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d=hostedemail.com; s=arc-20220608; t=1734630760; h=from:from:sender:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=CkKpQe6atsYpnKW/zC7uyX6XyA0bsM+FDucLe9MrO+8=; b=5/fcbnC3PMdNcpeQ/F7mup6vNuku1Cu52xyoixAFgcK5CReCcDamGNnJCHFmNdVmdukzI7 mUJ25WMRdUR7xXI34ad4DzhJ5ypQhY5whk/vJ3vucnC/VIOeVzkiQbZbKTQlovXSPsJ/tk DLzMlif9UsgsICo5f9y9TyhjnFc3SI0= Received: from fangorn.home.surriel.com ([10.0.13.7]) by shelob.surriel.com with esmtpsa (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.97.1) (envelope-from ) id 1tOKeu-000000008Pp-2Nv4; Thu, 19 Dec 2024 12:50:00 -0500 Message-ID: Subject: Re: [PATCH] mm: add maybe_lru_add_drain() that only drains when threshold is exceeded From: Rik van Riel To: David Hildenbrand , Andrew Morton Cc: Chris Li , Ryan Roberts , "Matthew Wilcox (Oracle)" , linux-kernel@vger.kernel.org, linux-mm@kvack.org, kernel-team@meta.com Date: Thu, 19 Dec 2024 12:50:00 -0500 In-Reply-To: References: <20241218115604.7e56bedb@fangorn> <189f4767-e7c2-4522-b943-b644126bf897@redhat.com> <58d69446edb0e2b3b4edec442043cd0a9748f15f.camel@surriel.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.54.1 (3.54.1-1.fc41) MIME-Version: 1.0 X-Stat-Signature: 1z3e88g1gkt74yrj1dzeu5dnddyguxau X-Rspam-User: X-Rspamd-Queue-Id: 0127A2000C X-Rspamd-Server: rspam08 X-HE-Tag: 1734630757-212260 X-HE-Meta: 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 os2wAaoT 85OsMJf+DzIt7e+EkICD4GcDh6EHJ3nJyYX8x4PWIRhLxvvmbwA1xa+Oixut0X1s4d1eB4+jKJj59Q5vHbWNOOLBlOeAHUI671zVyRhTyPXRAQD7tKjc9X2+FHDI3Exdm0HiP6rTBqYnAvAy9jb5Umhefj1LuwvDe0Jc6mwOBecPsJ79lot1Yh9kB1sw7bCrhwR8HYlIfXA54xIeWSPO4QU3fOPuGAwXLXt/0q+EdcVfG710GpXoMH00QzZsM4WVFNL93Zh7DZjfJHf6xQHqOGtToHshW4e4KaaIlJB9xQ7JC8QCf0rYCCNjdEg== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, 2024-12-19 at 18:23 +0100, David Hildenbrand wrote: > On 19.12.24 15:11, Rik van Riel wrote: > >=20 > > I think we need to free those pending pages at > > some point. They can't accumulate there forever. > > However, I am not sure where those points should > > be. >=20 > The number of entries are limited,=C2=A0 ... > folio_batch_add() drains if folio_batch_space() returns 0 (no slots > left). >=20 > Apparently we have PAGEVEC_SIZE slots, which is 31 ... 31 * PAGE_SIZE > stranded there. Sure enough! That was the piece I was missing last night. I guess we can get away with just draining these in the reclaim and compaction paths, and not touch them the rest of the time? That could be a nice improvement in some situations. --=20 All Rights Reversed.