Messages in this thread | | | Subject | Re: [PATCH] mm/memcontrol: update lruvec counters in mem_cgroup_move_account | From | Konstantin Khlebnikov <> | Date | Tue, 15 Oct 2019 13:49:14 +0300 |
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On 15/10/2019 13.36, Michal Hocko wrote: > On Tue 15-10-19 11:44:22, Konstantin Khlebnikov wrote: >> On 15/10/2019 11.20, Michal Hocko wrote: >>> On Tue 15-10-19 11:09:59, Konstantin Khlebnikov wrote: >>>> Mapped, dirty and writeback pages are also counted in per-lruvec stats. >>>> These counters needs update when page is moved between cgroups. >>> >>> Please describe the user visible effect. >> >> Surprisingly I don't see any users at this moment. >> So, there is no effect in mainline kernel. > > Those counters are exported right? Or do we exclude them for v1?
It seems per-lruvec statistics is not exposed anywhere. And per-lruvec NR_FILE_MAPPED, NR_FILE_DIRTY, NR_WRITEBACK never had users.
I've found this because I'm using mem_cgroup_move_account for recharging pages at mlock and playing right now with debug for memory cgroup which validates statistics and counters when cgroup dies.
> >>>> Fixes: 00f3ca2c2d66 ("mm: memcontrol: per-lruvec stats infrastructure") >>>> Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> >>> >>> We want Cc: stable I suspect because broken stats might be really >>> misleading. >>> >>> The patch looks ok to me otherwise >>> Acked-by: Michal Hocko <mhocko@suse.com> >>> >>>> --- >>>> mm/memcontrol.c | 18 ++++++++++++------ >>>> 1 file changed, 12 insertions(+), 6 deletions(-) >>>> >>>> diff --git a/mm/memcontrol.c b/mm/memcontrol.c >>>> index bdac56009a38..363106578876 100644 >>>> --- a/mm/memcontrol.c >>>> +++ b/mm/memcontrol.c >>>> @@ -5420,6 +5420,8 @@ static int mem_cgroup_move_account(struct page *page, >>>> struct mem_cgroup *from, >>>> struct mem_cgroup *to) >>>> { >>>> + struct lruvec *from_vec, *to_vec; >>>> + struct pglist_data *pgdat; >>>> unsigned long flags; >>>> unsigned int nr_pages = compound ? hpage_nr_pages(page) : 1; >>>> int ret; >>>> @@ -5443,11 +5445,15 @@ static int mem_cgroup_move_account(struct page *page, >>>> anon = PageAnon(page); >>>> + pgdat = page_pgdat(page); >>>> + from_vec = mem_cgroup_lruvec(pgdat, from); >>>> + to_vec = mem_cgroup_lruvec(pgdat, to); >>>> + >>>> spin_lock_irqsave(&from->move_lock, flags); >>>> if (!anon && page_mapped(page)) { >>>> - __mod_memcg_state(from, NR_FILE_MAPPED, -nr_pages); >>>> - __mod_memcg_state(to, NR_FILE_MAPPED, nr_pages); >>>> + __mod_lruvec_state(from_vec, NR_FILE_MAPPED, -nr_pages); >>>> + __mod_lruvec_state(to_vec, NR_FILE_MAPPED, nr_pages); >>>> } >>>> /* >>>> @@ -5459,14 +5465,14 @@ static int mem_cgroup_move_account(struct page *page, >>>> struct address_space *mapping = page_mapping(page); >>>> if (mapping_cap_account_dirty(mapping)) { >>>> - __mod_memcg_state(from, NR_FILE_DIRTY, -nr_pages); >>>> - __mod_memcg_state(to, NR_FILE_DIRTY, nr_pages); >>>> + __mod_lruvec_state(from_vec, NR_FILE_DIRTY, -nr_pages); >>>> + __mod_lruvec_state(to_vec, NR_FILE_DIRTY, nr_pages); >>>> } >>>> } >>>> if (PageWriteback(page)) { >>>> - __mod_memcg_state(from, NR_WRITEBACK, -nr_pages); >>>> - __mod_memcg_state(to, NR_WRITEBACK, nr_pages); >>>> + __mod_lruvec_state(from_vec, NR_WRITEBACK, -nr_pages); >>>> + __mod_lruvec_state(to_vec, NR_WRITEBACK, nr_pages); >>>> } >>>> #ifdef CONFIG_TRANSPARENT_HUGEPAGE >>> >
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