mirror of https://gitee.com/openkylin/linux.git
778 Commits
| Author | SHA1 | Message | Date |
|---|---|---|---|
Arnd Bergmann
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af27d9403f |
mm: hide a #warning for COMPILE_TEST
We get a warning about some slow configurations in randconfig kernels:
mm/memory.c:83:2: error: #warning Unfortunate NUMA and NUMA Balancing config, growing page-frame for last_cpupid. [-Werror=cpp]
The warning is reasonable by itself, but gets in the way of randconfig
build testing, so I'm hiding it whenever CONFIG_COMPILE_TEST is set.
The warning was added in 2013 in commit
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Linus Torvalds
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a2e5790d84 |
Merge branch 'akpm' (patches from Andrew)
Merge misc updates from Andrew Morton: - kasan updates - procfs - lib/bitmap updates - other lib/ updates - checkpatch tweaks - rapidio - ubsan - pipe fixes and cleanups - lots of other misc bits * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (114 commits) Documentation/sysctl/user.txt: fix typo MAINTAINERS: update ARM/QUALCOMM SUPPORT patterns MAINTAINERS: update various PALM patterns MAINTAINERS: update "ARM/OXNAS platform support" patterns MAINTAINERS: update Cortina/Gemini patterns MAINTAINERS: remove ARM/CLKDEV SUPPORT file pattern MAINTAINERS: remove ANDROID ION pattern mm: docs: add blank lines to silence sphinx "Unexpected indentation" errors mm: docs: fix parameter names mismatch mm: docs: fixup punctuation pipe: read buffer limits atomically pipe: simplify round_pipe_size() pipe: reject F_SETPIPE_SZ with size over UINT_MAX pipe: fix off-by-one error when checking buffer limits pipe: actually allow root to exceed the pipe buffer limits pipe, sysctl: remove pipe_proc_fn() pipe, sysctl: drop 'min' parameter from pipe-max-size converter kasan: rework Kconfig settings crash_dump: is_kdump_kernel can be boolean kernel/mutex: mutex_is_locked can be boolean ... |
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Sergey Senozhatsky
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e7c98df598 |
mm: remove unneeded kallsyms include
The file was converted from print_symbol() to %pSR a while ago in commit
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Linus Torvalds
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3ff1b28caa |
libnvdimm for 4.16
* Require struct page by default for filesystem DAX to remove a number of
surprising failure cases. This includes failures with direct I/O, gdb and
fork(2).
* Add support for the new Platform Capabilities Structure added to the NFIT in
ACPI 6.2a. This new table tells us whether the platform supports flushing
of CPU and memory controller caches on unexpected power loss events.
* Revamp vmem_altmap and dev_pagemap handling to clean up code and better
support future future PCI P2P uses.
* Deprecate the ND_IOCTL_SMART_THRESHOLD command whose payload has become
out-of-sync with recent versions of the NVDIMM_FAMILY_INTEL spec, and
instead rely on the generic ND_CMD_CALL approach used by the two other IOCTL
families, NVDIMM_FAMILY_{HPE,MSFT}.
* Enhance nfit_test so we can test some of the new things added in version 1.6
of the DSM specification. This includes testing firmware download and
simulating the Last Shutdown State (LSS) status.
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Merge tag 'libnvdimm-for-4.16' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm
Pull libnvdimm updates from Ross Zwisler:
- Require struct page by default for filesystem DAX to remove a number
of surprising failure cases. This includes failures with direct I/O,
gdb and fork(2).
- Add support for the new Platform Capabilities Structure added to the
NFIT in ACPI 6.2a. This new table tells us whether the platform
supports flushing of CPU and memory controller caches on unexpected
power loss events.
- Revamp vmem_altmap and dev_pagemap handling to clean up code and
better support future future PCI P2P uses.
- Deprecate the ND_IOCTL_SMART_THRESHOLD command whose payload has
become out-of-sync with recent versions of the NVDIMM_FAMILY_INTEL
spec, and instead rely on the generic ND_CMD_CALL approach used by
the two other IOCTL families, NVDIMM_FAMILY_{HPE,MSFT}.
- Enhance nfit_test so we can test some of the new things added in
version 1.6 of the DSM specification. This includes testing firmware
download and simulating the Last Shutdown State (LSS) status.
* tag 'libnvdimm-for-4.16' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: (37 commits)
libnvdimm, namespace: remove redundant initialization of 'nd_mapping'
acpi, nfit: fix register dimm error handling
libnvdimm, namespace: make min namespace size 4K
tools/testing/nvdimm: force nfit_test to depend on instrumented modules
libnvdimm/nfit_test: adding support for unit testing enable LSS status
libnvdimm/nfit_test: add firmware download emulation
nfit-test: Add platform cap support from ACPI 6.2a to test
libnvdimm: expose platform persistence attribute for nd_region
acpi: nfit: add persistent memory control flag for nd_region
acpi: nfit: Add support for detect platform CPU cache flush on power loss
device-dax: Fix trailing semicolon
libnvdimm, btt: fix uninitialized err_lock
dax: require 'struct page' by default for filesystem dax
ext2: auto disable dax instead of failing mount
ext4: auto disable dax instead of failing mount
mm, dax: introduce pfn_t_special()
mm: Fix devm_memremap_pages() collision handling
mm: Fix memory size alignment in devm_memremap_pages_release()
memremap: merge find_dev_pagemap into get_dev_pagemap
memremap: change devm_memremap_pages interface to use struct dev_pagemap
...
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William Kucharski
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da391d640c |
mm: correct comments regarding do_fault_around()
There are multiple comments surrounding do_fault_around that memtion fault_around_pages() and fault_around_mask(), two routines that do not exist. These comments should be reworded to reference fault_around_bytes, the value which is used to determine how much do_fault_around() will attempt to read when processing a fault. These comments should have been updated when fault_around_pages() and fault_around_mask() were removed in commit |
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Matthew Wilcox
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977fbdcd59 |
mm: add unmap_mapping_pages()
Several users of unmap_mapping_range() would prefer to express their range in pages rather than bytes. Unfortuately, on a 32-bit kernel, you have to remember to cast your page number to a 64-bit type before shifting it, and four places in the current tree didn't remember to do that. That's a sign of a bad interface. Conveniently, unmap_mapping_range() actually converts from bytes into pages, so hoist the guts of unmap_mapping_range() into a new function unmap_mapping_pages() and convert the callers which want to use pages. Link: http://lkml.kernel.org/r/20171206142627.GD32044@bombadil.infradead.org Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com> Reported-by: "zhangyi (F)" <yi.zhang@huawei.com> Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.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> |
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Mike Rapoport
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ef549e13cf |
mm: update comment describing tlb_gather_mmu
The comment describes @fullmm argument, but the function has no such parameter. Update the comment to match the code and convert it to kernel-doc markup. Link: http://lkml.kernel.org/r/1512394531-2264-1-git-send-email-rppt@linux.vnet.ibm.com Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Dan Williams
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785a3fab4a |
mm, dax: introduce pfn_t_special()
In support of removing the VM_MIXEDMAP indication from DAX VMAs, introduce pfn_t_special() for drivers to indicate that _PAGE_SPECIAL should be used for DAX ptes. This also helps identify drivers like dccssblk that only want to use DAX in a read-only fashion without get_user_pages() support. Ideally we could delete axonram and dcssblk DAX support, but if we need to keep it better make it explicit that axonram and dcssblk only support a sub-set of DAX due to missing _PAGE_DEVMAP support. Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com> |
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Minchan Kim
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f80207727a |
mm/memory.c: release locked page in do_swap_page()
James reported a bug in swap paging-in from his testing. It is that
do_swap_page doesn't release locked page so system hang-up happens due
to a deadlock on PG_locked.
