* [PATCH] mm/memcontrol: fix wrong statistics in memory.stat
@ 2019-07-03 1:22 Yafang Shao
2019-07-03 3:50 ` Shakeel Butt
0 siblings, 1 reply; 6+ messages in thread
From: Yafang Shao @ 2019-07-03 1:22 UTC (permalink / raw)
To: akpm; +Cc: linux-mm, Yafang Shao, Shakeel Butt, Michal Hocko, Yafang Shao
When we calculate total statistics for memcg1_stats and memcg1_events, we
use the the index 'i' in the for loop as the events index.
Actually we should use memcg1_stats[i] and memcg1_events[i] as the
events index.
Fixes: 8de7ecc6483b ("memcg: reduce memcg tree traversals for stats collection")
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Yafang Shao <shaoyafang@didiglobal.com>
---
mm/memcontrol.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 3ee806b..2ad94d0 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -3528,12 +3528,13 @@ static int memcg_stat_show(struct seq_file *m, void *v)
if (memcg1_stats[i] == MEMCG_SWAP && !do_memsw_account())
continue;
seq_printf(m, "total_%s %llu\n", memcg1_stat_names[i],
- (u64)memcg_page_state(memcg, i) * PAGE_SIZE);
+ (u64)memcg_page_state(memcg, memcg1_stats[i]) *
+ PAGE_SIZE);
}
for (i = 0; i < ARRAY_SIZE(memcg1_events); i++)
seq_printf(m, "total_%s %llu\n", memcg1_event_names[i],
- (u64)memcg_events(memcg, i));
+ (u64)memcg_events(memcg, memcg1_events[i]));
for (i = 0; i < NR_LRU_LISTS; i++)
seq_printf(m, "total_%s %llu\n", mem_cgroup_lru_names[i],
--
1.8.3.1
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH] mm/memcontrol: fix wrong statistics in memory.stat 2019-07-03 1:22 [PATCH] mm/memcontrol: fix wrong statistics in memory.stat Yafang Shao @ 2019-07-03 3:50 ` Shakeel Butt 2019-07-03 3:51 ` Shakeel Butt 2019-07-03 4:27 ` Yafang Shao 0 siblings, 2 replies; 6+ messages in thread From: Shakeel Butt @ 2019-07-03 3:50 UTC (permalink / raw) To: Yafang Shao; +Cc: Andrew Morton, Linux MM, Michal Hocko, Yafang Shao +Johannes Weiner On Tue, Jul 2, 2019 at 6:23 PM Yafang Shao <laoar.shao@gmail.com> wrote: > > When we calculate total statistics for memcg1_stats and memcg1_events, we > use the the index 'i' in the for loop as the events index. > Actually we should use memcg1_stats[i] and memcg1_events[i] as the > events index. > > Fixes: 8de7ecc6483b ("memcg: reduce memcg tree traversals for stats collection") Actually it fixes 42a300353577 ("mm: memcontrol: fix recursive statistics correctness & scalabilty"). > Signed-off-by: Yafang Shao <laoar.shao@gmail.com> > Cc: Shakeel Butt <shakeelb@google.com> > Cc: Michal Hocko <mhocko@suse.com> > Cc: Yafang Shao <shaoyafang@didiglobal.com> > --- > mm/memcontrol.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index 3ee806b..2ad94d0 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -3528,12 +3528,13 @@ static int memcg_stat_show(struct seq_file *m, void *v) > if (memcg1_stats[i] == MEMCG_SWAP && !do_memsw_account()) > continue; > seq_printf(m, "total_%s %llu\n", memcg1_stat_names[i], > - (u64)memcg_page_state(memcg, i) * PAGE_SIZE); > + (u64)memcg_page_state(memcg, memcg1_stats[i]) * > + PAGE_SIZE); It seems like I made the above very subtle in 8de7ecc6483b and Johannes missed this subtlety in 42a300353577 (and I missed it in the review). > } > > for (i = 0; i < ARRAY_SIZE(memcg1_events); i++) > seq_printf(m, "total_%s %llu\n", memcg1_event_names[i], > - (u64)memcg_events(memcg, i)); > + (u64)memcg_events(memcg, memcg1_events[i])); > > for (i = 0; i < NR_LRU_LISTS; i++) > seq_printf(m, "total_%s %llu\n", mem_cgroup_lru_names[i], > -- > 1.8.3.1 > Reviewed-by: Shakeel Butt <shakeelb@google.com> ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] mm/memcontrol: fix wrong statistics in memory.stat 2019-07-03 3:50 ` Shakeel Butt @ 2019-07-03 3:51 ` Shakeel Butt 2019-07-03 4:27 ` Yafang Shao 1 sibling, 0 replies; 6+ messages in thread From: Shakeel Butt @ 2019-07-03 3:51 UTC (permalink / raw) To: Yafang Shao, Johannes Weiner Cc: Andrew Morton, Linux MM, Michal Hocko, Yafang Shao +Johannes for real On Tue, Jul 2, 2019 at 8:50 PM Shakeel Butt <shakeelb@google.com> wrote: > > +Johannes Weiner > > On Tue, Jul 2, 2019 at 6:23 PM Yafang Shao <laoar.shao@gmail.com> wrote: > > > > When we calculate total statistics for memcg1_stats and memcg1_events, we > > use the the index 'i' in the for loop as the events index. > > Actually we should use memcg1_stats[i] and memcg1_events[i] as the > > events index. > > > > Fixes: 8de7ecc6483b ("memcg: reduce memcg tree traversals for stats collection") > > Actually it fixes 42a300353577 ("mm: memcontrol: fix recursive > statistics correctness & scalabilty"). > > > Signed-off-by: Yafang Shao <laoar.shao@gmail.com> > > Cc: Shakeel Butt <shakeelb@google.com> > > Cc: Michal Hocko <mhocko@suse.com> > > Cc: Yafang Shao <shaoyafang@didiglobal.com> > > --- > > mm/memcontrol.c | 5 +++-- > > 1 file changed, 3 insertions(+), 2 deletions(-) > > > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > > index 3ee806b..2ad94d0 100644 > > --- a/mm/memcontrol.c > > +++ b/mm/memcontrol.c > > @@ -3528,12 +3528,13 @@ static int memcg_stat_show(struct seq_file *m, void *v) > > if (memcg1_stats[i] == MEMCG_SWAP && !do_memsw_account()) > > continue; > > seq_printf(m, "total_%s %llu\n", memcg1_stat_names[i], > > - (u64)memcg_page_state(memcg, i) * PAGE_SIZE); > > + (u64)memcg_page_state(memcg, memcg1_stats[i]) * > > + PAGE_SIZE); > > It seems like I made the above very subtle in 8de7ecc6483b and > Johannes missed this subtlety in 42a300353577 (and I missed it in the > review). > > > } > > > > for (i = 0; i < ARRAY_SIZE(memcg1_events); i++) > > seq_printf(m, "total_%s %llu\n", memcg1_event_names[i], > > - (u64)memcg_events(memcg, i)); > > + (u64)memcg_events(memcg, memcg1_events[i])); > > > > for (i = 0; i < NR_LRU_LISTS; i++) > > seq_printf(m, "total_%s %llu\n", mem_cgroup_lru_names[i], > > -- > > 1.8.3.1 > > > > Reviewed-by: Shakeel Butt <shakeelb@google.com> ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] mm/memcontrol: fix wrong statistics in memory.stat 2019-07-03 3:50 ` Shakeel Butt 2019-07-03 3:51 ` Shakeel Butt @ 2019-07-03 4:27 ` Yafang Shao 2019-07-03 5:16 ` Shakeel Butt 1 sibling, 1 reply; 6+ messages in thread From: Yafang Shao @ 2019-07-03 4:27 UTC (permalink / raw) To: Shakeel Butt; +Cc: Andrew Morton, Linux MM, Michal Hocko, Yafang Shao On Wed, Jul 3, 2019 at 11:50 AM Shakeel Butt <shakeelb@google.com> wrote: > > +Johannes Weiner > > On Tue, Jul 2, 2019 at 6:23 PM Yafang Shao <laoar.shao@gmail.com> wrote: > > > > When we calculate total