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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 731C7C433F5 for ; Sat, 4 Dec 2021 11:25:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1384662AbhLDL3H (ORCPT ); Sat, 4 Dec 2021 06:29:07 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50188 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240942AbhLDL3E (ORCPT ); Sat, 4 Dec 2021 06:29:04 -0500 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B2390C061751 for ; Sat, 4 Dec 2021 03:25:38 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=bVB5oIsXQHv4ziTx9938Q2uNGGtepbHu4+yJBjfeTCE=; b=kZeHnS8DVZ4A6f7CkGLYe7B2mN XrsByLAbrSXCcLyGyIV0PzKclteS2iio9YoTW4s5LuQLH14IbHgcVIFEbVW3xzigMhuuyfdDVNnIe uNlH8DXA2aiOP+WdXdSBWSH+0uWo99InJThK2EQ7DHH522sCw6gm3Zg1218/otMGVBDgEDd67ANL2 8JL2jIP0d1ovBK2gMm6I7BL+2uoIRNi7c5usU6Pr7HCceuoNDQi3oEIrr5WYA73845LWLlnLcoWsX mXsTvC1OLKewixGR7hpsxfgOezT33fR2h4lyP861Rz5SzJKjuuhizvQr7lXl0YkYQdm4COKXu8Fst NQvth2Hg==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=worktop.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1mtT9S-00Co5l-MR; Sat, 04 Dec 2021 11:24:23 +0000 Received: by worktop.programming.kicks-ass.net (Postfix, from userid 1000) id B1EF598106D; Sat, 4 Dec 2021 12:24:22 +0100 (CET) Date: Sat, 4 Dec 2021 12:24:22 +0100 From: Peter Zijlstra To: Barry Song <21cnbao@gmail.com> Cc: bristot@redhat.com, bsegall@google.com, dietmar.eggemann@arm.com, juri.lelli@redhat.com, mgorman@suse.de, mingo@redhat.com, rostedt@goodmis.org, vincent.guittot@linaro.org, linux-kernel@vger.kernel.org, linuxarm@huawei.com, yangyicong@hisilicon.com, Barry Song Subject: Re: [PATCH v2] sched/fair: Document the slow path and fast path in select_task_rq_fair Message-ID: <20211204112422.GU16608@worktop.programming.kicks-ass.net> References: <20211016111109.5559-1-21cnbao@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20211016111109.5559-1-21cnbao@gmail.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Oct 16, 2021 at 07:11:09PM +0800, Barry Song wrote: > From: Barry Song > > All People I know including myself took a long time to figure out > that typical wakeup will always go to fast path and never go to > slow path except WF_FORK and WF_EXEC. > Vincent reminded me once in a linaro meeting and made me understand > slow path won't happen for WF_TTWU. But my other friends repeatedly > wasted a lot of time on testing this path like me before I reminded > them. > So obviously the code needs some document. > > Cc: Vincent Guittot > Signed-off-by: Barry Song > --- Thanks!