in __vma_adjust for non-case 8.  And at the beginning next is calculated
from vma->vm_next, which implies vma is next->vm_prev.

The above statement sounds a little complicated, while to think in
another point of view, no matter whether vma and next is swapped, the
mmap link list still preserves its property.  It is proper to access
vma->vm_prev.

Link: http://lkml.kernel.org/r/20191006012636.31521-1-richardw.yang@linux.intel.com
Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01 06:29:19 -08:00
Konstantin Khlebnikov eef1a429f2 mm/swap.c: piggyback lru_add_drain_all() calls
This is a very slow operation.  Right now POSIX_FADV_DONTNEED is the top
user because it has to freeze page references when removing it from the
cache.  invalidate_bdev() calls it for the same reason.  Both are
triggered from userspace, so it's easy to generate a storm.

mlock/mlockall no longer calls lru_add_drain_all - I've seen here
serious slowdown on older kernels.

There are some less obvious paths in memory migration/CMA/offlining
which shouldn't call frequently.

The worst case requires a non-trivial workload because
lru_add_drain_all() skips cpus where vectors are empty.  Something must
constantly generate a flow of pages for each cpu.  Also cpus must be
busy to make scheduling per-cpu works slower.  And the machine must be
big enough (64+ cpus in our case).

In our case that was a massive series of mlock calls in map-reduce while
other tasks write logs (and generates flows of new pages in per-cpu
vectors).  Mlock calls were serialized by mutex and accumulated latency
up to 10 seconds or more.

The kernel does not call lru_add_drain_all on mlock paths since 4.15,
but the same scenario could be triggered by fadvise(POSIX_FADV_DONTNEED)
or any other remaining user.

There is no reason to do the drain again if somebody else already
drained all the per-cpu vectors while we waited for the lock.

Piggyback on a drain starting and finishing while we wait for the lock:
all pages pending at the time of our entry were drained from the
vectors.

Callers like POSIX_FADV_DONTNEED retry their operations once after
draining per-cpu vectors when pages have unexpected references.

Link: http://lkml.kernel.org/r/157019456205.3142.3369423180908482020.stgit@buzz
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01 06:29:19 -08:00
Wei Yang 408a60eddd mm/mmap.c: remove a never-triggered warning in __vma_adjust()
The upper level of "if" makes sure (end >= next->vm_end), which means
there are only two possibilities:

   1) end == next->vm_end
   2) end > next->vm_end

remove_next is assigned to be (1 + end > next->vm_end).  This means if
remove_next is 1, end must equal to next->vm_end.

The VM_WARN_ON will never trigger.

Link: http://lkml.kernel.org/r/20190912063126.13250-1-richardw.yang@linux.intel.com
Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yang Shi <yang.shi@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01 06:29:18 -08:00
Joel Fernandes (Google) e4dcad204d rss_stat: add support to detect RSS updates of external mm
When a process updates the RSS of a different process, the rss_stat
tracepoint appears in the context of the process doing the update.  This
can confuse userspace that the RSS of process doing the update is
updated, while in reality a different process's RSS was updated.

This issue happens in reclaim paths such as with direct reclaim or
background reclaim.

This patch adds more information to the tracepoint about whether the mm
being updated belongs to the current process's context (curr field).  We
also include a hash of the mm pointer so that the process who the mm
belongs to can be uniquely identified (mm_id field).

Also vsprintf.c is refactored a bit to allow reuse of hashing code.

[akpm@linux-foundation.org: remove unused local `str']
[joelaf@google.com: inline call to ptr_to_hashval]
  Link: http://lore.kernel.org/r/20191113153816.14b95acd@gandalf.local.home
  Link: http://lkml.kernel.org/r/20191114164622.GC233237@google.com
Link: http://lkml.kernel.org/r/20191106024452.81923-1-joel@joelfernandes.org
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Reported-by: Ioannis Ilkos <ilkos@google.com>
Acked-by: Petr Mladek <pmladek@suse.com>	[lib/vsprintf.c]
Cc: Tim Murray <timmurray@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Carmen Jackson <carmenjackson@google.com>
Cc: Mayank Gupta <mayankgupta@google.com>
Cc: Daniel Colascione <dancol@google.com>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01 06:29:18 -08:00
Joel Fernandes (Google) b3d1411b67 mm: emit tracepoint when RSS changes
Useful to track how RSS is changing per TGID to detect spikes in RSS and
memory hogs.  Several Android teams have been using this patch in
various kernel trees for half a year now.  Many reported to me it is
really useful so I'm posting it upstream.

Initial patch developed by Tim Murray.  Changes I made from original
patch: o Prevent any additional space consumed by mm_struct.

Regarding the fact that the RSS may change too often thus flooding the
traces - note that, there is some "hysterisis" with this already.  That
is - We update the counter only if we receive 64 page faults due to
SPLIT_RSS_ACCOUNTING.  However, during zapping or copying of pte range,
the RSS is updated immediately which can become noisy/flooding.  In a
previous discussion, we agreed that BPF or ftrace can be used to rate
limit the signal if this becomes an issue.

Also note that I added wrappers to trace_rss_stat to prevent compiler
errors where linux/mm.h is included from tracing code, causing errors
such as:

    CC      kernel/trace/power-traces.o
  In file included from ./include/trace/define_trace.h:102,
                   from ./include/trace/events/kmem.h:342,
                   from ./include/linux/mm.h:31,
                   from ./include/linux/ring_buffer.h:5,
                   from ./include/linux/trace_events.h:6,
                   from ./include/trace/events/power.h:12,
                   from kernel/trace/power-traces.c:15:
  ./include/trace/trace_events.h:113:22: error: field `ent' has incomplete type
     struct trace_entry ent;    \

Link: http://lore.kernel.org/r/20190903200905.198642-1-joel@joelfernandes.org
Link: http://lkml.kernel.org/r/20191001172817.234886-1-joel@joelfernandes.org
Co-developed-by: Tim Murray <timmurray@google.com>
Signed-off-by: Tim Murray <timmurray@google.com>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Carmen Jackson <carmenjackson@google.com>
Cc: Mayank Gupta <mayankgupta@google.com>
Cc: Daniel Colascione <dancol@google.com>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01 06:29:18 -08:00
Kirill A. Shutemov 8897c1b1a1 shmem: pin the file in shmem_fault() if mmap_sem is dropped
syzbot found the following crash:

  BUG: KASAN: use-after-free in perf_trace_lock_acquire+0x401/0x530 include/trace/events/lock.h:13
  Read of size 8 at addr ffff8880a5cf2c50 by task syz-executor.0/26173

  CPU: 0 PID: 26173 Comm: syz-executor.0 Not tainted 5.3.0-rc6 #146
  Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
  Call Trace:
     perf_trace_lock_acquire+0x401/0x530 include/trace/events/lock.h:13
     trace_lock_acquire include/trace/events/lock.h:13 [inline]
     lock_acquire+0x2de/0x410 kernel/locking/lockdep.c:4411
     __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
     _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151
     spin_lock include/linux/spinlock.h:338 [inline]
     shmem_fault+0x5ec/0x7b0 mm/shmem.c:2034
     __do_fault+0x111/0x540 mm/memory.c:3083
     do_shared_fault mm/memory.c:3535 [inline]
     do_fault mm/memory.c:3613 [inline]
     handle_pte_fault mm/memory.c:3840 [inline]
     __handle_mm_fault+0x2adf/0x3f20 mm/memory.c:3964
     handle_mm_fault+0x1b5/0x6b0 mm/memory.c:4001
     do_user_addr_fault arch/x86/mm/fault.c:1441 [inline]
     __do_page_fault+0x536/0xdd0 arch/x86/mm/fault.c:1506
     do_page_fault+0x38/0x590 arch/x86/mm/fault.c:1530
     page_fault+0x39/0x40 arch/x86/entry/entry_64.S:1202

It happens if the VMA got unmapped under us while we dropped mmap_sem
and inode got freed.

Pinning the file if we drop mmap_sem fixes the issue.

Link: http://lkml.kernel.org/r/20190927083908.rhifa4mmaxefc24r@box
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reported-by: syzbot+03ee87124ee05af991bd@syzkaller.appspotmail.com
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01 06:29:18 -08:00
Johannes Weiner 89b15332af mm: drop mmap_sem before calling balance_dirty_pages() in write fault
One of our services is observing hanging ps/top/etc under heavy write
IO, and the task states show this is an mmap_sem priority inversion:

A write fault is holding the mmap_sem in read-mode and waiting for
(heavily cgroup-limited) IO in balance_dirty_pages():

    balance_dirty_pages+0x724/0x905
    balance_dirty_pages_ratelimited+0x254/0x390
    fault_dirty_shared_page.isra.96+0x4a/0x90
    do_wp_page+0x33e/0x400
    __handle_mm_fault+0x6f0/0xfa0
    handle_mm_fault+0xe4/0x200
    __do_page_fault+0x22b/0x4a0
    page_fault+0x45/0x50

Somebody tries to change the address space, contending for the mmap_sem in
write-mode:

    call_rwsem_down_write_failed_killable+0x13/0x20
    do_mprotect_pkey+0xa8/0x330
    SyS_mprotect+0xf/0x20
    do_syscall_64+0x5b/0x100
    entry_SYSCALL_64_after_hwframe+0x3d/0xa2

The waiting writer locks out all subsequent readers to avoid lock
starvation, and several threads can be seen hanging like this:

    call_rwsem_down_read_failed+0x14/0x30
    proc_pid_cmdline_read+0xa0/0x480
    __vfs_read+0x23/0x140
    vfs_read+0x87/0x130
    SyS_read+0x42/0x90
    do_syscall_64+0x5b/0x100
    entry_SYSCALL_64_after_hwframe+0x3d/0xa2

To fix this, do what we do for cache read faults already: drop the
mmap_sem before calling into anything IO bound, in this case the
balance_dirty_pages() function, and return VM_FAULT_RETRY.

Link: http://lkml.kernel.org/r/20190924194238.GA29030@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01 06:29:18 -08:00
Shakeel Butt fa40d1ee9f mm: vmscan: memcontrol: remove mem_cgroup_select_victim_node()
Since commit 1ba6fc9af3 ("mm: vmscan: do not share cgroup iteration
between reclaimers"), the memcg reclaim does not bail out earlier based
on sc->nr_reclaimed and will traverse all the nodes.  All the
reclaimable pages of the memcg on all the nodes will be scanned relative
to the reclaim priority.  So, there is no need to maintain state
regarding which node to start the memcg reclaim from.

This patch effectively reverts the commit 889976dbcb ("memcg: reclaim
memory from nodes in round-robin order") and commit 453a9bf347
("memcg: fix numa scan information update to be triggered by memory
event").

[shakeelb@google.com: v2]
  Link: http://lkml.kernel.org/r/20191030204232.139424-1-shakeelb@google.com
Link: http://lkml.kernel.org/r/20191029234753.224143-1-shakeelb@google.com
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Roman Gushchin <guro@fb.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Greg Thelen <gthelen@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01 06:29:18 -08:00
Johannes Weiner 8c8c383c04 mm: memcontrol: try harder to set a new memory.high
Setting a memory.high limit below the usage makes almost no effort to
shrink the cgroup to the new target size.

While memory.high is a "soft" limit that isn't supposed to cause OOM
situations, we should still try harder to meet a user request through
persistent reclaim.

