From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758824Ab0J1NrB (ORCPT ); Thu, 28 Oct 2010 09:47:01 -0400 Received: from bombadil.infradead.org ([18.85.46.34]:36169 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755459Ab0J1Nq6 (ORCPT ); Thu, 28 Oct 2010 09:46:58 -0400 Date: Thu, 28 Oct 2010 09:46:41 -0400 From: Christoph Hellwig To: Pekka Enberg Cc: Aidar Kultayev , Ingo Molnar , linux-kernel@vger.kernel.org, linux-mm@kvack.org, npiggin@kernel.dk, Dave Chinner , Andrew Morton Subject: Re: 2.6.36 io bring the system to its knees Message-ID: <20101028134641.GA4416@infradead.org> References: <20101028090002.GA12446@elte.hu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.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 On Thu, Oct 28, 2010 at 02:48:20PM +0300, Pekka Enberg wrote: > On Thu, Oct 28, 2010 at 2:33 PM, Aidar Kultayev wrote: > > if it wasn't picasa, it would have been something else. I mean if I > > kill picasa ( later on it was done indexing new pics anyway ), it > > would have been for virtualbox to thrash the io. So, nope, getting rid > > of picasa doesn't help either. In general the systems responsiveness > > or sluggishness is dominated by those io operations going on - the DD > > & CP & probably VBOX issuing whole bunch of its load for IO. > > Do you still see high latencies in vfs_lseek() and vfs_fsync()? I'm > not a VFS expert but looking at your latencytop output, it seems that > fsync grabs ->i_mutex which blocks vfs_llseek(), for example. I'm not > sure why that causes high latencies though it's a mutex we're holding. It does. But what workload does a lot of llseeks while fsyncing the same file? I'd bet some application is doing really stupid things here. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail143.messagelabs.com (mail143.messagelabs.com [216.82.254.35]) by kanga.kvack.org (Postfix) with ESMTP id F25608D0015 for ; Thu, 28 Oct 2010 09:47:54 -0400 (EDT) Date: Thu, 28 Oct 2010 09:46:41 -0400 From: Christoph Hellwig Subject: Re: 2.6.36 io bring the system to its knees Message-ID: <20101028134641.GA4416@infradead.org> References: <20101028090002.GA12446@elte.hu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org To: Pekka Enberg Cc: Aidar Kultayev , Ingo Molnar , linux-kernel@vger.kernel.org, linux-mm@kvack.org, npiggin@kernel.dk, Dave Chinner , Andrew Morton List-ID: On Thu, Oct 28, 2010 at 02:48:20PM +0300, Pekka Enberg wrote: > On Thu, Oct 28, 2010 at 2:33 PM, Aidar Kultayev wrote: > > if it wasn't picasa, it would have been something else. I mean if I > > kill picasa ( later on it was done indexing new pics anyway ), it > > would have been for virtualbox to thrash the io. So, nope, getting rid > > of picasa doesn't help either. In general the systems responsiveness > > or sluggishness is dominated by those io operations going on - the DD > > & CP & probably VBOX issuing whole bunch of its load for IO. > > Do you still see high latencies in vfs_lseek() and vfs_fsync()? I'm > not a VFS expert but looking at your latencytop output, it seems that > fsync grabs ->i_mutex which blocks vfs_llseek(), for example. I'm not > sure why that causes high latencies though it's a mutex we're holding. It does. But what workload does a lot of llseeks while fsyncing the same file? I'd bet some application is doing really stupid things here. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org