From: "T.J. Mercier" <tjmercier@google.com>
To: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Richard Chang <richardycc@google.com>,
Andrew Morton <akpm@linux-foundation.org>,
Kairui Song <kasong@tencent.com>, Qi Zheng <qi.zheng@linux.dev>,
Barry Song <baohua@kernel.org>,
Axel Rasmussen <axelrasmussen@google.com>,
Yuanchu Xie <yuanchu@google.com>, Wei Xu <weixugc@google.com>,
Johannes Weiner <hannes@cmpxchg.org>,
David Hildenbrand <david@kernel.org>,
Michal Hocko <mhocko@kernel.org>,
Lorenzo Stoakes <ljs@kernel.org>,
Suren Baghdasaryan <surenb@google.com>,
Martin Liu <liumartin@google.com>,
Minchan Kim <minchan@kernel.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm: vmscan: abort proactive reclaim early when freezing
Date: Wed, 8 Jul 2026 09:03:17 -0700 [thread overview]
Message-ID: <CABdmKX2C-XPN7Z3G7joSHUxhzEmp5dgNf_oA_ojQ_coM_CmvPQ@mail.gmail.com> (raw)
In-Reply-To: <ak5wxwj8cID-QQCF@linux.dev>
On Wed, Jul 8, 2026 at 8:48 AM Shakeel Butt <shakeel.butt@linux.dev> wrote:
>
> On Wed, Jul 08, 2026 at 03:24:15PM +0800, Richard Chang wrote:
> > On Wed, Jul 8, 2026 at 12:54 PM Shakeel Butt <shakeel.butt@linux.dev> wrote:
> > >
> > > What's so special about proactive reclaim? Why the same situation can not happen
> > > for global or memcg reclaim?
> > >
> >
> > The target batch size of the global/memcg reclaim is typically very
> > small -- usually SWAP_CLUSTER_MAX (32 pages), allowing the task to
> > yield or check signals between attempts.
> > Furthermore, kswapd is a kernel thread designed to be freezable, it
> > explicitly checks kthread_freezable_should_stop() in the main loop.
> > In contrast, the target batch size in proactive reclaim is
> > user-defined and can be extremely large. Without signal checks in the
> > inner loops, the task may continue scanning and evicting pages for
> > seconds at a time.
>
> Why can't the proactive reclaim use the same batch size as memcg and global
> reclaim?
Because it is very slow:
https://lore.kernel.org/all/20240202233855.1236422-1-tjmercier@google.com/
next prev parent reply other threads:[~2026-07-08 16:03 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-06 8:12 Richard Chang
2026-07-06 12:54 ` Barry Song
2026-07-07 8:00 ` Richard Chang
2026-07-06 23:38 ` Andrew Morton
2026-07-07 10:13 ` Richard Chang
2026-07-07 2:20 ` Yosry Ahmed
2026-07-07 8:04 ` Richard Chang
2026-07-07 18:28 ` Yosry Ahmed
2026-07-07 19:48 ` Shakeel Butt
2026-07-08 4:14 ` Richard Chang
2026-07-08 4:54 ` Shakeel Butt
2026-07-08 7:24 ` Richard Chang
2026-07-08 15:47 ` Shakeel Butt
2026-07-08 16:03 ` T.J. Mercier [this message]
2026-07-08 16:51 ` Shakeel Butt
2026-07-09 7:22 ` [PATCH v2] mm: vmscan: abort proactive reclaim early when freezing for suspend Richard Chang
2026-07-09 12:06 ` Michal Hocko
2026-07-10 3:29 ` Richard Chang
2026-07-10 6:27 ` Michal Hocko
2026-07-14 9:00 ` Richard Chang
2026-07-14 12:23 ` Michal Hocko
2026-07-14 12:40 ` Michal Hocko
2026-07-15 7:56 ` Richard Chang
2026-07-15 8:49 ` Michal Hocko
2026-07-15 17:47 ` Oleg Nesterov
2026-07-15 19:58 ` Michal Hocko
2026-07-17 9:14 ` Richard Chang
2026-07-17 18:12 ` [PATCH v3] " Richard Chang
2026-07-17 18:47 ` Oleg Nesterov
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