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AHgh+Rrx8XMubksRzO/LZFxifEwUB1fe6aLjZ/X+dkHERLD2pCWbvhJReEkr2Bh96hK89rtbnibuqiEAxXOfUNg=@vger.kernel.org X-Gm-Message-State: AOJu0YxL4buQvtD4kWUZE7cqDEOclje86InIlrF2DDB54+uqbaAtGcfs q38LeWMVmUr/1wJ3DxdwH0mTpOsNc3KJlighfM67Q3cO0guVtpDe6o0HmolMMidYZ1nD+XM7BDg xwXex7MuQOVeIrGrclp+3hwAFYL7pE8Fjy1gLTPw= X-Gm-Gg: AfdE7cnLyVVmvT+tslqwtU3qeJNlE5KIW8uDWbA60+IhCesNN+7CW3emCor1YHSM78v wKiseS+d+Qhj0y1JeyxI4AcC7p/Cdr17FzyG5CqlLKxJpwvnXWGvtezy1mMZbAbtFb/e8YWSctW uwG4RLWaa7cWUfTU0Innqy0urPotBMu1Or7N8IkKFfYU7vOauYFlooxtISec5XXhjMRBHh7SLBj 3o+IRyCzUjExYFHe++RQmko2ZVWc0ATIcdV/vxaxFodoUNtLfg8lBhoz0ixtj9gyhCddwyz5dog iYMIIQ== X-Received: by 2002:a05:6512:3da8:b0:5ae:bfe1:737b with SMTP id 2adb3069b0e04-5b00ad0be3emr126280e87.10.1783411224922; Tue, 07 Jul 2026 01:00:24 -0700 (PDT) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 References: <20260706081218.3438762-1-richardycc@google.com> In-Reply-To: From: Richard Chang Date: Tue, 7 Jul 2026 16:00:13 +0800 X-Gm-Features: AVVi8Cf3ibBWWIWOluFT0ClIxymtOO0JsOIGpXKypqkH0c6u-2_EYE3zJqMFF4I Message-ID: Subject: Re: [PATCH] mm: vmscan: abort proactive reclaim early when freezing To: Barry Song Cc: Andrew Morton , Kairui Song , Qi Zheng , Shakeel Butt , Axel Rasmussen , Yuanchu Xie , Wei Xu , Johannes Weiner , David Hildenbrand , Michal Hocko , Lorenzo Stoakes , Suren Baghdasaryan , "T . J . Mercier" , Martin Liu , Minchan Kim , linux-mm@kvack.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Hi Barry, I use the following commands to test. The CGROUP_PATH depends on the platform settings. echo 1000 > /sys/power/pm_freeze_timeout echo freezer > /sys/power/pm_test while true; do echo 1024M > /sys/fs/cgroup/$CGROUP_PATH/memory.reclaim; sleep 1; done echo mem > /sys/power/state BR, Richard On Mon, Jul 6, 2026 at 8:54=E2=80=AFPM Barry Song wrote= : > > On Mon, Jul 6, 2026 at 4:12=E2=80=AFPM Richard Chang wrote: > > > > Proactive reclaim (via memory.reclaim or node reclaim) checks for pendi= ng > > signals in its outer loop in user_proactive_reclaim(). However, the inn= er > > reclaim loops=E2=80=94scanning cgroups in shrink_many() and evicting fo= lios 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 siz= es. > > > > This latency in responding to signals can block the freezer (both cgrou= p > > freezer and system suspend), leading to freezer timeouts. This issue wa= s > > 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 recla= im > > paths. Since should_abort_scan() is called within the inner scanning an= d > > eviction loops, this allows proactive reclaim to abort early and return= to > > the outer loop, ensuring the task can enter the refrigerator in a timel= y > > manner. > > > > 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 *lruv= ec, struct scan_control *sc) > > int i; > > enum zone_watermarks mark; > > > > + if (unlikely(sc->proactive && signal_pending(current))) > > + return true; > > + > > Seems reasonable to me. I wonder if you have a script to > reproduce the issue. I'd like to test it. > > Best Regards > Barry