Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752665AbaBXNKb (ORCPT ); Mon, 24 Feb 2014 08:10:31 -0500 Received: from merlin.infradead.org ([205.233.59.134]:36898 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751834AbaBXNKa (ORCPT ); Mon, 24 Feb 2014 08:10:30 -0500 Date: Mon, 24 Feb 2014 14:10:25 +0100 From: Peter Zijlstra To: Michael wang Cc: Sasha Levin , Ingo Molnar , LKML Subject: Re: sched: hang in migrate_swap Message-ID: <20140224131025.GG3104@twins.programming.kicks-ass.net> References: <5304F32A.4040907@oracle.com> <5305856F.3000109@linux.vnet.ibm.com> <53078241.3060201@oracle.com> <53080122.609@linux.vnet.ibm.com> <530ABB44.5000601@oracle.com> <530AD653.3000808@linux.vnet.ibm.com> <20140224071028.GW9987@twins.programming.kicks-ass.net> <530B1B80.4000307@linux.vnet.ibm.com> <20140224121218.GR15586@twins.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140224121218.GR15586@twins.programming.kicks-ass.net> 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 On Mon, Feb 24, 2014 at 01:12:18PM +0100, Peter Zijlstra wrote: > + if (p) { > + if (unlikely(p == RETRY_TASK)) > + goto again; We could even make that: unlikely(p & 1), I think most CPUs can encode that far better than the full pointer immediate. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/