It was introduced by
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Linus Torvalds
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f6f3732162 |
Revert "mm: replace p??_write with pte_access_permitted in fault + gup paths"
This reverts commits |
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Geert Uytterhoeven
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183f24aa5b |
mm/memory.c: mark wp_huge_pmd() inline to prevent build failure
With gcc 4.1.2:
mm/memory.o: In function `wp_huge_pmd':
memory.c:(.text+0x9b4): undefined reference to `do_huge_pmd_wp_page'
Interestingly, wp_huge_pmd() is emitted in the assembler output, but
never called.
Apparently replacing the call to pmd_write() in __handle_mm_fault() by a
call to the more complex pmd_access_permitted() reduced the ability of
the compiler to remove unused code.
Fix this by marking wp_huge_pmd() inline, like was done in commit
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Linus Torvalds
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a0908a1b7d |
Merge branch 'akpm' (patches from Andrew)
Mergr misc fixes from Andrew Morton: "28 fixes" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (28 commits) fs/hugetlbfs/inode.c: change put_page/unlock_page order in hugetlbfs_fallocate() mm/hugetlb: fix NULL-pointer dereference on 5-level paging machine autofs: revert "autofs: fix AT_NO_AUTOMOUNT not being honored" autofs: revert "autofs: take more care to not update last_used on path walk" fs/fat/inode.c: fix sb_rdonly() change mm, memcg: fix mem_cgroup_swapout() for THPs mm: migrate: fix an incorrect call of prep_transhuge_page() kmemleak: add scheduling point to kmemleak_scan() scripts/bloat-o-meter: don't fail with division by 0 fs/mbcache.c: make count_objects() more robust Revert "mm/page-writeback.c: print a warning if the vm dirtiness settings are illogical" mm/madvise.c: fix madvise() infinite loop under special circumstances exec: avoid RLIMIT_STACK races with prlimit() IB/core: disable memory registration of filesystem-dax vmas v4l2: disable filesystem-dax mapping support mm: fail get_vaddr_frames() for filesystem-dax mappings mm: introduce get_user_pages_longterm device-dax: implement ->split() to catch invalid munmap attempts mm, hugetlbfs: introduce ->split() to vm_operations_struct scripts/faddr2line: extend usage on generic arch ... |
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Dan Williams
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5c9d2d5c26 |
mm: replace pte_write with pte_access_permitted in fault + gup paths
The 'access_permitted' helper is used in the gup-fast path and goes beyond the simple _PAGE_RW check to also: - validate that the mapping is writable from a protection keys standpoint - validate that the pte has _PAGE_USER set since all fault paths where pte_write is must be referencing user-memory. Link: http://lkml.kernel.org/r/151043111604.2842.8051684481794973100.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: "Jérôme Glisse" <jglisse@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Dan Williams
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c7da82b894 |
mm: replace pmd_write with pmd_access_permitted in fault + gup paths
The 'access_permitted' helper is used in the gup-fast path and goes beyond the simple _PAGE_RW check to also: - validate that the mapping is writable from a protection keys standpoint - validate that the pte has _PAGE_USER set since all fault paths where pmd_write is must be referencing user-memory. Link: http://lkml.kernel.org/r/151043111049.2842.15241454964150083466.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: "Jérôme Glisse" <jglisse@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Dan Williams
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e7fe7b5cae |
mm: replace pud_write with pud_access_permitted in fault + gup paths
The 'access_permitted' helper is used in the gup-fast path and goes beyond the simple _PAGE_RW check to also: - validate that the mapping is writable from a protection keys standpoint - validate that the pte has _PAGE_USER set since all fault paths where pud_write is must be referencing user-memory. [dan.j.williams@intel.com: fix powerpc compile error] Link: http://lkml.kernel.org/r/151129127237.37405.16073414520854722485.stgit@dwillia2-desk3.amr.corp.intel.com Link: http://lkml.kernel.org/r/151043110453.2842.2166049702068628177.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Linus Torvalds
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f55e1014f9 |
Revert "mm, thp: Do not make pmd/pud dirty without a reason"
This reverts commit
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Kirill A. Shutemov
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152e93af3c |
mm, thp: Do not make pmd/pud dirty without a reason
Currently we make page table entries dirty all the time regardless of access type and don't even consider if the mapping is write-protected. The reasoning is that we don't really need dirty tracking on THP and making the entry dirty upfront may save some time on first write to the page. Unfortunately, such approach may result in false-positive can_follow_write_pmd() for huge zero page or read-only shmem file. Let's only make page dirty only if we about to write to the page anyway (as we do for small pages). I've restructured the code to make entry dirty inside maybe_p[mu]d_mkwrite(). It also takes into account if the vma is write-protected. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Michal Hocko
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0a7f682d04 |
mm: do not rely on preempt_count in print_vma_addr
The preempt count check on print_vma_addr has been added by commit |
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Kirill A. Shutemov
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c4812909f5 |
mm: introduce wrappers to access mm->nr_ptes
Let's add wrappers for ->nr_ptes with the same interface as for nr_pmd and nr_pud. The patch also makes nr_ptes accounting dependent onto CONFIG_MMU. Page table accounting doesn't make sense if you don't have page tables. It's preparation for consolidation of page-table counters in mm_struct. Link: http://lkml.kernel.org/r/20171006100651.44742-1-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Kirill A. Shutemov
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b4e98d9ac7 |
mm: account pud page tables
On a machine with 5-level paging support a process can allocate
significant amount of memory and stay unnoticed by oom-killer and memory
cgroup. The trick is to allocate a lot of PUD page tables. We don't
account PUD page tables, only PMD and PTE.
