From: Shakeel Butt <shakeel.butt@linux.dev>
To: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Johannes Weiner <hannes@cmpxchg.org>,
Michal Hocko <mhocko@kernel.org>,
Muchun Song <muchun.song@linux.dev>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 5/7] memcg: pr_warn_once for unexpected events and stats
Date: Mon, 29 Apr 2024 12:56:25 -0700 [thread overview]
Message-ID: <tmz7rmypu6whkuz6jkek3oog5p6zioaraujjhve5uxnjoegzmc@vzel5asjhdla> (raw)
In-Reply-To: <Zi_Ff_iAs_PTph4l@P9FQF9L96D>
On Mon, Apr 29, 2024 at 09:06:23AM -0700, Roman Gushchin wrote:
> On Fri, Apr 26, 2024 at 05:37:31PM -0700, Shakeel Butt wrote:
> > To reduce memory usage by the memcg events and stats, the kernel uses
> > indirection table and only allocate stats and events which are being
> > used by the memcg code. To make this more robust, let's add warnings
> > where unexpected stats and events indexes are used.
> >
> > Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev>
> > ---
> > mm/memcontrol.c | 43 ++++++++++++++++++++++++++++++++++---------
> > 1 file changed, 34 insertions(+), 9 deletions(-)
> >
> > diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> > index 103e0e53e20a..36145089dcf5 100644
> > --- a/mm/memcontrol.c
> > +++ b/mm/memcontrol.c
> > @@ -671,9 +671,11 @@ unsigned long lruvec_page_state(struct lruvec *lruvec, enum node_stat_item idx)
> > return node_page_state(lruvec_pgdat(lruvec), idx);
> >
> > i = memcg_stats_index(idx);
> > - if (i >= 0) {
> > + if (likely(i >= 0)) {
> > pn = container_of(lruvec, struct mem_cgroup_per_node, lruvec);
> > x = READ_ONCE(pn->lruvec_stats->state[i]);
> > + } else {
> > + pr_warn_once("%s: stat item index: %d\n", __func__, idx);
> > }
>
> I think it's generally a CONFIG_DEBUG_VM material. Do we have some extra
> concerns here?
>
> Having pr_warn_on_once() would be nice here.
No extra concern, just want this indirection table to be up to date in
future.
next prev parent reply other threads:[~2024-04-29 19:56 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-27 0:37 [PATCH v2 0/7] memcg: reduce memory consumption by memcg stats Shakeel Butt
2024-04-27 0:37 ` [PATCH v2 1/7] memcg: reduce memory size of mem_cgroup_events_index Shakeel Butt
2024-04-27 0:42 ` Yosry Ahmed
2024-04-27 1:15 ` Shakeel Butt
2024-04-29 15:36 ` Roman Gushchin
2024-04-27 0:37 ` [PATCH v2 2/7] memcg: dynamically allocate lruvec_stats Shakeel Butt
2024-04-27 1:23 ` Yosry Ahmed
2024-04-29 15:50 ` Roman Gushchin
2024-04-29 19:46 ` Shakeel Butt
2024-04-29 21:02 ` Roman Gushchin
2024-04-29 21:59 ` Shakeel Butt
2024-04-27 0:37 ` [PATCH v2 3/7] memcg: reduce memory for the lruvec and memcg stats Shakeel Butt
2024-04-27 0:51 ` Yosry Ahmed
2024-04-27 1:16 ` Shakeel Butt
2024-04-27 1:18 ` Yosry Ahmed
2024-04-29 16:00 ` Roman Gushchin
2024-04-29 20:00 ` Shakeel Butt
2024-04-29 17:35 ` T.J. Mercier
2024-04-29 20:13 ` Shakeel Butt
2024-04-29 22:23 ` T.J. Mercier
2024-04-27 0:37 ` [PATCH v2 4/7] memcg: cleanup __mod_memcg_lruvec_state Shakeel Butt
2024-04-27 0:53 ` Yosry Ahmed
2024-04-29 15:45 ` Roman Gushchin
2024-04-27 0:37 ` [PATCH v2 5/7] memcg: pr_warn_once for unexpected events and stats Shakeel Butt
2024-04-27 0:58 ` Yosry Ahmed
2024-04-27 1:18 ` Shakeel Butt
2024-04-27 14:22 ` Johannes Weiner
2024-04-29 19:54 ` Shakeel Butt
2024-04-29 16:06 ` Roman Gushchin
2024-04-29 19:56 ` Shakeel Butt [this message]
2024-04-27 0:37 ` [PATCH v2 6/7] memcg: use proper type for mod_memcg_state Shakeel Butt
2024-04-27 0:37 ` [PATCH v2 7/7] mm: cleanup WORKINGSET_NODES in workingset Shakeel Butt
2024-04-29 16:07 ` Roman Gushchin
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