Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753438AbYJCECR (ORCPT ); Fri, 3 Oct 2008 00:02:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750721AbYJCECE (ORCPT ); Fri, 3 Oct 2008 00:02:04 -0400 Received: from casper.infradead.org ([85.118.1.10]:42599 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750718AbYJCECC (ORCPT ); Fri, 3 Oct 2008 00:02:02 -0400 Date: Thu, 2 Oct 2008 21:01:17 -0700 From: Arjan van de Ven To: Andrew Morton Cc: Jens Axboe , linux-kernel@vger.kernel.org, Alan Cox Subject: Re: [PATCH] Give kjournald a IOPRIO_CLASS_RT io priority Message-ID: <20081002210117.0f5062f7@infradead.org> In-Reply-To: <20081002132457.46ad8d05.akpm@linux-foundation.org> References: <20081001200034.65eb67d6@infradead.org> <20081001215638.3a65134c.akpm@linux-foundation.org> <20081002062736.GR19428@kernel.dk> <20081001235501.2b7f50fe.akpm@linux-foundation.org> <20081002061236.3c71c877@infradead.org> <20081002132457.46ad8d05.akpm@linux-foundation.org> Organization: Intel X-Mailer: Claws Mail 3.5.0 (GTK+ 2.12.12; i386-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1212 Lines: 41 On Thu, 2 Oct 2008 13:24:57 -0700 Andrew Morton wrote: > Of course, that could all be wrong and we could be stuck somewhere > else. A good way to diagnose this stuff would be > > --- a/kernel/sched.c~a > +++ a/kernel/sched.c > @@ -5567,10 +5567,14 @@ EXPORT_SYMBOL(yield); > void __sched io_schedule(void) > { > struct rq *rq = &__raw_get_cpu_var(runqueues); > + unsigned long in, out; > > delayacct_blkio_start(); > atomic_inc(&rq->nr_iowait); > + in = jiffies; > schedule(); > + out = jiffies; > + WARN_ON(time_after(out, in + 1 * HZ)); > atomic_dec(&rq->nr_iowait); > delayacct_blkio_end(); > } > _ > > perhaps for varying values of "1". I'll run with this. (well with a value of "1000" for 1 ;-) Also I'll tell latencytop to give me the full backtrace as well ;-) -- Arjan van de Ven Intel Open Source Technology Centre For development, discussion and tips for power savings, visit http://www.lesswatts.org -- 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/