summaryrefslogtreecommitdiff
path: root/mm/memory.c
AgeCommit message (Collapse)Author
2019-03-29mm/memory.c: fix modifying of page protection by insert_pfn()Jan Kara
Aneesh has reported that PPC triggers the following warning when excercising DAX code: IP set_pte_at+0x3c/0x190 LR insert_pfn+0x208/0x280 Call Trace: insert_pfn+0x68/0x280 dax_iomap_pte_fault.isra.7+0x734/0xa40 __xfs_filemap_fault+0x280/0x2d0 do_wp_page+0x48c/0xa40 __handle_mm_fault+0x8d0/0x1fd0 handle_mm_fault+0x140/0x250 __do_page_fault+0x300/0xd60 handle_page_fault+0x18 Now that is WARN_ON in set_pte_at which is VM_WARN_ON(pte_hw_valid(*ptep) && !pte_protnone(*ptep)); The problem is that on some architectures set_pte_at() cannot cope with a situation where there is already some (different) valid entry present. Use ptep_set_access_flags() instead to modify the pfn which is built to deal with modifying existing PTE. Link: http://lkml.kernel.org/r/20190311084537.16029-1-jack@suse.cz Fixes: b2770da64254 "mm: add vm_insert_mixed_mkwrite()" Signed-off-by: Jan Kara <jack@suse.cz> Reported-by: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com> Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Acked-by: Dan Williams <dan.j.williams@intel.com> Cc: Chandan Rajendra <chandan@linux.ibm.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05mm/memory.c: do_fault: avoid usage of stale vm_area_structJan Stancek
LTP testcase mtest06 [1] can trigger a crash on s390x running 5.0.0-rc8. This is a stress test, where one thread mmaps/writes/munmaps memory area and other thread is trying to read from it: CPU: 0 PID: 2611 Comm: mmap1 Not tainted 5.0.0-rc8+ #51 Hardware name: IBM 2964 N63 400 (z/VM 6.4.0) Krnl PSW : 0404e00180000000 00000000001ac8d8 (__lock_acquire+0x7/0x7a8) Call Trace: ([<0000000000000000>] (null)) [<00000000001adae4>] lock_acquire+0xec/0x258 [<000000000080d1ac>] _raw_spin_lock_bh+0x5c/0x98 [<000000000012a780>] page_table_free+0x48/0x1a8 [<00000000002f6e54>] do_fault+0xdc/0x670 [<00000000002fadae>] __handle_mm_fault+0x416/0x5f0 [<00000000002fb138>] handle_mm_fault+0x1b0/0x320 [<00000000001248cc>] do_dat_exception+0x19c/0x2c8 [<000000000080e5ee>] pgm_check_handler+0x19e/0x200 page_table_free() is called with NULL mm parameter, but because "0" is a valid address on s390 (see S390_lowcore), it keeps going until it eventually crashes in lockdep's lock_acquire. This crash is reproducible at least since 4.14. Problem is that "vmf->vma" used in do_fault() can become stale. Because mmap_sem may be released, other threads can come in, call munmap() and cause "vma" be returned to kmem cache, and get zeroed/re-initialized and re-used: handle_mm_fault | __handle_mm_fault | do_fault | vma = vmf->vma | do_read_fault | __do_fault | vma->vm_ops->fault(vmf); | mmap_sem is released | | | do_munmap() | remove_vma_list() | remove_vma() | vm_area_free() | # vma is released | ... | # same vma is allocated | # from kmem cache | do_mmap() | vm_area_alloc() | memset(vma, 0, ...) | pte_free(vma->vm_mm, ...); | page_table_free | spin_lock_bh(&mm->context.lock);| <crash> | Cache mm_struct to avoid using potentially stale "vma". [1] https://github.com/linux-test-project/ltp/blob/master/testcases/kernel/mem/mtest06/mmap1.c Link: http://lkml.kernel.org/r/5b3fdf19e2a5be460a384b936f5b56e13733f1b8.1551595137.git.jstancek@redhat.com Signed-off-by: Jan Stancek <jstancek@redhat.com> Reviewed-by: Andrea Arcangeli <aarcange@redhat.com> Reviewed-by: Matthew Wilcox <willy@infradead.org> Acked-by: Rafael Aquini <aquini@redhat.com> Reviewed-by: Minchan Kim <minchan@kernel.org> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Rik van Riel <riel@surriel.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Huang Ying <ying.huang@intel.com> Cc: Souptick Joarder <jrdr.linux@gmail.com> Cc: Jerome Glisse <jglisse@redhat.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: David Hildenbrand <david@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05docs/core-api/mm: fix return value descriptions in mm/Mike Rapoport
Many kernel-doc comments in mm/ have the return value descriptions either misformatted or omitted at all which makes kernel-doc script unhappy: $ make V=1 htmldocs ... ./mm/util.c:36: info: Scanning doc for kstrdup ./mm/util.c:41: warning: No description found for return value of 'kstrdup' ./mm/util.c:57: info: Scanning doc for kstrdup_const ./mm/util.c:66: warning: No description found for return value of 'kstrdup_const' ./mm/util.c:75: info: Scanning doc for kstrndup ./mm/util.c:83: warning: No description found for return value of 'kstrndup' ... Fixing the formatting and adding the missing return value descriptions eliminates ~100 such warnings. Link: http://lkml.kernel.org/r/1549549644-4903-4-git-send-email-rppt@linux.ibm.com Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05mm: update ptep_modify_prot_commit to take old pte value as argAneesh Kumar K.V
Architectures like ppc64 require to do a conditional tlb flush based on the old and new value of pte. Enable that by passing old pte value as the arg. Link: http://lkml.kernel.org/r/20190116085035.29729-3-aneesh.kumar@linux.ibm.com Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Paul Mackerras <paulus@samba.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>
2019-03-05mm: update ptep_modify_prot_start/commit to take vm_area_struct as argAneesh Kumar K.V
Patch series "NestMMU pte upgrade workaround for mprotect", v5. We can upgrade pte access (R -> RW transition) via mprotect. We need to make sure we follow the recommended pte update sequence as outlined in commit bd5050e38aec ("powerpc/mm/radix: Change pte relax sequence to handle nest MMU hang") for such updates. This patch series does that. This patch (of 5): Some architectures may want to call flush_tlb_range from these helpers. Link: http://lkml.kernel.org/r/20190116085035.29729-2-aneesh.kumar@linux.ibm.com Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05mm: no need to check return value of debugfs_create functionsGreg Kroah-Hartman
When calling debugfs functions, there is no need to ever check the return value. The function can work or not, but the code logic should never do something different based on this. Link: http://lkml.kernel.org/r/20190122152151.16139-14-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: David Rientjes <rientjes@google.com> Cc: Laura Abbott <labbott@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05mm/memory.c: prevent mapping typed pages to userspaceMatthew Wilcox
Pages which use page_type must never be mapped to userspace as it would destroy their page type. Add an explicit check for this instead of assuming that kernel drivers always get this right. Link: http://lkml.kernel.org/r/20190129053830.3749-1-willy@infradead.org Signed-off-by: Matthew Wilcox <willy@infradead.org> Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: David Hildenbrand <david@redhat.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05mm: prevent mapping slab pages to userspaceMatthew Wilcox
It's never appropriate to map a page allocated by SLAB into userspace. A buggy device driver might try this, or an attacker might be able to find a way to make it happen. Christoph said: : Let's just fail the code. Currently this may work with SLUB. But SLAB : and SLOB overlay fields with mapcount. So you would have a corrupted page : struct if you mapped a slab page to user space. Link: http://lkml.kernel.org/r/20190125173827.2658-1-willy@infradead.org Signed-off-by: Matthew Wilcox <willy@infradead.org> Reviewed-by: Kees Cook <keescook@chromium.org> Acked-by: Pekka Enberg <penberg@kernel.org> Cc: Rik van Riel <riel@surriel.com> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05mm: reuse only-pte-mapped KSM page in do_wp_page()Kirill Tkhai