We already addressed the same issue for PMD page tables, see commit
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Jérôme Glisse
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4645b9fe84 |
mm/mmu_notifier: avoid call to invalidate_range() in range_end()
This is an optimization patch that only affect mmu_notifier users which
rely on the invalidate_range() callback. This patch avoids calling that
callback twice in a row from inside __mmu_notifier_invalidate_range_end
Existing pattern (before this patch):
mmu_notifier_invalidate_range_start()
pte/pmd/pud_clear_flush_notify()
mmu_notifier_invalidate_range()
mmu_notifier_invalidate_range_end()
mmu_notifier_invalidate_range()
New pattern (after this patch):
mmu_notifier_invalidate_range_start()
pte/pmd/pud_clear_flush_notify()
mmu_notifier_invalidate_range()
mmu_notifier_invalidate_range_only_end()
We call the invalidate_range callback after clearing the page table
under the page table lock and we skip the call to invalidate_range
inside the __mmu_notifier_invalidate_range_end() function.
Idea from Andrea Arcangeli
Link: http://lkml.kernel.org/r/20171017031003.7481-3-jglisse@redhat.com
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Joerg Roedel <jroedel@suse.de>
Cc: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Alistair Popple <alistair@popple.id.au>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Minchan Kim
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aa8d22a11d |
mm: swap: SWP_SYNCHRONOUS_IO: skip swapcache only if swapped page has no other reference
When SWP_SYNCHRONOUS_IO swapped-in pages are shared by several processes, it can cause unnecessary memory wastage by skipping swap cache. Because, with swapin fault by read, they could share a page if the page were in swap cache. Thus, it avoids allocating same content new pages. This patch makes the swapcache skipping work only if the swap pte is non-sharable. [akpm@linux-foundation.org: coding-style fixes] Link: http://lkml.kernel.org/r/1507620825-5537-1-git-send-email-minchan@kernel.org Signed-off-by: Minchan Kim <minchan@kernel.org> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Hugh Dickins <hughd@google.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Ilya Dryomov <idryomov@gmail.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Huang Ying <ying.huang@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Minchan Kim
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0bcac06f27 |
mm, swap: skip swapcache for swapin of synchronous device
With fast swap storage, the platforms want to use swap more aggressively and swap-in is crucial to application latency. The rw_page() based synchronous devices like zram, pmem and btt are such fast storage. When I profile swapin performance with zram lz4 decompress test, S/W overhead is more than 70%. Maybe, it would be bigger in nvdimm. This patch aims to reduce swap-in latency by skipping swapcache if the swap device is synchronous device like rw_page based device. It enhances 45% my swapin test(5G sequential swapin, no readahead, from 2.41sec to 1.64sec). Link: http://lkml.kernel.org/r/1505886205-9671-5-git-send-email-minchan@kernel.org Signed-off-by: Minchan Kim <minchan@kernel.org> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Hugh Dickins <hughd@google.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Ilya Dryomov <idryomov@gmail.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Huang Ying <ying.huang@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Paul E. McKenney
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b03a0fe0c5 |
locking/atomics, mm: Convert ACCESS_ONCE() to READ_ONCE()/WRITE_ONCE()
For several reasons, it is desirable to use {READ,WRITE}_ONCE() in
preference to ACCESS_ONCE(), and new code is expected to use one of the
former. So far, there's been no reason to change most existing uses of
ACCESS_ONCE(), as these aren't currently harmful.
However, for some features it is necessary to instrument reads and
writes separately, which is not possible with ACCESS_ONCE(). This
distinction is critical to correct operation.
It's possible to transform the bulk of kernel code using the Coccinelle
script below. However, this doesn't handle comments, leaving references
to ACCESS_ONCE() instances which have been removed. As a preparatory
step, this patch converts the mm code and comments to use
{READ,WRITE}_ONCE() consistently.
----
virtual patch
@ depends on patch @
expression E1, E2;
@@
- ACCESS_ONCE(E1) = E2
+ WRITE_ONCE(E1, E2)
@ depends on patch @
expression E;
@@
- ACCESS_ONCE(E)
+ READ_ONCE(E)
----
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: davem@davemloft.net
Cc: linux-arch@vger.kernel.org
Cc: mpe@ellerman.id.au
Cc: shuah@kernel.org
Cc: snitzer@redhat.com
Cc: thor.thayer@linux.intel.com
Cc: tj@kernel.org
Cc: viro@zeniv.linux.org.uk
Link: http://lkml.kernel.org/r/1508792849-3115-15-git-send-email-paulmck@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Reza Arbab
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7d790d2da3 |
mm/device-public-memory: fix edge case in _vm_normal_page()
With device public pages at the end of my memory space, I'm getting
output from _vm_normal_page():
BUG: Bad page map in process migrate_pages pte:c0800001ffff0d06 pmd:f95d3000
addr:00007fff89330000 vm_flags:00100073 anon_vma:c0000000fa899320 mapping: (null) index:7fff8933
file: (null) fault: (null) mmap: (null) readpage: (null)
CPU: 0 PID: 13963 Comm: migrate_pages Tainted: P B OE 4.14.0-rc1-wip #155
Call Trace:
dump_stack+0xb0/0xf4 (unreliable)
print_bad_pte+0x28c/0x340
_vm_normal_page+0xc0/0x140
zap_pte_range+0x664/0xc10
unmap_page_range+0x318/0x670
unmap_vmas+0x74/0xe0
exit_mmap+0xe8/0x1f0
mmput+0xac/0x1f0
do_exit+0x348/0xcd0
do_group_exit+0x5c/0xf0
SyS_exit_group+0x1c/0x20
system_call+0x58/0x6c
The pfn causing this is the very last one. Correct the bounds check
accordingly.
Fixes:
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Davidlohr Bueso
|
f808c13fd3 |
lib/interval_tree: fast overlap detection
Allow interval trees to quickly check for overlaps to avoid unnecesary tree lookups in interval_tree_iter_first(). As of this patch, all interval tree flavors will require using a 'rb_root_cached' such that we can have the leftmost node easily available. While most users will make use of this feature, those with special functions (in addition to the generic insert, delete, search calls) will avoid using the cached option as they can do funky things with insertions -- for example, vma_interval_tree_insert_after(). [jglisse@redhat.com: fix deadlock from typo vm_lock_anon_vma()] Link: http://lkml.kernel.org/r/20170808225719.20723-1-jglisse@redhat.com Link: http://lkml.kernel.org/r/20170719014603.19029-12-dave@stgolabs.net Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Signed-off-by: Jérôme Glisse <jglisse@redhat.com> Acked-by: Christian König <christian.koenig@amd.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Doug Ledford <dledford@redhat.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Cc: David Airlie <airlied@linux.ie> Cc: Jason Wang <jasowang@redhat.com> Cc: Christian Benvenuti <benve@cisco.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Laurent Dufour
|
de0c799bba |
mm/memory.c: fix mem_cgroup_oom_disable() call missing
Seen while reading the code, in handle_mm_fault(), in the case
arch_vma_access_permitted() is failing the call to
mem_cgroup_oom_disable() is not made.