For example, after setting a 10M memory.high on an 800M cgroup full of
file cache, the usage shrinks to about 350M:

  + cat /cgroup/workingset/memory.current
  841568256
  + echo 10M
  + cat /cgroup/workingset/memory.current
  355729408

This isn't exactly what the user would expect to happen. Setting the
value a few more times eventually whittles the usage down to what we
are asking for:

  + echo 10M
  + cat /cgroup/workingset/memory.current
  104181760
  + echo 10M
  + cat /cgroup/workingset/memory.current
  31801344
  + echo 10M
  + cat /cgroup/workingset/memory.current
  10440704

To improve this, add reclaim retry loops to the memory.high write()
callback, similar to what we do for memory.max, to make a reasonable
effort that the usage meets the requested size after the call returns.

Afterwards, a single write() to memory.high is enough in all but extreme
cases:

  + cat /cgroup/workingset/memory.current
  841609216
  + echo 10M
  + cat /cgroup/workingset/memory.current
  10182656

790M is not a reasonable reclaim target to ask of a single reclaim
invocation.  And it wouldn't be reasonable to optimize the reclaim code
for it.  So asking for the full size but retrying is not a bad choice
here: we express our intent, and benefit if reclaim becomes better at
handling larger requests, but we also acknowledge that some of the
deltas we can encounter in memory_high_write() are just too ridiculously
big for a single reclaim invocation to manage.

Link: http://lkml.kernel.org/r/20191022201518.341216-2-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01 06:29:18 -08:00
Johannes Weiner 7249c9f01d mm: memcontrol: remove dead code from memory_max_write()
When the reclaim loop in memory_max_write() is ^C'd or similar, we set err
to -EINTR.  But we don't return err.  Once the limit is set, we always
return success (nbytes).  Delete the dead code.

Link: http://lkml.kernel.org/r/20191022201518.341216-1-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01 06:29:18 -08:00
Yafang Shao 9da83f3fc7 mm, memcg: clean up reclaim iter array
The mem_cgroup_reclaim_cookie is only used in memcg softlimit reclaim now,
and the priority of the reclaim is always 0.  We don't need to define the
iter in struct mem_cgroup_per_node as an array any more.  That could make
the code more clear and save some space.

Link: http://lkml.kernel.org/r/1569897728-1686-1-git-send-email-laoar.shao@gmail.com
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01 06:29:18 -08:00
Fengguang Wu a1100a7406 mm/swap.c: trivial mark_page_accessed() cleanup
This avoids duplicated PageReferenced() calls.  No behavior change.

Link: http://lkml.kernel.org/r/20191016225326.GB12497@wfg-t540p.sh.intel.com
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Liu Jingqi <jingqi.liu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01 06:29:18 -08:00
Naohiro Aota 12d2966d85 mm, swap: disallow swapon() on zoned block devices
A zoned block device consists of a number of zones.  Zones are either
conventional and accepting random writes or sequential and requiring
that writes be issued in LBA order from each zone write pointer
position.  For the write restriction, zoned block devices are not
suitable for a swap device.  Disallow swapon on them.

[akpm@linux-foundation.org: reflow and reword comment, per Christoph]
Link: http://lkml.kernel.org/r/20191015085814.637837-1-naohiro.aota@wdc.com
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: "Theodore Y. Ts'o" <tytso@mit.edu>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01 06:29:18 -08:00
Liu Xiang d2dfbe47fa mm/gup.c: fix comments of __get_user_pages() and get_user_pages_remote()
Fix comments of __get_user_pages() and get_user_pages_remote(), make
them more clear.

Link: http://lkml.kernel.org/r/1572443533-3118-1-git-send-email-liuxiang_1999@126.com
Signed-off-by: Liu Xiang <liuxiang_1999@126.com>
Suggested-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01 06:29:18 -08:00
zhong jiang b96cc65515 mm/gup.c: allow CMA migration to propagate errors back to caller
check_and_migrate_cma_pages() was recording the result of
__get_user_pages_locked() in an unsigned "nr_pages" variable.

Because __get_user_pages_locked() returns a signed value that can
include negative errno values, this had the effect of hiding errors.

Change check_and_migrate_cma_pages() implementation so that it uses a
signed variable instead, and propagates the results back to the caller
just as other gup internal functions do.

This was discovered with the help of unsigned_lesser_than_zero.cocci.

Link: http://lkml.kernel.org/r/1571671030-58029-1-git-send-email-zhongjiang@huawei.com
Signed-off-by: zhong jiang <zhongjiang@huawei.com>
Suggested-by: John Hubbard <jhubbard@nvidia.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01 06:29:18 -08:00
Konstantin Khlebnikov 9266a14033 mm/filemap.c: warn if stale pagecache is left after direct write
generic_file_direct_write() tries to invalidate pagecache after O_DIRECT
write.  Unlike to similar code in dio_complete() this silently ignores
error returned from invalidate_inode_pages2_range().

According to comment this code here because not all filesystems call
dio_complete() to do proper invalidation after O_DIRECT write.  Noticeable
example is a blkdev_direct_IO().

This patch calls dio_warn_stale_pagecache() if invalidation fails.

Link: http://lkml.kernel.org/r/157270038294.4812.2238891109785106069.stgit@buzz
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01 06:29:18 -08:00
Konstantin Khlebnikov a92853b674 fs/direct-io.c: keep dio_warn_stale_pagecache() when CONFIG_BLOCK=n
This helper prints warning if direct I/O write failed to invalidate cache,
and set EIO at inode to warn usersapce about possible data corruption.

See also commit 5a9d929d6e ("iomap: report collisions between directio
and buffered writes to userspace").

Direct I/O is supported by non-disk filesystems, for example NFS.  Thus
generic code needs this even in kernel without CONFIG_BLOCK.

Link: http://lkml.kernel.org/r/157270038074.4812.7980855544557488880.stgit@buzz
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01 06:29:18 -08:00
Konstantin Khlebnikov 80c1fe9026 mm/filemap.c: remove redundant cache invalidation after async direct-io write
generic_file_direct_write() invalidates cache at entry.  Second time this
should be done when request completes.  But this function calls second
invalidation at exit unconditionally even for async requests.

This patch skips second invalidation for async requests (-EIOCBQUEUED).

Link: http://lkml.kernel.org/r/157270037850.4812.15036239021726025572.stgit@buzz
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01 06:29:18 -08:00
Yu Zhao dd98afd4d6 mm/slub.c: clean up validate_slab()
The function doesn't need to return any value, and the check can be done
in one pass.

There is a behavior change: before the patch, we stop at the first invalid
free object; after the patch, we stop at the first invalid object, free or
in use.  This shouldn't matter because the original behavior isn't
intended anyway.

Link: http://lkml.kernel.org/r/20191108193958.205102-1-yuzhao@google.com
Signed-off-by: Yu Zhao <yuzhao@google.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.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: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01 06:29:18 -08:00
Yu Zhao aed6814894 mm/slub.c: update comments
Slub doesn't use PG_active and PG_error anymore.

Link: http://lkml.kernel.org/r/20191007222023.162256-1-yuzhao@google.com
Signed-off-by: Yu Zhao <yuzhao@google.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01 06:29:18 -08:00
Miles Chen e1b70dd1e6 mm: slub: print the offset of fault addresses
With commit ad67b74d24 ("printk: hash addresses printed with %p"), it
is a little bit harder to match the fault addresses printed by
check_bytes_and_report() or slab_pad_check() in the dump because the
fault addresses may not show up in the dump.

Print the offset of the fault addresses to make it easier to match the
incorrect poison or padding values in the dump.

Before: We have to search the "63" in the dump.  If we want to get the
offset of 63, we have to count it from the start of Object dump.

    =============================================================
    BUG kmalloc-128 (Not tainted): Poison overwritten
    -------------------------------------------------------------

    Disabling lock debugging due to kernel taint
    INFO: 0x00000000570da294-0x00000000570da294.
    First byte 0x63 instead of 0x6b
    ...
    INFO: Object 0x000000006ebb3b9e @offset=14208 fp=0x0000000065862488
    Redzone 00000000a6abccff: bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb
    Redzone 00000000741c16f0: bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb
    Redzone 0000000061ad278f: bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb
    Redzone 000000000467c1bd: bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb
    Redzone 000000008812766b: bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb
    Redzone 000000003d9b8f25: bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb
    Redzone 0000000000d80c33: bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb
    Redzone 00000000867b0d90: bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb
    Object 000000006ebb3b9e: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b
    Object 000000005ea59a9f: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b
    Object 000000003ef8bddc: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b
    Object 000000008190375d: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b
    Object 000000006df7fb32: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b
    Object 0000000069474eae: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b
    Object 0000000008073b7d: 6b 6b 6b 6b 63 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b
    Object 00000000b45ae74d: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b a5

After: We know the fault address is at @offset=1508, and the Object is
at @offset=1408, so we know the fault address is at offset=100 within
the object.

    =========================================================
    BUG kmalloc-128 (Not tainted): Poison overwritten
    ---------------------------------------------------------

    Disabling lock debugging due to kernel taint
    INFO: 0x00000000638ec1d1-0x00000000638ec1d1 @offset=1508.
    First byte 0x63 instead of 0x6b
    ...
    INFO: Object 0x000000008171818d @offset=1408 fp=0x0000000066dae230
    Redzone 00000000e2697ab6: bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb
    Redzone 0000000064b6a381: bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb
    Redzone 00000000e413a234: bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb
    Redzone 0000000004c1dfeb: bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb
    Redzone 000000009ad24d42: bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb
    Redzone 000000002a196a23: bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb
    Redzone 00000000a7b8468a: bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb
    Redzone 0000000088db6da3: bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb
    Object 000000008171818d: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b
    Object 000000007c4035d4: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b
    Object 000000004dd281a4: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b
    Object 0000000079121dff: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b
    Object 00000000756682a9: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b
    Object 0000000053b7e541: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b
    Object 0000000091f8d530: 6b 6b 6b 6b 63 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b
    Object 000000009c76035c: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b a5

Link: http://lkml.kernel.org/r/20190925140807.20490-1-miles.chen@mediatek.com
Signed-off-by: Miles Chen <miles.chen@mediatek.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01 06:29:18 -08:00
Pengfei Li 13657d0ad9 mm, slab_common: use enum kmalloc_cache_type to iterate over kmalloc caches
The type of local variable *type* of new_kmalloc_cache() should be enum
kmalloc_cache_type instead of int, so correct it.

Link: http://lkml.kernel.org/r/1569241648-26908-4-git-send-email-lpf.vector@gmail.com
Signed-off-by: Pengfei Li <lpf.vector@gmail.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Roman Gushchin <guro@fb.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01 06:29:17 -08:00
Pengfei Li dc0a7f7558 mm, slab: remove unused kmalloc_size()
The size of kmalloc can be obtained from kmalloc_info[], so remove
kmalloc_size() that will not be used anymore.

Link: http://lkml.kernel.org/r/1569241648-26908-3-git-send-email-lpf.vector@gmail.com
Signed-off-by: Pengfei Li <lpf.vector@gmail.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Roman Gushchin <guro@fb.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01 06:29:17 -08:00
Pengfei Li cb5d9fb38c mm, slab: make kmalloc_info[] contain all types of names
Patch series "mm, slab: Make kmalloc_info[] contain all types of names", v6.

There are three types of kmalloc, KMALLOC_NORMAL, KMALLOC_RECLAIM
and KMALLOC_DMA.

The name of KMALLOC_NORMAL is contained in kmalloc_info[].name,
but the names of KMALLOC_RECLAIM and KMALLOC_DMA are dynamically
generated by kmalloc_cache_name().

Patch1 predefines the names of all types of kmalloc to save
the time spent dynamically generating names.

These changes make sense, and the time spent by new_kmalloc_cache()
has been reduced by approximately 36.3%.

                         Time spent by new_kmalloc_cache()
                                  (CPU cycles)
5.3-rc7                              66264
5.3-rc7+patch                        42188

This patch (of 3):

There are three types of kmalloc, KMALLOC_NORMAL, KMALLOC_RECLAIM and
KMALLOC_DMA.

