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| author |   Cyrill Gorcunov <gorcunov@gmail.com> | 2013-09-11 14:22:47 -0700 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@linux-foundation.org> | 2013-09-11 15:58:06 -0700 |
| commit | fa0f281cf9de8e6877e6536f18a3fc77368df64d (patch) | |
| tree | f542d0f6b19d56f4bfddca7d971bac6c00fca63b /arch/x86/include/asm/pgtable_types.h | |
| parent | mm/page-writeback.c: add strictlimit feature (diff) | |
| download | linux-dev-fa0f281cf9de8e6877e6536f18a3fc77368df64d.tar.xz linux-dev-fa0f281cf9de8e6877e6536f18a3fc77368df64d.zip | |
mm: make sure _PAGE_SWP_SOFT_DIRTY bit is not set on present pte
_PAGE_SOFT_DIRTY bit should never be set on present pte so add VM_BUG_ON
to catch any potential future abuse.
Also add a comment on _PAGE_SWP_SOFT_DIRTY definition explaining scope of
its usage.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Acked-by: Pavel Emelyanov <xemul@parallels.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/x86/include/asm/pgtable_types.h')
| -rw-r--r-- | arch/x86/include/asm/pgtable_types.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h index f4843e031131..0ecac257fb26 100644 --- a/arch/x86/include/asm/pgtable_types.h +++ b/arch/x86/include/asm/pgtable_types.h @@ -75,6 +75,9 @@ * with swap entry format. On x86 bits 6 and 7 are *not* involved * into swap entry computation, but bit 6 is used for nonlinear * file mapping, so we borrow bit 7 for soft dirty tracking. + * + * Please note that this bit must be treated as swap dirty page + * mark if and only if the PTE has present bit clear! */ #ifdef CONFIG_MEM_SOFT_DIRTY #define _PAGE_SWP_SOFT_DIRTY _PAGE_PSE |