To fix that, move the call to mem_cgroup_oom_enable() after calling
arch_vma_access_permitted() as it should not have entered the memcg OOM.
Link: http://lkml.kernel.org/r/1504625439-31313-1-git-send-email-ldufour@linux.vnet.ibm.com
Fixes:
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Anshuman Khandual
|
fde26bed58 |
mm/memory.c: remove reduntant check for write access
Flags argument has been copied into vmf.flags and it is not changed in between. Hence a single write access check can be used for both PUD and PMD. Link: http://lkml.kernel.org/r/20170823082839.1812-1-khandual@linux.vnet.ibm.com Signed-off-by: Anshuman Khandual <khandual@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Jérôme Glisse
|
df6ad69838 |
mm/device-public-memory: device memory cache coherent with CPU
Platform with advance system bus (like CAPI or CCIX) allow device memory to be accessible from CPU in a cache coherent fashion. Add a new type of ZONE_DEVICE to represent such memory. The use case are the same as for the un-addressable device memory but without all the corners cases. Link: http://lkml.kernel.org/r/20170817000548.32038-19-jglisse@redhat.com Signed-off-by: Jérôme Glisse <jglisse@redhat.com> Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Balbir Singh <bsingharora@gmail.com> Cc: David Nellans <dnellans@nvidia.com> Cc: Evgeny Baskakov <ebaskakov@nvidia.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Mark Hairgrove <mhairgrove@nvidia.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Sherry Cheung <SCheung@nvidia.com> Cc: Subhash Gutti <sgutti@nvidia.com> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: Bob Liu <liubo95@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Jérôme Glisse
|
5042db43cc |
mm/ZONE_DEVICE: new type of ZONE_DEVICE for unaddressable memory
HMM (heterogeneous memory management) need struct page to support migration from system main memory to device memory. Reasons for HMM and migration to device memory is explained with HMM core patch. This patch deals with device memory that is un-addressable memory (ie CPU can not access it). Hence we do not want those struct page to be manage like regular memory. That is why we extend ZONE_DEVICE to support different types of memory. A persistent memory type is define for existing user of ZONE_DEVICE and a new device un-addressable type is added for the un-addressable memory type. There is a clear separation between what is expected from each memory type and existing user of ZONE_DEVICE are un-affected by new requirement and new use of the un-addressable type. All specific code path are protect with test against the memory type. Because memory is un-addressable we use a new special swap type for when a page is migrated to device memory (this reduces the number of maximum swap file). The main two additions beside memory type to ZONE_DEVICE is two callbacks. First one, page_free() is call whenever page refcount reach 1 (which means the page is free as ZONE_DEVICE page never reach a refcount of 0). This allow device driver to manage its memory and associated struct page. The second callback page_fault() happens when there is a CPU access to an address that is back by a device page (which are un-addressable by the CPU). This callback is responsible to migrate the page back to system main memory. Device driver can not block migration back to system memory, HMM make sure that such page can not be pin into device memory. If device is in some error condition and can not migrate memory back then a CPU page fault to device memory should end with SIGBUS. [arnd@arndb.de: fix warning] Link: http://lkml.kernel.org/r/20170823133213.712917-1-arnd@arndb.de Link: http://lkml.kernel.org/r/20170817000548.32038-8-jglisse@redhat.com Signed-off-by: Jérôme Glisse <jglisse@redhat.com> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Dan Williams <dan.j.williams@intel.com> Cc: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com> Cc: Balbir Singh <bsingharora@gmail.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: David Nellans <dnellans@nvidia.com> Cc: Evgeny Baskakov <ebaskakov@nvidia.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Mark Hairgrove <mhairgrove@nvidia.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Sherry Cheung <SCheung@nvidia.com> Cc: Subhash Gutti <sgutti@nvidia.com> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: Bob Liu <liubo95@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Zi Yan
|
84c3fc4e9c |
mm: thp: check pmd migration entry in common path
When THP migration is being used, memory management code needs to handle pmd migration entries properly. This patch uses !pmd_present() or is_swap_pmd() (depending on whether pmd_none() needs separate code or not) to check pmd migration entries at the places where a pmd entry is present. Since pmd-related code uses split_huge_page(), split_huge_pmd(), pmd_trans_huge(), pmd_trans_unstable(), or pmd_none_or_trans_huge_or_clear_bad(), this patch: 1. adds pmd migration entry split code in split_huge_pmd(), 2. takes care of pmd migration entries whenever pmd_trans_huge() is present, 3. makes pmd_none_or_trans_huge_or_clear_bad() pmd migration entry aware. Since split_huge_page() uses split_huge_pmd() and pmd_trans_unstable() is equivalent to pmd_none_or_trans_huge_or_clear_bad(), we do not change them. Until this commit, a pmd entry should be: 1. pointing to a pte page, 2. is_swap_pmd(), 3. pmd_trans_huge(), 4. pmd_devmap(), or 5. pmd_none(). Signed-off-by: Zi Yan <zi.yan@cs.rutgers.edu> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: David Nellans <dnellans@nvidia.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Minchan Kim <minchan@kernel.org> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.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> |
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Huang Ying
|
c79b57e462 |
mm: hugetlb: clear target sub-page last when clearing huge page
Huge page helps to reduce TLB miss rate, but it has higher cache footprint, sometimes this may cause some issue. For example, when clearing huge page on x86_64 platform, the cache footprint is 2M. But on a Xeon E5 v3 2699 CPU, there are 18 cores, 36 threads, and only 45M LLC (last level cache). That is, in average, there are 2.5M LLC for each core and 1.25M LLC for each thread. If the cache pressure is heavy when clearing the huge page, and we clear the huge page from the begin to the end, it is possible that the begin of huge page is evicted from the cache after we finishing clearing the end of the huge page. And it is possible for the application to access the begin of the huge page after clearing the huge page. To help the above situation, in this patch, when we clear a huge page, the order to clear sub-pages is changed. In quite some situation, we can get the address that the application will access after we clear the huge page, for example, in a page fault handler. Instead of clearing the huge page from begin to end, we will clear the sub-pages farthest from the the sub-page to access firstly, and clear the sub-page to access last. This will make the sub-page to access most cache-hot and sub-pages around it more cache-hot too. If we cannot know the address the application will access, the begin of the huge page is assumed to be the the address the application will access. With this patch, the throughput increases ~28.3% in vm-scalability anon-w-seq