The name of KMALLOC_NORMAL is contained in kmalloc_info[].name, but the
names of KMALLOC_RECLAIM and KMALLOC_DMA are dynamically generated by
kmalloc_cache_name().

This patch predefines the names of all types of kmalloc to save the time
spent dynamically generating names.

Besides, remove the kmalloc_cache_name() that is no longer used.

Link: http://lkml.kernel.org/r/1569241648-26908-2-git-send-email-lpf.vector@gmail.com
Signed-off-by: Pengfei Li <lpf.vector@gmail.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Roman Gushchin <guro@fb.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-01 06:29:17 -08:00
Linus Torvalds aa32f11691 hmm related patches for 5.5
This is another round of bug fixing and cleanup. This time the focus is on
 the driver pattern to use mmu notifiers to monitor a VA range. This code
 is lifted out of many drivers and hmm_mirror directly into the
 mmu_notifier core and written using the best ideas from all the driver
 implementations.
 
 This removes many bugs from the drivers and has a very pleasing
 diffstat. More drivers can still be converted, but that is for another
 cycle.
 
 - A shared branch with RDMA reworking the RDMA ODP implementation
 
 - New mmu_interval_notifier API. This is focused on the use case of
   monitoring a VA and simplifies the process for drivers
 
 - A common seq-count locking scheme built into the mmu_interval_notifier
   API usable by drivers that call get_user_pages() or hmm_range_fault()
   with the VA range
 
 - Conversion of mlx5 ODP, hfi1, radeon, nouveau, AMD GPU, and Xen GntDev
   drivers to the new API. This deletes a lot of wonky driver code.
 
 - Two improvements for hmm_range_fault(), from testing done by Ralph
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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:
 "This is another round of bug fixing and cleanup. This time the focus
  is on the driver pattern to use mmu notifiers to monitor a VA range.
  This code is lifted out of many drivers and hmm_mirror directly into
  the mmu_notifier core and written using the best ideas from all the
  driver implementations.

  This removes many bugs from the drivers and has a very pleasing
  diffstat. More drivers can still be converted, but that is for another
  cycle.

   - A shared branch with RDMA reworking the RDMA ODP implementation

   - New mmu_interval_notifier API. This is focused on the use case of
     monitoring a VA and simplifies the process for drivers

   - A common seq-count locking scheme built into the
     mmu_interval_notifier API usable by drivers that call
     get_user_pages() or hmm_range_fault() with the VA range

   - Conversion of mlx5 ODP, hfi1, radeon, nouveau, AMD GPU, and Xen
     GntDev drivers to the new API. This deletes a lot of wonky driver
     code.

   - Two improvements for hmm_range_fault(), from testing done by Ralph"

* tag 'for-linus-hmm' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma:
  mm/hmm: remove hmm_range_dma_map and hmm_range_dma_unmap
  mm/hmm: make full use of walk_page_range()
  xen/gntdev: use mmu_interval_notifier_insert
  mm/hmm: remove hmm_mirror and related
  drm/amdgpu: Use mmu_interval_notifier instead of hmm_mirror
  drm/amdgpu: Use mmu_interval_insert instead of hmm_mirror
  drm/amdgpu: Call find_vma under mmap_sem
  nouveau: use mmu_interval_notifier instead of hmm_mirror
  nouveau: use mmu_notifier directly for invalidate_range_start
  drm/radeon: use mmu_interval_notifier_insert
  RDMA/hfi1: Use mmu_interval_notifier_insert for user_exp_rcv
  RDMA/odp: Use mmu_interval_notifier_insert()
  mm/hmm: define the pre-processor related parts of hmm.h even if disabled
  mm/hmm: allow hmm_range to be used with a mmu_interval_notifier or hmm_mirror
  mm/mmu_notifier: add an interval tree notifier
  mm/mmu_notifier: define the header pre-processor parts even if disabled
  mm/hmm: allow snapshot of the special zero page
2019-11-30 10:33:14 -08:00
Linus Torvalds d5bb349dbb mm + drm coherent memory support for vmwgfx
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Merge tag 'drm-vmwgfx-coherent-2019-11-29' of git://anongit.freedesktop.org/drm/drm

Pull drm coherent memory support for vmwgfx from Dave Airlie:
 "This is a separate pull for the mm pagewalking + drm/vmwgfx work
  Thomas did and you were involved in, I've left it separate in case you
  don't feel as comfortable with it as the other stuff.

  It has mm acks/r-b in the right places from what I can see"

* tag 'drm-vmwgfx-coherent-2019-11-29' of git://anongit.freedesktop.org/drm/drm:
  drm/vmwgfx: Add surface dirty-tracking callbacks
  drm/vmwgfx: Implement an infrastructure for read-coherent resources
  drm/vmwgfx: Use an RBtree instead of linked list for MOB resources
  drm/vmwgfx: Implement an infrastructure for write-coherent resources
  mm: Add write-protect and clean utilities for address space ranges
  mm: Add a walk_page_mapping() function to the pagewalk code
  mm: pagewalk: Take the pagetable lock in walk_pte_range()
  mm: Remove BUG_ON mmap_sem not held from xxx_trans_huge_lock()
  drm/ttm: Convert vm callbacks to helpers
  drm/ttm: Remove explicit typecasts of vm_private_data
2019-11-30 09:38:11 -08:00
Dave Airlie 0a6cad5df5 Merge branch 'vmwgfx-coherent' of git://people.freedesktop.org/~thomash/linux into drm-next
Graphics APIs like OpenGL 4.4 and Vulkan require the graphics driver
to provide coherent graphics memory, meaning that the GPU sees any
content written to the coherent memory on the next GPU operation that
touches that memory, and the CPU sees any content written by the GPU
to that memory immediately after any fence object trailing the GPU
operation is signaled.

Paravirtual drivers that otherwise require explicit synchronization
needs to do this by hooking up dirty tracking to pagefault handlers
and buffer object validation.

Provide mm helpers needed for this and that also allow for huge pmd-
and pud entries (patch 1-3), and the associated vmwgfx code (patch 4-7).

The code has been tested and exercised by a tailored version of mesa
where we disable all explicit synchronization and assume graphics memory
is coherent. The performance loss varies of course; a typical number is
around 5%.

Signed-off-by: Dave Airlie <airlied@redhat.com>
From: Thomas Hellstrom <thomas_os@shipmail.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20191113131639.4653-1-thomas_os@shipmail.org
2019-11-28 14:33:01 +10:00
Linus Torvalds 168829ad09 Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking updates from Ingo Molnar:
 "The main changes in this cycle were:

   - A comprehensive rewrite of the robust/PI futex code's exit handling
     to fix various exit races. (Thomas Gleixner et al)

   - Rework the generic REFCOUNT_FULL implementation using
     atomic_fetch_* operations so that the performance impact of the
     cmpxchg() loops is mitigated for common refcount operations.

     With these performance improvements the generic implementation of
     refcount_t should be good enough for everybody - and this got
     confirmed by performance testing, so remove ARCH_HAS_REFCOUNT and
     REFCOUNT_FULL entirely, leaving the generic implementation enabled
     unconditionally. (Will Deacon)

   - Other misc changes, fixes, cleanups"

* 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (27 commits)
  lkdtm: Remove references to CONFIG_REFCOUNT_FULL
  locking/refcount: Remove unused 'refcount_error_report()' function
  locking/refcount: Consolidate implementations of refcount_t
  locking/refcount: Consolidate REFCOUNT_{MAX,SATURATED} definitions
  locking/refcount: Move saturation warnings out of line
  locking/refcount: Improve performance of generic REFCOUNT_FULL code
  locking/refcount: Move the bulk of the REFCOUNT_FULL implementation into the <linux/refcount.h> header
  locking/refcount: Remove unused refcount_*_checked() variants
  locking/refcount: Ensure integer operands are treated as signed
  locking/refcount: Define constants for saturation and max refcount values
  futex: Prevent exit livelock
  futex: Provide distinct return value when owner is exiting
  futex: Add mutex around futex exit
  futex: Provide state handling for exec() as well
  futex: Sanitize exit state handling
  futex: Mark the begin of futex exit explicitly
  futex: Set task::futex_state to DEAD right after handling futex exit
  futex: Split futex_mm_release() for exit/exec
  exit/exec: Seperate mm_release()
  futex: Replace PF_EXITPIDONE with a state
  ...
2019-11-26 16:02:40 -08:00
Linus Torvalds 386403a115 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next
Pull networking updates from David Miller:
 "Another merge window, another pull full of stuff:

   1) Support alternative names for network devices, from Jiri Pirko.

   2) Introduce per-netns netdev notifiers, also from Jiri Pirko.

   3) Support MSG_PEEK in vsock/virtio, from Matias Ezequiel Vara
      Larsen.

   4) Allow compiling out the TLS TOE code, from Jakub Kicinski.

   5) Add several new tracepoints to the kTLS code, also from Jakub.

   6) Support set channels ethtool callback in ena driver, from Sameeh
      Jubran.

   7) New SCTP events SCTP_ADDR_ADDED, SCTP_ADDR_REMOVED,
      SCTP_ADDR_MADE_PRIM, and SCTP_SEND_FAILED_EVENT. From Xin Long.

   8) Add XDP support to mvneta driver, from Lorenzo Bianconi.

   9) Lots of netfilter hw offload fixes, cleanups and enhancements,
      from Pablo Neira Ayuso.

  10) PTP support for aquantia chips, from Egor Pomozov.

  11) Add UDP segmentation offload support to igb, ixgbe, and i40e. From
      Josh Hunt.

  12) Add smart nagle to tipc, from Jon Maloy.

  13) Support L2 field rewrite by TC offloads in bnxt_en, from Venkat
      Duvvuru.

  14) Add a flow mask cache to OVS, from Tonghao Zhang.

  15) Add XDP support to ice driver, from Maciej Fijalkowski.

  16) Add AF_XDP support to ice driver, from Krzysztof Kazimierczak.

  17) Support UDP GSO offload in atlantic driver, from Igor Russkikh.

  18) Support it in stmmac driver too, from Jose Abreu.

  19) Support TIPC encryption and auth, from Tuong Lien.

  20) Introduce BPF trampolines, from Alexei Starovoitov.

  21) Make page_pool API more numa friendly, from Saeed Mahameed.

  22) Introduce route hints to ipv4 and ipv6, from Paolo Abeni.

  23) Add UDP segmentation offload to cxgb4, Rahul Lakkireddy"

* git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1857 commits)
  libbpf: Fix usage of u32 in userspace code
  mm: Implement no-MMU variant of vmalloc_user_node_flags
  slip: Fix use-after-free Read in slip_open
  net: dsa: sja1105: fix sja1105_parse_rgmii_delays()
  macvlan: schedule bc_work even if error
  enetc: add support Credit Based Shaper(CBS) for hardware offload
  net: phy: add helpers phy_(un)lock_mdio_bus
  mdio_bus: don't use managed reset-controller
  ax88179_178a: add ethtool_op_get_ts_info()
  mlxsw: spectrum_router: Fix use of uninitialized adjacency index
  mlxsw: spectrum_router: After underlay moves, demote conflicting tunnels
  bpf: Simplify __bpf_arch_text_poke poke type handling
  bpf: Introduce BPF_TRACE_x helper for the tracing tests
  bpf: Add bpf_jit_blinding_enabled for !CONFIG_BPF_JIT
  bpf, testing: Add various tail call test cases
  bpf, x86: Emit patchable direct jump as tail call
  bpf: Constant map key tracking for prog array pokes
  bpf: Add poke dependency tracking for prog array maps
  bpf: Add initial poke descriptor table for jit images
  bpf: Move owner type, jited info into array auxiliary data
  ...
2019-11-25 20:02:57 -08:00
Linus Torvalds 4ba380f616 arm64 updates for 5.5:
- On ARMv8 CPUs without hardware updates of the access flag, avoid
   failing cow_user_page() on PFN mappings if the pte is old. The patches
   introduce an arch_faults_on_old_pte() macro, defined as false on x86.
   When true, cow_user_page() makes the pte young before attempting
   __copy_from_user_inatomic().
 
