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J . Mercier" , Martin Liu , Minchan Kim , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm: vmscan: abort proactive reclaim early when freezing Message-ID: References: <20260706081218.3438762-1-richardycc@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20260706081218.3438762-1-richardycc@google.com> X-Rspam-User: X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: 7C30E40007 X-Stat-Signature: dytwx64n34z8p3578qb7ai8gxjfkyj6w X-HE-Tag: 1783390853-157887 X-HE-Meta: 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 HC4ze/Ec UhnhTzcd/QXoVZWBotO1vc7SKbz8Y6EnTYolDS3Q1us704S9VdL2fHHmp2INqZAahn4LRy57XZ+WhPrLlG5obn231Tlh+J/K5gHzGO9bhxMTwG5clq+ySqESI15Z1bY4/FimaxWzjB6rPniPCxYh3y1pEOfOlGeXApUWZ2/vZq3a5SpYJNf2X7HQAd0ACOa0UE9y83tmKPkA9iytF/9hQKhEx1+w97aCFbyZd45+6oWUtyGzfQ2MVvTveNNGYu7hykrHS5nwSKakRd0y5NZoJd+XkAsYuJrugmXQ0GT71Le+NRmzSTAPvTdfSHWf5M500Et7il1MZhmwhchRhVoAe0kBvcA== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, Jul 06, 2026 at 08:12:18AM +0000, Richard Chang wrote: > Proactive reclaim (via memory.reclaim or node reclaim) checks for pending > signals in its outer loop in user_proactive_reclaim(). However, the inner > reclaim loops—scanning cgroups in shrink_many() and evicting folios in > try_to_shrink_lruvec() can run for a long time before returning to the > outer loop, especially on systems with many cgroups or large memory sizes. > > This latency in responding to signals can block the freezer (both cgroup > freezer and system suspend), leading to freezer timeouts. This issue was > specifically observed on Android when attempting to freeze background > cgroups while proactive reclaim was active. > > Add a signal_pending() check to should_abort_scan() for proactive reclaim > paths. Since should_abort_scan() is called within the inner scanning and > eviction loops, this allows proactive reclaim to abort early and return to > the outer loop, ensuring the task can enter the refrigerator in a timely > manner. Do we still need the check in the outer loop? > > This check is limited to proactive reclaim (sc->proactive) to avoid > affecting reactive reclaim paths, and wrapped in unlikely() as it is a > slow path. > > Signed-off-by: Richard Chang > --- > mm/vmscan.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/mm/vmscan.c b/mm/vmscan.c > index 35c3bb15ae96..fb472e924fc7 100644 > --- a/mm/vmscan.c > +++ b/mm/vmscan.c > @@ -4929,6 +4929,9 @@ static bool should_abort_scan(struct lruvec *lruvec, struct scan_control *sc) > int i; > enum zone_watermarks mark; > > + if (unlikely(sc->proactive && signal_pending(current))) > + return true; > + > if (sc->nr_reclaimed >= max(sc->nr_to_reclaim, compact_gap(sc->order))) > return true; > > -- > 2.55.0.rc2.803.g1fd1e6609c-goog > >