Messages in this thread | | | Date | Tue, 09 Jun 2015 14:29:17 +0200 | From | Vlastimil Babka <> | Subject | Re: [PATCHv6 01/36] mm, proc: adjust PSS calculation |
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On 06/03/2015 07:05 PM, Kirill A. Shutemov wrote: > With new refcounting all subpages of the compound page are not nessessary > have the same mapcount. We need to take into account mapcount of every > sub-page. > > Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> > Tested-by: Sasha Levin <sasha.levin@oracle.com> > Acked-by: Jerome Marchand <jmarchan@redhat.com> > Acked-by: Vlastimil Babka <vbabka@suse.cz> > --- > fs/proc/task_mmu.c | 48 +++++++++++++++++++++++++++++++----------------- > 1 file changed, 31 insertions(+), 17 deletions(-) > > diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c > index 58be92e11939..f9b285761bc0 100644 > --- a/fs/proc/task_mmu.c > +++ b/fs/proc/task_mmu.c > @@ -449,9 +449,10 @@ struct mem_size_stats { > }; > > static void smaps_account(struct mem_size_stats *mss, struct page *page, > - unsigned long size, bool young, bool dirty) > + bool compound, bool young, bool dirty) > { > - int mapcount; > + int i, nr = compound ? HPAGE_PMD_NR : 1; > + unsigned long size = nr * PAGE_SIZE; > > if (PageAnon(page)) > mss->anonymous += size; > @@ -460,23 +461,36 @@ static void smaps_account(struct mem_size_stats *mss, struct page *page, > /* Accumulate the size in pages that have been accessed. */ > if (young || PageReferenced(page)) > mss->referenced += size; > - mapcount = page_mapcount(page); > - if (mapcount >= 2) { > - u64 pss_delta; > > - if (dirty || PageDirty(page)) > - mss->shared_dirty += size; > - else > - mss->shared_clean += size; > - pss_delta = (u64)size << PSS_SHIFT; > - do_div(pss_delta, mapcount); > - mss->pss += pss_delta; > - } else { > + /* > + * page_count(page) == 1 guarantees the page is mapped exactly once. > + * If any subpage of the compound page mapped with PTE it would elevate > + * page_count(). > + */ > + if (page_count(page) == 1) { > if (dirty || PageDirty(page)) > mss->private_dirty += size; > else > mss->private_clean += size; > - mss->pss += (u64)size << PSS_SHIFT;
Deleting the line above was a mistake, right?
> + return; > + } > + > + for (i = 0; i < nr; i++, page++) { > + int mapcount = page_mapcount(page); > + > + if (mapcount >= 2) { > + if (dirty || PageDirty(page)) > + mss->shared_dirty += PAGE_SIZE; > + else > + mss->shared_clean += PAGE_SIZE; > + mss->pss += (PAGE_SIZE << PSS_SHIFT) / mapcount; > + } else { > + if (dirty || PageDirty(page)) > + mss->private_dirty += PAGE_SIZE; > + else > + mss->private_clean += PAGE_SIZE; > + mss->pss += PAGE_SIZE << PSS_SHIFT; > + } > } > } > > @@ -500,7 +514,8 @@ static void smaps_pte_entry(pte_t *pte, unsigned long addr, > > if (!page) > return; > - smaps_account(mss, page, PAGE_SIZE, pte_young(*pte), pte_dirty(*pte)); > + > + smaps_account(mss, page, false, pte_young(*pte), pte_dirty(*pte)); > } > > #ifdef CONFIG_TRANSPARENT_HUGEPAGE > @@ -516,8 +531,7 @@ static void smaps_pmd_entry(pmd_t *pmd, unsigned long addr, > if (IS_ERR_OR_NULL(page)) > return; > mss->anonymous_thp += HPAGE_PMD_SIZE; > - smaps_account(mss, page, HPAGE_PMD_SIZE, > - pmd_young(*pmd), pmd_dirty(*pmd)); > + smaps_account(mss, page, true, pmd_young(*pmd), pmd_dirty(*pmd)); > } > #else > static void smaps_pmd_entry(pmd_t *pmd, unsigned long addr, >
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