 - Covert the synchronous exception handling paths in
   arch/arm64/kernel/entry.S to C.
 
 - FTRACE_WITH_REGS support for arm64.
 
 - ZONE_DMA re-introduced on arm64 to support Raspberry Pi 4
 
 - Several kselftest cases specific to arm64, together with a MAINTAINERS
   update for these files (moved to the ARM64 PORT entry).
 
 - Workaround for a Neoverse-N1 erratum where the CPU may fetch stale
   instructions under certain conditions.
 
 - Workaround for Cortex-A57 and A72 errata where the CPU may
   speculatively execute an AT instruction and associate a VMID with the
   wrong guest page tables (corrupting the TLB).
 
 - Perf updates for arm64: additional PMU topologies on HiSilicon
   platforms, support for CCN-512 interconnect, AXI ID filtering in the
   IMX8 DDR PMU, support for the CCPI2 uncore PMU in ThunderX2.
 
 - GICv3 optimisation to avoid a heavy barrier when accessing the
   ICC_PMR_EL1 register.
 
 - ELF HWCAP documentation updates and clean-up.
 
 - SMC calling convention conduit code clean-up.
 
 - KASLR diagnostics printed during boot
 
 - NVIDIA Carmel CPU added to the KPTI whitelist
 
 - Some arm64 mm clean-ups: use generic free_initrd_mem(), remove stale
   macro, simplify calculation in __create_pgd_mapping(), typos.
 
 - Kconfig clean-ups: CMDLINE_FORCE to depend on CMDLINE, choice for
   endinanness to help with allmodconfig.
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Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

Pull arm64 updates from Catalin Marinas:
 "Apart from the arm64-specific bits (core arch and perf, new arm64
  selftests), it touches the generic cow_user_page() (reviewed by
  Kirill) together with a macro for x86 to preserve the existing
  behaviour on this architecture.

  Summary:

   - On ARMv8 CPUs without hardware updates of the access flag, avoid
     failing cow_user_page() on PFN mappings if the pte is old. The
     patches introduce an arch_faults_on_old_pte() macro, defined as
     false on x86. When true, cow_user_page() makes the pte young before
     attempting __copy_from_user_inatomic().

   - Covert the synchronous exception handling paths in
     arch/arm64/kernel/entry.S to C.

   - FTRACE_WITH_REGS support for arm64.

   - ZONE_DMA re-introduced on arm64 to support Raspberry Pi 4

   - Several kselftest cases specific to arm64, together with a
     MAINTAINERS update for these files (moved to the ARM64 PORT entry).

   - Workaround for a Neoverse-N1 erratum where the CPU may fetch stale
     instructions under certain conditions.

   - Workaround for Cortex-A57 and A72 errata where the CPU may
     speculatively execute an AT instruction and associate a VMID with
     the wrong guest page tables (corrupting the TLB).

   - Perf updates for arm64: additional PMU topologies on HiSilicon
     platforms, support for CCN-512 interconnect, AXI ID filtering in
     the IMX8 DDR PMU, support for the CCPI2 uncore PMU in ThunderX2.

   - GICv3 optimisation to avoid a heavy barrier when accessing the
     ICC_PMR_EL1 register.

   - ELF HWCAP documentation updates and clean-up.

   - SMC calling convention conduit code clean-up.

   - KASLR diagnostics printed during boot

   - NVIDIA Carmel CPU added to the KPTI whitelist

   - Some arm64 mm clean-ups: use generic free_initrd_mem(), remove
     stale macro, simplify calculation in __create_pgd_mapping(), typos.

   - Kconfig clean-ups: CMDLINE_FORCE to depend on CMDLINE, choice for
     endinanness to help with allmodconfig"

* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (93 commits)
  arm64: Kconfig: add a choice for endianness
  kselftest: arm64: fix spelling mistake "contiguos" -> "contiguous"
  arm64: Kconfig: make CMDLINE_FORCE depend on CMDLINE
  MAINTAINERS: Add arm64 selftests to the ARM64 PORT entry
  arm64: kaslr: Check command line before looking for a seed
  arm64: kaslr: Announce KASLR status on boot
  kselftest: arm64: fake_sigreturn_misaligned_sp
  kselftest: arm64: fake_sigreturn_bad_size
  kselftest: arm64: fake_sigreturn_duplicated_fpsimd
  kselftest: arm64: fake_sigreturn_missing_fpsimd
  kselftest: arm64: fake_sigreturn_bad_size_for_magic0
  kselftest: arm64: fake_sigreturn_bad_magic
  kselftest: arm64: add helper get_current_context
  kselftest: arm64: extend test_init functionalities
  kselftest: arm64: mangle_pstate_invalid_mode_el[123][ht]
  kselftest: arm64: mangle_pstate_invalid_daif_bits
  kselftest: arm64: mangle_pstate_invalid_compat_toggle and common utils
  kselftest: arm64: extend toplevel skeleton Makefile
  drivers/perf: hisi: update the sccl_id/ccl_id for certain HiSilicon platform
  arm64: mm: reserve CMA and crashkernel in ZONE_DMA32
  ...
2019-11-25 15:39:19 -08:00
Andrii Nakryiko ed81745a4c mm: Implement no-MMU variant of vmalloc_user_node_flags
To fix build with !CONFIG_MMU, implement it for no-MMU configurations as well.

Fixes: fc9702273e ("bpf: Add mmap() support for BPF_MAP_TYPE_ARRAY")
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20191123220835.1237773-1-andriin@fb.com
2019-11-25 13:49:59 -08:00
Christoph Hellwig 93f4e735b6 mm/hmm: remove hmm_range_dma_map and hmm_range_dma_unmap
These two functions have never been used since they were added.

Link: https://lore.kernel.org/r/20191113134528.21187-1-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2019-11-23 19:56:45 -04:00
Ralph Campbell d28c2c9a48 mm/hmm: make full use of walk_page_range()
hmm_range_fault() calls find_vma() and walk_page_range() in a loop.  This
is unnecessary duplication since walk_page_range() calls find_vma() in a
loop already.

Simplify hmm_range_fault() by defining a walk_test() callback function to
filter unhandled vmas.

This also fixes a bug where hmm_range_fault() was not checking start >=
vma->vm_start before checking vma->vm_flags so hmm_range_fault() could
return an error based on the wrong vma for the requested range.

It also fixes a bug when the vma has no read access and the caller did not
request a fault, there shouldn't be any error return code.

Link: https://lore.kernel.org/r/20191104222141.5173-2-rcampbell@nvidia.com
Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2019-11-23 19:56:45 -04:00
Jason Gunthorpe a22dd50640 mm/hmm: remove hmm_mirror and related
The only two users of this are now converted to use mmu_interval_notifier,
delete all the code and update hmm.rst.

Link: https://lore.kernel.org/r/20191112202231.3856-14-jgg@ziepe.ca
Reviewed-by: Jérôme Glisse <jglisse@redhat.com>
Tested-by: Ralph Campbell <rcampbell@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2019-11-23 19:56:45 -04:00
Jason Gunthorpe 04ec32fbc2 mm/hmm: allow hmm_range to be used with a mmu_interval_notifier or hmm_mirror
hmm_mirror's handling of ranges does not use a sequence count which
results in this bug:

         CPU0                                   CPU1
                                     hmm_range_wait_until_valid(range)
                                         valid == true
                                     hmm_range_fault(range)
hmm_invalidate_range_start()
   range->valid = false
hmm_invalidate_range_end()
   range->valid = true
                                     hmm_range_valid(range)
                                          valid == true

Where the hmm_range_valid() should not have succeeded.

Adding the required sequence count would make it nearly identical to the
new mmu_interval_notifier. Instead replace the hmm_mirror stuff with
mmu_interval_notifier.

Co-existence of the two APIs is the first step.

Link: https://lore.kernel.org/r/20191112202231.3856-4-jgg@ziepe.ca
Reviewed-by: Jérôme Glisse <jglisse@redhat.com>
Tested-by: Philip Yang <Philip.Yang@amd.com>
Tested-by: Ralph Campbell <rcampbell@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2019-11-23 19:56:44 -04:00
Jason Gunthorpe 99cb252f5e mm/mmu_notifier: add an interval tree notifier
Of the 13 users of mmu_notifiers, 8 of them use only
invalidate_range_start/end() and immediately intersect the
mmu_notifier_range with some kind of internal list of VAs.  4 use an
interval tree (i915_gem, radeon_mn, umem_odp, hfi1). 4 use a linked list
of some kind (scif_dma, vhost, gntdev, hmm)

And the remaining 5 either don't use invalidate_range_start() or do some
special thing with it.

It turns out that building a correct scheme with an interval tree is
pretty complicated, particularly if the use case is synchronizing against
another thread doing get_user_pages().  Many of these implementations have
various subtle and difficult to fix races.

This approach puts the interval tree as common code at the top of the mmu
notifier call tree and implements a shareable locking scheme.

It includes:
 - An interval tree tracking VA ranges, with per-range callbacks
 - A read/write locking scheme for the interval tree that avoids
   sleeping in the notifier path (for OOM killer)
 - A sequence counter based collision-retry locking scheme to tell
   device page fault that a VA range is being concurrently invalidated.

This is based on various ideas:
- hmm accumulates invalidated VA ranges and releases them when all
  invalidates are done, via active_invalidate_ranges count.
  This approach avoids having to intersect the interval tree twice (as
  umem_odp does) at the potential cost of a longer device page fault.

- kvm/umem_odp use a sequence counter to drive the collision retry,
  via invalidate_seq

- a deferred work todo list on unlock scheme like RTNL, via deferred_list.
  This makes adding/removing interval tree members more deterministic

- seqlock, except this version makes the seqlock idea multi-holder on the
  write side by protecting it with active_invalidate_ranges and a spinlock

To minimize MM overhead when only the interval tree is being used, the
entire SRCU and hlist overheads are dropped using some simple
branches. Similarly the interval tree overhead is dropped when in hlist
mode.

The overhead from the mandatory spinlock is broadly the same as most of
existing users which already had a lock (or two) of some sort on the
invalidation path.

Link: https://lore.kernel.org/r/20191112202231.3856-3-jgg@ziepe.ca
Acked-by: Christian König <christian.koenig@amd.com>
Tested-by: Philip Yang <Philip.Yang@amd.com>
Tested-by: Ralph Campbell <rcampbell@nvidia.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2019-11-23 19:56:44 -04:00
Jakub Kicinski a9f852e92e Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Minor conflict in drivers/s390/net/qeth_l2_main.c, kept the lock
from commit c8183f5489 ("s390/qeth: fix potential deadlock on
workqueue flush"), removed the code which was removed by commit
9897d583b0 ("s390/qeth: consolidate some duplicated HW cmd code").

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
2019-11-22 16:27:24 -08:00
Andrey Ryabinin 9a63236f1a mm/ksm.c: don't WARN if page is still mapped in remove_stable_node()
It's possible to hit the WARN_ON_ONCE(page_mapped(page)) in
remove_stable_node() when it races with __mmput() and squeezes in
between ksm_exit() and exit_mmap().

  WARNING: CPU: 0 PID: 3295 at mm/ksm.c:888 remove_stable_node+0x10c/0x150

  Call Trace:
   remove_all_stable_nodes+0x12b/0x330
   run_store+0x4ef/0x7b0
   kernfs_fop_write+0x200/0x420
   vfs_write+0x154/0x450
   ksys_write+0xf9/0x1d0
   do_syscall_64+0x99/0x510
   entry_SYSCALL_64_after_hwframe+0x49/0xbe

Remove the warning as there is nothing scary going on.

