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authorCyrill Gorcunov <gorcunov@gmail.com>2013-08-14 03:00:51 +0400
committerLinus Torvalds <torvalds@linux-foundation.org>2013-08-14 04:57:48 +0400
commit41bb3476b361ef38576cf9d539b19bae2ac93167 (patch)
tree907f72f0cc27762a9cb9c2857fe6c360524112f9 /mm
parent179ef71cbc085252e3fe6b8159263a7ed1d88ea4 (diff)
downloadlinux-41bb3476b361ef38576cf9d539b19bae2ac93167.tar.xz
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')
-rw-r--r--mm/fremap.c11
-rw-r--r--mm/memory.c11
-rw-r--r--mm/rmap.c8
3 files changed, 22 insertions, 8 deletions
diff --git a/mm/fremap.c b/mm/fremap.c
index 87da3590c61e..5bff08147768 100644
--- a/mm/fremap.c
+++ b/mm/fremap.c
@@ -57,17 +57,22 @@ static int install_file_pte(struct mm_struct *mm, struct vm_area_struct *vma,
unsigned long addr, unsigned long pgoff, pgprot_t prot)
{
int err = -ENOMEM;
- pte_t *pte;
+ pte_t *pte, ptfile;
spinlock_t *ptl;
pte = get_locked_pte(mm, addr, &ptl);
if (!pte)
goto out;
- if (!pte_none(*pte))
+ ptfile = pgoff_to_pte(pgoff);
+
+ if (!pte_none(*pte)) {
+ if (pte_present(*pte) && pte_soft_dirty(*pte))
+ pte_file_mksoft_dirty(ptfile);
zap_pte(mm, vma, addr, pte);
+ }
- set_pte_at(mm, addr, pte, pgoff_to_pte(pgoff));
+ set_pte_at(mm, addr, pte, ptfile);
/*
* We don't need to run update_mmu_cache() here because the "file pte"
* being installed by install_file_pte() is not a real pte - it's a
diff --git a/mm/memory.c b/mm/memory.c
index e98ecad2b9c8..40268410732a 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1141,9 +1141,12 @@ again:
continue;
if (unlikely(details) && details->nonlinear_vma
&& linear_page_index(details->nonlinear_vma,
- addr) != page->index)
- set_pte_at(mm, addr, pte,
- pgoff_to_pte(page->index));
+ addr) != page->index) {
+ pte_t ptfile = pgoff_to_pte(page->index);
+ if (pte_soft_dirty(ptent))
+ pte_file_mksoft_dirty(ptfile);
+ set_pte_at(mm, addr, pte, ptfile);
+ }
if (PageAnon(page))
rss[MM_ANONPAGES]--;
else {
@@ -3410,6 +3413,8 @@ static int __do_fault(struct mm_struct *mm, struct vm_area_struct *vma,
entry = mk_pte(page, vma->vm_page_prot);
if (flags & FAULT_FLAG_WRITE)
entry = maybe_mkwrite(pte_mkdirty(entry), vma);
+ else if (pte_file(orig_pte) && pte_file_soft_dirty(orig_pte))
+ pte_mksoft_dirty(entry);
if (anon) {
inc_mm_counter_fast(mm, MM_ANONPAGES);
page_add_new_anon_rmap(page, vma, address);
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))