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1a4e58cce8
When a process expects no accesses to a certain memory range for a long time, it could hint kernel that the pages can be reclaimed instantly but data should be preserved for future use. This could reduce workingset eviction so it ends up increasing performance. This patch introduces the new MADV_PAGEOUT hint to madvise(2) syscall. MADV_PAGEOUT can be used by a process to mark a memory range as not expected to be used for a long time so that kernel reclaims *any LRU* pages instantly. The hint can help kernel in deciding which pages to evict proactively. A note: It doesn't apply SWAP_CLUSTER_MAX LRU page isolation limit intentionally because it's automatically bounded by PMD size. If PMD size(e.g., 256) makes some trouble, we could fix it later by limit it to SWAP_CLUSTER_MAX[1]. - man-page material MADV_PAGEOUT (since Linux x.x) Do not expect access in the near future so pages in the specified regions could be reclaimed instantly regardless of memory pressure. Thus, access in the range after successful operation could cause major page fault but never lose the up-to-date contents unlike MADV_DONTNEED. Pages belonging to a shared mapping are only processed if a write access is allowed for the calling process. MADV_PAGEOUT cannot be applied to locked pages, Huge TLB pages, or VM_PFNMAP pages. [1] https://lore.kernel.org/lkml/20190710194719.GS29695@dhcp22.suse.cz/ [minchan@kernel.org: clear PG_active on MADV_PAGEOUT] Link: http://lkml.kernel.org/r/20190802200643.GA181880@google.com [akpm@linux-foundation.org: resolve conflicts with hmm.git] Link: http://lkml.kernel.org/r/20190726023435.214162-5-minchan@kernel.org Signed-off-by: Minchan Kim <minchan@kernel.org> Reported-by: kbuild test robot <lkp@intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: James E.J. Bottomley <James.Bottomley@HansenPartnership.com> Cc: Richard Henderson <rth@twiddle.net> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Chris Zankel <chris@zankel.net> Cc: Daniel Colascione <dancol@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Hillf Danton <hdanton@sina.com> Cc: Joel Fernandes (Google) <joel@joelfernandes.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Oleksandr Natalenko <oleksandr@redhat.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: Sonny Rao <sonnyrao@google.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Tim Murray <timmurray@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
83 lines
3.5 KiB
C
83 lines
3.5 KiB
C
/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
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#ifndef __ALPHA_MMAN_H__
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#define __ALPHA_MMAN_H__
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#define PROT_READ 0x1 /* page can be read */
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#define PROT_WRITE 0x2 /* page can be written */
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#define PROT_EXEC 0x4 /* page can be executed */
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#define PROT_SEM 0x8 /* page may be used for atomic ops */
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#define PROT_NONE 0x0 /* page can not be accessed */
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#define PROT_GROWSDOWN 0x01000000 /* mprotect flag: extend change to start of growsdown vma */
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#define PROT_GROWSUP 0x02000000 /* mprotect flag: extend change to end of growsup vma */
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/* 0x01 - 0x03 are defined in linux/mman.h */
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#define MAP_TYPE 0x0f /* Mask for type of mapping (OSF/1 is _wrong_) */
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#define MAP_FIXED 0x100 /* Interpret addr exactly */
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#define MAP_ANONYMOUS 0x10 /* don't use a file */
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/* not used by linux, but here to make sure we don't clash with OSF/1 defines */
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#define _MAP_HASSEMAPHORE 0x0200
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#define _MAP_INHERIT 0x0400
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#define _MAP_UNALIGNED 0x0800
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/* These are linux-specific */
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#define MAP_GROWSDOWN 0x01000 /* stack-like segment */
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#define MAP_DENYWRITE 0x02000 /* ETXTBSY */
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#define MAP_EXECUTABLE 0x04000 /* mark it as an executable */
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#define MAP_LOCKED 0x08000 /* lock the mapping */
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#define MAP_NORESERVE 0x10000 /* don't check for reservations */
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#define MAP_POPULATE 0x20000 /* populate (prefault) pagetables */
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#define MAP_NONBLOCK 0x40000 /* do not block on IO */
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#define MAP_STACK 0x80000 /* give out an address that is best suited for process/thread stacks */
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#define MAP_HUGETLB 0x100000 /* create a huge page mapping */
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#define MAP_FIXED_NOREPLACE 0x200000/* MAP_FIXED which doesn't unmap underlying mapping */
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#define MS_ASYNC 1 /* sync memory asynchronously */
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#define MS_SYNC 2 /* synchronous memory sync */
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#define MS_INVALIDATE 4 /* invalidate the caches */
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#define MCL_CURRENT 8192 /* lock all currently mapped pages */
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#define MCL_FUTURE 16384 /* lock all additions to address space */
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#define MCL_ONFAULT 32768 /* lock all pages that are faulted in */
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#define MLOCK_ONFAULT 0x01 /* Lock pages in range after they are faulted in, do not prefault */
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#define MADV_NORMAL 0 /* no further special treatment */
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#define MADV_RANDOM 1 /* expect random page references */
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#define MADV_SEQUENTIAL 2 /* expect sequential page references */
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#define MADV_WILLNEED 3 /* will need these pages */
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#define MADV_SPACEAVAIL 5 /* ensure resources are available */
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#define MADV_DONTNEED 6 /* don't need these pages */
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/* common/generic parameters */
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#define MADV_FREE 8 /* free pages only if memory pressure */
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#define MADV_REMOVE 9 /* remove these pages & resources */
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#define MADV_DONTFORK 10 /* don't inherit across fork */
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#define MADV_DOFORK 11 /* do inherit across fork */
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#define MADV_MERGEABLE 12 /* KSM may merge identical pages */
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#define MADV_UNMERGEABLE 13 /* KSM may not merge identical pages */
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#define MADV_HUGEPAGE 14 /* Worth backing with hugepages */
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#define MADV_NOHUGEPAGE 15 /* Not worth backing with hugepages */
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#define MADV_DONTDUMP 16 /* Explicity exclude from the core dump,
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overrides the coredump filter bits */
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#define MADV_DODUMP 17 /* Clear the MADV_NODUMP flag */
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#define MADV_WIPEONFORK 18 /* Zero memory on fork, child only */
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#define MADV_KEEPONFORK 19 /* Undo MADV_WIPEONFORK */
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#define MADV_COLD 20 /* deactivate these pages */
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#define MADV_PAGEOUT 21 /* reclaim these pages */
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/* compatibility flags */
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#define MAP_FILE 0
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#define PKEY_DISABLE_ACCESS 0x1
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#define PKEY_DISABLE_WRITE 0x2
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#define PKEY_ACCESS_MASK (PKEY_DISABLE_ACCESS |\
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PKEY_DISABLE_WRITE)
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#endif /* __ALPHA_MMAN_H__ */
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