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dmarc=pass (policy=none) header.from=linux.alibaba.com; spf=pass (imf21.hostedemail.com: domain of baolin.wang@linux.alibaba.com designates 115.124.30.112 as permitted sender) smtp.mailfrom=baolin.wang@linux.alibaba.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1752214209; h=from:from: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:dkim-signature; bh=GviDtt0HM/H/nsHgI4GLwCPioqjPub/0QBTaXoqCufk=; b=MmrOLprwY3wZZtTValJHMIVeqOgmkNK7VNwH0TBd/mp6B5x117+0LYaK63sTGMEwyYTXZR yhsE8sS7OLNmSgUzqwybhaeqjooozg1i4QLiQIx4P+5cLiYc0PwxXJsmjirXSjVz+75VKi AsrXsGpIPQn2m6ooHi4IuRMi8Y57cxc= DKIM-Signature:v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1752214203; h=Message-ID:Date:MIME-Version:Subject:To:From:Content-Type; bh=GviDtt0HM/H/nsHgI4GLwCPioqjPub/0QBTaXoqCufk=; b=sbquC2wXrOYC1Ddcq4iguxQOZusYoRS+zo2fBN91WaBK2nS6nlbBJDc7bBB583d09Lyud+mfcif0TRGPQtCBRMckk9jJUik1jmff7wAoZNzcOPyIh5H3JM4ZvFxByWsowJ/NKkfSnD15MJTQYlIf1Ku+x36ZnyjXiRExldHQiec= Received: from 30.74.144.131(mailfrom:baolin.wang@linux.alibaba.com fp:SMTPD_---0WifmNlO_1752214200 cluster:ay36) by smtp.aliyun-inc.com; Fri, 11 Jul 2025 14:10:01 +0800 Message-ID: <1fe97413-03eb-433a-91b3-b53e58c65622@linux.alibaba.com> Date: Fri, 11 Jul 2025 14:10:00 +0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v5 5/8] mm/shmem, swap: never use swap cache and readahead for SWP_SYNCHRONOUS_IO To: Kairui Song , linux-mm@kvack.org Cc: Andrew Morton , Hugh Dickins , Matthew Wilcox , Kemeng Shi , Chris Li , Nhat Pham , Baoquan He , Barry Song , linux-kernel@vger.kernel.org References: <20250710033706.71042-1-ryncsn@gmail.com> <20250710033706.71042-6-ryncsn@gmail.com> From: Baolin Wang In-Reply-To: <20250710033706.71042-6-ryncsn@gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: C79231C0004 X-Stat-Signature: gudqemtar4za3zaxoqcr3pbj5af46483 X-HE-Tag: 1752214207-994538 X-HE-Meta: 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 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 2025/7/10 11:37, Kairui Song wrote: > From: Kairui Song > > For SWP_SYNCHRONOUS_IO devices, if a cache bypassing THP swapin failed > due to reasons like memory pressure, partially conflicting swap cache > or ZSWAP enabled, shmem will fallback to cached order 0 swapin. > > Right now the swap cache still has a non-trivial overhead, and readahead > is not helpful for SWP_SYNCHRONOUS_IO devices, so we should always skip > the readahead and swap cache even if the swapin falls back to order 0. > > So handle the fallback logic without falling back to the cached read. > > Signed-off-by: Kairui Song LGTM. Thanks. Reviewed-by: Baolin Wang