Link: http://lkml.kernel.org/r/20191119131850.5675-1-aryabinin@virtuozzo.com
Fixes: cbf86cfe04 ("ksm: remove old stable nodes more thoroughly")
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-11-22 09:11:18 -08:00
David Hildenbrand 7ce700bf11 mm/memory_hotplug: don't access uninitialized memmaps in shrink_zone_span()
Let's limit shrinking to !ZONE_DEVICE so we can fix the current code.
We should never try to touch the memmap of offline sections where we
could have uninitialized memmaps and could trigger BUGs when calling
page_to_nid() on poisoned pages.

There is no reliable way to distinguish an uninitialized memmap from an
initialized memmap that belongs to ZONE_DEVICE, as we don't have
anything like SECTION_IS_ONLINE we can use similar to
pfn_to_online_section() for !ZONE_DEVICE memory.

E.g., set_zone_contiguous() similarly relies on pfn_to_online_section()
and will therefore never set a ZONE_DEVICE zone consecutive.  Stopping
to shrink the ZONE_DEVICE therefore results in no observable changes,
besides /proc/zoneinfo indicating different boundaries - something we
can totally live with.

Before commit d0dc12e86b ("mm/memory_hotplug: optimize memory
hotplug"), the memmap was initialized with 0 and the node with the right
value.  So the zone might be wrong but not garbage.  After that commit,
both the zone and the node will be garbage when touching uninitialized
memmaps.

Toshiki reported a BUG (race between delayed initialization of
ZONE_DEVICE memmaps without holding the memory hotplug lock and
concurrent zone shrinking).

  https://lkml.org/lkml/2019/11/14/1040

"Iteration of create and destroy namespace causes the panic as below:

      kernel BUG at mm/page_alloc.c:535!
      CPU: 7 PID: 2766 Comm: ndctl Not tainted 5.4.0-rc4 #6
      Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.11.0-0-g63451fca13-prebuilt.qemu-project.org 04/01/2014
      RIP: 0010:set_pfnblock_flags_mask+0x95/0xf0
      Call Trace:
       memmap_init_zone_device+0x165/0x17c
       memremap_pages+0x4c1/0x540
       devm_memremap_pages+0x1d/0x60
       pmem_attach_disk+0x16b/0x600 [nd_pmem]
       nvdimm_bus_probe+0x69/0x1c0
       really_probe+0x1c2/0x3e0
       driver_probe_device+0xb4/0x100
       device_driver_attach+0x4f/0x60
       bind_store+0xc9/0x110
       kernfs_fop_write+0x116/0x190
       vfs_write+0xa5/0x1a0
       ksys_write+0x59/0xd0
       do_syscall_64+0x5b/0x180
       entry_SYSCALL_64_after_hwframe+0x44/0xa9

  While creating a namespace and initializing memmap, if you destroy the
  namespace and shrink the zone, it will initialize the memmap outside
  the zone and trigger VM_BUG_ON_PAGE(!zone_spans_pfn(page_zone(page),
  pfn), page) in set_pfnblock_flags_mask()."

This BUG is also mitigated by this commit, where we for now stop to
shrink the ZONE_DEVICE zone until we can do it in a safe and clean way.

Link: http://lkml.kernel.org/r/20191006085646.5768-5-david@redhat.com
Fixes: f1dd2cd13c ("mm, memory_hotplug: do not associate hotadded memory to zones until online")	[visible after d0dc12e86b]
Signed-off-by: David Hildenbrand <david@redhat.com>
Reported-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Reported-by: Toshiki Fukasawa <t-fukasawa@vx.jp.nec.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: David Hildenbrand <david@redhat.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Damian Tometzki <damian.tometzki@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Halil Pasic <pasic@linux.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jun Yao <yaojun8558363@gmail.com>
Cc: Logan Gunthorpe <logang@deltatee.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Pankaj Gupta <pagupta@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Pavel Tatashin <pavel.tatashin@microsoft.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Qian Cai <cai@lca.pw>
Cc: Rich Felker <dalias@libc.org>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Steve Capper <steve.capper@arm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Wei Yang <richardw.yang@linux.intel.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Yu Zhao <yuzhao@google.com>
Cc: <stable@vger.kernel.org>	[4.13+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-11-22 09:11:18 -08:00
David S. Miller ee5a489fd9 Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next
Daniel Borkmann says:

====================
pull-request: bpf-next 2019-11-20

The following pull-request contains BPF updates for your *net-next* tree.

We've added 81 non-merge commits during the last 17 day(s) which contain
a total of 120 files changed, 4958 insertions(+), 1081 deletions(-).

There are 3 trivial conflicts, resolve it by always taking the chunk from
196e8ca74886c433:

<<<<<<< HEAD
=======
void *bpf_map_area_mmapable_alloc(u64 size, int numa_node);
>>>>>>> 196e8ca748

<<<<<<< HEAD
void *bpf_map_area_alloc(u64 size, int numa_node)
=======
static void *__bpf_map_area_alloc(u64 size, int numa_node, bool mmapable)
>>>>>>> 196e8ca748

<<<<<<< HEAD
        if (size <= (PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER)) {
=======
        /* kmalloc()'ed memory can't be mmap()'ed */
        if (!mmapable && size <= (PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER)) {
>>>>>>> 196e8ca748

The main changes are:

1) Addition of BPF trampoline which works as a bridge between kernel functions,
   BPF programs and other BPF programs along with two new use cases: i) fentry/fexit
   BPF programs for tracing with practically zero overhead to call into BPF (as
   opposed to k[ret]probes) and ii) attachment of the former to networking related
   programs to see input/output of networking programs (covering xdpdump use case),
   from Alexei Starovoitov.

2) BPF array map mmap support and use in libbpf for global data maps; also a big
   batch of libbpf improvements, among others, support for reading bitfields in a
   relocatable manner (via libbpf's CO-RE helper API), from Andrii Nakryiko.

3) Extend s390x JIT with usage of relative long jumps and loads in order to lift
   the current 64/512k size limits on JITed BPF programs there, from Ilya Leoshkevich.

4) Add BPF audit support and emit messages upon successful prog load and unload in
   order to have a timeline of events, from Daniel Borkmann and Jiri Olsa.

5) Extension to libbpf and xdpsock sample programs to demo the shared umem mode
   (XDP_SHARED_UMEM) as well as RX-only and TX-only sockets, from Magnus Karlsson.

6) Several follow-up bug fixes for libbpf's auto-pinning code and a new API
   call named bpf_get_link_xdp_info() for retrieving the full set of prog
   IDs attached to XDP, from Toke Høiland-Jørgensen.

7) Add BTF support for array of int, array of struct and multidimensional arrays
   and enable it for skb->cb[] access in kfree_skb test, from Martin KaFai Lau.

8) Fix AF_XDP by using the correct number of channels from ethtool, from Luigi Rizzo.

9) Two fixes for BPF selftest to get rid of a hang in test_tc_tunnel and to avoid
   xdping to be run as standalone, from Jiri Benc.

10) Various BPF selftest fixes when run with latest LLVM trunk, from Yonghong Song.

11) Fix a memory leak in BPF fentry test run data, from Colin Ian King.

12) Various smaller misc cleanups and improvements mostly all over BPF selftests and
    samples, from Daniel T. Lee, Andre Guedes, Anders Roxell, Mao Wenan, Yue Haibing.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
2019-11-20 18:11:23 -08:00
Andrii Nakryiko fc9702273e bpf: Add mmap() support for BPF_MAP_TYPE_ARRAY
Add ability to memory-map contents of BPF array map. This is extremely useful
for working with BPF global data from userspace programs. It allows to avoid
typical bpf_map_{lookup,update}_elem operations, improving both performance
and usability.

There had to be special considerations for map freezing, to avoid having
writable memory view into a frozen map. To solve this issue, map freezing and
mmap-ing is happening under mutex now:
  - if map is already frozen, no writable mapping is allowed;
  - if map has writable memory mappings active (accounted in map->writecnt),
    map freezing will keep failing with -EBUSY;
  - once number of writable memory mappings drops to zero, map freezing can be
    performed again.

Only non-per-CPU plain arrays are supported right now. Maps with spinlocks
can't be memory mapped either.

For BPF_F_MMAPABLE array, memory allocation has to be done through vmalloc()
to be mmap()'able. We also need to make sure that array data memory is
page-sized and page-aligned, so we over-allocate memory in such a way that
struct bpf_array is at the end of a single page of memory with array->value
being aligned with the start of the second page. On deallocation we need to
accomodate this memory arrangement to free vmalloc()'ed memory correctly.

One important consideration regarding how memory-mapping subsystem functions.
Memory-mapping subsystem provides few optional callbacks, among them open()
and close().  close() is called for each memory region that is unmapped, so
that users can decrease their reference counters and free up resources, if
necessary. open() is *almost* symmetrical: it's called for each memory region
that is being mapped, **except** the very first one. So bpf_map_mmap does
initial refcnt bump, while open() will do any extra ones after that. Thus
number of close() calls is equal to number of open() calls plus one more.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Song Liu <songliubraving@fb.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Link: https://lore.kernel.org/bpf/20191117172806.2195367-4-andriin@fb.com
2019-11-18 11:41:59 +01:00
David S. Miller 19b7e21c55 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Lots of overlapping changes and parallel additions, stuff
like that.

Signed-off-by: David S. Miller <davem@davemloft.net>
2019-11-16 21:51:42 -08:00
Ralph Campbell 6855ac4acd mm/debug.c: PageAnon() is true for PageKsm() pages
PageAnon() and PageKsm() use the low two bits of the page->mapping
pointer to indicate the page type.  PageAnon() only checks the LSB while
PageKsm() checks the least significant 2 bits are equal to 3.

Therefore, PageAnon() is true for KSM pages.  __dump_page() incorrectly
will never print "ksm" because it checks PageAnon() first.  Fix this by
checking PageKsm() first.

Link: http://lkml.kernel.org/r/20191113000651.20677-1-rcampbell@nvidia.com
Fixes: 1c6fb1d89e ("mm: print more information about mapping in __dump_page")
Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-11-15 18:34:00 -08:00
Ralph Campbell 76a1850e45 mm/debug.c: __dump_page() prints an extra line
When dumping struct page information, __dump_page() prints the page type
with a trailing blank followed by the page flags on a separate line:

  anon
  flags: 0x100000000090034(uptodate|lru|active|head|swapbacked)

It looks like the intent was to use pr_cont() for printing "flags:" but
pr_cont() usage is discouraged so fix this by extending the format to
include the flags into a single line:

  anon flags: 0x100000000090034(uptodate|lru|active|head|swapbacked)

If the page is file backed, the name might be long so use two lines:

  shmem_aops name:"dev/zero"
  flags: 0x10000000008000c(uptodate|dirty|swapbacked)

Eliminate pr_conf() usage as well for appending compound_mapcount.

Link: http://lkml.kernel.org/r/20191112012608.16926-1-rcampbell@nvidia.com
Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Jerome Glisse <jglisse@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-11-15 18:34:00 -08:00
Vinayak Menon 5df373e956 mm/page_io.c: do not free shared swap slots
The following race is observed due to which a processes faulting on a
swap entry, finds the page neither in swapcache nor swap.  This causes
zram to give a zero filled page that gets mapped to the process,
resulting in a user space crash later.

Consider parent and child processes Pa and Pb sharing the same swap slot
with swap_count 2.  Swap is on zram with SWP_SYNCHRONOUS_IO set.
Virtual address 'VA' of Pa and Pb points to the shared swap entry.