Add an optimization for KSM pages almost in the same way that we have for ordinary anonymous pages. If there is a write fault in a page, which is mapped to an only pte, and it is not related to swap cache; the page may be reused without copying its content. [ Note that we do not consider PageSwapCache() pages at least for now, since we don't want to complicate __get_ksm_page(), which has nice optimization based on this (for the migration case). Currenly it is spinning on PageSwapCache() pages, waiting for when they have unfreezed counters (i.e., for the migration finish). But we don't want to make it also spinning on swap cache pages, which we try to reuse, since there is not a very high probability to reuse them. So, for now we do not consider PageSwapCache() pages at all. ] So in reuse_ksm_page() we check for 1) PageSwapCache() and 2) page_stable_node(), to skip a page, which KSM is currently trying to link to stable tree. Then we do page_ref_freeze() to prohibit KSM to merge one more page into the page, we are reusing. After that, nobody can refer to the reusing page: KSM skips !PageSwapCache() pages with zero refcount; and the protection against of all other participants is the same as for reused ordinary anon pages pte lock, page lock and mmap_sem. [akpm@linux-foundation.org: replace BUG_ON()s with WARN_ON()s] Link: http://lkml.kernel.org/r/154471491016.31352.1168978849911555609.stgit@localhost.localdomain Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com> Reviewed-by: Yang Shi <yang.shi@linux.alibaba.com> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Hugh Dickins <hughd@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Christian Koenig <christian.koenig@amd.com> Cc: Claudio Imbrenda <imbrenda@linux.vnet.ibm.com> Cc: Rik van Riel <riel@surriel.com> Cc: Huang Ying <ying.huang@intel.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Kirill Tkhai <ktkhai@virtuozzo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05mm: replace all open encodings for NUMA_NO_NODEAnshuman Khandual
Patch series "Replace all open encodings for NUMA_NO_NODE", v3. All these places for replacement were found by running the following grep patterns on the entire kernel code. Please let me know if this might have missed some instances. This might also have replaced some false positives. I will appreciate suggestions, inputs and review. 1. git grep "nid == -1" 2. git grep "node == -1" 3. git grep "nid = -1" 4. git grep "node = -1" This patch (of 2): At present there are multiple places where invalid node number is encoded as -1. Even though implicitly understood it is always better to have macros in there. Replace these open encodings for an invalid node number with the global macro NUMA_NO_NODE. This helps remove NUMA related assumptions like 'invalid node' from various places redirecting them to a common definition. Link: http://lkml.kernel.org/r/1545127933-10711-2-git-send-email-anshuman.khandual@arm.com Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com> Reviewed-by: David Hildenbrand <david@redhat.com> Acked-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com> [ixgbe] Acked-by: Jens Axboe <axboe@kernel.dk> [mtip32xx] Acked-by: Vinod Koul <vkoul@kernel.org> [dmaengine.c] Acked-by: Michael Ellerman <mpe@ellerman.id.au> [powerpc] Acked-by: Doug Ledford <dledford@redhat.com> [drivers/infiniband] Cc: Joseph Qi <jiangqi903@gmail.com> Cc: Hans Verkuil <hverkuil@xs4all.nl> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-01-08mm/memory.c: initialise mmu_notifier_range correctlyMatthew Wilcox
One of the paths in follow_pte_pmd() initialised the mmu_notifier_range incorrectly. Link: http://lkml.kernel.org/r/20190103002126.GM6310@bombadil.infradead.org Fixes: ac46d4f3c432 ("mm/mmu_notifier: use structure for invalidate_range_start/end calls v2") Signed-off-by: Matthew Wilcox <willy@infradead.org> Tested-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Jérôme Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.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>
2019-01-08mm, memcg: fix reclaim deadlock with writebackMichal Hocko
Liu Bo has experienced a deadlock between memcg (legacy) reclaim and the ext4 writeback task1: wait_on_page_bit+0x82/0xa0 shrink_page_list+0x907/0x960 shrink_inactive_list+0x2c7/0x680 shrink_node_memcg+0x404/0x830 shrink_node+0xd8/0x300 do_try_to_free_pages+0x10d/0x330 try_to_free_mem_cgroup_pages+0xd5/0x1b0 try_charge+0x14d/0x720 memcg_kmem_charge_memcg+0x3c/0xa0 memcg_kmem_charge+0x7e/0xd0 __alloc_pages_nodemask+0x178/0x260 alloc_pages_current+0x95/0x140 pte_alloc_one+0x17/0x40 __pte_alloc+0x1e/0x110 alloc_set_pte+0x5fe/0xc20 do_fault+0x103/0x970 handle_mm_fault+0x61e/0xd10 __do_page_fault+0x252/0x4d0 do_page_fault+0x30/0x80 page_fault+0x28/0x30 task2: __lock_page+0x86/0xa0 mpage_prepare_extent_to_map+0x2e7/0x310 [ext4] ext4_writepages+0x479/0xd60 do_writepages+0x1e/0x30 __writeback_single_inode+0x45/0x320 writeback_sb_inodes+0x272/0x600 __writeback_inodes_wb+0x92/0xc0 wb_writeback+0x268/0x300 wb_workfn+0xb4/0x390 process_one_work+0x189/0x420 worker_thread+0x4e/0x4b0 kthread+0xe6/0x100 ret_from_fork+0x41/0x50 He adds "task1 is waiting for the PageWriteback bit of the page that task2 has collected in mpd->io_submit->io_bio, and tasks2 is waiting for the LOCKED bit the page which tasks1 has locked" More precisely task1 is handling a page fault and it has a page locked while it charges a new page table to a memcg. That in turn hits a memory limit reclaim and the memcg reclaim for legacy controller is waiting on the writeback but that is never going to finish because the writeback itself is waiting for the page locked in the #PF path. So this is essentially ABBA deadlock: lock_page(A) SetPageWriteback(A) unlock_page(A) lock_page(B) lock_page(B) pte_alloc_pne shrink_page_list wait_on_page_writeback(A) SetPageWriteback(B) unlock_page(B) # flush A, B to clear the writeback This accumulating of more pages to flush is used by several filesystems to generate a more optimal IO patterns. Waiting for the writeback in legacy memcg controller is a workaround for pre-mature OOM killer invocations because there is no dirty IO throttling available for the controller. There is no easy way around that unfortunately. Therefore fix this specific issue by pre-allocating the page table outside of the page lock. We have that handy infrastructure for that already so simply reuse the fault-around pattern which already does this. There are probably other hidden __GFP_ACCOUNT | GFP_KERNEL allocations from under a fs page locked but they should be really rare. I am not aware of a better solution unfortunately. [akpm@linux-foundation.org: fix mm/memory.c:__do_fault()] [akpm@linux-foundation.org: coding-style fixes] [mhocko@kernel.org: enhance comment, per Johannes] Link: http://lkml.kernel.org/r/20181214084948.GA5624@dhcp22.suse.cz Link: http://lkml.kernel.org/r/20181213092221.27270-1-mhocko@kernel.org Fixes: c3b94f44fcb0 ("memcg: further prevent OOM with too many dirty pages") Signed-off-by: Michal Hocko <mhocko@suse.com> Reported-by: Liu Bo <bo.liu@linux.alibaba.com> Debugged-by: Liu Bo <bo.liu@linux.alibaba.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Liu Bo <bo.liu@linux.alibaba.com> Cc: Jan Kara <jack@suse.cz> Cc: Dave Chinner <david@fromorbit.com> Cc: Theodore Ts'o <tytso@mit.edu> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: Shakeel Butt <shakeelb@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>
2019-01-04mm: treewide: remove unused address argument from pte_alloc functionsJoel Fernandes (Google)
