Re: [PATCHv6 01/36] mm, proc: adjust PSS calculation

Kirill A. Shutemov
2015-06-22T10:03:27Z

On Tue, Jun 09, 2015 at 02:29:17PM +0200, Vlastimil Babka wrote:
> 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?

Yep :-/

--
Kirill A. Shutemov
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
Please read the FAQ at http://www.tux.org/lkml/