Messages in this thread | | | Date | Mon, 28 Dec 2009 19:24:47 +0900 | From | Minchan Kim <> | Subject | Re: [PATCH 2/3 -mmotm-2009-12-10-17-19] Count zero page as file_rss |
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I missed Hugh.
Minchan Kim wrote: > Long time ago, we counted zero page as file_rss. > But after reinstanted zero page, we don't do it. > It means rss of process would be smaller than old. > > It could chage OOM victim selection. > > Kame reported following as > "Before starting zero-page works, I checked "questions" in lkml and > found some reports that some applications start to go OOM after zero-page > removal. > > For me, I know one of my customer's application depends on behavior of > zero page (on RHEL5). So, I tried to add again it before RHEL6 because > I think removal of zero-page corrupts compatibility." > > So how about adding zero page as file_rss again for compatibility? > > Signed-off-by: Minchan Kim <minchan.kim@gmail.com> > --- > mm/memory.c | 7 +++++-- > 1 files changed, 5 insertions(+), 2 deletions(-) > > diff --git a/mm/memory.c b/mm/memory.c > index 3743fb5..a4ba271 100644 > --- a/mm/memory.c > +++ b/mm/memory.c > @@ -1995,6 +1995,7 @@ static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma, > int reuse = 0, ret = 0; > int page_mkwrite = 0; > struct page *dirty_page = NULL; > + int zero_pfn = 0; > > old_page = vm_normal_page(vma, address, orig_pte); > if (!old_page) { > @@ -2117,7 +2118,8 @@ gotten: > if (unlikely(anon_vma_prepare(vma))) > goto oom; > > - if (is_zero_pfn(pte_pfn(orig_pte))) { > + zero_pfn = is_zero_pfn(pte_pfn(orig_pte)); > + if (zero_pfn) { > new_page = alloc_zeroed_user_highpage_movable(vma, address); > if (!new_page) > goto oom; > @@ -2147,7 +2149,7 @@ gotten: > */ > page_table = pte_offset_map_lock(mm, pmd, address, &ptl); > if (likely(pte_same(*page_table, orig_pte))) { > - if (old_page) { > + if (old_page || zero_pfn) { > if (!PageAnon(old_page)) { > dec_mm_counter(mm, file_rss); > inc_mm_counter(mm, anon_rss); > @@ -2650,6 +2652,7 @@ static int do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma, > spin_lock(ptl); > if (!pte_none(*page_table)) > goto unlock; > + inc_mm_counter(mm, file_rss); > goto setpte; > } >
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