Patch series "Add support for fast mremap". This series speeds up the mremap(2) syscall by copying page tables at the PMD level even for non-THP systems. There is concern that the extra 'address' argument that mremap passes to pte_alloc may do something subtle architecture related in the future that may make the scheme not work. Also we find that there is no point in passing the 'address' to pte_alloc since its unused. This patch therefore removes this argument tree-wide resulting in a nice negative diff as well. Also ensuring along the way that the enabled architectures do not do anything funky with the 'address' argument that goes unnoticed by the optimization. Build and boot tested on x86-64. Build tested on arm64. The config enablement patch for arm64 will be posted in the future after more testing. The changes were obtained by applying the following Coccinelle script. (thanks Julia for answering all Coccinelle questions!). Following fix ups were done manually: * Removal of address argument from pte_fragment_alloc * Removal of pte_alloc_one_fast definitions from m68k and microblaze. // Options: --include-headers --no-includes // Note: I split the 'identifier fn' line, so if you are manually // running it, please unsplit it so it runs for you. virtual patch @pte_alloc_func_def depends on patch exists@ identifier E2; identifier fn =~ "^(__pte_alloc|pte_alloc_one|pte_alloc|__pte_alloc_kernel|pte_alloc_one_kernel)$"; type T2; @@ fn(... - , T2 E2 ) { ... } @pte_alloc_func_proto_noarg depends on patch exists@ type T1, T2, T3, T4; identifier fn =~ "^(__pte_alloc|pte_alloc_one|pte_alloc|__pte_alloc_kernel|pte_alloc_one_kernel)$"; @@ ( - T3 fn(T1, T2); + T3 fn(T1); | - T3 fn(T1, T2, T4); + T3 fn(T1, T2); ) @pte_alloc_func_proto depends on patch exists@ identifier E1, E2, E4; type T1, T2, T3, T4; identifier fn =~ "^(__pte_alloc|pte_alloc_one|pte_alloc|__pte_alloc_kernel|pte_alloc_one_kernel)$"; @@ ( - T3 fn(T1 E1, T2 E2); + T3 fn(T1 E1); | - T3 fn(T1 E1, T2 E2, T4 E4); + T3 fn(T1 E1, T2 E2); ) @pte_alloc_func_call depends on patch exists@ expression E2; identifier fn =~ "^(__pte_alloc|pte_alloc_one|pte_alloc|__pte_alloc_kernel|pte_alloc_one_kernel)$"; @@ fn(... -, E2 ) @pte_alloc_macro depends on patch exists@ identifier fn =~ "^(__pte_alloc|pte_alloc_one|pte_alloc|__pte_alloc_kernel|pte_alloc_one_kernel)$"; identifier a, b, c; expression e; position p; @@ ( - #define fn(a, b, c) e + #define fn(a, b) e | - #define fn(a, b) e + #define fn(a) e ) Link: http://lkml.kernel.org/r/20181108181201.88826-2-joelaf@google.com Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org> Suggested-by: Kirill A. Shutemov <kirill@shutemov.name> Acked-by: Kirill A. Shutemov <kirill@shutemov.name> Cc: Michal Hocko <mhocko@kernel.org> Cc: Julia Lawall <Julia.Lawall@lip6.fr> Cc: Kirill A. Shutemov <kirill@shutemov.name> 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>
2018-12-28mm, thp, proc: report THP eligibility for each vmaMichal Hocko
Userspace falls short when trying to find out whether a specific memory range is eligible for THP. There are usecases that would like to know that http://lkml.kernel.org/r/alpine.DEB.2.21.1809251248450.50347@chino.kir.corp.google.com : This is used to identify heap mappings that should be able to fault thp : but do not, and they normally point to a low-on-memory or fragmentation : issue. The only way to deduce this now is to query for hg resp. nh flags and confronting the state with the global setting. Except that there is also PR_SET_THP_DISABLE that might change the picture. So the final logic is not trivial. Moreover the eligibility of the vma depends on the type of VMA as well. In the past we have supported only anononymous memory VMAs but things have changed and shmem based vmas are supported as well these days and the query logic gets even more complicated because the eligibility depends on the mount option and another global configuration knob. Simplify the current state and report the THP eligibility in /proc/<pid>/smaps for each existing vma. Reuse transparent_hugepage_enabled for this purpose. The original implementation of this function assumes that the caller knows that the vma itself is supported for THP so make the core checks into __transparent_hugepage_enabled and use it for existing callers. __show_smap just use the new transparent_hugepage_enabled which also checks the vma support status (please note that this one has to be out of line due to include dependency issues). [mhocko@kernel.org: fix oops with NULL ->f_mapping] Link: http://lkml.kernel.org/r/20181224185106.GC16738@dhcp22.suse.cz Link: http://lkml.kernel.org/r/20181211143641.3503-3-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Dan Williams <dan.j.williams@intel.com> Cc: David Rientjes <rientjes@google.com> Cc: Jan Kara <jack@suse.cz> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Paul Oppenheimer <bepvte@gmail.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>
2018-12-28mm/mmu_notifier: use structure for invalidate_range_start/end calls v2Jérôme Glisse
To avoid having to change many call sites everytime we want to add a parameter use a structure to group all parameters for the mmu_notifier invalidate_range_start/end cakks. No functional changes with this patch. [akpm@linux-foundation.org: coding style fixes] Link: http://lkml.kernel.org/r/20181205053628.3210-3-jglisse@redhat.com Signed-off-by: Jérôme Glisse <jglisse@redhat.com> Acked-by: Christian König <christian.koenig@amd.com> Acked-by: Jan Kara <jack@suse.cz> Cc: Matthew Wilcox <mawilcox@microsoft.com> Cc: Ross Zwisler <zwisler@kernel.org> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Radim Krcmar <rkrcmar@redhat.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Felix Kuehling <felix.kuehling@amd.com> Cc: Ralph Campbell <rcampbell@nvidia.com> Cc: John Hubbard <jhubbard@nvidia.com> From: Jérôme Glisse <jglisse@redhat.com> Subject: mm/mmu_notifier: use structure for invalidate_range_start/end calls v3 fix build warning in migrate.c when CONFIG_MMU_NOTIFIER=n Link: http://lkml.kernel.org/r/20181213171330.8489-3-jglisse@redhat.com Signed-off-by: Jérôme Glisse <jglisse@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-31mm: Fix warning in insert_pfn()Jan Kara
In DAX mode a write pagefault can race with write(2) in the following way: CPU0 CPU1 write fault for mapped zero page (hole) dax_iomap_rw() iomap_apply() xfs_file_iomap_begin() - allocates blocks dax_iomap_actor() invalidate_inode_pages2_range() - invalidates radix tree entries in given range dax_iomap_pte_fault() grab_mapping_entry() - no entry found, creates empty ... xfs_file_iomap_begin() - finds already allocated block ... vmf_insert_mixed_mkwrite() - WARNs and does nothing because there is still zero page mapped in PTE unmap_mapping_pages() This race results in WARN_ON from insert_pfn() and is occasionally triggered by fstest generic/344. Note that the race is otherwise harmless as before write(2) on CPU0 is finished, we will invalidate page tables properly and thus user of mmap will see modified data from write(2) from that point on. So just restrict the warning only to the case when the PFN in PTE is not zero page. Link: http://lkml.kernel.org/r/20180824154542.26872-1-jack@suse.cz Signed-off-by: Jan Kara <jack@suse.cz> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Jiang <dave.jiang@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-26mm/memory.c: recheck page table entry with page table lock heldAneesh Kumar K.V
