From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 41D0BCCFA13 for ; Tue, 11 Nov 2025 03:04:32 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 9E3258E000D; Mon, 10 Nov 2025 22:04:31 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 96C8E8E0002; Mon, 10 Nov 2025 22:04:31 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 85B408E000D; Mon, 10 Nov 2025 22:04:31 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id 700A68E0002 for ; Mon, 10 Nov 2025 22:04:31 -0500 (EST) Received: from smtpin22.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 0C20F16034E for ; Tue, 11 Nov 2025 03:04:31 +0000 (UTC) X-FDA: 84096833142.22.47B1A54 Received: from out-173.mta1.migadu.com (out-173.mta1.migadu.com [95.215.58.173]) by imf27.hostedemail.com (Postfix) with ESMTP id B3FB04000E for ; Tue, 11 Nov 2025 03:04:27 +0000 (UTC) Authentication-Results: imf27.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=m1VOnbj0; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf27.hostedemail.com: domain of qi.zheng@linux.dev designates 95.215.58.173 as permitted sender) smtp.mailfrom=qi.zheng@linux.dev ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1762830267; a=rsa-sha256; cv=none; b=0G12y/UAb8Md/YVSTDe1MBkWUl1IKCzCeJ2Pt66zXju6ArhsSUGfj6WJ6ygcT+Q4XMFm9d Dduic+7N5vfwsS1oO8pCvse0MD0PnhjKsYIPMs16gOPgkYu4S+VIQ71sqPvscesYXCp9Oq BeEsAho+1uo2dWnou7tK8Fo6aiu3upQ= ARC-Authentication-Results: i=1; imf27.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=m1VOnbj0; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf27.hostedemail.com: domain of qi.zheng@linux.dev designates 95.215.58.173 as permitted sender) smtp.mailfrom=qi.zheng@linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1762830267; 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=V5c8zazQymbCh3EJOF0KTydVfHgB+HL63txNkj2DBcg=; b=YZX6BG4OGl5jlQm/OlO07AGtCpx0gmz05hnzFpntGkoew9wmaXSnAtu2QlbCu8csMnYP5u y6beiRqP6HaArPf2fWDN9fPk+9TZjHAj2fDAjAAONKIezv9Xa61bfwS28SaF0imQ7VtKxW 4bGe35HhHM4ziS6e1D/sd57rIWKxN6o= Message-ID: <8d6655f8-2756-45bb-85c1-223c3a5e656c@linux.dev> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1762830265; h=from:from: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=V5c8zazQymbCh3EJOF0KTydVfHgB+HL63txNkj2DBcg=; b=m1VOnbj0B52FF5eqkgvxn2ibcAZ2AlUdQ2OpPrHQmPQeylgDhQJZc44smuZ/tFwxYYmsLz MO94ShQBlC2V/Nu2D3aYvij6xrHH3NeUozTm0MkGI8F9M9YBE2vzLtaW4CW2d3AV3LqiNx ieAfXns9GSZy2EFyQl44C+OKbFBoyNc= Date: Tue, 11 Nov 2025 11:04:09 +0800 MIME-Version: 1.0 Subject: Re: [PATCH v1 04/26] mm: vmscan: refactor move_folios_to_lru() To: Shakeel Butt , Harry Yoo Cc: hannes@cmpxchg.org, hughd@google.com, mhocko@suse.com, roman.gushchin@linux.dev, muchun.song@linux.dev, david@redhat.com, lorenzo.stoakes@oracle.com, ziy@nvidia.com, imran.f.khan@oracle.com, kamalesh.babulal@oracle.com, axelrasmussen@google.com, yuanchu@google.com, weixugc@google.com, akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, Muchun Song , Qi Zheng , Sebastian Andrzej Siewior , Clark Williams , Steven Rostedt , linux-rt-devel@lists.linux.dev References: <97ea4728568459f501ddcab6c378c29064630bb9.1761658310.git.zhengqi.arch@bytedance.com> <366385a3-ed0e-440b-a08b-9cf14165ee8f@linux.dev> <2a68bddf-e6e6-4960-b5bc-1a39d747ea9b@linux.dev> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Qi Zheng In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT X-Rspam-User: X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: B3FB04000E X-Stat-Signature: ubuz5gt39genj89pny7cbk8jasq7ayb9 X-HE-Tag: 1762830267-606479 X-HE-Meta: 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 iWH2M37i YWPG10keJFfx+EapN1YERAc8L4O80ol9TOVZM6E1SCLOS9CKxB0IU3Iz5IIF3vwAwmbx9LCQJ4WwPH39HfhkrKQJwPfsABD14BziG1v2OQ1WyMlA29Ie8NRYuBeVOvNf9gHZTz0m8uGRqA02SOhVjK1Ep2y17q+5IG/h1VcRc77fEjLwsbnjd9kloKZ49aYRSFBkh5UheCXIm19ts3VuYhSc+lXenr1qkBttubFHFlP8S1paA4fjtwAvkHQ896Cr3RiYv 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 11/11/25 12:47 AM, Shakeel Butt wrote: > On Mon, Nov 10, 2025 at 02:43:21PM +0900, Harry Yoo wrote: >> On Mon, Nov 10, 2025 at 12:30:06PM +0800, Qi Zheng wrote: >>>> Maybe we could make it safe against re-entrant IRQ handlers by using >>>> read-modify-write operations? >>> >>> Isn't it because of the RMW operation that we need to use IRQ to >>> guarantee atomicity? Or have I misunderstood something? >> >> I meant using atomic operations instead of disabling IRQs, like, by >> using this_cpu_add() or cmpxchg() instead. > > We already have mod_node_page_state() which is safe from IRQs and is > optimized to not disable IRQs for archs with HAVE_CMPXCHG_LOCAL which > includes x86 and arm64. However, in the !CONFIG_HAVE_CMPXCHG_LOCAL case, mod_node_page_state() still calls local_irq_save(). Is this feasible in the PREEMPT_RT kernel? > > Let me send the patch to cleanup the memcg code which uses > __mod_node_page_state.