test case with 72 processes on a 2 socket Xeon E5 v3 2699 system (36 cores, 72 threads). The test case creates 72 processes, each process mmap a big anonymous memory area and writes to it from the begin to the end. For each process, other processes could be seen as other workload which generates heavy cache pressure. At the same time, the cache miss rate reduced from ~33.4% to ~31.7%, the IPC (instruction per cycle) increased from 0.56 to 0.74, and the time spent in user space is reduced ~7.9% Christopher Lameter suggests to clear bytes inside a sub-page from end to begin too. But tests show no visible performance difference in the tests. May because the size of page is small compared with the cache size. Thanks Andi Kleen to propose to use address to access to determine the order of sub-pages to clear. The hugetlbfs access address could be improved, will do that in another patch. [ying.huang@intel.com: improve readability of clear_huge_page()] Link: http://lkml.kernel.org/r/20170830051842.1397-1-ying.huang@intel.com Link: http://lkml.kernel.org/r/20170815014618.15842-1-ying.huang@intel.com Suggested-by: Andi Kleen <andi.kleen@intel.com> Signed-off-by: "Huang, Ying" <ying.huang@intel.com> Acked-by: Jan Kara <jack@suse.cz> Reviewed-by: Michal Hocko <mhocko@suse.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Nadia Yvette Chambers <nyc@holomorphy.com> Cc: Matthew Wilcox <mawilcox@microsoft.com> Cc: Hugh Dickins <hughd@google.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Shaohua Li <shli@fb.com> Cc: Christopher Lameter <cl@linux.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Huang Ying
|
ec560175c0 |
mm, swap: VMA based swap readahead
The swap readahead is an important mechanism to reduce the swap in latency. Although pure sequential memory access pattern isn't very popular for anonymous memory, the space locality is still considered valid. In the original swap readahead implementation, the consecutive blocks in swap device are readahead based on the global space locality estimation. But the consecutive blocks in swap device just reflect the order of page reclaiming, don't necessarily reflect the access pattern in virtual memory. And the different tasks in the system may have different access patterns, which makes the global space locality estimation incorrect. In this patch, when page fault occurs, the virtual pages near the fault address will be readahead instead of the swap slots near the fault swap slot in swap device. This avoid to readahead the unrelated swap slots. At the same time, the swap readahead is changed to work on per-VMA from globally. So that the different access patterns of the different VMAs could be distinguished, and the different readahead policy could be applied accordingly. The original core readahead detection and scaling algorithm is reused, because it is an effect algorithm to detect the space locality. The test and result is as follow, Common test condition ===================== Test Machine: Xeon E5 v3 (2 sockets, 72 threads, 32G RAM) Swap device: NVMe disk Micro-benchmark with combined access pattern ============================================ vm-scalability, sequential swap test case, 4 processes to eat 50G virtual memory space, repeat the sequential memory writing until 300 seconds. The first round writing will trigger swap out, the following rounds will trigger sequential swap in and out. At the same time, run vm-scalability random swap test case in background, 8 processes to eat 30G virtual memory space, repeat the random memory write until 300 seconds. This will trigger random swap-in in the background. This is a combined workload with sequential and random memory accessing at the same time. The result (for sequential workload) is as follow, Base Optimized ---- --------- throughput 345413 KB/s 414029 KB/s (+19.9%) latency.average 97.14 us 61.06 us (-37.1%) latency.50th 2 us 1 us latency.60th 2 us 1 us latency.70th 98 us 2 us latency.80th 160 us 2 us latency.90th 260 us 217 us latency.95th 346 us 369 us latency.99th 1.34 ms 1.09 ms ra_hit% 52.69% 99.98% The original swap readahead algorithm is confused by the background random access workload, so readahead hit rate is lower. The VMA-base readahead algorithm works much better. Linpack ======= The test memory size is bigger than RAM to trigger swapping. Base Optimized ---- --------- elapsed_time 393.49 s 329.88 s (-16.2%) ra_hit% 86.21% 98.82% The score of base and optimized kernel hasn't visible changes. But the elapsed time reduced and readahead hit rate improved, so the optimized kernel runs better for startup and tear down stages. And the absolute value of readahead hit rate is high, shows that the space locality is still valid in some practical workloads. Link: http://lkml.kernel.org/r/20170807054038.1843-4-ying.huang@intel.com Signed-off-by: "Huang, Ying" <ying.huang@intel.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Rik van Riel <riel@redhat.com> Cc: Shaohua Li <shli@kernel.org> Cc: Hugh Dickins <hughd@google.com> Cc: Fengguang Wu <fengguang.wu@intel.com> Cc: Tim Chen <tim.c.chen@intel.com> Cc: Dave Hansen <dave.hansen@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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|
Huang Ying
|
ba3c4ce6de |
mm, THP, swap: make reuse_swap_page() works for THP swapped out
After supporting to delay THP (Transparent Huge Page) splitting after swapped out, it is possible that some page table mappings of the THP are turned into swap entries. So reuse_swap_page() need to check the swap count in addition to the map count as before. This patch done that. In the huge PMD write protect fault handler, in addition to the page map count, the swap count need to be checked too, so the page lock need to be acquired too when calling reuse_swap_page() in addition to the page table lock. [ying.huang@intel.com: silence a compiler warning] Link: http://lkml.kernel.org/r/87bmnzizjy.fsf@yhuang-dev.intel.com Link: http://lkml.kernel.org/r/20170724051840.2309-4-ying.huang@intel.com Signed-off-by: "Huang, Ying" <ying.huang@intel.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Hugh Dickins <hughd@google.com> Cc: Shaohua Li <shli@kernel.org> Cc: Rik van Riel <riel@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Michal Hocko <mhocko@kernel.org> Cc: Ross Zwisler <ross.zwisler@intel.com> [for brd.c, zram_drv.c, pmem.c] Cc: Vishal L Verma <vishal.l.verma@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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|
Mel Gorman
|
4647706ebe |
mm: always flush VMA ranges affected by zap_page_range
Nadav Amit report zap_page_range only specifies that the caller protect
the VMA list but does not specify whether it is held for read or write
with callers using either. madvise holds mmap_sem for read meaning that
a parallel zap operation can unmap PTEs which are then potentially
skipped by madvise which potentially returns with stale TLB entries
present. While the API could be extended, it would be a difficult API
to use. This patch causes zap_page_range() to always consider flushing
the full affected range. For small ranges or sparsely populated
mappings, this may result in one additional spurious TLB flush. For
larger ranges, it is possible that the TLB has already been flushed and
the overhead is negligible. Either way, this approach is safer overall
and avoids stale entries being present when madvise returns.
