From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932447Ab2CFRlK (ORCPT ); Tue, 6 Mar 2012 12:41:10 -0500 Received: from perches-mx.perches.com ([206.117.179.246]:41296 "EHLO labridge.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1755640Ab2CFRlI (ORCPT ); Tue, 6 Mar 2012 12:41:08 -0500 Message-ID: <1331055666.2140.3.camel@joe2Laptop> Subject: Re: [RFC PATCH] checkpatch: Warn on use of yield() From: Joe Perches To: Peter Zijlstra Cc: Andrew Morton , Mel Gorman , Miao Xie , Christoph Lameter , linux-mm@kvack.org, linux-kernel@vger.kernel.org, "Theodore Ts'o" Date: Tue, 06 Mar 2012 09:41:06 -0800 In-Reply-To: <1331037942.11248.307.camel@twins> References: <20120302112358.GA3481@suse.de> <1330723262.11248.233.camel@twins> <20120305121804.3b4daed4.akpm@linux-foundation.org> <1330999280.10358.3.camel@joe2Laptop> <1331037942.11248.307.camel@twins> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.2- Content-Transfer-Encoding: 7bit Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2012-03-06 at 13:45 +0100, Peter Zijlstra wrote: > The case at hand was a life-lock due to expecting that yield() would run > another process which it needed in order to complete. Yield() does not > provide that guarantee. OK. Perhaps the kernel-doc comments in sched/core.c should/could be expanded/updated. /** * sys_sched_yield - yield the current processor to other threads. * * This function yields the current CPU to other tasks. If there are no * other threads running on this CPU then this function will return. */ [] /** * yield - yield the current processor to other threads. * * This is a shortcut for kernel-space yielding - it marks the * thread runnable and calls sys_sched_yield(). */ void __sched yield(void) { set_current_state(TASK_RUNNING); sys_sched_yield(); } EXPORT_SYMBOL(yield);