Pa                                       Pb

fault on VA                              fault on VA
do_swap_page                             do_swap_page
lookup_swap_cache fails                  lookup_swap_cache fails
                                         Pb scheduled out
swapin_readahead (deletes zram entry)
swap_free (makes swap_count 1)
                                         Pb scheduled in
                                         swap_readpage (swap_count == 1)
                                         Takes SWP_SYNCHRONOUS_IO path
                                         zram enrty absent
                                         zram gives a zero filled page

Fix this by making sure that swap slot is freed only when swap count
drops down to one.

Link: http://lkml.kernel.org/r/1571743294-14285-1-git-send-email-vinmenon@codeaurora.org
Fixes: aa8d22a11d ("mm: swap: SWP_SYNCHRONOUS_IO: skip swapcache only if swapped page has no other reference")
Signed-off-by: Vinayak Menon <vinmenon@codeaurora.org>
Suggested-by: Minchan Kim <minchan@google.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-11-15 18:34:00 -08:00
David Hildenbrand 2c91f8fc6c mm/memory_hotplug: fix try_offline_node()
try_offline_node() is pretty much broken right now:

 - The node span is updated when onlining memory, not when adding it. We
   ignore memory that was mever onlined. Bad.

 - We touch possible garbage memmaps. The pfn_to_nid(pfn) can easily
   trigger a kernel panic. Bad for memory that is offline but also bad
   for subsection hotadd with ZONE_DEVICE, whereby the memmap of the
   first PFN of a section might contain garbage.

 - Sections belonging to mixed nodes are not properly considered.

As memory blocks might belong to multiple nodes, we would have to walk
all pageblocks (or at least subsections) within present sections.
However, we don't have a way to identify whether a memmap that is not
online was initialized (relevant for ZONE_DEVICE).  This makes things
more complicated.

Luckily, we can piggy pack on the node span and the nid stored in memory
blocks.  Currently, the node span is grown when calling
move_pfn_range_to_zone() - e.g., when onlining memory, and shrunk when
removing memory, before calling try_offline_node().  Sysfs links are
created via link_mem_sections(), e.g., during boot or when adding
memory.

If the node still spans memory or if any memory block belongs to the
nid, we don't set the node offline.  As memory blocks that span multiple
nodes cannot get offlined, the nid stored in memory blocks is reliable
enough (for such online memory blocks, the node still spans the memory).

Introduce for_each_memory_block() to efficiently walk all memory blocks.

Note: We will soon stop shrinking the ZONE_DEVICE zone and the node span
when removing ZONE_DEVICE memory to fix similar issues (access of
garbage memmaps) - until we have a reliable way to identify whether
these memmaps were properly initialized.  This implies later, that once
a node had ZONE_DEVICE memory, we won't be able to set a node offline -
which should be acceptable.

Since commit f1dd2cd13c ("mm, memory_hotplug: do not associate
hotadded memory to zones until online") memory that is added is not
assoziated with a zone/node (memmap not initialized).  The introducing
commit 60a5a19e74 ("memory-hotplug: remove sysfs file of node")
already missed that we could have multiple nodes for a section and that
the zone/node span is updated when onlining pages, not when adding them.

I tested this by hotplugging two DIMMs to a memory-less and cpu-less
NUMA node.  The node is properly onlined when adding the DIMMs.  When
removing the DIMMs, the node is properly offlined.

Masayoshi Mizuma reported:

: Without this patch, memory hotplug fails as panic:
:
:  BUG: kernel NULL pointer dereference, address: 0000000000000000
:  ...
:  Call Trace:
:   remove_memory_block_devices+0x81/0xc0
:   try_remove_memory+0xb4/0x130
:   __remove_memory+0xa/0x20
:   acpi_memory_device_remove+0x84/0x100
:   acpi_bus_trim+0x57/0x90
:   acpi_bus_trim+0x2e/0x90
:   acpi_device_hotplug+0x2b2/0x4d0
:   acpi_hotplug_work_fn+0x1a/0x30
:   process_one_work+0x171/0x380
:   worker_thread+0x49/0x3f0
:   kthread+0xf8/0x130
:   ret_from_fork+0x35/0x40

[david@redhat.com: v3]
  Link: http://lkml.kernel.org/r/20191102120221.7553-1-david@redhat.com
Link: http://lkml.kernel.org/r/20191028105458.28320-1-david@redhat.com
Fixes: 60a5a19e74 ("memory-hotplug: remove sysfs file of node")
Fixes: f1dd2cd13c ("mm, memory_hotplug: do not associate hotadded memory to zones until online") # visiable after d0dc12e86b
Signed-off-by: David Hildenbrand <david@redhat.com>
Tested-by: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com>
Cc: Tang Chen <tangchen@cn.fujitsu.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Nayna Jain <nayna@linux.ibm.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-11-15 18:34:00 -08:00
Song Liu 4655e5e5f3 mm,thp: recheck each page before collapsing file THP
In collapse_file(), for !is_shmem case, current check cannot guarantee
the locked page is up-to-date.  Specifically, xas_unlock_irq() should
not be called before lock_page() and get_page(); and it is necessary to
recheck PageUptodate() after locking the page.

With this bug and CONFIG_READ_ONLY_THP_FOR_FS=y, madvise(HUGE)'ed .text
may contain corrupted data.  This is because khugepaged mistakenly
collapses some not up-to-date sub pages into a huge page, and assumes
the huge page is up-to-date.  This will NOT corrupt data in the disk,
because the page is read-only and never written back.  Fix this by
properly checking PageUptodate() after locking the page.  This check
replaces "VM_BUG_ON_PAGE(!PageUptodate(page), page);".

Also, move PageDirty() check after locking the page.  Current khugepaged
should not try to collapse dirty file THP, because it is limited to
read-only .text.  The only case we hit a dirty page here is when the
page hasn't been written since write.  Bail out and retry when this
happens.

syzbot reported bug on previous version of this patch.

Link: http://lkml.kernel.org/r/20191106060930.2571389-2-songliubraving@fb.com
Fixes: 99cb0dbd47 ("mm,thp: add read-only THP support for (non-shmem) FS")
Signed-off-by: Song Liu <songliubraving@fb.com>
Reported-by: syzbot+efb9e48b9fbdc49bb34a@syzkaller.appspotmail.com
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: William Kucharski <william.kucharski@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-11-15 18:34:00 -08:00
Laura Abbott aea4df4c53 mm: slub: really fix slab walking for init_on_free
Commit 1b7e816fc8 ("mm: slub: Fix slab walking for init_on_free")
fixed one problem with the slab walking but missed a key detail: When
walking the list, the head and tail pointers need to be updated since we
end up reversing the list as a result.  Without doing this, bulk free is
broken.

One way this is exposed is a NULL pointer with slub_debug=F:

  =============================================================================
  BUG skbuff_head_cache (Tainted: G                T): Object already free
  -----------------------------------------------------------------------------

  INFO: Slab 0x000000000d2d2f8f objects=16 used=3 fp=0x0000000064309071 flags=0x3fff00000000201
  BUG: kernel NULL pointer dereference, address: 0000000000000000
  Oops: 0000 [#1] PREEMPT SMP PTI
  RIP: 0010:print_trailer+0x70/0x1d5
  Call Trace:
   <IRQ>
   free_debug_processing.cold.37+0xc9/0x149
   __slab_free+0x22a/0x3d0
   kmem_cache_free_bulk+0x415/0x420
   __kfree_skb_flush+0x30/0x40
   net_rx_action+0x2dd/0x480
   __do_softirq+0xf0/0x246
   irq_exit+0x93/0xb0
   do_IRQ+0xa0/0x110
   common_interrupt+0xf/0xf
   </IRQ>

Given we're now almost identical to the existing debugging code which
correctly walks the list, combine with that.

Link: https://lkml.kernel.org/r/20191104170303.GA50361@gandi.net
Link: http://lkml.kernel.org/r/20191106222208.26815-1-labbott@redhat.com
Fixes: 1b7e816fc8 ("mm: slub: Fix slab walking for init_on_free")
Signed-off-by: Laura Abbott <labbott@redhat.com>
Reported-by: Thibaut Sautereau <thibaut.sautereau@clip-os.org>
Acked-by: David Rientjes <rientjes@google.com>
Tested-by: Alexander Potapenko <glider@google.com>
Acked-by: Alexander Potapenko <glider@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: <clipos@ssi.gouv.fr>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-11-15 18:34:00 -08:00
Roman Gushchin 0362f326d8 mm: hugetlb: switch to css_tryget() in hugetlb_cgroup_charge_cgroup()
An exiting task might belong to an offline cgroup.  In this case an
attempt to grab a cgroup reference from the task can end up with an
infinite loop in hugetlb_cgroup_charge_cgroup(), because neither the
cgroup will become online, neither the task will be migrated to a live
cgroup.

Fix this by switching over to css_tryget().  As css_tryget_online()
can't guarantee that the cgroup won't go offline, in most cases the
check doesn't make sense.  In this particular case users of
hugetlb_cgroup_charge_cgroup() are not affected by this change.

A similar problem is described by commit 18fa84a2db ("cgroup: Use
css_tryget() instead of css_tryget_online() in task_get_css()").

Link: http://lkml.kernel.org/r/20191106225131.3543616-2-guro@fb.com
Signed-off-by: Roman Gushchin <guro@fb.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-11-15 18:34:00 -08:00
Roman Gushchin 00d484f354 mm: memcg: switch to css_tryget() in get_mem_cgroup_from_mm()
We've encountered a rcu stall in get_mem_cgroup_from_mm():

  rcu: INFO: rcu_sched self-detected stall on CPU
  rcu: 33-....: (21000 ticks this GP) idle=6c6/1/0x4000000000000002 softirq=35441/35441 fqs=5017
  (t=21031 jiffies g=324821 q=95837) NMI backtrace for cpu 33
  <...>
  RIP: 0010:get_mem_cgroup_from_mm+0x2f/0x90
  <...>
   __memcg_kmem_charge+0x55/0x140
   __alloc_pages_nodemask+0x267/0x320
   pipe_write+0x1ad/0x400
   new_sync_write+0x127/0x1c0
   __kernel_write+0x4f/0xf0
   dump_emit+0x91/0xc0
   writenote+0xa0/0xc0
   elf_core_dump+0x11af/0x1430
   do_coredump+0xc65/0xee0
   get_signal+0x132/0x7c0
   do_signal+0x36/0x640
   exit_to_usermode_loop+0x61/0xd0
   do_syscall_64+0xd4/0x100
   entry_SYSCALL_64_after_hwframe+0x44/0xa9

The problem is caused by an exiting task which is associated with an
offline memcg.  We're iterating over and over in the do {} while
(!css_tryget_online()) loop, but obviously the memcg won't become online
and the exiting task won't be migrated to a live memcg.

Let's fix it by switching from css_tryget_online() to css_tryget().

As css_tryget_online() cannot guarantee that the memcg won't go offline,
the check is usually useless, except some rare cases when for example it
determines if something should be presented to a user.

A similar problem is described by commit 18fa84a2db ("cgroup: Use
css_tryget() instead of css_tryget_online() in task_get_css()").

Johannes:

: The bug aside, it doesn't matter whether the cgroup is online for the
: callers.  It used to matter when offlining needed to evacuate all charges
: from the memcg, and so needed to prevent new ones from showing up, but we
: don't care now.