This can be illustrated with the following program provided by Nadav
Amit and slightly modified. With the patch applied, it has an exit code
of 0 indicating a stale TLB entry did not leak to userspace.
---8<---
volatile int sync_step = 0;
volatile char *p;
static inline unsigned long rdtsc()
{
unsigned long hi, lo;
__asm__ __volatile__ ("rdtsc" : "=a"(lo), "=d"(hi));
return lo | (hi << 32);
}
static inline void wait_rdtsc(unsigned long cycles)
{
unsigned long tsc = rdtsc();
while (rdtsc() - tsc < cycles);
}
void *big_madvise_thread(void *ign)
{
sync_step = 1;
while (sync_step != 2);
madvise((void*)p, PAGE_SIZE * N_PAGES, MADV_DONTNEED);
}
int main(void)
{
pthread_t aux_thread;
p = mmap(0, PAGE_SIZE * N_PAGES, PROT_READ|PROT_WRITE,
MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
memset((void*)p, 8, PAGE_SIZE * N_PAGES);
pthread_create(&aux_thread, NULL, big_madvise_thread, NULL);
while (sync_step != 1);
*p = 8; // Cache in TLB
sync_step = 2;
wait_rdtsc(100000);
madvise((void*)p, PAGE_SIZE, MADV_DONTNEED);
printf("data: %d (%s)\n", *p, (*p == 8 ? "stale, broken" : "cleared, fine"));
return *p == 8 ? -1 : 0;
}
---8<---
Link: http://lkml.kernel.org/r/20170725101230.5v7gvnjmcnkzzql3@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@suse.de>
Reported-by: Nadav Amit <nadav.amit@gmail.com>
Cc: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Ross Zwisler
|
b2770da642 |
mm: add vm_insert_mixed_mkwrite()
When servicing mmap() reads from file holes the current DAX code allocates a page cache page of all zeroes and places the struct page pointer in the mapping->page_tree radix tree. This has three major drawbacks: 1) It consumes memory unnecessarily. For every 4k page that is read via a DAX mmap() over a hole, we allocate a new page cache page. This means that if you read 1GiB worth of pages, you end up using 1GiB of zeroed memory. 2) It is slower than using a common zero page because each page fault has more work to do. Instead of just inserting a common zero page we have to allocate a page cache page, zero it, and then insert it. 3) The fact that we had to check for both DAX exceptional entries and for page cache pages in the radix tree made the DAX code more complex. This series solves these issues by following the lead of the DAX PMD code and using a common 4k zero page instead. This reduces memory usage and decreases latencies for some workloads, and it simplifies the DAX code, removing over 100 lines in total. This patch (of 5): To be able to use the common 4k zero page in DAX we need to have our PTE fault path look more like our PMD fault path where a PTE entry can be marked as dirty and writeable as it is first inserted rather than waiting for a follow-up dax_pfn_mkwrite() => finish_mkwrite_fault() call. Right now we can rely on having a dax_pfn_mkwrite() call because we can distinguish between these two cases in do_wp_page(): case 1: 4k zero page => writable DAX storage case 2: read-only DAX storage => writeable DAX storage This distinction is made by via vm_normal_page(). vm_normal_page() returns false for the common 4k zero page, though, just as it does for DAX ptes. Instead of special casing the DAX + 4k zero page case we will simplify our DAX PTE page fault sequence so that it matches our DAX PMD sequence, and get rid of the dax_pfn_mkwrite() helper. We will instead use dax_iomap_fault() to handle write-protection faults. This means that insert_pfn() needs to follow the lead of insert_pfn_pmd() and allow us to pass in a 'mkwrite' flag. If 'mkwrite' is set insert_pfn() will do the work that was previously done by wp_page_reuse() as part of the dax_pfn_mkwrite() call path. Link: http://lkml.kernel.org/r/20170724170616.25810-2-ross.zwisler@linux.intel.com Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com> Reviewed-by: Jan Kara <jack@suse.cz> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: "Darrick J. Wong" <darrick.wong@oracle.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Christoph Hellwig <hch@lst.de> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Matthew Wilcox <mawilcox@microsoft.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> |
|
|
Jérôme Glisse
|
a4d1a88525 |
dax: update to new mmu_notifier semantic
Replace all mmu_notifier_invalidate_page() calls by *_invalidate_range() and make sure it is bracketed by calls to *_invalidate_range_start()/end(). Note that because we can not presume the pmd value or pte value we have to assume the worst and unconditionaly report an invalidation as happening. Signed-off-by: Jérôme Glisse <jglisse@redhat.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Bernhard Held <berny156@gmx.de> Cc: Adam Borowski <kilobyte@angband.pl> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Radim Krčmář <rkrcmar@redhat.com> Cc: Wanpeng Li <kernellwp@gmail.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Takashi Iwai <tiwai@suse.de> Cc: Nadav Amit <nadav.amit@gmail.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: axie <axie@amd.com> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
|
|
Michal Hocko
|
6b31d5955c |
mm, oom: fix potential data corruption when oom_reaper races with writer
Wenwei Tao has noticed that our current assumption that the oom victim
is dying and never doing any visible changes after it dies, and so the
oom_reaper can tear it down, is not entirely true.
__task_will_free_mem consider a task dying when SIGNAL_GROUP_EXIT is set
but do_group_exit sends SIGKILL to all threads _after_ the flag is set.
So there is a race window when some threads won't have
fatal_signal_pending while the oom_reaper could start unmapping the
address space. Moreover some paths might not check for fatal signals
before each PF/g-u-p/copy_from_user.
We already have a protection for oom_reaper vs. PF races by checking
MMF_UNSTABLE. This has been, however, checked only for kernel threads
(use_mm users) which can outlive the oom victim. A simple fix would be
to extend the current check in handle_mm_fault for all tasks but that
wouldn't be sufficient because the current check assumes that a kernel
thread would bail out after EFAULT from get_user*/copy_from_user and
never re-read the same address which would succeed because the PF path
has established page tables already. This seems to be the case for the
only existing use_mm user currently (virtio driver) but it is rather
fragile in general.
This is even more fragile in general for more complex paths such as
generic_perform_write which can re-read the same address more times
(e.g. iov_iter_copy_from_user_atomic to fail and then
iov_iter_fault_in_readable on retry).
Therefore we have to implement MMF_UNSTABLE protection in a robust way
and never make a potentially corrupted content visible. That requires
to hook deeper into the PF path and check for the flag _every time_
before a pte for anonymous memory is established (that means all
!VM_SHARED mappings).
The corruption can be triggered artificially
(http://lkml.kernel.org/r/201708040646.v746kkhC024636@www262.sakura.ne.jp)
but there doesn't seem to be any real life bug report. The race window
should be quite tight to trigger most of the time.