We clear the pte temporarily during read/modify/write update of the pte. If we take a page fault while the pte is cleared, the application can get SIGBUS. One such case is with remap_pfn_range without a backing vm_ops->fault callback. do_fault will return SIGBUS in that case. cpu 0 cpu1 mprotect() ptep_modify_prot_start()/pte cleared. . . page fault. . . prep_modify_prot_commit() Fix this by taking page table lock and rechecking for pte_none. [aneesh.kumar@linux.ibm.com: fix crash observed with syzkaller run] Link: http://lkml.kernel.org/r/87va6bwlfg.fsf@linux.ibm.com Link: http://lkml.kernel.org/r/20180926031858.9692-1-aneesh.kumar@linux.ibm.com Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Willem de Bruijn <willemdebruijn.kernel@gmail.com> Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Ido Schimmel <idosch@idosch.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-26mm: convert insert_pfn() to vm_fault_tMatthew Wilcox
All callers convert its errno into a vm_fault_t, so convert it to return a vm_fault_t directly. Link: http://lkml.kernel.org/r/20180828145728.11873-11-willy@infradead.org Signed-off-by: Matthew Wilcox <willy@infradead.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Nicolas Pitre <nicolas.pitre@linaro.org> Cc: Souptick Joarder <jrdr.linux@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-26mm: convert __vm_insert_mixed() to vm_fault_tMatthew Wilcox
Both of its callers currently convert its errno return into a vm_fault_t, so move the conversion into __vm_insert_mixed(). Link: http://lkml.kernel.org/r/20180828145728.11873-10-willy@infradead.org Signed-off-by: Matthew Wilcox <willy@infradead.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Nicolas Pitre <nicolas.pitre@linaro.org> Cc: Souptick Joarder <jrdr.linux@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-26mm: inline vm_insert_pfn_prot() into callerMatthew Wilcox
vm_insert_pfn_prot() is only called from vmf_insert_pfn_prot(), so inline it and convert some of the errnos into vm_fault codes earlier. Link: http://lkml.kernel.org/r/20180828145728.11873-9-willy@infradead.org Signed-off-by: Matthew Wilcox <willy@infradead.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Nicolas Pitre <nicolas.pitre@linaro.org> Cc: Souptick Joarder <jrdr.linux@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-26mm: remove vm_insert_pfn()Matthew Wilcox
All callers are now converted to vmf_insert_pfn() so convert vmf_insert_pfn() from being a compatibility wrapper around vm_insert_pfn() to being a compatibility wrapper around vmf_insert_pfn_prot(). Link: http://lkml.kernel.org/r/20180828145728.11873-8-willy@infradead.org Signed-off-by: Matthew Wilcox <willy@infradead.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Nicolas Pitre <nicolas.pitre@linaro.org> Cc: Souptick Joarder <jrdr.linux@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-26mm: make vm_insert_pfn_prot() staticMatthew Wilcox
Now this is no longer used outside mm/memory.c, make it static. Link: http://lkml.kernel.org/r/20180828145728.11873-6-willy@infradead.org Signed-off-by: Matthew Wilcox <willy@infradead.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Nicolas Pitre <nicolas.pitre@linaro.org> Cc: Souptick Joarder <jrdr.linux@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-26mm: introduce vmf_insert_pfn_prot()Matthew Wilcox
Like vm_insert_pfn_prot(), but returns a vm_fault_t instead of an errno. Also unexport vm_insert_pfn_prot as it has no modular users. Link: http://lkml.kernel.org/r/20180828145728.11873-4-willy@infradead.org Signed-off-by: Matthew Wilcox <willy@infradead.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Nicolas Pitre <nicolas.pitre@linaro.org> Cc: Souptick Joarder <jrdr.linux@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-26mm: remove vm_insert_mixed()Matthew Wilcox
All callers are now converted to vmf_insert_mixed() so convert vmf_insert_mixed() from being a compatibility wrapper into the real function. Link: http://lkml.kernel.org/r/20180828145728.11873-3-willy@infradead.org Signed-off-by: Matthew Wilcox <willy@infradead.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Nicolas Pitre <nicolas.pitre@linaro.org> Cc: Souptick Joarder <jrdr.linux@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-09-07mm/memory: Move mmu_gather and TLB invalidation code into its own filePeter Zijlstra
In preparation for maintaining the mmu_gather code as its own entity, move the implementation out of memory.c and into its own file. Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Michal Hocko <mhocko@suse.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Will Deacon <will.deacon@arm.com>
2018-09-04asm-generic/tlb: Track which levels of the page tables have been clearedWill Deacon
It is common for architectures with hugepage support to require only a single TLB invalidation operation per hugepage during unmap(), rather than iterating through the mapping at a PAGE_SIZE increment. Currently, however, the level in the page table where the unmap() operation occurs is not stored in the mmu_gather structure, therefore forcing architectures to issue additional TLB invalidation operations or to give up and over-invalidate by e.g. invalidating the entire TLB. Ideally, we could add an interval rbtree to the mmu_gather structure, which would allow us to associate the correct mapping granule with the various sub-mappings within the range being invalidated. However, this is costly in terms of book-keeping and memory management, so instead we approximate by keeping track of the page table levels that are cleared and provide a means to query the smallest granule required for invalidation. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
2018-08-25mm/cow: don't bother write protecting already write-protected pagesLinus Torvalds
This is not normally noticeable, but repeated forks are unnecessarily expensive because they repeatedly dirty the parent page tables during the page table copy operation. It's trivial to just avoid write protecting the page table entry if it was already not writable. This patch was inspired by https://bugzilla.kernel.org/show_bug.cgi?id=200447 which points to an ancient "waste time re-doing fork" issue in the presence of lots of signals. That bug was fixed by Eric Biederman's signal handling series culminating in commit c3ad2c3b02e9 ("signal: Don't restart fork when signals come in"), but the unnecessary work for repeated forks is still work just fixing, particularly since the fix is trivial. Cc: Eric Biederman <ebiederm@xmission.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-08-23Merge branch 'akpm' (patches from Andrew)Linus Torvalds
Merge yet more updates from Andrew Morton: - the rest of MM - various misc fixes and tweaks * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (22 commits) mm: Change return type int to vm_fault_t for fault handlers lib/fonts: convert comments to utf-8 s390: ebcdic: convert comments to UTF-8 treewide: convert ISO_8859-1 text comments to utf-8 drivers/gpu/drm/gma500/: change return type to vm_fault_t docs/core-api: mm-api: add section about GFP flags docs/mm: make GFP flags descriptions usable as kernel-doc docs/core-api: split memory management API to a separate file docs/core-api: move *{str,mem}dup* to "String Manipulation" docs/core-api: kill trailing whitespace in kernel-api.rst mm/util: add kernel-doc for kvfree mm/util: make strndup_user description a kernel-doc comment fs/proc/vmcore.c: hide vmcoredd_mmap_dumps() for nommu builds treewide: correct "differenciate" and "instanciate" typos fs/afs: use new return type vm_fault_t drivers/hwtracing/intel_th/msu.c: change return type to vm_fault_t mm: soft-offline: close the race against page allocation mm: fix race on soft-offlining free huge pages namei: allow restricted O_CREAT of FIFOs and regular files hfs: prevent crash on exit from failed search ...
