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* tlb: mmu_gather: Remove start/end arguments from tlb_gather_mmu()Will Deacon2021-01-291-14/+8
| | | | | | | | | | | | | | | The 'start' and 'end' arguments to tlb_gather_mmu() are no longer needed now that there is a separate function for 'fullmm' flushing. Remove the unused arguments and update all callers. Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Yu Zhao <yuzhao@google.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Link: https://lore.kernel.org/r/CAHk-=wjQWa14_4UpfDf=fiineNP+RH74kZeDMo_f1D35xNzq9w@mail.gmail.com
* tlb: mmu_gather: Introduce tlb_gather_mmu_fullmm()Will Deacon2021-01-291-2/+14
| | | | | | | | | | | | | | | | | | | | Passing the range '0, -1' to tlb_gather_mmu() sets the 'fullmm' flag, which indicates that the mm_struct being operated on is going away. In this case, some architectures (such as arm64) can elide TLB invalidation by ensuring that the TLB tag (ASID) associated with this mm is not immediately reclaimed. Although this behaviour is documented in asm-generic/tlb.h, it's subtle and easily missed. Introduce tlb_gather_mmu_fullmm() to make it clearer that this is for the entire mm and WARN() if tlb_gather_mmu() is called with the 'fullmm' address range. Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Yu Zhao <yuzhao@google.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Link: https://lkml.kernel.org/r/20210127235347.1402-4-will@kernel.org
* tlb: mmu_gather: Remove unused start/end arguments from tlb_finish_mmu()Will Deacon2021-01-291-4/+1
| | | | | | | | | | | | | | | | Since commit 7a30df49f63a ("mm: mmu_gather: remove __tlb_reset_range() for force flush"), the 'start' and 'end' arguments to tlb_finish_mmu() are no longer used, since we flush the whole mm in case of a nested invalidation. Remove the unused arguments and update all callers. Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Yu Zhao <yuzhao@google.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Link: https://lkml.kernel.org/r/20210127235347.1402-3-will@kernel.org
* mmap locking API: convert mmap_sem commentsMichel Lespinasse2020-06-091-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | Convert comments that reference mmap_sem to reference mmap_lock instead. [akpm@linux-foundation.org: fix up linux-next leftovers] [akpm@linux-foundation.org: s/lockaphore/lock/, per Vlastimil] [akpm@linux-foundation.org: more linux-next fixups, per Michel] Signed-off-by: Michel Lespinasse <walken@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Laurent Dufour <ldufour@linux.ibm.com> Cc: Liam Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ying Han <yinghan@google.com> Link: http://lkml.kernel.org/r/20200520052908.204642-13-walken@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* asm-generic/tlb: provide MMU_GATHER_TABLE_FREEPeter Zijlstra2020-02-041-32/+88
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | As described in the comment, the correct order for freeing pages is: 1) unhook page 2) TLB invalidate page 3) free page This order equally applies to page directories. Currently there are two correct options: - use tlb_remove_page(), when all page directores are full pages and there are no futher contraints placed by things like software walkers (HAVE_FAST_GUP). - use MMU_GATHER_RCU_TABLE_FREE and tlb_remove_table() when the architecture does not do IPI based TLB invalidate and has HAVE_FAST_GUP (or software TLB fill). This however leaves architectures that don't have page based directories but don't need RCU in a bind. For those, provide MMU_GATHER_TABLE_FREE, which provides the independent batching for directories without the additional RCU freeing. Link: http://lkml.kernel.org/r/20200116064531.483522-10-aneesh.kumar@linux.ibm.com Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.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>
* asm-generic/tlb: rename HAVE_MMU_GATHER_NO_GATHERPeter Zijlstra2020-02-041-5/+5
| | | | | | | | | | | Towards a more consistent naming scheme. Link: http://lkml.kernel.org/r/20200116064531.483522-9-aneesh.kumar@linux.ibm.com Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.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>
* asm-generic/tlb: rename HAVE_MMU_GATHER_PAGE_SIZEPeter Zijlstra2020-02-041-2/+2
| | | | | | | | | | | Towards a more consistent naming scheme. Link: http://lkml.kernel.org/r/20200116064531.483522-8-aneesh.kumar@linux.ibm.com Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.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>
* asm-generic/tlb: rename HAVE_RCU_TABLE_FREEPeter Zijlstra2020-02-041-4/+4
| | | | | | | | | | | | Towards a more consistent naming scheme. [akpm@linux-foundation.org: fix sparc64 Kconfig] Link: http://lkml.kernel.org/r/20200116064531.483522-7-aneesh.kumar@linux.ibm.com Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.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>
