Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758693AbcCVMvY (ORCPT ); Tue, 22 Mar 2016 08:51:24 -0400 Received: from casper.infradead.org ([85.118.1.10]:52816 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751894AbcCVMvQ (ORCPT ); Tue, 22 Mar 2016 08:51:16 -0400 Date: Tue, 22 Mar 2016 13:51:13 +0100 From: Peter Zijlstra To: Michal Hocko Cc: Andrew Morton , linux-mm@kvack.org, LKML , Tetsuo Handa , David Rientjes , Ingo Molnar Subject: Re: [PATCH 1/9] sched: add schedule_timeout_idle() Message-ID: <20160322125113.GO6344@twins.programming.kicks-ass.net> References: <1458644426-22973-1-git-send-email-mhocko@kernel.org> <1458644426-22973-2-git-send-email-mhocko@kernel.org> <20160322122345.GN6344@twins.programming.kicks-ass.net> <20160322123314.GD10381@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160322123314.GD10381@dhcp22.suse.cz> User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1592 Lines: 42 On Tue, Mar 22, 2016 at 01:33:14PM +0100, Michal Hocko wrote: > On Tue 22-03-16 13:23:45, Peter Zijlstra wrote: > > On Tue, Mar 22, 2016 at 12:00:18PM +0100, Michal Hocko wrote: > > > > > extern signed long schedule_timeout_interruptible(signed long timeout); > > > extern signed long schedule_timeout_killable(signed long timeout); > > > extern signed long schedule_timeout_uninterruptible(signed long timeout); > > > +extern signed long schedule_timeout_idle(signed long timeout); > > > > > +/* > > > + * Like schedule_timeout_uninterruptible(), except this task will not contribute > > > + * to load average. > > > + */ > > > +signed long __sched schedule_timeout_idle(signed long timeout) > > > +{ > > > + __set_current_state(TASK_IDLE); > > > + return schedule_timeout(timeout); > > > +} > > > +EXPORT_SYMBOL(schedule_timeout_idle); > > > > Yes we have 3 such other wrappers, but I've gotta ask: why? They seem > > pretty pointless. > > It seems it is just too easy to miss the __set_current_state (I am > talking from my own experience). Well, that's what you get; if you call schedule() and forget to set a blocking state you also don't block, where the problem? > This also seems to be a pretty common > pattern so why not wrap it under a common call. It just seems extremely silly to create a (out-of-line even) function for a store and a call. > > Why not kill the lot? > > We have over 400 users, would it be much better if we open code all of > them? It doesn't sound like a huge win to me. Dunno, changing them around isn't much work, we've got coccinelle for that.