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| author | Cyrill Gorcunov <gorcunov@gmail.com> | 2013-08-13 16:00:51 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-08-13 17:57:48 -0700 |
| commit | 41bb3476b361ef38576cf9d539b19bae2ac93167 (patch) | |
| tree | 907f72f0cc27762a9cb9c2857fe6c360524112f9 /mm/rmap.c | |
| parent | 179ef71cbc085252e3fe6b8159263a7ed1d88ea4 (diff) | |
| download | lwn-41bb3476b361ef38576cf9d539b19bae2ac93167.tar.gz lwn-41bb3476b361ef38576cf9d539b19bae2ac93167.zip | |
mm: save soft-dirty bits on file pages
Andy reported that if file page get reclaimed we lose the soft-dirty bit
if it was there, so save _PAGE_BIT_SOFT_DIRTY bit when page address get
encoded into pte entry. Thus when #pf happens on such non-present pte
we can restore it back.
Reported-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Acked-by: Pavel Emelyanov <xemul@parallels.com>
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: Minchan Kim <minchan@kernel.org>
Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/rmap.c')
| -rw-r--r-- | mm/rmap.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/mm/rmap.c b/mm/rmap.c index 83325b80142b..b2e29acd7e3d 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -1405,8 +1405,12 @@ static int try_to_unmap_cluster(unsigned long cursor, unsigned int *mapcount, pteval = ptep_clear_flush(vma, address, pte); /* If nonlinear, store the file page offset in the pte. */ - if (page->index != linear_page_index(vma, address)) - set_pte_at(mm, address, pte, pgoff_to_pte(page->index)); + if (page->index != linear_page_index(vma, address)) { + pte_t ptfile = pgoff_to_pte(page->index); + if (pte_soft_dirty(pteval)) + pte_file_mksoft_dirty(ptfile); + set_pte_at(mm, address, pte, ptfile); + } /* Move the dirty bit to the physical page now the pte is gone. */ if (pte_dirty(pteval)) |