Link: http://lkml.kernel.org/r/20170807113839.16695-3-mhocko@kernel.org
Fixes:
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|
|
Michal Hocko
|
5b53a6ea88 |
mm: fix double mmap_sem unlock on MMF_UNSTABLE enforced SIGBUS
Tetsuo Handa has noticed that MMF_UNSTABLE SIGBUS path in
handle_mm_fault causes a lockdep splat
Out of memory: Kill process 1056 (a.out) score 603 or sacrifice child
Killed process 1056 (a.out) total-vm:4268108kB, anon-rss:2246048kB, file-rss:0kB, shmem-rss:0kB
a.out (1169) used greatest stack depth: 11664 bytes left
DEBUG_LOCKS_WARN_ON(depth <= 0)
------------[ cut here ]------------
WARNING: CPU: 6 PID: 1339 at kernel/locking/lockdep.c:3617 lock_release+0x172/0x1e0
CPU: 6 PID: 1339 Comm: a.out Not tainted 4.13.0-rc3-next-20170803+ #142
Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 07/02/2015
RIP: 0010:lock_release+0x172/0x1e0
Call Trace:
up_read+0x1a/0x40
__do_page_fault+0x28e/0x4c0
do_page_fault+0x30/0x80
page_fault+0x28/0x30
The reason is that the page fault path might have dropped the mmap_sem
and returned with VM_FAULT_RETRY. MMF_UNSTABLE check however rewrites
the error path to VM_FAULT_SIGBUS and we always expect mmap_sem taken in
that path. Fix this by taking mmap_sem when VM_FAULT_RETRY is held in
the MMF_UNSTABLE path.
We cannot simply add VM_FAULT_SIGBUS to the existing error code because
all arch specific page fault handlers and g-u-p would have to learn a
new error code combination.
Link: http://lkml.kernel.org/r/20170807113839.16695-2-mhocko@kernel.org
Fixes:
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|
|
Minchan Kim
|
99baac21e4 |
mm: fix MADV_[FREE|DONTNEED] TLB flush miss problem
Nadav reported parallel MADV_DONTNEED on same range has a stale TLB problem and Mel fixed it[1] and found same problem on MADV_FREE[2]. Quote from Mel Gorman: "The race in question is CPU 0 running madv_free and updating some PTEs while CPU 1 is also running madv_free and looking at the same PTEs. CPU 1 may have writable TLB entries for a page but fail the pte_dirty check (because CPU 0 has updated it already) and potentially fail to flush. Hence, when madv_free on CPU 1 returns, there are still potentially writable TLB entries and the underlying PTE is still present so that a subsequent write does not necessarily propagate the dirty bit to the underlying PTE any more. Reclaim at some unknown time at the future may then see that the PTE is still clean and discard the page even though a write has happened in the meantime. I think this is possible but I could have missed some protection in madv_free that prevents it happening." This patch aims for solving both problems all at once and is ready for other problem with KSM, MADV_FREE and soft-dirty story[3]. TLB batch API(tlb_[gather|finish]_mmu] uses [inc|dec]_tlb_flush_pending and mmu_tlb_flush_pending so that when tlb_finish_mmu is called, we can catch there are parallel threads going on. In that case, forcefully, flush TLB to prevent for user to access memory via stale TLB entry although it fail to gather page table entry. I confirmed this patch works with [4] test program Nadav gave so this patch supersedes "mm: Always flush VMA ranges affected by zap_page_range v2" in current mmotm. NOTE: This patch modifies arch-specific TLB gathering interface(x86, ia64, s390, sh, um). It seems most of architecture are straightforward but s390 need to be careful because tlb_flush_mmu works only if mm->context.flush_mm is set to non-zero which happens only a pte entry really is cleared by ptep_get_and_clear and friends. However, this problem never changes the pte entries but need to flush to prevent memory access from stale tlb. [1] http://lkml.kernel.org/r/20170725101230.5v7gvnjmcnkzzql3@techsingularity.net [2] http://lkml.kernel.org/r/20170725100722.2dxnmgypmwnrfawp@suse.de [3] http://lkml.kernel.org/r/BD3A0EBE-ECF4-41D4-87FA-C755EA9AB6BD@gmail.com [4] https://patchwork.kernel.org/patch/9861621/ [minchan@kernel.org: decrease tlb flush pending count in tlb_finish_mmu] Link: http://lkml.kernel.org/r/20170808080821.GA31730@bbox Link: http://lkml.kernel.org/r/20170802000818.4760-7-namit@vmware.com Signed-off-by: Minchan Kim <minchan@kernel.org> Signed-off-by: Nadav Amit <namit@vmware.com> Reported-by: Nadav Amit <namit@vmware.com> Reported-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Mel Gorman <mgorman@techsingularity.net> Cc: Ingo Molnar <mingo@redhat.com> Cc: Russell King <linux@armlinux.org.uk> Cc: Tony Luck <tony.luck@intel.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: Jeff Dike <jdike@addtoit.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Nadav Amit <nadav.amit@gmail.com> Cc: Rik van Riel <riel@redhat.com> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
|
|
Minchan Kim
|
56236a5955 |
mm: refactor TLB gathering API
This patch is a preparatory patch for solving race problems caused by TLB batch. For that, we will increase/decrease TLB flush pending count of mm_struct whenever tlb_[gather|finish]_mmu is called. Before making it simple, this patch separates architecture specific part and rename it to arch_tlb_[gather|finish]_mmu and generic part just calls it. It shouldn't change any behavior. Link: http://lkml.kernel.org/r/20170802000818.4760-5-namit@vmware.com Signed-off-by: Minchan Kim <minchan@kernel.org> Signed-off-by: Nadav Amit <namit@vmware.com> Acked-by: Mel Gorman <mgorman@techsingularity.net> Cc: Ingo Molnar <mingo@redhat.com> Cc: Russell King <linux@armlinux.org.uk> Cc: Tony Luck <tony.luck@intel.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: Jeff Dike <jdike@addtoit.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Nadav Amit <nadav.amit@gmail.com> Cc: Rik van Riel <riel@redhat.com> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
|
|
Mel Gorman
|
3ea277194d |
mm, mprotect: flush TLB if potentially racing with a parallel reclaim leaving stale TLB entries
Nadav Amit identified a theoritical race between page reclaim and
mprotect due to TLB flushes being batched outside of the PTL being held.
