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Mon, 07 Sep 2026 18:19:35 -0700 (PDT) From: Joshua Hahn To: Shakeel Butt Cc: hannes@cmpxchg.org, mhocko@kernel.org, roman.gushchin@linux.dev, muchun.song@linux.dev, akpm@linux-foundation.org, david@kernel.org, ljs@kernel.org, liam@infradead.org, vbabka@kernel.org, rppt@kernel.org, surenb@google.com, dev@lankhorst.se, mripard@kernel.org, nat@pixelcluster.dev, tj@kernel.org, mkoutny@suse.com, osalvador@suse.de, cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, kernel-team@meta.com Subject: Re: [PATCH v5 5/7] mm/page_counter: introduce an asynchronous drainer Date: Mon, 7 Sep 2026 18:19:34 -0700 Message-ID: <20260908011934.1737458-1-joshua.hahnjy@gmail.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 6C1AB40006 X-Stat-Signature: jcuddh5cpz3pjoiw4e8keh7oijkxwd46 X-Rspam-User: X-HE-Tag: 1788830378-512221 X-HE-Meta: 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 XTvqGY6Q 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, 7 Sep 2026 16:25:31 -0700 Shakeel Butt wrote: Hi Shakeel, Thanks for your review on the series! > On Mon, Aug 31, 2026 at 09:37:49AM -0700, Joshua Hahn wrote: > > The existing percpu memcg stock drainer schedules a stock drain worker > > per-cpu, one for every CPU containing the target memcg's stock. > > But you are introducing remote draining. Why do you need async drainer at all? > Just always drain synchronously. I was trying to match parity with the existing code as much as possible. But I see now that this series is a bit complicated because I'm trying to do two things at once and mixing up the page_counter migration and the scalable draining together. In the next version I'll keep parity and only migrate to page_counter and in a follow-up I'll address the drainers separately. Thanks again! Joshua