statistics for memcg1_stats and memcg1_events, we > > use the the index 'i' in the for loop as the events index. > > Actually we should use memcg1_stats[i] and memcg1_events[i] as the > > events index. > > > > Fixes: 8de7ecc6483b ("memcg: reduce memcg tree traversals for stats collection") > > Actually it fixes 42a300353577 ("mm: memcontrol: fix recursive > statistics correctness & scalabilty"). > Hi Shakeel, In 8de7ecc6483b, this code was changed from memcg_page_state(mi, memcg1_stats[i]) to acc.stat[i]. - for_each_mem_cgroup_tree(mi, memcg) - val += memcg_page_state(mi, memcg1_stats[i]) * - PAGE_SIZE; - seq_printf(m, "total_%s %llu\n", memcg1_stat_names[i], val); + seq_printf(m, "total_%s %llu\n", memcg1_stat_names[i], + (u64)acc.stat[i] * PAGE_SIZE); In 42a300353577, this code was changed from acc.vmstats[i] to memcg_events(memcg, i). - (u64)acc.vmstats[i] * PAGE_SIZE); + (u64)memcg_page_state(memcg, i) * PAGE_SIZE); So seems this issue was introduced in 8de7ecc6483b, isn't it ? > > Signed-off-by: Yafang Shao <laoar.shao@gmail.com> > > Cc: Shakeel Butt <shakeelb@google.com> > > Cc: Michal Hocko <mhocko@suse.com> > > Cc: Yafang Shao <shaoyafang@didiglobal.com> > > --- > > mm/memcontrol.c | 5 +++-- > > 1 file changed, 3 insertions(+), 2 deletions(-) > > > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > > index 3ee806b..2ad94d0 100644 > > --- a/mm/memcontrol.c > > +++ b/mm/memcontrol.c > > @@ -3528,12 +3528,13 @@ static int memcg_stat_show(struct seq_file *m, void *v) > > if (memcg1_stats[i] == MEMCG_SWAP && !do_memsw_account()) > > continue; > > seq_printf(m, "total_%s %llu\n", memcg1_stat_names[i], > > - (u64)memcg_page_state(memcg, i) * PAGE_SIZE); > > + (u64)memcg_page_state(memcg, memcg1_stats[i]) * > > + PAGE_SIZE); > > It seems like I made the above very subtle in 8de7ecc6483b and > Johannes missed this subtlety in 42a300353577 (and I missed it in the > review). > > > } > > > > for (i = 0; i < ARRAY_SIZE(memcg1_events); i++) > > seq_printf(m, "total_%s %llu\n", memcg1_event_names[i], > > - (u64)memcg_events(memcg, i)); > > + (u64)memcg_events(memcg, memcg1_events[i])); > > > > for (i = 0; i < NR_LRU_LISTS; i++) > > seq_printf(m, "total_%s %llu\n", mem_cgroup_lru_names[i], > > -- > > 1.8.3.1 > > > > Reviewed-by: Shakeel Butt <shakeelb@google.com> ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] mm/memcontrol: fix wrong statistics in memory.stat 2019-07-03 4:27 ` Yafang Shao @ 2019-07-03 5:16 ` Shakeel Butt 2019-07-03 5:56 ` Yafang Shao 0 siblings, 1 reply; 6+ messages in thread From: Shakeel Butt @ 2019-07-03 5:16 UTC (permalink / raw) To: Yafang Shao; +Cc: Andrew Morton, Linux MM, Michal Hocko, Yafang Shao On Tue, Jul 2, 2019 at 9:28 PM Yafang Shao <laoar.shao@gmail.com> wrote: > > On Wed, Jul 3, 2019 at 11:50 AM Shakeel Butt <shakeelb@google.com> wrote: > > > > +Johannes Weiner > > > > On Tue, Jul 2, 2019 at 6:23 PM Yafang Shao <laoar.shao@gmail.com> wrote: > > > > > > When we calculate total statistics for memcg1_stats and memcg1_events, we > > > use the the index 'i' in the for loop as the events index. > > > Actually we should use memcg1_stats[i] and memcg1_events[i] as the > > > events index. > > > > > > Fixes: 8de7ecc6483b ("memcg: reduce memcg tree traversals