Re: [PATCH v3 6/8] workingset: memcg: sleep when flushing stats in workingset_refault()

From: "Michal Koutný" <mkoutny@suse.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>,
	Shakeel Butt <shakeelb@google.com>,
	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, Michal Hocko <mhocko@suse.com>
Subject: Re: [PATCH v3 6/8] workingset: memcg: sleep when flushing stats in workingset_refault()
Date: Wed, 5 Apr 2023 10:00:47 +0200	[thread overview]
Message-ID: <20230405080047.5omnatjbwz46f3y5@blackpad> (raw)
In-Reply-To: <CAJD7tkb-0rXL9V2TX-Ax-3OkwJPYx_GaOT4D=VCA60riit+dOw@mail.gmail.com>

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On Tue, Apr 04, 2023 at 11:09:02AM -0700, Yosry Ahmed <yosryahmed@google.com> wrote:
> IIUC there are multiple places where we can sleep in this path, we can
> sleep waiting for a page to be read from disk, we can sleep during
> allocating the page to read into, and IIUC the allocations on the
> fault path can even run into reclaim, going into the vmscan code. So
> there are precedents, but I am not sure if that's enough argument.

I expect it'd depend on the proportion of the slow/fast paths.
OK, let's see how it turns out in wider population.

Thanks,
Michal

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