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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: <20260706163833.19b6c869407d51ba8e278f56@linux-foundation.org> In-Reply-To: <20260706081218.3438762-1-richardycc@google.com> References: <20260706081218.3438762-1-richardycc@google.com> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 9629740004 X-Stat-Signature: 6byhmqi4mr31zhzcsxtn8gtohorhtfpd X-HE-Tag: 1783381115-842621 X-HE-Meta: U2FsdGVkX18ipYav2tzN4tuSU2KncNBOKHBYVdBFF+2kiGzbchijW141Np57/D8qDzqpBJzp05wYUGGbPorB88SR+85vy7EYlcY7yMDtbj8rWD9kNx/kYKvw/yCDksPOiyV+mThUyix79vMj00jXkeoGudLAKD6L94EHbOH25NTUizavq0z0RTDtUbF8Caaq2vCNunuTTD4JspVJU6FpOnloYlP3psEBSjBzq2Hn1H/I0qXa/VIt/Lmfoq/0bM6WzlX94ySS5WKCZMHbdTudq0+JCwDE9UYN4nZwi+XZF/vmhVlzCKcjPuNMnaiXCqQx6ujqb6QQCHNM3M+Nt59ewf5KZw7rQqYkBZzDsnixuaTIdd77yO3Md17SBm3SqQL9ar2Xi4Bxtn6k5CTHpEjq5jkrl37eXw6on+elwC1C7OQBT02FnrEzLYaLg7PDOzh4veVrOJ89NBSiP7Hnv/EIved+zfoidKJKbvFtGX7Cfkc7vj3p38qiaLBHe77cAgfcKM6XWZ9X2LcRk+SVrvEnI9GYjHAG71u7U1XIi6Q2TgehFxeU/0DlERBdFiHbmckvxB3/hpznNZYQ2fgkDJLWkmfAdiztnKPSIClmDuiZftZuB8bIbRjwOCxTCI8xDo4krMJihflwPkq3MZv6wEjRyIlpQ5THLWoFHRqQH/Zm+X9gccHlLJKqPiFJSIoE0qwP85BU42A9IIm26GYo5EMMnG7guvrsILjV+OQBVQzV0rDZQo/mKcOSiYJDZ+Zu5RsJyTleRxgNS97ekV9Ihjyg2j28+jIBbEPcFWhOYDxf5MIJHlsRGIuG3aAZmMFWRcprLZQdFwDL6NMzDoQ5ef+4R2Jt9IqHT7P0vDza6APA15q6wGm2KdMSKyf2CwvS9CK2rBf2oGzuInugPmVfpfiMsfrRMs45Oz3gjG0cG1YgDtHhxn1ehucqNV+PI5+y9Ts4ClMOT+FPnIS6sBhViK2 p1hG/AUn P65C0JnAuKK7YR33IjUhLpUOkwzGXF/NIlLFJkhsmV7V/ajFDjeCAeY8Zjwc7fgEDRKY8bKCFI2mPK0SZSbu5C3erMUSdrzqC1IKetu0lA8mZnqVzWdP8lZlMzKuoz1sJbUfiZWX2DM1D5IhFjWru0/UO5pT5odDMeq9gf400Rbl+EbiFMmHF8MhETbsvPmu/wrQQhubrJ4okL+JpPQW5wwbAScOsR5hSID8hwJgOha8fWXC4HyAc4k9XAfZvoVs0sdKdnnWraS/qjW76WMNzIhEhp1KyEgKE1gxCI98hfxDGtPyUDZkbwIQ325CNxfeHkPokncuDnF0/T6kDRc7t1S8tZilaxC8mUGTDRmyaT2sordA= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, 6 Jul 2026 08:12:18 +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. > > 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. There are a number of ways of getting into proactive reclaim. Have you checked that all of them appropriately check and handle signal_pending()? AI review thinks that classic LRU might need the same fix: https://sashiko.dev/#/patchset/20260706081218.3438762-1-richardycc@google.com