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 0B19CC624D3 for ; Sat, 5 Sep 2026 00:39:17 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id ED5136B0088; Fri, 4 Sep 2026 20:39:16 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id E862B6B008A; Fri, 4 Sep 2026 20:39:16 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D752E6B008C; Fri, 4 Sep 2026 20:39:16 -0400 (EDT) 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 BA9276B0088 for ; Fri, 4 Sep 2026 20:39:16 -0400 (EDT) Received: from smtpin06.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 4A50C160259 for ; Sat, 5 Sep 2026 00:39:16 +0000 (UTC) X-FDA: 85177849512.06.EF3EDEE Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf27.hostedemail.com (Postfix) with ESMTP id 9DA0A4000A for ; Sat, 5 Sep 2026 00:39:14 +0000 (UTC) Authentication-Results: imf27.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=AvEUS6Nk; spf=pass (imf27.hostedemail.com: domain of sj@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=sj@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1788568754; 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-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=R6yHFneG9gGinH8AjxIgMQTUoNVBxKENGCLfZaasrsI=; b=u2Vlc5sJXC0pEdnpJvoudkasV05ZBUgzKavw1LP7z5TRVN8lzvVOsdp1J3IFM0di82vV0t pzWi9KIJLPcHv7gbhpQNGkJesv5+2ss+ShppLjwbTsxgbPkp7T16ZD9c7MfVuMEj/qD3Zi SME8CNedy99m4OyGruUyywjwrt4p/ys= ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1788568754; b=MnG3elJ1G95b1wlx2gdECmQBDrtuts1rZ5giSEEU6KcrdLHHKN0PLvSagU6QSAt8kVHfup YXub374a488imPJOkdlLzaSPze4seIJYyCvVtJCy/L8zRNxzfGDeHjYTZ2c8DIh5nGjP1H QrX5JJcNE8pae8NQbBwUqOD+dJiQ8+E= ARC-Authentication-Results: i=1; imf27.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=AvEUS6Nk; spf=pass (imf27.hostedemail.com: domain of sj@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=sj@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 1096640603; Sat, 5 Sep 2026 00:39:13 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A9D931F00A3D; Sat, 5 Sep 2026 00:39:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788568752; bh=R6yHFneG9gGinH8AjxIgMQTUoNVBxKENGCLfZaasrsI=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=AvEUS6NkSPVMlhLKLbX4UG/OOEsSVFr+j2sipzgAeUCj3XXQVYOf++b9ZmlhvDZ4q DFTpeVidIZI7mAkMF/qb8aHoEa74O7TLMIxpP4s+nxD1ecTcnoOyGf0jbPieAOYGB7 h9drwFWv90dkOKxZ9Y7j6R4mGkvkGdAYaMHh/FhV1/Ga+u1RzNtvhYMc7rlL+On7/s doRwWJSiAg5GZUHLxieYCQ/LTGFryZ8+xXMVpH14u/AeWx6xnlLmi2xBsB5reX4oqv dowANEravTfM3DgtsYhMDa7DenvWCIgFVQ9N7w0owaE8JUCj6jkLfjPmD7XurVHKra 2MBu2bavNDQWQ== From: SJ Park To: Ye Liu Cc: SJ Park , Miaohe Lin , Andrew Morton , Ye Liu , Naoya Horiguchi , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 4/8] mm/memory-failure: convert process iterator to for_each_process_rcu Date: Fri, 4 Sep 2026 17:39:05 -0700 Message-ID: <20260905003905.68362-1-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260904083001.553587-5-ye.liu@linux.dev> References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 9DA0A4000A X-Stat-Signature: muxiaoo3jxpp8gh6uxemfoaq7fb4spzm X-HE-Tag: 1788568754-495006 X-HE-Meta: U2FsdGVkX199ekX+GBWyGAbgHvn2zo4y6DmFI+zhcIvqGqPzT2RtbvISOmJHlpecr+QLAyUOUOXzf52FKrmYUmKhOmrfxG1/tKrSOoChEbNJ+17Rol+cmmWCBqFUSQDjuYDXv3evWXJHYVZDkB7ZwrkLJaRO/HqjOhWkY4V9W6IsTiFlMmTUEeKsRec4/gxYNcrsncfRQFU6GuevgvCSjKL5rT33FG7so5h06J2Dge3A1jop8MhpoSQOSiXG3gaAvcm+JPjVtVvFr0gVYGKnouqYK9RkKOZ2J3zOdrEA92//nmfTvhY9oglbjf8/EpsGzrEc+SbX94xXIKKYyhUDJtKGb0jijGzqpmJnz2BdBTKpptaeVATpHhUFt2oZxl87nUv1G6Esu4IUYY3PBXt8gR9MQd153TUcL7j5q6xo29mS2zL9Z/ReQiBLElfD7uTW72f+cv0jhsvh1SdzRvHG+6SW4sakowDWuUxkBBe1uvu1QiLb/6qDV95se8HCm7Uj2UMcxJBQOfCvXXoCuwZRUN2QvxRM/lDaT+19CYVveRMJt2N9dRKvEGR/9fSXirmPODwLNTO7/FhXInbBEO7Ijkn6KszCpAGdvPn22DiflfelO+IARD6t/V+otNLiY9jUNal7q7umft1qJo3IoMYI7qSwnVpNr+Wup1WSIEK4R+u9hI6hnCWkFxfLpLPbM2wePx3AmMikrBKlAz0dSL388NP2vy292ONZbb2xgfqUe+LTe2+0ja9W56aZzOVIAk8DAv04JlvOIaED1CKYN/JvXljv3ZSWxrjdlCrgSiKKkpv4VplTuontr+VJlpWSIXe3yPpfjY1h2QDnHtsEePHUjuf8dpsCsqfndWnO2nTQm2R5PzSr2k3WZ/lUBMl5iGcblJeYDQ1d2HsD62BBsOSSB1Lr6RTOr3LDP10JQFsiF76Soez1DZSRlF0+NMwS/FfGeHJCTn+1S3FBPRDOUC2 pFNnmUAN I/8wtpc4wXiQUNWOb9JVc/bNcqMoeaMeSGKQ1Yj1v3DL+WcUrqtPqugyGZzPKuRlmQipOJJKqB1/DSfL+emBkbIAZkcBzCamd5NSxfEsQHCXQZ9op3RiD6p/XFvVDqtnZdWLYsCMQWWzdCZEd2GEfbqY13oSGsSw52ybZlpqptjIpkYY2iIyvmqAaLQD+9gvWbzg5l4biTqYRaXKXqFSQqdyyMRxbuLCkyvix+jBFkNwfONzaZDsJi1zyEegGxc+a7jgk9/+Tif/3aIHHYuarUp4GWOMrZF54fVwlLeZLGMEDwmYh18NrHLPI8wWKO/eZOcAYm/X5rRVJUkc= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Fri, 4 Sep 2026 16:29:56 +0800 Ye Liu wrote: > From: Ye Liu > > Replace the manual rcu_read_lock()/rcu_read_unlock() pairs combined > with for_each_process() loop in mm/memory-failure.c with > for_each_process_rcu(). > > No functional change. > > Signed-off-by: Ye Liu > --- > mm/memory-failure.c | 16 ++++------------ > 1 file changed, 4 insertions(+), 12 deletions(-) > > diff --git a/mm/memory-failure.c b/mm/memory-failure.c > index a8b03e2920ba..63a2ff08ee33 100644 > --- a/mm/memory-failure.c > +++ b/mm/memory-failure.c > @@ -555,8 +555,7 @@ static void collect_procs_anon(const struct folio *folio, > return; > > pgoff = page_pgoff(folio, page); > - rcu_read_lock(); > - for_each_process(tsk) { > + for_each_process_rcu(tsk) { > struct vm_area_struct *vma; > struct anon_vma_chain *vmac; > struct task_struct *t = task_early_kill(tsk, force_early); > @@ -572,7 +571,6 @@ static void collect_procs_anon(const struct folio *folio, > add_to_kill_anon_file(t, page, vma, to_kill, addr); > } > } > - rcu_read_unlock(); > anon_vma_unlock_read(av); > } > > @@ -589,9 +587,8 @@ static void collect_procs_file(const struct folio *folio, > pgoff_t pgoff; > > i_mmap_lock_read(mapping); > - rcu_read_lock(); > pgoff = page_pgoff(folio, page); > - for_each_process(tsk) { > + for_each_process_rcu(tsk) { > struct task_struct *t = task_early_kill(tsk, force_early); > unsigned long addr; This moves pgoff assignment out of the RCU critical section. Is this fine and making no real functional change? If it is fine and no functiona change, could we clarify the reasons on the commit message? Thanks, SJ [...]