On Thu, May 13, 2021 at 9:50 AM Yang Shi <shy828301@xxxxxxxxx> wrote: > > On Thu, May 13, 2021 at 12:20 AM Anshuman Khandual > <anshuman.khandual@xxxxxxx> wrote: > > > > Although the zero huge page is being shared across various processes, each > > mapping needs to update its mm's MM_ANONPAGES stat by HPAGE_PMD_NR in order > > to be consistent. This just updates the stats in set_huge_zero_page() after > > the mapping gets created. > > I don't get why MM_ANONPAGES needs to be inc'ed when huge zero page is > installed. This may cause inconsistency between some counters, for > example, MM_ANONPAGES may be much bigger than anon LRU. > > MM_ANONPAGES should not be inc'ed unless a new page is allocated and > installed, right? I just realized I mixed MM_ANONPAGES up with the global anon pages counter. Take back my comment. Sorry for the confusion. > > > > > Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> > > Cc: Zi Yan <ziy@xxxxxxxxxx> > > Cc: linux-mm@xxxxxxxxx > > Cc: linux-kernel@xxxxxxxxxxxxxxx > > Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx> > > --- > > Should it update MM_SHMEM_PAGES instead ? Applies on latest mainline. > > > > mm/huge_memory.c | 1 + > > 1 file changed, 1 insertion(+) > > > > diff --git a/mm/huge_memory.c b/mm/huge_memory.c > > index 63ed6b25deaa..262703304807 100644 > > --- a/mm/huge_memory.c > > +++ b/mm/huge_memory.c > > @@ -706,6 +706,7 @@ static void set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm, > > if (pgtable) > > pgtable_trans_huge_deposit(mm, pmd, pgtable); > > set_pmd_at(mm, haddr, pmd, entry); > > + add_mm_counter(mm, MM_ANONPAGES, HPAGE_PMD_NR); > > mm_inc_nr_ptes(mm); > > } > > > > -- > > 2.20.1 > > > >