2018-08-23mm: Change return type int to vm_fault_t for fault handlersSouptick Joarder
Use new return type vm_fault_t for fault handler. For now, this is just documenting that the function returns a VM_FAULT value rather than an errno. Once all instances are converted, vm_fault_t will become a distinct type. Ref-> commit 1c8f422059ae ("mm: change return type to vm_fault_t") The aim is to change the return type of finish_fault() and handle_mm_fault() to vm_fault_t type. As part of that clean up return type of all other recursively called functions have been changed to vm_fault_t type. The places from where handle_mm_fault() is getting invoked will be change to vm_fault_t type but in a separate patch. vmf_error() is the newly introduce inline function in 4.17-rc6. [akpm@linux-foundation.org: don't shadow outer local `ret' in __do_huge_pmd_anonymous_page()] Link: http://lkml.kernel.org/r/20180604171727.GA20279@jordon-HP-15-Notebook-PC Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com> Reviewed-by: Matthew Wilcox <mawilcox@microsoft.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.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>
2018-08-23mm: mmu_notifier fix for tlb_end_vmaNicholas Piggin
The generic tlb_end_vma does not call invalidate_range mmu notifier, and it resets resets the mmu_gather range, which means the notifier won't be called on part of the range in case of an unmap that spans multiple vmas. ARM64 seems to be the only arch I could see that has notifiers and uses the generic tlb_end_vma. I have not actually tested it. [ Catalin and Will point out that ARM64 currently only uses the notifiers for KVM, which doesn't use the ->invalidate_range() callback right now, so it's a bug, but one that happens to not affect them. So not necessary for stable. - Linus ] Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-08-23mm/tlb, x86/mm: Support invalidating TLB caches for RCU_TABLE_FREEPeter Zijlstra
Jann reported that x86 was missing required TLB invalidates when he hit the !*batch slow path in tlb_remove_table(). This is indeed the case; RCU_TABLE_FREE does not provide TLB (cache) invalidates, the PowerPC-hash where this code originated and the Sparc-hash where this was subsequently used did not need that. ARM which later used this put an explicit TLB invalidate in their __p*_free_tlb() functions, and PowerPC-radix followed that example. But when we hooked up x86 we failed to consider this. Fix this by (optionally) hooking tlb_remove_table() into the TLB invalidate code. NOTE: s390 was also needing something like this and might now be able to use the generic code again. [ Modified to be on top of Nick's cleanups, which simplified this patch now that tlb_flush_mmu_tlbonly() really only flushes the TLB - Linus ] Fixes: 9e52fc2b50de ("x86/mm: Enable RCU based page table freeing (CONFIG_HAVE_RCU_TABLE_FREE=y)") Reported-by: Jann Horn <jannh@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Rik van Riel <riel@surriel.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: David Miller <davem@davemloft.net> Cc: Will Deacon <will.deacon@arm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-08-23mm/tlb: Remove tlb_remove_table() non-concurrent conditionPeter Zijlstra
Will noted that only checking mm_users is incorrect; we should also check mm_count in order to cover CPUs that have a lazy reference to this mm (and could do speculative TLB operations). If removing this turns out to be a performance issue, we can re-instate a more complete check, but in tlb_table_flush() eliding the call_rcu_sched(). Fixes: 267239116987 ("mm, powerpc: move the RCU page-table freeing into generic code") Reported-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Rik van Riel <riel@surriel.com> Acked-by: Will Deacon <will.deacon@arm.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: David Miller <davem@davemloft.net> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-08-23mm: move tlb_table_flush to tlb_flush_mmu_freeNicholas Piggin
There is no need to call this from tlb_flush_mmu_tlbonly, it logically belongs with tlb_flush_mmu_free. This makes future fixes simpler. [ This was originally done to allow code consolidation for the mmu_notifier fix, but it also ends up helping simplify the HAVE_RCU_TABLE_INVALIDATE fix. - Linus ] Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Acked-by: Will Deacon <will.deacon@arm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-08-22x86/mm/tlb: Revert the recent lazy TLB patchesPeter Zijlstra
Revert commits: 95b0e6357d3e x86/mm/tlb: Always use lazy TLB mode 64482aafe55f x86/mm/tlb: Only send page table free TLB flush to lazy TLB CPUs ac0315896970 x86/mm/tlb: Make lazy TLB mode lazier 61d0beb5796a x86/mm/tlb: Restructure switch_mm_irqs_off() 2ff6ddf19c0e x86/mm/tlb: Leave lazy TLB mode at page table free time In order to simplify the TLB invalidate fixes for x86 and unify the parts that need backporting. We'll try again later. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Rik van Riel <riel@surriel.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-08-17Revert "mm: always flush VMA ranges affected by zap_page_range"Rik van Riel
There was a bug in Linux that could cause madvise (and mprotect?) system calls to return to userspace without the TLB having been flushed for all the pages involved. This could happen when multiple threads of a process made simultaneous madvise and/or mprotect calls. This was noticed in the summer of 2017, at which time two solutions were created: 56236a59556c ("mm: refactor TLB gathering API") 99baac21e458 ("mm: fix MADV_[FREE|DONTNEED] TLB flush miss problem") and 4647706ebeee ("mm: always flush VMA ranges affected by zap_page_range") We need only one of these solutions, and the former appears to be a little more efficient than the latter, so revert that one. This reverts 4647706ebeee6e50 ("mm: always flush VMA ranges affected by zap_page_range") Link: http://lkml.kernel.org/r/20180706131019.51e3a5f0@imladris.surriel.com Signed-off-by: Rik van Riel <riel@surriel.com> Acked-by: Mel Gorman <mgorman@techsingularity.net> Cc: Andy Lutomirski <luto@kernel.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Minchan Kim <minchan@kernel.org> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> Cc: Nicholas Piggin <npiggin@gmail.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>
2018-08-17memcg, oom: move out_of_memory back to the charge pathMichal Hocko
Commit 3812c8c8f395 ("mm: memcg: do not trap chargers with full callstack on OOM") has changed the ENOMEM semantic of memcg charges. Rather than invoking the oom killer from the charging context it delays the oom killer to the page fault path (pagefault_out_of_memory). This in turn means that many users (e.g. slab or g-u-p) will get ENOMEM when the corresponding memcg hits the hard limit and the memcg is is OOM. This is behavior is inconsistent with !memcg case where the oom killer is invoked from the allocation context and the allocator keeps retrying until it succeeds. The difference in the behavior is user visible. mmap(MAP_POPULATE) might result in not fully populated ranges while the mmap return code doesn't tell that to the userspace. Random syscalls might fail with ENOMEM etc. The primary motivation of the different memcg oom semantic was the deadlock avoidance. Things have changed since then, though. We have an async oom teardown by the oom reaper now and so we do not have to rely on the victim to tear down its memory anymore. Therefore we can return to the original semantic as long as the memcg oom killer is not handed over to the users space. There is still one thing to be careful about here though. If the oom killer is not able to make any forward progress - e.g. because there is no eligible task to kill - then we have to bail out of the charge path to prevent from same class of deadlocks. We have basically two options here. Either we fail the charge with ENOMEM or force the charge and allow overcharge. The first option has been considered more harmful than useful because rare inconsistencies in the ENOMEM behavior is hard to test for and error prone. Basically the same reason why the page allocator doesn't fail allocations under such conditions. The later might allow runaways but those should be really unlikely unless somebody misconfigures the system. E.g. allowing to migrate tasks away from the memcg to a different unlimited memcg with move_charge_at_immigrate disabled. Link: http://lkml.kernel.org/r/20180628151101.25307-1-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Acked-by: Greg Thelen <gthelen@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Shakeel Butt <shakeelb@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-08-17mm, huge page: copy target sub-page last when copy huge pageHuang Ying
