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| author | Cyrill Gorcunov <gorcunov@gmail.com> | 2013-09-12 01:22:24 +0400 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-09-12 02:57:56 +0400 |
| commit | d9104d1ca9662498339c0de975b4666c30485f4e (patch) | |
| tree | cb95c72dde19930ca985b9834d604958ef4eecde /include | |
| parent | 3b11f0aaae830f0f569cb8fb7fd26f4133ebdabd (diff) | |
| download | linux-d9104d1ca9662498339c0de975b4666c30485f4e.tar.xz | |
mm: track vma changes with VM_SOFTDIRTY bit
Pavel reported that in case if vma area get unmapped and then mapped (or
expanded) in-place, the soft dirty tracker won't be able to recognize this
situation since it works on pte level and ptes are get zapped on unmap,
loosing soft dirty bit of course.
So to resolve this situation we need to track actions on vma level, there
VM_SOFTDIRTY flag comes in. When new vma area created (or old expanded)
we set this bit, and keep it here until application calls for clearing
soft dirty bit.
Thus when user space application track memory changes now it can detect if
vma area is renewed.
Reported-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Matt Mackall <mpm@selenic.com>
Cc: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@gmail.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Rob Landley <rob@landley.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/mm.h | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h index d2d59b4149d0..dce24569f8fc 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -115,6 +115,12 @@ extern unsigned int kobjsize(const void *objp); #define VM_ARCH_1 0x01000000 /* Architecture-specific flag */ #define VM_DONTDUMP 0x04000000 /* Do not include in the core dump */ +#ifdef CONFIG_MEM_SOFT_DIRTY +# define VM_SOFTDIRTY 0x08000000 /* Not soft dirty clean area */ +#else +# define VM_SOFTDIRTY 0 +#endif + #define VM_MIXEDMAP 0x10000000 /* Can contain "struct page" and pure PFN pages */ #define VM_HUGEPAGE 0x20000000 /* MADV_HUGEPAGE marked this vma */ #define VM_NOHUGEPAGE 0x40000000 /* MADV_NOHUGEPAGE marked this vma */ |