From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Sun, 6 Oct 2002 18:32:59 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Sun, 6 Oct 2002 18:32:58 -0400 Received: from svr-ganmtc-appserv-mgmt.ncf.coxexpress.com ([24.136.46.5]:60428 "EHLO svr-ganmtc-appserv-mgmt.ncf.coxexpress.com") by vger.kernel.org with ESMTP id ; Sun, 6 Oct 2002 18:32:24 -0400 Subject: Re: 2.5.40-mm2 From: Robert Love To: Andrew Morton Cc: Dave Hansen , lkml , "linux-mm@kvack.org" , Ingo Molnar In-Reply-To: <3DA0BA33.5B295A46@digeo.com> References: <3DA0B422.C23B23D4@digeo.com> <1033943021.27093.29.camel@phantasy> <3DA0BA33.5B295A46@digeo.com> Content-Type: text/plain Content-Transfer-Encoding: 7bit X-Mailer: Ximian Evolution 1.0.8 (1.0.8-10) Date: 06 Oct 2002 18:38:05 -0400 Message-Id: <1033943886.26955.33.camel@phantasy> Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sun, 2002-10-06 at 18:33, Andrew Morton wrote: > I think it's a way of doing "cond_resched() if cond_resched() is > a legal thing to do right now". > > I'm sure David isn't using preempt though. If the system is preemptible, then the call can be replaced with preempt_check_resched() which avoids the unneeded inc and dec. But if the system is preemptible, it probably does not accomplish much because we will already have preempted (e.g. the interrupt handler that woke up a new task set need_resched and on return from interrupt we serviced it). If the system is not preemptible (non-zero preempt_count here) this accomplishes nothing. Robert Love