Huge page helps to reduce TLB miss rate, but it has higher cache footprint, sometimes this may cause some issue. For example, when copying huge page on x86_64 platform, the cache footprint is 4M. 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 contention is heavy when copying the huge page, and we copy 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 copying the end of the huge page. And it is possible for the application to access the begin of the huge page after copying the huge page. In c79b57e462b5d ("mm: hugetlb: clear target sub-page last when clearing huge page"), to keep the cache lines of the target subpage hot, the order to clear the subpages in the huge page in clear_huge_page() is changed to clearing the subpage which is furthest from the target subpage firstly, and the target subpage last. The similar order changing helps huge page copying too. That is implemented in this patch. Because we have put the order algorithm into a separate function, the implementation is quite simple. The patch is a generic optimization which should benefit quite some workloads, not for a specific use case. To demonstrate the performance benefit of the patch, we tested it with vm-scalability run on transparent huge page. With this patch, the throughput increases ~16.6% in vm-scalability anon-cow-seq test case with 36 processes on a 2 socket Xeon E5 v3 2699 system (36 cores, 72 threads). The test case set /sys/kernel/mm/transparent_hugepage/enabled to be always, mmap() a big anonymous memory area and populate it, then forked 36 child processes, each writes to the anonymous memory area from the begin to the end, so cause copy on write. For each child process, other child processes could be seen as other workloads which generate heavy cache pressure. At the same time, the IPC (instruction per cycle) increased from 0.63 to 0.78, and the time spent in user space is reduced ~7.2%. Link: http://lkml.kernel.org/r/20180524005851.4079-3-ying.huang@intel.com Signed-off-by: "Huang, Ying" <ying.huang@intel.com> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> Cc: Andi Kleen <andi.kleen@intel.com> Cc: Jan Kara <jack@suse.cz> Cc: Michal Hocko <mhocko@suse.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Hugh Dickins <hughd@google.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Shaohua Li <shli@fb.com> Cc: Christopher Lameter <cl@linux.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-08-17mm, clear_huge_page: move order algorithm into a separate functionHuang Ying
Patch series "mm, huge page: Copy target sub-page last when copy huge page", v2. Huge page helps to reduce TLB miss rate, but it has higher cache footprint, sometimes this may cause some issue. For example, when copying huge page on x86_64 platform, the cache footprint is 4M. 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 contention is heavy when copying the huge page, and we copy 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 copying the end of the huge page. And it is possible for the application to access the begin of the huge page after copying the huge page. In c79b57e462b5d ("mm: hugetlb: clear target sub-page last when clearing huge page"), to keep the cache lines of the target subpage hot, the order to clear the subpages in the huge page in clear_huge_page() is changed to clearing the subpage which is furthest from the target subpage firstly, and the target subpage last. The similar order changing helps huge page copying too. That is implemented in this patchset. The patchset is a generic optimization which should benefit quite some workloads, not for a specific use case. To demonstrate the performance benefit of the patchset, we have tested it with vm-scalability run on transparent huge page. With this patchset, the throughput increases ~16.6% in vm-scalability anon-cow-seq test case with 36 processes on a 2 socket Xeon E5 v3 2699 system (36 cores, 72 threads). The test case set /sys/kernel/mm/transparent_hugepage/enabled to be always, mmap() a big anonymous memory area and populate it, then forked 36 child processes, each writes to the anonymous memory area from the begin to the end, so cause copy on write. For each child process, other child processes could be seen as other workloads which generate heavy cache pressure. At the same time, the IPC (instruction per cycle) increased from 0.63 to 0.78, and the time spent in user space is reduced ~7.2%. This patch (of 4): In c79b57e462b5d ("mm: hugetlb: clear target sub-page last when clearing huge page"), to keep the cache lines of the target subpage hot, the order to clear the subpages in the huge page in clear_huge_page() is changed to clearing the subpage which is furthest from the target subpage firstly, and the target subpage last. This optimization could be applied to copying huge page too with the same order algorithm. To avoid code duplication and reduce maintenance overhead, in this patch, the order algorithm is moved out of clear_huge_page() into a separate function: process_huge_page(). So that we can use it for copying huge page too. This will change the direct calls to clear_user_highpage() into the indirect calls. But with the proper inline support of the compilers, the indirect call will be optimized to be the direct call. Our tests show no performance change with the patch. This patch is a code cleanup without functionality change. Link: http://lkml.kernel.org/r/20180524005851.4079-2-ying.huang@intel.com Signed-off-by: "Huang, Ying" <ying.huang@intel.com> Suggested-by: Mike Kravetz <mike.kravetz@oracle.com> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> Cc: Andi Kleen <andi.kleen@intel.com> Cc: Jan Kara <jack@suse.cz> Cc: Michal Hocko <mhocko@suse.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Hugh Dickins <hughd@google.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Shaohua Li <shli@fb.com> Cc: Christopher Lameter <cl@linux.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-08-17thp: use mm_file_counter to determine update which rss counterYang Shi
Since commit eca56ff906bd ("mm, shmem: add internal shmem resident memory accounting"), MM_SHMEMPAGES is added to separate the shmem accounting from regular files. So, all shmem pages should be accounted to MM_SHMEMPAGES instead of MM_FILEPAGES. And, normal 4K shmem pages have been accounted to MM_SHMEMPAGES, so shmem thp pages should be not treated differently. Account them to MM_SHMEMPAGES via mm_counter_file() since shmem pages are swap backed to keep consistent with normal 4K shmem pages. This will not change the rss counter of processes since shmem pages are still a part of it. The /proc/pid/status and /proc/pid/statm counters will however be more accurate wrt shmem usage, as originally intended. And as eca56ff906bd ("mm, shmem: add internal shmem resident memory accounting") mentioned, oom also could report more accurate "shmem-rss". Link: http://lkml.kernel.org/r/1529442518-17398-1-git-send-email-yang.shi@linux.alibaba.com Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Hugh Dickins <hughd@google.com> Cc: 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>
2018-08-17dax: remove VM_MIXEDMAP for fsdax and device daxDave Jiang
