From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6011F175A84 for ; Sat, 5 Sep 2026 00:39:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788568754; cv=none; b=nNH7Bqkfi0GGVdxPpFWCxdyYfRFtbmPjHBgGjmBPWiTd0rOmeOdvjIWnQiuKTQcv5WqhX7JLM950/fDLj7IlPfonWFP9XCDKmcnzUY4zCMLRGgNRQMuEhL0m5HFzQ9gM7IDTGpyF6z1vysGo+QsOO1+PLjKjqfmvnjPX6jkwJ4Q= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788568754; c=relaxed/simple; bh=V1B/Fowzw3nSgR/lAnUDRRaHyfQSKoRx9a2l6Miilqg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=CHqLHuuCqygHbqzoWFniwZrqMoJkGTw8Gv0BtHsciV1vJZSXwAa/15KaPMUbV37BGcNj5J1o5rSEMSx5wzCCBfjj8uB2FXoc7dJEIFPT6v2lbMxIcCR63E3Psm/Itarck7eQw2aHkUzkVJ1AjCrt0Ld/KMZxEral3V4LvZjiF1U= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=AvEUS6Nk; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="AvEUS6Nk" 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: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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 [...]