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From: Shakeel Butt To: Richard Chang Cc: Andrew Morton , Kairui Song , Qi Zheng , Barry Song , 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 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: X-Migadu-Flow: FLOW_OUT X-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 4E89120006 X-Stat-Signature: ju5reg84hku8meq9oat8nf8mzjb6uo64 X-HE-Tag: 1783486453-708062 X-HE-Meta: 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 53I1xJKs SwCJ52FCJTLlL/1DVkXw5E8phGqAvYyc49VRRXSftJ/g9b/jk7NFambc1hgezHFEuhV3EwwE5kuR+0zX67r9Lr2upHkQGaa9SI5Zl4gO6OFu33DMtQgo+5t/Pw8/JZvY7wRujAXa2h+jrZVJAxP2NlBXv7N2yHwH0fNiVfHWeTfNxcDZgsH2/Zl7lbirMoSErvHLv+TYZA91SPaukvsI5OL8PEjJe/jolNBsUwGSo6Ulnqjc= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Wed, Jul 08, 2026 at 12:14:50PM +0800, Richard Chang wrote: > On Wed, Jul 8, 2026 at 3:48 AM Shakeel Butt wrote: > > > > Can you please explain how freezing operation was delayed due to proactive > > reclaim? > > > Hi Shakeel, > > When system suspend is initiated, the Power Management (PM) freezer > attempts to freeze all user-space processes by calling > freeze_processes(), signaling user space processes to enter the > refrigerator. When a user-space task writes to memory.reclaim to > trigger proactive reclaim, it executes in kernel context and enters > the reclaim loop. Currently the task does not check signal_pending() > within the inner loops, it cannot abort the reclaim pass early. It > continues reclaiming memory, ignoring the freeze request. The PM > freezer waits for all tasks to freeze. If the proactive reclaim task > remains in the inner loops longer than the freeze timeout, the freezer > times out, and suspend fails. What's so special about proactive reclaim? Why the same situation can not happen for global or memcg reclaim?