This patch is reworked from an earlier patch that Dan has posted: https://patchwork.kernel.org/patch/10131727/ VM_MIXEDMAP is used by dax to direct mm paths like vm_normal_page() that the memory page it is dealing with is not typical memory from the linear map. The get_user_pages_fast() path, since it does not resolve the vma, is already using {pte,pmd}_devmap() as a stand-in for VM_MIXEDMAP, so we use that as a VM_MIXEDMAP replacement in some locations. In the cases where there is no pte to consult we fallback to using vma_is_dax() to detect the VM_MIXEDMAP special case. Now that we have explicit driver pfn_t-flag opt-in/opt-out for get_user_pages() support for DAX we can stop setting VM_MIXEDMAP. This also means we no longer need to worry about safely manipulating vm_flags in a future where we support dynamically changing the dax mode of a file. DAX should also now be supported with madvise_behavior(), vma_merge(), and copy_page_range(). This patch has been tested against ndctl unit test. It has also been tested against xfstests commit: 625515d using fake pmem created by memmap and no additional issues have been observed. Link: http://lkml.kernel.org/r/152847720311.55924.16999195879201817653.stgit@djiang5-desk3.ch.intel.com Signed-off-by: Dave Jiang <dave.jiang@intel.com> Acked-by: Dan Williams <dan.j.williams@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>
2018-08-14Merge tag 'for-4.19/block-20180812' of git://git.kernel.dk/linux-blockLinus Torvalds
Pull block updates from Jens Axboe: "First pull request for this merge window, there will also be a followup request with some stragglers. This pull request contains: - Fix for a thundering heard issue in the wbt block code (Anchal Agarwal) - A few NVMe pull requests: * Improved tracepoints (Keith) * Larger inline data support for RDMA (Steve Wise) * RDMA setup/teardown fixes (Sagi) * Effects log suppor for NVMe target (Chaitanya Kulkarni) * Buffered IO suppor for NVMe target (Chaitanya Kulkarni) * TP4004 (ANA) support (Christoph) * Various NVMe fixes - Block io-latency controller support. Much needed support for properly containing block devices. (Josef) - Series improving how we handle sense information on the stack (Kees) - Lightnvm fixes and updates/improvements (Mathias/Javier et al) - Zoned device support for null_blk (Matias) - AIX partition fixes (Mauricio Faria de Oliveira) - DIF checksum code made generic (Max Gurtovoy) - Add support for discard in iostats (Michael Callahan / Tejun) - Set of updates for BFQ (Paolo) - Removal of async write support for bsg (Christoph) - Bio page dirtying and clone fixups (Christoph) - Set of bcache fix/changes (via Coly) - Series improving blk-mq queue setup/teardown speed (Ming) - Series improving merging performance on blk-mq (Ming) - Lots of other fixes and cleanups from a slew of folks" * tag 'for-4.19/block-20180812' of git://git.kernel.dk/linux-block: (190 commits) blkcg: Make blkg_root_lookup() work for queues in bypass mode bcache: fix error setting writeback_rate through sysfs interface null_blk: add lock drop/acquire annotation Blk-throttle: reduce tail io latency when iops limit is enforced block: paride: pd: mark expected switch fall-throughs block: Ensure that a request queue is dissociated from the cgroup controller block: Introduce blk_exit_queue() blkcg: Introduce blkg_root_lookup() block: Remove two superfluous #include directives blk-mq: count the hctx as active before allocating tag block: bvec_nr_vecs() returns value for wrong slab bcache: trivial - remove tailing backslash in macro BTREE_FLAG bcache: make the pr_err statement used for ENOENT only in sysfs_attatch section bcache: set max writeback rate when I/O request is idle bcache: add code comments for bset.c bcache: fix mistaken comments in request.c bcache: fix mistaken code comments in bcache.h bcache: add a comment in super.c bcache: avoid unncessary cache prefetch bch_btree_node_get() bcache: display rate debug parameters to 0 when writeback is not running ...
2018-08-14Merge branch 'l1tf-final' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Merge L1 Terminal Fault fixes from Thomas Gleixner: "L1TF, aka L1 Terminal Fault, is yet another speculative hardware engineering trainwreck. It's a hardware vulnerability which allows unprivileged speculative access to data which is available in the Level 1 Data Cache when the page table entry controlling the virtual address, which is used for the access, has the Present bit cleared or other reserved bits set. If an instruction accesses a virtual address for which the relevant page table entry (PTE) has the Present bit cleared or other reserved bits set, then speculative execution ignores the invalid PTE and loads the referenced data if it is present in the Level 1 Data Cache, as if the page referenced by the address bits in the PTE was still present and accessible. While this is a purely speculative mechanism and the instruction will raise a page fault when it is retired eventually, the pure act of loading the data and making it available to other speculative instructions opens up the opportunity for side channel attacks to unprivileged malicious code, similar to the Meltdown attack. While Meltdown breaks the user space to kernel space protection, L1TF allows to attack any physical memory address in the system and the attack works across all protection domains. It allows an attack of SGX and also works from inside virtual machines because the speculation bypasses the extended page table (EPT) protection mechanism. The assoicated CVEs are: CVE-2018-3615, CVE-2018-3620, CVE-2018-3646 The mitigations provided by this pull request include: - Host side protection by inverting the upper address bits of a non present page table entry so the entry points to uncacheable memory. - Hypervisor protection by flushing L1 Data Cache on VMENTER. - SMT (HyperThreading) control knobs, which allow to 'turn off' SMT by offlining the sibling CPU threads. The knobs are available on the kernel command line and at runtime via sysfs - Control knobs for the hypervisor mitigation, related to L1D flush and SMT control. The knobs are available on the kernel command line and at runtime via sysfs - Extensive documentation about L1TF including various degrees of mitigations. Thanks to all people who have contributed to this in various ways - patches, review, testing, backporting - and the fruitful, sometimes heated, but at the end constructive discussions. There is work in progress to provide other forms of mitigations, which might be less horrible performance wise for a particular kind of workloads, but this is not yet ready for consumption due to their complexity and limitations" * 'l1tf-final' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (75 commits) x86/microcode: Allow late microcode loading with SMT disabled tools headers: Synchronise x86 cpufeatures.h for L1TF additions x86/mm/kmmio: Make the tracer robust against L1TF x86/mm/pat: Make set_memory_np() L1TF safe x86/speculation/l1tf: Make pmd/pud_mknotpresent() invert x86/speculation/l1tf: Invert all not present mappings cpu/hotplug: Fix SMT supported evaluation KVM: VMX: Tell the nested hypervisor to skip L1D flush on vmentry x86/speculation: Use ARCH_CAPABILITIES to skip L1D flush on vmentry x86/speculation: Simplify sysfs report of VMX L1TF vulnerability Documentation/l1tf: Remove Yonah processors from not vulnerable list x86/KVM/VMX: Don't set l1tf_flush_l1d from vmx_handle_external_intr() x86/irq: Let interrupt handlers set kvm_cpu_l1tf_flush_l1d x86: Don't include linux/irq.h from asm/hardirq.h x86/KVM/VMX: Introduce per-host-cpu analogue of l1tf_flush_l1d x86/irq: Demote irq_cpustat_t::__softirq_pending to u16 x86/KVM/VMX: Move the l1tf_flush_l1d test to vmx_l1d_flush() x86/KVM/VMX: Replace 'vmx_l1d_flush_always' with 'vmx_l1d_flush_cond' x86/KVM/VMX: Don't set l1tf_flush_l1d to true from vmx_l1d_flush() cpu/hotplug: detect SMT disabled by BIOS ...
