diff options
| author | Hugh Dickins <hugh@veritas.com> | 2004-10-27 18:17:23 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2004-10-27 18:17:23 -0700 |
| commit | 8586febd93ed02668b9d0ad87963610425e44977 (patch) | |
| tree | 0af00bc05254a13d8d1c37c67673fed816e2cb5e /mm | |
| parent | da63671a5c506729abb8fe383704c264967c53c0 (diff) | |
| download | history-8586febd93ed02668b9d0ad87963610425e44977.tar.gz | |
[PATCH] statm: shared = rss - anon_rss
The third "shared" field of /proc/$pid/statm in 2.4 was a count of pages in
the mm whose page_count is more than 1 (oddly, including pages shared just
with swapcache). That's too costly to calculate each time, so 2.6 changed
it to the total file-backed extent. But Andrea knows apps and users
surprised when (rss - shared) goes negative: we need to provide an rss-like
statistic, close to the 2.4 interpretation.
Something that's quick and easy to maintain accurately is mm->anon_rss, the
count of anonymous pages in the mm. Then shared = rss - anon_rss gives a
pretty good and meaningful approximation to 2.4's intention: wli confirms
that this will be useful to Oracle too.
Where to show it? I think it's best to treat this as a bugfix and show it
in the third field of /proc/$pid/statm, after resident, as before - there's
no evidence that the total file-backed extent was found useful.
Albert would like other fields to revert to page counts, but that's a lot
harder: if mprotect can change the category of a page, then it can't be
accounted as simply as this. Only go that route if real need shown.
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Acked-by: William Irwin <wli@holomorphy.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/memory.c | 8 | ||||
| -rw-r--r-- | mm/rmap.c | 3 |
2 files changed, 10 insertions, 1 deletions
diff --git a/mm/memory.c b/mm/memory.c index 170f3f90cc0220..e5c68a782442bb 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -334,6 +334,8 @@ skip_copy_pte_range: pte = pte_mkold(pte); get_page(page); dst->rss++; + if (PageAnon(page)) + dst->anon_rss++; set_pte(dst_pte, pte); page_dup_rmap(page); cont_copy_pte_range_noset: @@ -424,7 +426,9 @@ static void zap_pte_range(struct mmu_gather *tlb, set_pte(ptep, pgoff_to_pte(page->index)); if (pte_dirty(pte)) set_page_dirty(page); - if (pte_young(pte) && !PageAnon(page)) + if (PageAnon(page)) + tlb->mm->anon_rss--; + else if (pte_young(pte)) mark_page_accessed(page); tlb->freed++; page_remove_rmap(page); @@ -1109,6 +1113,8 @@ static int do_wp_page(struct mm_struct *mm, struct vm_area_struct * vma, spin_lock(&mm->page_table_lock); page_table = pte_offset_map(pmd, address); if (likely(pte_same(*page_table, pte))) { + if (PageAnon(old_page)) + mm->anon_rss--; if (PageReserved(old_page)) ++mm->rss; else diff --git a/mm/rmap.c b/mm/rmap.c index d4a9a6a50fc87b..b2f242f76cd734 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -432,6 +432,8 @@ void page_add_anon_rmap(struct page *page, BUG_ON(PageReserved(page)); BUG_ON(!anon_vma); + vma->vm_mm->anon_rss++; + anon_vma = (void *) anon_vma + PAGE_MAPPING_ANON; index = (address - vma->vm_start) >> PAGE_SHIFT; index += vma->vm_pgoff; @@ -584,6 +586,7 @@ static int try_to_unmap_one(struct page *page, struct vm_area_struct *vma) } set_pte(pte, swp_entry_to_pte(entry)); BUG_ON(pte_file(*pte)); + mm->anon_rss--; } mm->rss--; |