Link: http://lkml.kernel.org/r/20191106225131.3543616-1-guro@fb.com
Signed-off-by: Roman Gushchin <guro@fb.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Shakeel Butt <shakeeb@google.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michal Koutn <mkoutny@suse.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-11-15 18:34:00 -08:00
zhong jiang 8207296297 mm: fix trying to reclaim unevictable lru page when calling madvise_pageout
Recently, I hit the following issue when running upstream.

  kernel BUG at mm/vmscan.c:1521!
  invalid opcode: 0000 [#1] SMP KASAN PTI
  CPU: 0 PID: 23385 Comm: syz-executor.6 Not tainted 5.4.0-rc4+ #1
  RIP: 0010:shrink_page_list+0x12b6/0x3530 mm/vmscan.c:1521
  Call Trace:
   reclaim_pages+0x499/0x800 mm/vmscan.c:2188
   madvise_cold_or_pageout_pte_range+0x58a/0x710 mm/madvise.c:453
   walk_pmd_range mm/pagewalk.c:53 [inline]
   walk_pud_range mm/pagewalk.c:112 [inline]
   walk_p4d_range mm/pagewalk.c:139 [inline]
   walk_pgd_range mm/pagewalk.c:166 [inline]
   __walk_page_range+0x45a/0xc20 mm/pagewalk.c:261
   walk_page_range+0x179/0x310 mm/pagewalk.c:349
   madvise_pageout_page_range mm/madvise.c:506 [inline]
   madvise_pageout+0x1f0/0x330 mm/madvise.c:542
   madvise_vma mm/madvise.c:931 [inline]
   __do_sys_madvise+0x7d2/0x1600 mm/madvise.c:1113
   do_syscall_64+0x9f/0x4c0 arch/x86/entry/common.c:290
   entry_SYSCALL_64_after_hwframe+0x49/0xbe

madvise_pageout() accesses the specified range of the vma and isolates
them, then runs shrink_page_list() to reclaim its memory.  But it also
isolates the unevictable pages to reclaim.  Hence, we can catch the
cases in shrink_page_list().

The root cause is that we scan the page tables instead of specific LRU
list.  and so we need to filter out the unevictable lru pages from our
end.

Link: http://lkml.kernel.org/r/1572616245-18946-1-git-send-email-zhongjiang@huawei.com
Fixes: 1a4e58cce8 ("mm: introduce MADV_PAGEOUT")
Signed-off-by: zhong jiang <zhongjiang@huawei.com>
Suggested-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Minchan Kim <minchan@kernel.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-11-15 18:33:59 -08:00
Yang Shi a85dfc305a mm: mempolicy: fix the wrong return value and potential pages leak of mbind
Commit d883544515 ("mm: mempolicy: make the behavior consistent when
MPOL_MF_MOVE* and MPOL_MF_STRICT were specified") fixed the return value
of mbind() for a couple of corner cases.  But, it altered the errno for
some other cases, for example, mbind() should return -EFAULT when part
or all of the memory range specified by nodemask and maxnode points
outside your accessible address space, or there was an unmapped hole in
the specified memory range specified by addr and len.

Fix this by preserving the errno returned by queue_pages_range().  And,
the pagelist may be not empty even though queue_pages_range() returns
error, put the pages back to LRU since mbind_range() is not called to
really apply the policy so those pages should not be migrated, this is
also the old behavior before the problematic commit.

Link: http://lkml.kernel.org/r/1572454731-3925-1-git-send-email-yang.shi@linux.alibaba.com
Fixes: d883544515 ("mm: mempolicy: make the behavior consistent when MPOL_MF_MOVE* and MPOL_MF_STRICT were specified")
Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com>
Reported-by: Li Xinhai <lixinhai.lxh@gmail.com>
Reviewed-by: Li Xinhai <lixinhai.lxh@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: <stable@vger.kernel.org>	[4.19 and 5.2+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-11-15 18:33:59 -08:00
Jason Gunthorpe 56f434f40f mm/mmu_notifier: define the header pre-processor parts even if disabled
Now that we have KERNEL_HEADER_TEST all headers are generally compile
tested, so relying on makefile tricks to avoid compiling code that depends
on CONFIG_MMU_NOTIFIER is more annoying.

Instead follow the usual pattern and provide most of the header with only
the functions stubbed out when CONFIG_MMU_NOTIFIER is disabled. This
ensures code compiles no matter what the config setting is.

While here, struct mmu_notifier_mm is private to mmu_notifier.c, move it.

Link: https://lore.kernel.org/r/20191112202231.3856-2-jgg@ziepe.ca
Reviewed-by: Jérôme Glisse <jglisse@redhat.com>
Tested-by: Ralph Campbell <rcampbell@nvidia.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2019-11-12 20:18:27 -04:00
David S. Miller 14684b9301 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
One conflict in the BPF samples Makefile, some fixes in 'net' whilst
we were converting over to Makefile.target rules in 'net-next'.

Signed-off-by: David S. Miller <davem@davemloft.net>
2019-11-09 11:04:37 -08:00
Johannes Weiner 869712fd3d mm: memcontrol: fix network errors from failing __GFP_ATOMIC charges
While upgrading from 4.16 to 5.2, we noticed these allocation errors in
the log of the new kernel:

  SLUB: Unable to allocate memory on node -1, gfp=0xa20(GFP_ATOMIC)
    cache: tw_sock_TCPv6(960:helper-logs), object size: 232, buffer size: 240, default order: 1, min order: 0
    node 0: slabs: 5, objs: 170, free: 0

        slab_out_of_memory+1
        ___slab_alloc+969
        __slab_alloc+14
        kmem_cache_alloc+346
        inet_twsk_alloc+60
        tcp_time_wait+46
        tcp_fin+206
        tcp_data_queue+2034
        tcp_rcv_state_process+784
        tcp_v6_do_rcv+405
        __release_sock+118
        tcp_close+385
        inet_release+46
        __sock_release+55
        sock_close+17
        __fput+170
        task_work_run+127
        exit_to_usermode_loop+191
        do_syscall_64+212
        entry_SYSCALL_64_after_hwframe+68

accompanied by an increase in machines going completely radio silent
under memory pressure.

One thing that changed since 4.16 is e699e2c6a6 ("net, mm: account
sock objects to kmemcg"), which made these slab caches subject to cgroup
memory accounting and control.

The problem with that is that cgroups, unlike the page allocator, do not
maintain dedicated atomic reserves.  As a cgroup's usage hovers at its
limit, atomic allocations - such as done during network rx - can fail
consistently for extended periods of time.  The kernel is not able to
operate under these conditions.

We don't want to revert the culprit patch, because it indeed tracks a
potentially substantial amount of memory used by a cgroup.

We also don't want to implement dedicated atomic reserves for cgroups.
There is no point in keeping a fixed margin of unused bytes in the
cgroup's memory budget to accomodate a consumer that is impossible to
predict - we'd be wasting memory and get into configuration headaches,
not unlike what we have going with min_free_kbytes.  We do this for
physical mem because we have to, but cgroups are an accounting game.

Instead, account these privileged allocations to the cgroup, but let
them bypass the configured limit if they have to.  This way, we get the
benefits of accounting the consumed memory and have it exert pressure on
the rest of the cgroup, but like with the page allocator, we shift the
burden of reclaimining on behalf of atomic allocations onto the regular
allocations that can block.

Link: http://lkml.kernel.org/r/20191022233708.365764-1-hannes@cmpxchg.org
Fixes: e699e2c6a6 ("net, mm: account sock objects to kmemcg")
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Suleiman Souhlal <suleiman@google.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: <stable@vger.kernel.org>	[4.18+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-11-06 08:47:50 -08:00
David Hildenbrand 656d571193 mm/memory_hotplug: fix updating the node span
We recently started updating the node span based on the zone span to
avoid touching uninitialized memmaps.

Currently, we will always detect the node span to start at 0, meaning a
node can easily span too many pages.  pgdat_is_empty() will still work
correctly if all zones span no pages.  We should skip over all zones
without spanned pages and properly handle the first detected zone that
spans pages.

Unfortunately, in contrast to the zone span (/proc/zoneinfo), the node
span cannot easily be inspected and tested.  The node span gives no real
guarantees when an architecture supports memory hotplug, meaning it can
easily contain holes or span pages of different nodes.

The node span is not really used after init on architectures that
support memory hotplug.

E.g., we use it in mm/memory_hotplug.c:try_offline_node() and in
mm/kmemleak.c:kmemleak_scan().  These users seem to be fine.

Link: http://lkml.kernel.org/r/20191027222714.5313-1-david@redhat.com
Fixes: 00d6c019b5 ("mm/memory_hotplug: don't access uninitialized memmaps in shrink_pgdat_span()")
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-11-06 08:47:50 -08:00
Roman Gushchin 221ec5c0a4 mm: slab: make page_cgroup_ino() to recognize non-compound slab pages properly
page_cgroup_ino() doesn't return a valid memcg pointer for non-compound
slab pages, because it depends on PgHead AND PgSlab flags to be set to
determine the memory cgroup from the kmem_cache.  It's correct for
compound pages, but not for generic small pages.  Those don't have PgHead
set, so it ends up returning zero.

Fix this by replacing the condition to PageSlab() && !PageTail().

Before this patch:
  [root@localhost ~]# ./page-types -c /sys/fs/cgroup/user.slice/user-0.slice/user@0.service/ | grep slab
  0x0000000000000080	        38        0  _______S___________________________________	slab

After this patch:
  [root@localhost ~]# ./page-types -c /sys/fs/cgroup/user.slice/user-0.slice/user@0.service/ | grep slab
  0x0000000000000080	       147        0  _______S___________________________________	slab

Also, hwpoison_filter_task() uses output of page_cgroup_ino() in order
to filter error injection events based on memcg.  So if
page_cgroup_ino() fails to return memcg pointer, we just fail to inject
memory error.  Considering that hwpoison filter is for testing, affected
users are limited and the impact should be marginal.

[n-horiguchi@ah.jp.nec.com: changelog additions]
Link: http://lkml.kernel.org/r/20191031012151.2722280-1-guro@fb.com
Fixes: 4d96ba3530 ("mm: memcg/slab: stop setting page->mem_cgroup pointer for slab pages")
Signed-off-by: Roman Gushchin <guro@fb.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-11-06 08:47:50 -08:00
Johannes Weiner 1be334e5c0 mm/page_alloc.c: ratelimit allocation failure warnings more aggressively
While investigating a bug related to higher atomic allocation failures,
we noticed the failure warnings positively drowning the console, and in
our case trigger lockup warnings because of a serial console too slow to
handle all that output.

But even if we had a faster console, it's unclear what additional
information the current level of repetition provides.

Allocation failures happen for three reasons: The machine is OOM, the VM
is failing to handle reasonable requests, or somebody is making
unreasonable requests (and didn't acknowledge their opportunism with
__GFP_NOWARN).  Having the memory dump, a callstack, and the ratelimit
stats on skipped failure warnings should provide enough information to
let users/admins/developers know whether something is wrong and point
them in the right direction for debugging, bpftracing etc.

Limit allocation failure warnings to one spew every ten seconds.

Link: http://lkml.kernel.org/r/20191028194906.26899-1-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-11-06 08:47:50 -08:00
Ville Syrjälä ec649c9d45 mm/khugepaged: fix might_sleep() warn with CONFIG_HIGHPTE=y
I got some khugepaged spew on a 32bit x86:

  BUG: sleeping function called from invalid context at include/linux/mmu_notifier.h:346
  in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 25, name: khugepaged
  INFO: lockdep is turned off.
  CPU: 1 PID: 25 Comm: khugepaged Not tainted 5.4.0-rc5-elk+ #206
  Hardware name: System manufacturer P5Q-EM/P5Q-EM, BIOS 2203    07/08/2009
  Call Trace:
   dump_stack+0x66/0x8e
   ___might_sleep.cold.96+0x95/0xa6
   __might_sleep+0x2e/0x80
   collapse_huge_page.isra.51+0x5ac/0x1360
   khugepaged+0x9a9/0x20f0
   kthread+0xf5/0x110
   ret_from_fork+0x2e/0x38

Looks like it's due to CONFIG_HIGHPTE=y pte_offset_map()->kmap_atomic()
vs.  mmu_notifier_invalidate_range_start().  Let's do the naive approach
and just reorder the two operations.

