From: Shakeel Butt <shakeelb@google.com>
To: Yosry Ahmed <yosryahmed@google.com>
Cc: Tejun Heo <tj@kernel.org>, Josef Bacik <josef@toxicpanda.com>,
Jens Axboe <axboe@kernel.dk>, Zefan Li <lizefan.x@bytedance.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Michal Hocko <mhocko@kernel.org>,
Roman Gushchin <roman.gushchin@linux.dev>,
Muchun Song <muchun.song@linux.dev>,
Andrew Morton <akpm@linux-foundation.org>,
Vasily Averin <vasily.averin@linux.dev>,
cgroups@vger.kernel.org, linux-block@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
bpf@vger.kernel.org
Subject: Re: [RFC PATCH 1/7] cgroup: rstat: only disable interrupts for the percpu lock
Date: Fri, 24 Mar 2023 21:46:05 -0700 [thread overview]
Message-ID: <CALvZod41ecuCKmuFBNtAjoKJjQgWYzoe4_B8zRK37HYk-rYDkA@mail.gmail.com> (raw)
In-Reply-To: <CAJD7tkY_ESpMYMw72bsATpp6tPphv8qS6VbfEUjpKZW6vUqQSQ@mail.gmail.com>
On Fri, Mar 24, 2023 at 9:37 PM Yosry Ahmed <yosryahmed@google.com> wrote:
>
> On Fri, Mar 24, 2023 at 9:31 PM Shakeel Butt <shakeelb@google.com> wrote:
> >
> > On Fri, Mar 24, 2023 at 7:18 PM Yosry Ahmed <yosryahmed@google.com> wrote:
> > >
> > [...]
> > > Any ideas here are welcome!
> > >
> >
> > Let's move forward. It seems like we are not going to reach an
> > agreement on making cgroup_rstat_lock a non-irq lock. However there is
> > agreement on the memcg code of not flushing in irq context and the
> > cleanup Johannes has requested. Let's proceed with those for now. We
> > can come back to cgroup_rstat_lock later if we still see issues in
> > production.
>
> Even if we do not flush from irq context, we still flush from atomic
> contexts that will currently hold the lock with irqs disabled
> throughout the entire flush sequence. A primary purpose of this reason
> is to avoid that.
>
> We can either:
> (a) Proceed with the following approach of making cgroup_rstat_lock a
> non-irq lock.
> (b) Proceed with Tejun's suggestion of always releasing and
> reacquiring the lock at CPU boundaries, even for atomic flushes (if
> the spinlock needs a break ofc).
> (c) Something else.
(d) keep the status quo regarding cgroup_rstat_lock
(e) decouple the discussion of cgroup_rstat_lock from the agreed
improvements. Send the patches for the agreed ones and continue
discussing cgroup_rstat_lock.
next prev parent reply other threads:[~2023-03-25 4:46 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-23 4:00 [RFC PATCH 0/7] Make rstat flushing IRQ and sleep friendly Yosry Ahmed
2023-03-23 4:00 ` [RFC PATCH 1/7] cgroup: rstat: only disable interrupts for the percpu lock Yosry Ahmed
2023-03-23 4:29 ` Shakeel Butt
2023-03-23 5:15 ` Yosry Ahmed
2023-03-23 6:33 ` Shakeel Butt
2023-03-23 13:35 ` Yosry Ahmed
2023-03-23 15:40 ` Shakeel Butt
2023-03-23 15:42 ` Yosry Ahmed
2023-03-23 15:46 ` Shakeel Butt
2023-03-23 16:09 ` Shakeel Butt
2023-03-23 16:17 ` Yosry Ahmed
2023-03-23 16:29 ` Shakeel Butt
2023-03-23 16:36 ` Yosry Ahmed
2023-03-23 16:45 ` Shakeel Butt
2023-03-23 16:51 ` Yosry Ahmed
2023-03-23 19:09 ` Shakeel Butt
2023-03-23 17:33 ` Johannes Weiner
2023-03-23 18:09 ` Yosry Ahmed
2023-03-23 18:19 ` Johannes Weiner
2023-03-24 1:39 ` Tejun Heo
2023-03-24 7:22 ` Yosry Ahmed
2023-03-24 14:12 ` Waiman Long
2023-03-24 22:50 ` Yosry Ahmed
2023-03-25 1:54 ` Tejun Heo
2023-03-25 2:17 ` Yosry Ahmed
2023-03-25 4:30 ` Shakeel Butt
2023-03-25 4:37 ` Yosry Ahmed
2023-03-25 4:46 ` Shakeel Butt [this message]
2023-03-27 23:23 ` Yosry Ahmed
2023-03-29 18:53 ` Tejun Heo
2023-03-29 19:22 ` Hugh Dickins
2023-03-29 20:00 ` Tejun Heo
2023-03-29 20:38 ` Hugh Dickins
2023-03-30 4:26 ` Yosry Ahmed
2023-03-31 1:51 ` Tejun Heo
2023-03-23 4:00 ` [RFC PATCH 2/7] memcg: do not disable interrupts when holding stats_flush_lock Yosry Ahmed
2023-03-23 4:32 ` Shakeel Butt
2023-03-23 5:16 ` Yosry Ahmed
2023-03-23 4:00 ` [RFC PATCH 3/7] cgroup: rstat: remove cgroup_rstat_flush_irqsafe() Yosry Ahmed
2023-03-23 15:43 ` Johannes Weiner
2023-03-23 15:45 ` Yosry Ahmed
2023-03-23 4:00 ` [RFC PATCH 4/7] memcg: sleep during flushing stats in safe contexts Yosry Ahmed
2023-03-23 15:56 ` Johannes Weiner
2023-03-23 16:01 ` Yosry Ahmed
2023-03-23 17:27 ` Johannes Weiner
2023-03-23 18:07 ` Yosry Ahmed
2023-03-23 19:35 ` Shakeel Butt
2023-03-23 4:00 ` [RFC PATCH 5/7] vmscan: memcg: sleep when flushing stats during reclaim Yosry Ahmed
2023-03-23 4:00 ` [RFC PATCH 6/7] workingset: memcg: sleep when flushing stats in workingset_refault() Yosry Ahmed
2023-03-23 15:50 ` Johannes Weiner
2023-03-23 16:02 ` Yosry Ahmed
2023-03-23 16:00 ` Johannes Weiner
2023-03-23 16:02 ` Yosry Ahmed
2023-03-23 4:00 ` [RFC PATCH 7/7] memcg: do not modify rstat tree for zero updates Yosry Ahmed
2023-03-23 4:10 ` [RFC PATCH 0/7] Make rstat flushing IRQ and sleep friendly Shakeel Butt
2023-03-23 5:07 ` Yosry Ahmed
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