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 A68F722A80D for ; Fri, 26 Jun 2026 13:44:26 +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=1782481467; cv=none; b=So31T8KyOFl6+MZncYvec+TUKJP8FerFW8R3s0opiC1hFbX2B5uZRZZ7gSMfHz+gU/ygFop607AWnjS9SlYlqVz8jGn0ow5HnPK16eKBh4uPkXAkdtR9X0rTzowtH9r6+kpCziTOsuThI2kTrl8j/06rVGD1JBLRFIjjkkyPfQM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782481467; c=relaxed/simple; bh=xiQaG4D2+J50epucBChroWQk+D/Q0fIR4Ds+Y/Fbh8w=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=VRmIq/o7tuOFdKtEQBH6kiOhxx0pUB8B/jmM/xbtXrYQUOgZSvjEuJEZ/I75pQCH61kT6AOWTBfIXE1kA4y5nJ6Cq4gJkzq6weA7s266MrxNoY5XSoTE+xEFNcSswveSg8YlMOUBRisk6jqu0Yu/Ue1z5RPqCl1W69WAk5CUqKg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=YgpKjiH3; 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="YgpKjiH3" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7B9D91F000E9; Fri, 26 Jun 2026 13:44:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1782481466; bh=378IohjEArFUskKg4Pjwx2nIgLfV40yrE2HNB3m+KKs=; h=From:To:Cc:Subject:In-Reply-To:References:Date; b=YgpKjiH3xZfxR885Y6hb7wCa8ZJXdwRzjanoMBXM3TGuigmPWLWnYx3jc8Ku78t4F x/XVigK0kJpWy24B3828u33ng8JkeVsd724QYJQhZLKfE75ou3EL0q6szZz3YyCPh7 XPahFtcOGy5FjcjUK5SzSEKbQkdR45TfeZ/nEoKRPvYIOAFZ3Jj5E7q2ORU3qIXgrp bjH8tyoAk72LFoD+zSXLujj4JzKYZ3Qj0u74NHGkgH3QKfmradqKdXHzL7QtxVe7N9 36YpMOpspCxCAU6DqprKf8wEVBl36/Nz4FkA7W9IvUjKecYER8kHj3EnuHKLy5sazR m2qjE5SATM2jg== From: Thomas Gleixner To: Chuyi Zhou , mingo@redhat.com, luto@kernel.org, peterz@infradead.org, paulmck@kernel.org, muchun.song@linux.dev, bp@alien8.de, dave.hansen@linux.intel.com, pbonzini@redhat.com, bigeasy@linutronix.de, clrkwllms@kernel.org, rostedt@goodmis.org, nadav.amit@gmail.com, vkuznets@redhat.com Cc: linux-kernel@vger.kernel.org, Chuyi Zhou Subject: Re: [PATCH v8 02/14] smp: Enable preemption early in smp_call_function_single() In-Reply-To: <20260616111127.966468-3-zhouchuyi@bytedance.com> References: <20260616111127.966468-1-zhouchuyi@bytedance.com> <20260616111127.966468-3-zhouchuyi@bytedance.com> Date: Fri, 26 Jun 2026 15:44:23 +0200 Message-ID: <877bnlju14.ffs@fw13> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain On Tue, Jun 16 2026 at 19:11, Chuyi Zhou wrote: > Now smp_call_function_single() disables preemption mainly for the following > reasons: s/Now// Because this describes always the current context so 'Now' is redundant. > - To protect the per-cpu csd_data from concurrent modification by other > tasks on the current CPU in the !wait case. For the wait case, > synchronization is not a concern as on-stack csd is used. Please format bullet points so that they are readable - To protect the per-cpu csd_data from concurrent modification by other tasks on the current CPU in the !wait case. For the wait case, synchronization is not a concern as on-stack csd is used. ... > - To prevent the remote online CPU from being offlined. Specifically, we > want to ensure that no new IPIs are queued after smpcfd_dying_cpu() has > finished. s/we want to ensure/to ensure/ Changelogs want to be written in passive voice. See Documentation. > Disabling preemption for the entire execution is unnecessary, especially > csd_lock_wait() part does not require preemption protection. This patch especially the csd_lock_wait() invocation at the end of the execution.... s/This patch enables/Enable/ See Documentation.