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]) by smtp.lore.kernel.org (Postfix) with ESMTP id CC275C61DA4 for ; Tue, 7 Mar 2023 01:58:29 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 522CB6B0071; Mon, 6 Mar 2023 20:58:29 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 4D2576B0072; Mon, 6 Mar 2023 20:58:29 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3C2086B0073; Mon, 6 Mar 2023 20:58:29 -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 2CBD46B0071 for ; Mon, 6 Mar 2023 20:58:29 -0500 (EST) Received: from smtpin21.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id F04FB80405 for ; Tue, 7 Mar 2023 01:58:28 +0000 (UTC) X-FDA: 80540442696.21.582A014 Received: from sin.source.kernel.org (sin.source.kernel.org [145.40.73.55]) by imf21.hostedemail.com (Postfix) with ESMTP id E174B1C000C for ; Tue, 7 Mar 2023 01:58:26 +0000 (UTC) Authentication-Results: imf21.hostedemail.com; dkim=none; dmarc=none; spf=pass (imf21.hostedemail.com: domain of "SRS0=tVOi=67=goodmis.org=rostedt@kernel.org" designates 145.40.73.55 as permitted sender) smtp.mailfrom="SRS0=tVOi=67=goodmis.org=rostedt@kernel.org" ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1678154307; 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; bh=t/Myw/D/OxQi3bsGDM0ctnUY1n39++WI00gSHw3233g=; b=rOkUtoHtP4QNRXLcgSTvONBu3caJr2tQo4CvTBRp4sAQN1XWIir3FV4xL8rgUT/9XVo1xv kpZKKZsP10UFHzsZ6K30nZpVLbxTSmBTswznQw9fUSv/OKO4OYZPTgMLB18dAjUbRAyGrZ wZEJTrwhM+3Rv4ihZgk8WCaW9huV9yE= ARC-Authentication-Results: i=1; imf21.hostedemail.com; dkim=none; dmarc=none; spf=pass (imf21.hostedemail.com: domain of "SRS0=tVOi=67=goodmis.org=rostedt@kernel.org" designates 145.40.73.55 as permitted sender) smtp.mailfrom="SRS0=tVOi=67=goodmis.org=rostedt@kernel.org" ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1678154307; a=rsa-sha256; cv=none; b=5zH6W/wSNscB3LihpJ0UqVapqWnVJW48xuXn6xI3rvp7ond+jz2XFhV0CyY8V8qZO2OLwt FE9HuB84kfVgBzcgV1czs2SQJu0JCkh8mJ9tSMt/w827WdKhg9EePId5uOueYX9tqa3udS Wequ+5L8o/mkDRmkR03+L4MeOhjD10s= Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by sin.source.kernel.org (Postfix) with ESMTPS id DC56BCE192F; Tue, 7 Mar 2023 01:58:22 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 277FCC433EF; Tue, 7 Mar 2023 01:58:20 +0000 (UTC) Date: Mon, 6 Mar 2023 20:58:18 -0500 From: Steven Rostedt To: Hillf Danton Cc: John Stultz , LKML , Wei Wang , Midas Chien , "Chunhui Li (=?UTF-8?B?5p2O5pil6L6J?=)" , Kees Cook , Anton Vorontsov , "Guilherme G. Piccoli" , Tony Luck , linux-mm@kvack.org Subject: Re: [PATCH v2] pstore: Revert pmsg_lock back to a normal mutex Message-ID: <20230306205818.5a2bc51a@gandalf.local.home> In-Reply-To: <20230307003106.1768-1-hdanton@sina.com> References: <20230302062741.483079-1-jstultz@google.com> <20230304031029.3037914-1-jstultz@google.com> <20230306010323.2909-1-hdanton@sina.com> <20230307003106.1768-1-hdanton@sina.com> X-Mailer: Claws Mail 3.17.8 (GTK+ 2.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: E174B1C000C X-Stat-Signature: 9cysqi54zdawyc5t81z344c6i7qowe9q X-Rspam-User: X-HE-Tag: 1678154306-490589 X-HE-Meta: U2FsdGVkX1/+vU/5G2MRVZ8cGGzzZDw0OX6U2M7oCRO4WH0pYoTD6tcebsAKvWdsgxmYYCcRgqv3S5h+BzLl49kHomHVjg/d6zwcTpBPq4xW5hn7dTb077ypZds3vOUdbg5TtwTrooZtgnNPb/eY/yuVNqkzaFpHaH1LV1xj+CDQW5hAK0VhBeMZ1N6S/dgeay3ZSb2XcCwov+TAkjkcjALMxo95XEjBbUzUcjSfI1lavr+dhOvTsNa6h8U+spDZ+mzPT+y4dwhW3QXf86Eo07JyRPcNq76C3kiXoBx+MbBjJZnalgf+JGZ1B3vN34fk7ZQa47nzpJewIlz+p69JnSPiAUNKJb6JGtpYuDpRmOHc63YBZNk5UEDClg0rqJivy5BdqfwvKyjOcc+xsb7sjNVd9pFVTpD128yxMp2/Y/frnYKZvMae9QXWhN6zmYcHfqpMhhcWoj7D1D0WxlhKbbteeg0heIvpT1wBGfONMPGmeyFjPsk1B4B3qx2ghtihP+h3N3OzcsIzMGOMf9X5ubIgKE0f1sCFhLm/8F6LWJTyIhL/0pQz59cBbISx+ueOjqaBv/al+KpobhZdW68+qj01ngjB8etYXShWoxxiSaDsj8cYFtwhUCQsPdZY4csN3Nof+3W8gfXV1MlGr/YXFP1/AwrClkunpOnce+ET/dM7/uzy0yRi+bd/nUF0zB0riWltd6Q93AvFIZqQ+7R2YW/wj7VqyjhDAiR74Q5kYarezKrFJCmjhmBhFWwXi/bnnpRow0OdKY67zVDV49TKTaagtYEcoHgHOY5odw5mm7MfMmRKV0yUS+DW5/IE5GXjrvc5vx+4mxGM6JLDax2ZKpLQ2To7tsz8seNfNk/wufmpv4D30i4slddlGRUhEY1itdr1ZFBhEpUGo9aJqYQhreSRKX6gzF9praL/24TcGG0IHm/F4P7VayNTnwW7AyfiXAIHjFivzoyhAy28Hhx Fu2svCUD 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 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: On Tue, 7 Mar 2023 08:31:06 +0800 Hillf Danton wrote: > On Mon, 6 Mar 2023 10:28:44 -0500 Steven Rostedt > > On Mon, 6 Mar 2023 09:03:23 +0800 Hillf Danton wrote: > > > > > > PS what sense made by spinning on owner until need_resched() with preempt > > > disabled in the non-rt context? > > > > Not sure what the question you have here is? If need_resched() is set, we > > want to schedule out. > > Given the critical section under mutex could be preempted, what is hard to > understand is the wakeup of a ten-minute sleeper could not preempt a nice-10 > mutex spinner for instance. But it can. Most wakeups are done by interrupts or softirqs. Both of which will happen even if a task is running with preemption disabled. -- Steve