for stats collection") > > > > Actually it fixes 42a300353577 ("mm: memcontrol: fix recursive > > statistics correctness & scalabilty"). > > > > Hi Shakeel, > > In 8de7ecc6483b, this code was changed from memcg_page_state(mi, > memcg1_stats[i]) to acc.stat[i]. > > - for_each_mem_cgroup_tree(mi, memcg) > - val += memcg_page_state(mi, memcg1_stats[i]) * > - PAGE_SIZE; > - seq_printf(m, "total_%s %llu\n", memcg1_stat_names[i], val); > + seq_printf(m, "total_%s %llu\n", memcg1_stat_names[i], > + (u64)acc.stat[i] * PAGE_SIZE); > > In 42a300353577, this code was changed from acc.vmstats[i] to > memcg_events(memcg, i). > - (u64)acc.vmstats[i] * PAGE_SIZE); > + (u64)memcg_page_state(memcg, i) * PAGE_SIZE); > > So seems this issue was introduced in 8de7ecc6483b, isn't it ? > > That's the reason I said 8de7ecc6483b made it subtle but not wrong. Check accumulate_memcg_tree() in 8de7ecc6483b, the memcg_page_state() and memcg_events() are called with correct index but saved at 'i' index in acc array. > > > Signed-off-by: Yafang Shao <laoar.shao@gmail.com> > > > Cc: Shakeel Butt <shakeelb@google.com> > > > Cc: Michal Hocko <mhocko@suse.com> > > > Cc: Yafang Shao <shaoyafang@didiglobal.com> > > > --- > > > mm/memcontrol.c | 5 +++-- > > > 1 file changed, 3 insertions(+), 2 deletions(-) > > > > > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > > > index 3ee806b..2ad94d0 100644 > > > --- a/mm/memcontrol.c > > > +++ b/mm/memcontrol.c > > > @@ -3528,12 +3528,13 @@ static int memcg_stat_show(struct seq_file *m, void *v) > > > if (memcg1_stats[i] == MEMCG_SWAP && !do_memsw_account()) > > > continue; > > > seq_printf(m, "total_%s %llu\n", memcg1_stat_names[i], > > > - (u64)memcg_page_state(memcg, i) * PAGE_SIZE); > > > + (u64)memcg_page_state(memcg, memcg1_stats[i]) * > > > + PAGE_SIZE); > > > > It seems like I made the above very subtle in 8de7ecc6483b and > > Johannes missed this subtlety in 42a300353577 (and I missed it in the > > review). > > > > > } > > > > > > for (i = 0; i < ARRAY_SIZE(memcg1_events); i++) > > > seq_printf(m, "total_%s %llu\n", memcg1_event_names[i], > > > - (u64)memcg_events(memcg, i)); > > > + (u64)memcg_events(memcg, memcg1_events[i])); > > > > > > for (i = 0; i < NR_LRU_LISTS; i++) > > > seq_printf(m, "total_%s %llu\n", mem_cgroup_lru_names[i], > > > -- > > > 1.8.3.1 > > > > > > > Reviewed-by: Shakeel Butt <shakeelb@google.com> ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] mm/memcontrol: fix wrong statistics in memory.stat 2019-07-03 5:16 ` Shakeel Butt @ 2019-07-03 5:56 ` Yafang Shao 0 siblings, 0 replies; 6+ messages in thread From: Yafang Shao @ 2019-07-03 5:56 UTC (permalink / raw) To: Shakeel Butt; +Cc: Andrew Morton, Linux MM, Michal Hocko, Yafang Shao On Wed, Jul 3, 2019 at 1:17 PM Shakeel Butt <shakeelb@google.com> wrote: > > On Tue, Jul 2, 2019 at 9:28 PM Yafang Shao <laoar.shao@gmail.com> wrote: > > > > On Wed, Jul 3, 2019 at 11:50 AM Shakeel Butt <shakeelb@google.com> wrote: > > > > > > +Johannes Weiner > > > > > > On Tue, Jul 2, 2019 at 6:23 PM Yafang Shao <laoar.shao@gmail.com> wrote: > > > > > > > > When we calculate total statistics for memcg1_stats and memcg1_events, we > > > > use the the index 'i' in the for loop as the events index. > > > > Actually