f822566165
Currently, copy-on-write may change the physical address of a page even if the user requested that the page is pinned in memory (either by mlock or by get_user_pages). This happens if the process forks meanwhile, and the parent writes to that page. As a result, the page is orphaned: in case of get_user_pages, the application will never see any data hardware DMA's into this page after the COW. In case of mlock'd memory, the parent is not getting the realtime/security benefits of mlock. In particular, this affects the Infiniband modules which do DMA from and into user pages all the time. This patch adds madvise options to control whether memory range is inherited across fork. Useful e.g. for when hardware is doing DMA from/into these pages. Could also be useful to an application wanting to speed up its forks by cutting large areas out of consideration. Signed-off-by: Michael S. Tsirkin <mst@mellanox.co.il> Acked-by: Hugh Dickins <hugh@veritas.com> Cc: Michael Kerrisk <mtk-manpages@gmx.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
66 lines
2.9 KiB
C
66 lines
2.9 KiB
C
/* $Id: mman.h,v 1.9 2000/03/15 02:44:23 davem Exp $ */
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#ifndef __SPARC_MMAN_H__
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#define __SPARC_MMAN_H__
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/* SunOS'ified... */
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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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#define MAP_SHARED 0x01 /* Share changes */
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#define MAP_PRIVATE 0x02 /* Changes are private */
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#define MAP_TYPE 0x0f /* Mask for type of mapping */
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#define MAP_FIXED 0x10 /* Interpret addr exactly */
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#define MAP_ANONYMOUS 0x20 /* don't use a file */
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#define MAP_RENAME MAP_ANONYMOUS /* In SunOS terminology */
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#define MAP_NORESERVE 0x40 /* don't reserve swap pages */
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#define MAP_INHERIT 0x80 /* SunOS doesn't do this, but... */
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#define MAP_LOCKED 0x100 /* lock the mapping */
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#define _MAP_NEW 0x80000000 /* Binary compatibility is fun... */
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#define MAP_GROWSDOWN 0x0200 /* stack-like segment */
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#define MAP_DENYWRITE 0x0800 /* ETXTBSY */
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#define MAP_EXECUTABLE 0x1000 /* mark it as an executable */
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#define MS_ASYNC 1 /* sync memory asynchronously */
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#define MS_INVALIDATE 2 /* invalidate the caches */
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#define MS_SYNC 4 /* synchronous memory sync */
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#define MCL_CURRENT 0x2000 /* lock all currently mapped pages */
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#define MCL_FUTURE 0x4000 /* lock all additions to address space */
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#define MAP_POPULATE 0x8000 /* populate (prefault) pagetables */
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#define MAP_NONBLOCK 0x10000 /* do not block on IO */
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/* XXX Need to add flags to SunOS's mctl, mlockall, and madvise system
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* XXX calls.
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*/
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/* SunOS sys_mctl() stuff... */
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#define MC_SYNC 1 /* Sync pages in memory with storage (usu. a file) */
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#define MC_LOCK 2 /* Lock pages into core ram, do not allow swapping of them */
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#define MC_UNLOCK 3 /* Unlock pages locked via previous mctl() with MC_LOCK arg */
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#define MC_LOCKAS 5 /* Lock an entire address space of the calling process */
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#define MC_UNLOCKAS 6 /* Unlock entire address space of calling process */
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#define MADV_NORMAL 0x0 /* default page-in behavior */
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#define MADV_RANDOM 0x1 /* page-in minimum required */
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#define MADV_SEQUENTIAL 0x2 /* read-ahead aggressively */
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#define MADV_WILLNEED 0x3 /* pre-fault pages */
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#define MADV_DONTNEED 0x4 /* discard these pages */
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#define MADV_FREE 0x5 /* (Solaris) contents can be freed */
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#define MADV_REMOVE 0x6 /* remove these pages & resources */
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#define MADV_DONTFORK 0x30 /* dont inherit across fork */
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#define MADV_DOFORK 0x31 /* do inherit across fork */
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/* compatibility flags */
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#define MAP_ANON MAP_ANONYMOUS
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#define MAP_FILE 0
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#endif /* __SPARC_MMAN_H__ */
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