He described the race as follows:
CPU0 CPU1
---- ----
user accesses memory using RW PTE
[PTE now cached in TLB]
try_to_unmap_one()
==> ptep_get_and_clear()
==> set_tlb_ubc_flush_pending()
mprotect(addr, PROT_READ)
==> change_pte_range()
==> [ PTE non-present - no flush ]
user writes using cached RW PTE
...
try_to_unmap_flush()
The same type of race exists for reads when protecting for PROT_NONE and
also exists for operations that can leave an old TLB entry behind such
as munmap, mremap and madvise.
For some operations like mprotect, it's not necessarily a data integrity
issue but it is a correctness issue as there is a window where an
mprotect that limits access still allows access. For munmap, it's
potentially a data integrity issue although the race is massive as an
munmap, mmap and return to userspace must all complete between the
window when reclaim drops the PTL and flushes the TLB. However, it's
theoritically possible so handle this issue by flushing the mm if
reclaim is potentially currently batching TLB flushes.
Other instances where a flush is required for a present pte should be ok
as either the page lock is held preventing parallel reclaim or a page
reference count is elevated preventing a parallel free leading to
corruption. In the case of page_mkclean there isn't an obvious path
that userspace could take advantage of without using the operations that
are guarded by this patch. Other users such as gup as a race with
reclaim looks just at PTEs. huge page variants should be ok as they
don't race with reclaim. mincore only looks at PTEs. userfault also
should be ok as if a parallel reclaim takes place, it will either fault
the page back in or read some of the data before the flush occurs
triggering a fault.
Note that a variant of this patch was acked by Andy Lutomirski but this
was for the x86 parts on top of his PCID work which didn't make the 4.13
merge window as expected. His ack is dropped from this version and
there will be a follow-on patch on top of PCID that will include his
ack.
[akpm@linux-foundation.org: tweak comments]
[akpm@linux-foundation.org: fix spello]
Link: http://lkml.kernel.org/r/20170717155523.emckq2esjro6hf3z@suse.de
Reported-by: Nadav Amit <nadav.amit@gmail.com>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: <stable@vger.kernel.org> [v4.4+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
|
Geert Uytterhoeven
|
91a90140f9 |
mm/memory.c: mark create_huge_pmd() inline to prevent build failure
With gcc 4.1.2:
mm/memory.o: In function `create_huge_pmd':
memory.c:(.text+0x93e): undefined reference to `do_huge_pmd_anonymous_page'
Interestingly, create_huge_pmd() is emitted in the assembler output, but
never called.
Converting transparent_hugepage_enabled() from a macro to a static
inline function reduced the ability of the compiler to remove unused
code.
Fix this by marking create_huge_pmd() inline.
Fixes:
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|
|
Yevgen Pronenko
|
0a1345f8fe |
mm/memory.c: convert to DEFINE_DEBUGFS_ATTRIBUTE
The preferred strategy to define debugfs attributes is to use the DEFINE_DEBUGFS_ATTRIBUTE() macro and to use debugfs_create_file_unsafe(). Link: http://lkml.kernel.org/r/20170528145948.32127-1-y.pronenko@gmail.com Signed-off-by: Yevgen Pronenko <y.pronenko@gmail.com> Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com> Cc: Jan Kara <jack@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
|
|
Roman Gushchin
|
2262185c5b |
mm: per-cgroup memory reclaim stats
Track the following reclaim counters for every memory cgroup: PGREFILL, PGSCAN, PGSTEAL, PGACTIVATE, PGDEACTIVATE, PGLAZYFREE and PGLAZYFREED. These values are exposed using the memory.stats interface of cgroup v2. The meaning of each value is the same as for global counters, available using /proc/vmstat. Also, for consistency, rename mem_cgroup_count_vm_event() to count_memcg_event_mm(). Link: http://lkml.kernel.org/r/1494530183-30808-1-git-send-email-guro@fb.com Signed-off-by: Roman Gushchin <guro@fb.com> Suggested-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Vladimir Davydov <vdavydov.dev@gmail.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Tejun Heo <tj@kernel.org> Cc: Li Zefan <lizefan@huawei.com> Cc: Balbir Singh <bsingharora@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
|
|
Naoya Horiguchi
|
8bc3c3fe4f |
mm: drop NULL return check of pte_offset_map_lock()
pte_offset_map_lock() finds and takes ptl, and returns pte. But some callers return without unlocking the ptl when pte == NULL, which seems weird. Git history said that !pte check in change_pte_range() was introduced in commit |
|
|
Hugh Dickins
|
1be7107fbe |
mm: larger stack guard gap, between vmas
Stack guard page is a useful feature to reduce a risk of stack smashing into a different mapping. We have been using a single page gap which is sufficient to prevent having stack adjacent to a different mapping. But this seems to be insufficient in the light of the stack usage in userspace. E.g. glibc uses as large as 64kB alloca() in many commonly used functions. Others use constructs liks gid_t buffer[NGROUPS_MAX] which is 256kB or stack strings with MAX_ARG_STRLEN. This will become especially dangerous for suid binaries and the default no limit for the stack size limit because those applications can be tricked to consume a large portion of the stack and a single glibc call could jump over the guard page. These attacks are not theoretical, unfortunatelly. Make those attacks less probable by increasing the stack guard gap to 1MB (on systems with 4k pages; but make it depend on the page size because systems with larger base pages might cap stack allocations in the PAGE_SIZE units) which should cover larger alloca() and VLA stack allocations. It is obviously not a full fix because the problem is somehow inherent, but it should reduce attack space a lot. One could argue that the gap size should be configurable from userspace, but that can be done later when somebody finds that the new 1MB is wrong for some special case applications. For now, add a kernel command line option (stack_guard_gap) to specify the stack gap size (in page units). Implementation wise, first delete all the old code for stack guard page: because although we could get away with accounting one extra page in a stack vma, accounting a larger gap can break userspace - case in point, a program run with "ulimit -S -v 20000" failed when the 1MB gap was counted for RLIMIT_AS; similar problems could come with RLIMIT_MLOCK and strict non-overcommit mode. Instead of keeping gap inside the stack vma, maintain the stack guard gap as a gap between vmas: using vm_start_gap() in place of vm_start (or vm_end_gap() in place of vm_end if VM_GROWSUP) in just those few places which need to respect the gap - mainly arch_get_unmapped_area(), and and the vma tree's subtree_gap support for that. Original-patch-by: Oleg Nesterov <oleg@redhat.com> Original-patch-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Tested-by: Helge Deller <deller@gmx.de> # parisc Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
|
|
Ross Zwisler
|
d0f0931de9 |
mm: avoid spurious 'bad pmd' warning messages
When the pmd_devmap() checks were added by |
|
|
Al Viro
|
bee3f412d6 | Merge branch 'parisc-4.11-3' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux into uaccess.parisc | |
|
Al Viro
|
db68ce10c4 |
new helper: uaccess_kernel()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> |