2018-08-13Merge branch 'x86-mm-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 mm updates from Thomas Gleixner: - Make lazy TLB mode even lazier to avoid pointless switch_mm() operations, which reduces CPU load by 1-2% for memcache workloads - Small cleanups and improvements all over the place * 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/mm: Remove redundant check for kmem_cache_create() arm/asm/tlb.h: Fix build error implicit func declaration x86/mm/tlb: Make clear_asid_other() static x86/mm/tlb: Skip atomic operations for 'init_mm' in switch_mm_irqs_off() x86/mm/tlb: Always use lazy TLB mode x86/mm/tlb: Only send page table free TLB flush to lazy TLB CPUs x86/mm/tlb: Make lazy TLB mode lazier x86/mm/tlb: Restructure switch_mm_irqs_off() x86/mm/tlb: Leave lazy TLB mode at page table free time mm: Allocate the mm_cpumask (mm->cpu_bitmap[]) dynamically based on nr_cpu_ids x86/mm: Add TLB purge to free pmd/pte page interfaces ioremap: Update pgtable free interfaces with addr x86/mm: Disable ioremap free page handling on x86-PAE
2018-08-10mm/memory.c: check return value of ioremap_protjie@chenjie6@huwei.com
ioremap_prot() can return NULL which could lead to an oops. Link: http://lkml.kernel.org/r/1533195441-58594-1-git-send-email-chenjie6@huawei.com Signed-off-by: chen jie <chenjie6@huawei.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Li Zefan <lizefan@huawei.com> Cc: chenjie <chenjie6@huawei.com> Cc: Yang Shi <shy828301@gmail.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-08-01mm: delete historical BUG from zap_pmd_range()Hugh Dickins
Delete the old VM_BUG_ON_VMA() from zap_pmd_range(), which asserted that mmap_sem must be held when splitting an "anonymous" vma there. Whether that's still strictly true nowadays is not entirely clear, but the danger of sometimes crashing on the BUG is now fairly clear. Even with the new stricter rules for anonymous vma marking, the condition it checks for can possible trigger. Commit 44960f2a7b63 ("staging: ashmem: Fix SIGBUS crash when traversing mmaped ashmem pages") is good, and originally I thought it was safe from that VM_BUG_ON_VMA(), because the /dev/ashmem fd exposed to the user is disconnected from the vm_file in the vma, and madvise(,,MADV_REMOVE) insists on VM_SHARED. But after I read John's earlier mail, drawing attention to the vfs_fallocate() in there: I may be wrong, and I don't know if Android has THP in the config anyway, but it looks to me like an unmap_mapping_range() from ashmem's vfs_fallocate() could hit precisely the VM_BUG_ON_VMA(), once it's vma_is_anonymous(). Signed-off-by: Hugh Dickins <hughd@google.com> Cc: John Stultz <john.stultz@linaro.org> Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-07-17x86/mm/tlb: Leave lazy TLB mode at page table free timeRik van Riel
Andy discovered that speculative memory accesses while in lazy TLB mode can crash a system, when a CPU tries to dereference a speculative access using memory contents that used to be valid page table memory, but have since been reused for something else and point into la-la land. The latter problem can be prevented in two ways. The first is to always send a TLB shootdown IPI to CPUs in lazy TLB mode, while the second one is to only send the TLB shootdown at page table freeing time. The second should result in fewer IPIs, since operationgs like mprotect and madvise are very common with some workloads, but do not involve page table freeing. Also, on munmap, batching of page table freeing covers much larger ranges of virtual memory than the batching of unmapped user pages. Tested-by: Song Liu <songliubraving@fb.com> Signed-off-by: Rik van Riel <riel@surriel.com> Acked-by: Dave Hansen <dave.hansen@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: efault@gmx.de Cc: kernel-team@fb.com Cc: luto@kernel.org Link: http://lkml.kernel.org/r/20180716190337.26133-3-riel@surriel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-07-09memcontrol: schedule throttling if we are congestedTejun Heo
Memory allocations can induce swapping via kswapd or direct reclaim. If we are having IO done for us by kswapd and don't actually go into direct reclaim we may never get scheduled for throttling. So instead check to see if our cgroup is congested, and if so schedule the throttling. Before we return to user space the throttling stuff will only throttle if we actually required it. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Josef Bacik <jbacik@fb.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-06-20x86/speculation/l1tf: Disallow non privileged high MMIO PROT_NONE mappingsAndi Kleen
For L1TF PROT_NONE mappings are protected by inverting the PFN in the page table entry. This sets the high bits in the CPU's address space, thus making sure to point to not point an unmapped entry to valid cached memory. Some server system BIOSes put the MMIO mappings high up in the physical address space. If such an high mapping was mapped to unprivileged users they could attack low memory by setting such a mapping to PROT_NONE. This could happen through a special device driver which is not access protected. Normal /dev/mem is of course access protected. To avoid this forbid PROT_NONE mappings or mprotect for high MMIO mappings. Valid page mappings are allowed because the system is then unsafe anyways. It's not expected that users commonly use PROT_NONE on MMIO. But to minimize any impact this is only enforced if the mapping actually refers to a high MMIO address (defined as the MAX_PA-1 bit being set), and also skip the check for root. For mmaps this is straight forward and can be handled in vm_insert_pfn and in remap_pfn_range(). For mprotect it's a bit trickier. At the point where the actual PTEs are accessed a lot of state has been changed and it would be difficult to undo on an error. Since this is a uncommon case use a separate early page talk walk pass for MMIO PROT_NONE mappings that checks for this condition early. For non MMIO and non PROT_NONE there are no changes. Signed-off-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com> Acked-by: Dave Hansen <dave.hansen@intel.com>
2018-06-07Merge branch 'akpm' (patches from Andrew)Linus Torvalds
Merge updates from Andrew Morton: - a few misc things - ocfs2 updates - v9fs updates - MM - procfs updates - lib/ updates - autofs updates * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (118 commits) autofs: small cleanup in autofs_getpath() autofs: clean up includes autofs: comment on selinux changes needed for module autoload autofs: update MAINTAINERS entry for autofs autofs: use autofs instead of autofs4 in documentation autofs: rename autofs documentation files autofs: create autofs Kconfig and Makefile autofs: delete fs/autofs4 source files autofs: update fs/autofs4/Makefile autofs: update fs/autofs4/Kconfig autofs: copy autofs4 to autofs autofs4: use autofs instead of autofs4 everywhere autofs4: merge auto_fs.h and auto_fs4.h fs/binfmt_misc.c: do not allow offset overflow checkpatch: improve patch recognition lib/ucs2_string.c: add MODULE_LICENSE() lib/mpi: headers cleanup lib/percpu_ida.c: use _irqsave() instead of local_irq_save() + spin_lock lib/idr.c: remove simple_ida_lock lib/bitmap.c: micro-optimization for __bitmap_complement() ...
2018-06-07mm: remove odd HAVE_PTE_SPECIALLaurent Dufour
Remove the additional define HAVE_PTE_SPECIAL and rely directly on CONFIG_ARCH_HAS_PTE_SPECIAL. There is no functional change introduced by this patch Link: http://lkml.kernel.org/r/1523533733-25437-1-git-send-email-ldufour@linux.vnet.ibm.com Signed-off-by: Laurent Dufour <ldufour@linux.vnet.ibm.com> Acked-by: David Rientjes <rientjes@google.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Jerome Glisse <jglisse@redhat.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Christophe LEROY <christophe.leroy@c-s.fr> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
generated by cgit v1.2.3 (git 2.25.1) at 2024-12-12 05:17:55 +0000