Link: http://lkml.kernel.org/r/20191029201513.GG1208@intel.com
Fixes: 810e24e009 ("mm/mmu_notifiers: annotate with might_sleep()")
Signed-off-by: Ville Syrjl <ville.syrjala@linux.intel.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.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: Jérôme Glisse <jglisse@redhat.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jason Gunthorpe <jgg@mellanox.com>
Cc: Daniel Vetter <daniel.vetter@intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-11-06 08:47:50 -08:00
Michal Hocko 93b3a67448 mm, vmstat: reduce zone->lock holding time by /proc/pagetypeinfo
pagetypeinfo_showfree_print is called by zone->lock held in irq mode.
This is not really nice because it blocks both any interrupts on that
cpu and the page allocator.  On large machines this might even trigger
the hard lockup detector.

Considering the pagetypeinfo is a debugging tool we do not really need
exact numbers here.  The primary reason to look at the outuput is to see
how pageblocks are spread among different migratetypes and low number of
pages is much more interesting therefore putting a bound on the number
of pages on the free_list sounds like a reasonable tradeoff.

The new output will simply tell
  [...]
  Node    6, zone   Normal, type      Movable >100000 >100000 >100000 >100000  41019  31560  23996  10054   3229    983    648

instead of
  Node    6, zone   Normal, type      Movable 399568 294127 221558 102119  41019  31560  23996  10054   3229    983    648

The limit has been chosen arbitrary and it is a subject of a future
change should there be a need for that.

While we are at it, also drop the zone lock after each free_list
iteration which will help with the IRQ and page allocator responsiveness
even further as the IRQ lock held time is always bound to those 100k
pages.

[akpm@linux-foundation.org: tweak comment text, per David Hildenbrand]
Link: http://lkml.kernel.org/r/20191025072610.18526-3-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Waiman Long <longman@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Rafael Aquini <aquini@redhat.com>
Acked-by: David Rientjes <rientjes@google.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jann Horn <jannh@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Roman Gushchin <guro@fb.com>
Cc: Song Liu <songliubraving@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-11-06 08:47:50 -08:00
Michal Hocko abaed0112c mm, vmstat: hide /proc/pagetypeinfo from normal users
/proc/pagetypeinfo is a debugging tool to examine internal page
allocator state wrt to fragmentation.  It is not very useful for any
other use so normal users really do not need to read this file.

Waiman Long has noticed that reading this file can have negative side
effects because zone->lock is necessary for gathering data and that a)
interferes with the page allocator and its users and b) can lead to hard
lockups on large machines which have very long free_list.

Reduce both issues by simply not exporting the file to regular users.

Link: http://lkml.kernel.org/r/20191025072610.18526-2-mhocko@kernel.org
Fixes: 467c996c1e ("Print out statistics in relation to fragmentation avoidance to /proc/pagetypeinfo")
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reported-by: Waiman Long <longman@redhat.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Waiman Long <longman@redhat.com>
Acked-by: Rafael Aquini <aquini@redhat.com>
Acked-by: David Rientjes <rientjes@google.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Roman Gushchin <guro@fb.com>
Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Jann Horn <jannh@google.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-11-06 08:47:50 -08:00
Jason Gunthorpe df2ec7641b mm/mmu_notifiers: use the right return code for WARN_ON
The return code from the op callback is actually in _ret, while the
WARN_ON was checking ret which causes it to misfire.

Link: http://lkml.kernel.org/r/20191025175502.GA31127@ziepe.ca
Fixes: 8402ce61be ("mm/mmu_notifiers: check if mmu notifier callbacks are allowed to fail")
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-11-06 08:47:50 -08:00
Mel Gorman 3e8fc0075e mm, meminit: recalculate pcpu batch and high limits after init completes
Deferred memory initialisation updates zone->managed_pages during the
initialisation phase but before that finishes, the per-cpu page
allocator (pcpu) calculates the number of pages allocated/freed in
batches as well as the maximum number of pages allowed on a per-cpu
list.  As zone->managed_pages is not up to date yet, the pcpu
initialisation calculates inappropriately low batch and high values.

This increases zone lock contention quite severely in some cases with
the degree of severity depending on how many CPUs share a local zone and
the size of the zone.  A private report indicated that kernel build
times were excessive with extremely high system CPU usage.  A perf
profile indicated that a large chunk of time was lost on zone->lock
contention.

This patch recalculates the pcpu batch and high values after deferred
initialisation completes for every populated zone in the system.  It was
tested on a 2-socket AMD EPYC 2 machine using a kernel compilation
workload -- allmodconfig and all available CPUs.

mmtests configuration: config-workload-kernbench-max Configuration was
modified to build on a fresh XFS partition.

kernbench
                                5.4.0-rc3              5.4.0-rc3
                                  vanilla           resetpcpu-v2
Amean     user-256    13249.50 (   0.00%)    16401.31 * -23.79%*
Amean     syst-256    14760.30 (   0.00%)     4448.39 *  69.86%*
Amean     elsp-256      162.42 (   0.00%)      119.13 *  26.65%*
Stddev    user-256       42.97 (   0.00%)       19.15 (  55.43%)
Stddev    syst-256      336.87 (   0.00%)        6.71 (  98.01%)
Stddev    elsp-256        2.46 (   0.00%)        0.39 (  84.03%)

                   5.4.0-rc3    5.4.0-rc3
                     vanilla resetpcpu-v2
Duration User       39766.24     49221.79
Duration System     44298.10     13361.67
Duration Elapsed      519.11       388.87

The patch reduces system CPU usage by 69.86% and total build time by
26.65%.  The variance of system CPU usage is also much reduced.

Before, this was the breakdown of batch and high values over all zones
was:

    256               batch: 1
    256               batch: 63
    512               batch: 7
    256               high:  0
    256               high:  378
    512               high:  42

512 pcpu pagesets had a batch limit of 7 and a high limit of 42.  After
the patch:

    256               batch: 1
    768               batch: 63
    256               high:  0
    768               high:  378

[mgorman@techsingularity.net: fix merge/linkage snafu]
  Link: http://lkml.kernel.org/r/20191023084705.GD3016@techsingularity.netLink: http://lkml.kernel.org/r/20191021094808.28824-2-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Qian Cai <cai@lca.pw>
Cc: <stable@vger.kernel.org>	[4.1+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-11-06 08:28:58 -08:00
Shakeel Butt 7961eee397 mm: memcontrol: fix NULL-ptr deref in percpu stats flush
__mem_cgroup_free() can be called on the failure path in
mem_cgroup_alloc().  However memcg_flush_percpu_vmstats() and
memcg_flush_percpu_vmevents() which are called from __mem_cgroup_free()
access the fields of memcg which can potentially be null if called from
failure path from mem_cgroup_alloc().  Indeed syzbot has reported the
following crash:

	kasan: CONFIG_KASAN_INLINE enabled
	kasan: GPF could be caused by NULL-ptr deref or user memory access
	general protection fault: 0000 [#1] PREEMPT SMP KASAN
	CPU: 0 PID: 30393 Comm: syz-executor.1 Not tainted 5.4.0-rc2+ #0
	Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
	RIP: 0010:memcg_flush_percpu_vmstats+0x4ae/0x930 mm/memcontrol.c:3436
	Code: 05 41 89 c0 41 0f b6 04 24 41 38 c7 7c 08 84 c0 0f 85 5d 03 00 00 44 3b 05 33 d5 12 08 0f 83 e2 00 00 00 4c 89 f0 48 c1 e8 03 <42> 80 3c 28 00 0f 85 91 03 00 00 48 8b 85 10 fe ff ff 48 8b b0 90
	RSP: 0018:ffff888095c27980 EFLAGS: 00010206
	RAX: 0000000000000012 RBX: ffff888095c27b28 RCX: ffffc90008192000
	RDX: 0000000000040000 RSI: ffffffff8340fae7 RDI: 0000000000000007
	RBP: ffff888095c27be0 R08: 0000000000000000 R09: ffffed1013f0da33
	R10: ffffed1013f0da32 R11: ffff88809f86d197 R12: fffffbfff138b760
	R13: dffffc0000000000 R14: 0000000000000090 R15: 0000000000000007
	FS:  00007f5027170700(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000
	CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
	CR2: 0000000000710158 CR3: 00000000a7b18000 CR4: 00000000001406f0
	DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
	DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
	Call Trace:
	__mem_cgroup_free+0x1a/0x190 mm/memcontrol.c:5021
	mem_cgroup_free mm/memcontrol.c:5033 [inline]
	mem_cgroup_css_alloc+0x3a1/0x1ae0 mm/memcontrol.c:5160
	css_create kernel/cgroup/cgroup.c:5156 [inline]
	cgroup_apply_control_enable+0x44d/0xc40 kernel/cgroup/cgroup.c:3119
	cgroup_mkdir+0x899/0x11b0 kernel/cgroup/cgroup.c:5401
	kernfs_iop_mkdir+0x14d/0x1d0 fs/kernfs/dir.c:1124
	vfs_mkdir+0x42e/0x670 fs/namei.c:3807
	do_mkdirat+0x234/0x2a0 fs/namei.c:3830
	__do_sys_mkdir fs/namei.c:3846 [inline]
	__se_sys_mkdir fs/namei.c:3844 [inline]
	__x64_sys_mkdir+0x5c/0x80 fs/namei.c:3844
	do_syscall_64+0xfa/0x760 arch/x86/entry/common.c:290
	entry_SYSCALL_64_after_hwframe+0x49/0xbe

Fixing this by moving the flush to mem_cgroup_free as there is no need
to flush anything if we see failure in mem_cgroup_alloc().

Link: http://lkml.kernel.org/r/20191018165231.249872-1-shakeelb@google.com
Fixes: bb65f89b7d ("mm: memcontrol: flush percpu vmevents before releasing memcg")
Fixes: c350a99ea2 ("mm: memcontrol: flush percpu vmstats before releasing memcg")
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Reported-by: syzbot+515d5bcfe179cdf049b2@syzkaller.appspotmail.com
Reviewed-by: Roman Gushchin <guro@fb.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.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>
2019-11-06 08:28:58 -08:00
Thomas Hellstrom c5acad84cf mm: Add write-protect and clean utilities for address space ranges
Add two utilities to 1) write-protect and 2) clean all ptes pointing into
a range of an address space.
The utilities are intended to aid in tracking dirty pages (either
driver-allocated system memory or pci device memory).
The write-protect utility should be used in conjunction with
page_mkwrite() and pfn_mkwrite() to trigger write page-faults on page
accesses. Typically one would want to use this on sparse accesses into
large memory regions. The clean utility should be used to utilize
hardware dirtying functionality and avoid the overhead of page-faults,
typically on large accesses into small memory regions.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
2019-11-06 13:03:36 +01:00
Thomas Hellstrom ecaad8aca2 mm: Add a walk_page_mapping() function to the pagewalk code
For users that want to travers all page table entries pointing into a
region of a struct address_space mapping, introduce a walk_page_mapping()
function.

The walk_page_mapping() function will be initially be used for dirty-
tracking in virtual graphics drivers.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
2019-11-06 13:02:43 +01:00
Thomas Hellstrom ace88f1018 mm: pagewalk: Take the pagetable lock in walk_pte_range()
Without the lock, anybody modifying a pte from within this function might
have it concurrently modified by someone else.

Cc: Matthew Wilcox <willy@infradead.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
2019-11-06 13:02:25 +01:00