From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.subspace.kernel.org (Postfix) with ESMTP id A82A0606A31C for ; Wed, 11 Nov 2026 17:19:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=CQ3YcXyn Received: by kanga.kvack.org (Postfix) id BEE6D6B05B1; Wed, 11 Nov 2026 12:19:52 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id B9F036B05B2; Wed, 11 Nov 2026 12:19:52 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id AB4EE6B05B3; Wed, 11 Nov 2026 12:19:52 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 84D916B05B1 for ; Wed, 11 Nov 2026 12:19:52 -0500 (EST) Received: from smtpin17.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay01.hostedemail.com (Postfix) with ESMTP id 1380D1C39FF for ; Wed, 11 Nov 2026 17:19:52 +0000 (UTC) X-FDA: 85423500624.17.382264A Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf07.hostedemail.com (Postfix) with ESMTP id 70B5840005 for ; Wed, 11 Nov 2026 17:19:50 +0000 (UTC) Authentication-Results: imf07.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=CQ3YcXyn; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf07.hostedemail.com: domain of sashiko-bot@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=sashiko-bot@kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1794417590; h=from:from:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=SzVvTj1tb0Ep/dVhlciwGP6JmNFPxZFsMdX03oVDkMc=; b=uYmNcUHTFjFd3O5PDJUT7jsJQvlwSu2J/xl7dJpkvCeh3CF7yR0lFbS2EN8elD3Og5llHz PqKDTGRelLg8YkBDT3f6nlKWqJbNy32U72v1AWnLOvw1VGG8kQY6TAu6YFRjUQqcmcqnRn Z4NOF8PsmZXZKMk/3XBnMZBkxPj3KaE= ARC-Authentication-Results: i=1; imf07.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=CQ3YcXyn; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf07.hostedemail.com: domain of sashiko-bot@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=sashiko-bot@kernel.org ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1794417590; b=t/+RpUsymZIej7Fpi/8gd16cBs51S7VbOKZPZm4yk6aWFHbz9cLK8MQ7tBsry5LIx9gmQd ZK8mHi9Z9rSM/P80yrH8AxcQLtJchym+mDfPAVwIhaTGC+KoD7oeDYqbBf1P/lcflUCfkB LrsZH3RXviFp6T62/GpfgjkYu70oI58= Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 956A14024B; Wed, 11 Nov 2026 17:19:49 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C98DD1F00A06; Wed, 11 Nov 2026 17:19:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794417589; bh=SzVvTj1tb0Ep/dVhlciwGP6JmNFPxZFsMdX03oVDkMc=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=CQ3YcXynk2NNxkFh7xuYG+u1w6DYEZQOJNfKlFFaE/sNwPgn4RKaz4gOQ20GQbOX+ yhiH7qyqQ3QQrpE2UQ8ugqPlDZ1mIOOckrHEjqpDqZlr43m4asZBpiwy5xONb/VcrC 3d9Y6PyMSNsQsH7ej70xHWaRigvetj/wYkW3BjHy2Ozc+0MhiMQFXTsOXSnsEvErpZ XkTFlTMTopy3TrLGAvumKZQCx7FDJT/IIikxhIhnzV5MY3+lx7+Uch3VbofCJjs2Qd tbYyZUJ8j9v3WA/x4sJMTl/5PkIimtqddygHCjinVCcPrXBYh40OkmJQV5PB6ssFVr 33RV1UalcUW4g== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH v3 3/3] mm/khugepaged: release contended mmap read lock after scanning enough VMAs Reply-To: sashiko-reviews@lists.linux.dev To: =?utf-8?b?TG9yZW56byBTdG9ha2VzIChBUk0p?= , "David Hildenbrand" , "Zi Yan" , "Baolin Wang" , "Liam R. Howlett" , "Nico Pache" , "Ryan Roberts" , "Dev Jain" , "Barry Song" , "Lance Yang" , "Usama Arif" , "Kiryl Shutsemau" , "Andrew Morton" Cc: linux-mm@kvack.org In-Reply-To: <20261110-khugepaged-latency-fix-v3-3-6eea743cf9a3@kernel.org> References: <20261110-khugepaged-latency-fix-v3-0-6eea743cf9a3@kernel.org> <20261110-khugepaged-latency-fix-v3-3-6eea743cf9a3@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Wed, 11 Nov 2026 17:19:48 +0000 X-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 70B5840005 X-Spam-Status: No, score=-5.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_PASS,SPF_PASS autolearn=no autolearn_force=no version=4.0.1 X-Stat-Signature: cxnb7yyt87i1cn6pgmyzpcbyugnn9t3h X-HE-Tag: 1794417590-137639 X-HE-Meta: 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 QQDOmjDK V5Upv8+NO3vCqGQr0mpdwImey18EQSd1Qy0Fd280vIudUrwrkwTHA7oJlgUtm0wx0P9WMvhS2+bqrOiZKn/SA/wHxAFgLzTnpRITFFVV04ZdYSGXMd08Fzt6e7HEbZxWlng1ZMIoGQalySvteMQfndkXvmGlCpEtB9ruff9+m1mAcaO1LkC/SRyh6IkPpp0NoUgcOsx2vg/dfMDttUPdEIw5diPWD6bsAzZc1uSJbYOfobGB4B8GECDXTYYg4PueDFUNlnX8gTioXwDKBvxNdxO6DiDTgzXnWKbZoFaQmhIlflGxK7eQYFASFN5jpTVaYf5vhvehiNbhjhgBtqAl7XG5o0o0REVpzEo8mDdcZgdGiPlPqvBs0xoAVvEl+jMUtDZwTO+R6PDTr9OuSI6rX4iZxMtO5CgnHMjpBoocOVPyVznSRdQWOxSi6KEitlio/I/0gbqqhud2/e9SHsFmLy5AifKNDUNrWKeG+LzO73vYc/5lfL3ANjtJSvUHQnG9Wi/yRIkOmTlPEr66rQrz/SrH+0jNtR4nyb5xY5i8pchW/52A+whQ2PWKfjru4mkyY6yWObfTF0w1OJ8wlcfI6hI95oUdMK3OUK8F9msNC6KvvJ8/FmnAqu3BYSsTpAOIOsjhA Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 X-Archived-By: Thank you for your contribution! Sashiko AI review found 1 potential issue to consider: - [Low] mm/khugepaged: stale jiffies-based check description in commit message -- commit bce7aeac77f8f4e7344a0f568e13d01a781dac5f Author: Lorenzo Stoakes (ARM) mm/khugepaged: release contended mmap read lock after scanning enough VMAs This commit drops and reacquires the mmap read lock in collapse_scan_mm_slot() if the lock is contended after walking a batch of 1024 VMAs. Link: https://lore.kernel.org/all/20261105-rwsem-dont-steal-from-queued-wri= ter-v1-1-275e070f426f@kernel.org/ > Address this by checking whether the mmap lock is contended after 1-10 > ms (depending on CONFIG_HZ), i.e. the granularity of jiffies. This is a > long time for a lock to be held, so is a reasonable compromise for > determining when best to do this. [Severity: Low] Is this paragraph left over from an earlier jiffies-based version of the patch? The code checks mmap_lock_is_contended() every KHUGEPAGED_MAX_VMA_SCAN_BATCH (1024) VMAs, as described in the following paragraph, rather than using jiffies. --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261110-khugepaged= -latency-fix-v3-0-6eea743cf9a3@kernel.org?part=3D3