* mm/mmu_gather: invalidate TLB correctly on batch allocation failure and flushPeter Zijlstra2020-02-041-8/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Architectures for which we have hardware walkers of Linux page table should flush TLB on mmu gather batch allocation failures and batch flush. Some architectures like POWER supports multiple translation modes (hash and radix) and in the case of POWER only radix translation mode needs the above TLBI. This is because for hash translation mode kernel wants to avoid this extra flush since there are no hardware walkers of linux page table. With radix translation, the hardware also walks linux page table and with that, kernel needs to make sure to TLB invalidate page walk cache before page table pages are freed. More details in commit d86564a2f085 ("mm/tlb, x86/mm: Support invalidating TLB caches for RCU_TABLE_FREE") The changes to sparc are to make sure we keep the old behavior since we are now removing HAVE_RCU_TABLE_NO_INVALIDATE. The default value for tlb_needs_table_invalidate is to always force an invalidate and sparc can avoid the table invalidate. Hence we define tlb_needs_table_invalidate to false for sparc architecture. Link: http://lkml.kernel.org/r/20200116064531.483522-3-aneesh.kumar@linux.ibm.com Fixes: a46cc7a90fd8 ("powerpc/mm/radix: Improve TLB/PWC flushes") Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Acked-by: Michael Ellerman <mpe@ellerman.id.au> [powerpc] Cc: <stable@vger.kernel.org> [4.14+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: remove quicklist page table cachesNicholas Piggin2019-09-251-2/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Patch series "mm: remove quicklist page table caches". A while ago Nicholas proposed to remove quicklist page table caches [1]. I've rebased his patch on the curren upstream and switched ia64 and sh to use generic versions of PTE allocation. [1] https://lore.kernel.org/linux-mm/20190711030339.20892-1-npiggin@gmail.com This patch (of 3): Remove page table allocator "quicklists". These have been around for a long time, but have not got much traction in the last decade and are only used on ia64 and sh architectures. The numbers in the initial commit look interesting but probably don't apply anymore. If anybody wants to resurrect this it's in the git history, but it's unhelpful to have this code and divergent allocator behaviour for minor archs. Also it might be better to instead make more general improvements to page allocator if this is still so slow. Link: http://lkml.kernel.org/r/1565250728-21721-2-git-send-email-rppt@linux.ibm.com Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: mmu_gather: remove __tlb_reset_range() for force flushYang Shi2019-06-141-5/+19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | A few new fields were added to mmu_gather to make TLB flush smarter for huge page by telling what level of page table is changed. __tlb_reset_range() is used to reset all these page table state to unchanged, which is called by TLB flush for parallel mapping changes for the same range under non-exclusive lock (i.e. read mmap_sem). Before commit dd2283f2605e ("mm: mmap: zap pages with read mmap_sem in munmap"), the syscalls (e.g. MADV_DONTNEED, MADV_FREE) which may update PTEs in parallel don't remove page tables. But, the forementioned commit may do munmap() under read mmap_sem and free page tables. This may result in program hang on aarch64 reported by Jan Stancek. The problem could be reproduced by his test program with slightly modified below. ---8<--- static int map_size = 4096; static int num_iter = 500; static long threads_total; static void *distant_area; void *map_write_unmap(void *ptr) { int *fd = ptr; unsigned char *map_address; int i, j = 0; for (i = 0; i < num_iter; i++) { map_address = mmap(distant_area, (size_t) map_size, PROT_WRITE | PROT_READ, MAP_SHARED | MAP_ANONYMOUS, -1, 0); if (map_address == MAP_FAILED) { perror("mmap"); exit(1); } for (j = 0; j < map_size; j++) map_address[j] = 'b'; if (munmap(map_address, map_size) == -1) { perror("munmap"); exit(1); } } return NULL; } void *dummy(void *ptr) { return NULL; } int main(void) { pthread_t thid[2]; /* hint for mmap in map_write_unmap() */ distant_area = mmap(0, DISTANT_MMAP_SIZE, PROT_WRITE | PROT_READ, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0); munmap(distant_area, (size_t)DISTANT_MMAP_SIZE); distant_area += DISTANT_MMAP_SIZE / 2; while (1) { pthread_create(&thid[0], NULL, map_write_unmap, NULL); pthread_create(&thid[1], NULL, dummy, NULL); pthread_join(thid[0], NULL); pthread_join(thid[1], NULL); } } ---8<--- The program may bring in parallel execution like below: t1 t2 munmap(map_address) downgrade_write(&mm->mmap_sem); unmap_region() tlb_gather_mmu() inc_tlb_flush_pending(tlb->mm); free_pgtables() tlb->freed_tables = 1 tlb->cleared_pmds = 1 pthread_exit() madvise(thread_stack, 8M, MADV_DONTNEED) zap_page_range() tlb_gather_mmu() inc_tlb_flush_pending(tlb->mm); tlb_finish_mmu() if (mm_tlb_flush_nested(tlb->mm)) __tlb_reset_range() __tlb_reset_range() would reset freed_tables and cleared_* bits, but this may cause inconsistency for munmap() which do free page tables. Then it may result in some architectures, e.g. aarch64, may not flush TLB completely as expected to have stale TLB entries remained. Use fullmm flush since it yields much better performance on aarch64 and non-fullmm doesn't yields significant difference on x86. The original proposed fix came from Jan Stancek who mainly debugged this issue, I just wrapped up everything together. Jan's testing results: v5.2-rc2-24-gbec7550cca10 -------------------------- mean stddev real 37.382 2.780 user 1.420 0.078 sys 54.658 1.855 v5.2-rc2-24-gbec7550cca10 + "mm: mmu_gather: remove __tlb_reset_range() for force