we should use memcg1_stats[i] and memcg1_events[i] as the > > > > events index. > > > > > > > > Fixes: 8de7ecc6483b ("memcg: reduce memcg tree traversals for stats collection") > > > > > > Actually it fixes 42a300353577 ("mm: memcontrol: fix recursive > > > statistics correctness & scalabilty"). > > > > > > > Hi Shakeel, > > > > In 8de7ecc6483b, this code was changed from memcg_page_state(mi, > > memcg1_stats[i]) to acc.stat[i]. > > > > - for_each_mem_cgroup_tree(mi, memcg) > > - val += memcg_page_state(mi, memcg1_stats[i]) * > > - PAGE_SIZE; > > - seq_printf(m, "total_%s %llu\n", memcg1_stat_names[i], val); > > + seq_printf(m, "total_%s %llu\n", memcg1_stat_names[i], > > + (u64)acc.stat[i] * PAGE_SIZE); > > > > In 42a300353577, this code was changed from acc.vmstats[i] to > > memcg_events(memcg, i). > > - (u64)acc.vmstats[i] * PAGE_SIZE); > > + (u64)memcg_page_state(memcg, i) * PAGE_SIZE); > > > > So seems this issue was introduced in 8de7ecc6483b, isn't it ? > > > > > > That's the reason I said 8de7ecc6483b made it subtle but not wrong. > Check accumulate_memcg_tree() in 8de7ecc6483b, the memcg_page_state() > and memcg_events() are called with correct index but saved at 'i' > index in acc array. > Got it. Thanks for your explanation and review. Thanks Yafang > > > > > Signed-off-by: Yafang Shao <laoar.shao@gmail.com> > > > > Cc: Shakeel Butt <shakeelb@google.com> > > > > Cc: Michal Hocko <mhocko@suse.com> > > > > Cc: Yafang Shao <shaoyafang@didiglobal.com> > > > > --- > > > > mm/memcontrol.c | 5 +++-- > > > > 1 file changed, 3 insertions(+), 2 deletions(-) > > > > > > > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > > > > index 3ee806b..2ad94d0 100644 > > > > --- a/mm/memcontrol.c > > > > +++ b/mm/memcontrol.c > > > > @@ -3528,12 +3528,13 @@ static int memcg_stat_show(struct seq_file *m, void *v) > > > > if (memcg1_stats[i] == MEMCG_SWAP && !do_memsw_account()) > > > > continue; > > > > seq_printf(m, "total_%s %llu\n", memcg1_stat_names[i], > > > > - (u64)memcg_page_state(memcg, i) * PAGE_SIZE); > > > > + (u64)memcg_page_state(memcg, memcg1_stats[i]) * > > > > + PAGE_SIZE); > > > > > > It seems like I made the above very subtle in 8de7ecc6483b and > > > Johannes missed this subtlety in 42a300353577 (and I missed it in the > > > review). > > > > > > > } > > > > > > > > for (i = 0; i < ARRAY_SIZE(memcg1_events); i++) > > > > seq_printf(m, "total_%s %llu\n", memcg1_event_names[i], > > > > - (u64)memcg_events(memcg, i)); > > > > + (u64)memcg_events(memcg, memcg1_events[i])); > > > > > > > > for (i = 0; i < NR_LRU_LISTS; i++) > > > > seq_printf(m, "total_%s %llu\n", mem_cgroup_lru_names[i], > > > > -- > > > > 1.8.3.1 > > > > > > > > > > Reviewed-by: Shakeel Butt <shakeelb@google.com> ^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2019-07-03 5:57 UTC | newest] Thread overview: 6+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2019-07-03 1:22 [PATCH] mm/memcontrol: fix wrong statistics in memory.stat Yafang Shao 2019-07-03 3:50 ` Shakeel Butt 2019-07-03 3:51 ` Shakeel Butt 2019-07-03 4:27 ` Yafang Shao 2019-07-03 5:16 ` Shakeel Butt 2019-07-03 5:56 ` Yafang Shao
This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox; as well as URLs for NNTP newsgroup(s).