flush" ---------------------------------------------------------------------------------------_ mean stddev real 37.119 2.105 user 1.548 0.087 sys 55.698 1.357 [akpm@linux-foundation.org: coding-style fixes] Link: http://lkml.kernel.org/r/1558322252-113575-1-git-send-email-yang.shi@linux.alibaba.com Fixes: dd2283f2605e ("mm: mmap: zap pages with read mmap_sem in munmap") Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com> Signed-off-by: Jan Stancek <jstancek@redhat.com> Reported-by: Jan Stancek <jstancek@redhat.com> Tested-by: Jan Stancek <jstancek@redhat.com> Suggested-by: Will Deacon <will.deacon@arm.com> Tested-by: Will Deacon <will.deacon@arm.com> Acked-by: Will Deacon <will.deacon@arm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Nick Piggin <npiggin@gmail.com> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com> Cc: Nadav Amit <namit@vmware.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Mel Gorman <mgorman@suse.de> Cc: <stable@vger.kernel.org> [4.20+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* asm-generic/tlb: Remove tlb_table_flush()Peter Zijlstra2019-04-031-17/+17
| | | | | | | | | | | | | | | | | There are no external users of this API (nor should there be); remove it. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Will Deacon <will.deacon@arm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@surriel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org>
* asm-generic/tlb: Remove tlb_flush_mmu_free()Peter Zijlstra2019-04-031-1/+1
| | | | | | | | | | | | | | | | | | | | | As the comment notes; it is a potentially dangerous operation. Just use tlb_flush_mmu(), that will skip the (double) TLB invalidate if it really isn't needed anyway. No change in behavior intended. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Will Deacon <will.deacon@arm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@surriel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org>
* asm-generic/tlb: Remove CONFIG_HAVE_GENERIC_MMU_GATHERPeter Zijlstra2019-04-031-4/+0
| | | | | | | | | | | | | | | | | Since all architectures are now using it, it is redundant. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Will Deacon <will.deacon@arm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@surriel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org>
* asm-generic/tlb: Remove arch_tlb*_mmu()Peter Zijlstra2019-04-031-51/+42
| | | | | | | | | | | | | | | | | | | | Now that all architectures are converted to the generic code, remove the arch hooks. No change in behavior intended. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Will Deacon <will.deacon@arm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@surriel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org>
* asm-generic/tlb: Introduce CONFIG_HAVE_MMU_GATHER_NO_GATHER=yMartin Schwidefsky2019-04-031-47/+60
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add the Kconfig option HAVE_MMU_GATHER_NO_GATHER to the generic mmu_gather code. If the option is set the mmu_gather will not track individual pages for delayed page free anymore. A platform that enables the option needs to provide its own implementation of the __tlb_remove_page_size() function to free pages. No change in behavior intended. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Will Deacon <will.deacon@arm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@surriel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: aneesh.kumar@linux.vnet.ibm.com Cc: heiko.carstens@de.ibm.com Cc: linux@armlinux.org.uk Cc: npiggin@gmail.com Link: http://lkml.kernel.org/r/20180918125151.31744-2-schwidefsky@de.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* asm-generic/tlb, arch: Invert CONFIG_HAVE_RCU_TABLE_INVALIDATEPeter Zijlstra2019-04-031-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | Make issuing a TLB invalidate for page-table pages the normal case. The reason is twofold: - too many invalidates is safer than too few, - most architectures use the linux page-tables natively and would thus require this. Make it an opt-out, instead of an opt-in. No change in behavior intended. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Will Deacon <will.deacon@arm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@surriel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org>
* asm-generic/tlb, arch: Provide CONFIG_HAVE_MMU_GATHER_PAGE_SIZEPeter Zijlstra2019-04-031-0/+5
| | | | | | | | | | | | | | | | | | | | | | Move the mmu_gather::page_size things into the generic code instead of PowerPC specific bits. No change in behavior intended. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Will Deacon <will.deacon@arm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Nick Piggin <npiggin@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@surriel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org>
* mm: Replace call_rcu_sched() with call_rcu()Paul E. McKenney2018-11-271-1/+1
| | | | | | | | | Now that call_rcu()'s callback is not invoked until after all preempt-disable regions of code have completed (in addition to explicitly marked RCU read-side critical sections), call_rcu() can be used in place of call_rcu_sched(). This commit therefore makes that change. Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
* mm/memory: Move mmu_gather and TLB invalidation code into its own filePeter Zijlstra2018-09-071-0/+261
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>