Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755367Ab0DOF61 (ORCPT ); Thu, 15 Apr 2010 01:58:27 -0400 Received: from mail-vw0-f46.google.com ([209.85.212.46]:55075 "EHLO mail-vw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755047Ab0DOF60 convert rfc822-to-8bit (ORCPT ); Thu, 15 Apr 2010 01:58:26 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc:content-type:content-transfer-encoding; b=XtpinHUijt34NPQL776luy/m0ZHmO8WwnHLSm9/+h5L0PZgQLJy1WmxyA3pu7g2ETo k68NYFmyQiQBe/3ChXNXILDw6VloYg5qtjlzZQBWTWWpE/8ZO9XESRiupEYQTpjgzcBV DbazihI4zlVIxIQhUCe4pZcD5AIe43lFVwZ7c= MIME-Version: 1.0 In-Reply-To: <20100413135416.b537eee8.akpm@linux-foundation.org> References: <20100331124834.192500@gmx.com> <20100413135416.b537eee8.akpm@linux-foundation.org> From: Steven B Date: Thu, 15 Apr 2010 00:58:05 -0500 Message-ID: Subject: Re: high iowait problem(Bug 12309 on bugzilla.kernel.org) To: Andrew Morton Cc: Frank Ren , mingo , "a.p.zijlstra" , "jens.axboe" , linux-kernel@vger.kernel.org, stable@kernel.org, dm-devel@redhat.com, Alasdair G Kergon , "Martin K. Petersen" Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1978 Lines: 60 Hi Andrew, > So something between 2.6.32.3 and 2.6.32.8 inclusive rebroke the > kernel. ?That's useful info. > > Looking at the changelogs, the only thing I can immediately see in the > block-core area is > > : commit cb723ba5d03bf719dbc7409b4d67572d4472ef8b > : Author: Dmitry Monakhov > : Date: ? Wed Jan 27 22:44:36 2010 +0300 > : > : ? ? block: fix bio_add_page for non trivial merge_bvec_fn case > > which seems unlikely. > > I'm seeing just one device-mapper change whcih went in over that > timeframe: > > : commit e0f5cfa7c18b411634e73923841eccd3a4c0ce7f > : Author: Martin K. Petersen > : Date: ? Mon Jan 11 03:21:50 2010 -0500 > : > : ? ? DM: Fix device mapper topology stacking > > Although I can't provide any big details, I went through the commits between 2.6.32.2 and 2.6.32.8 and as many things that could affect IO and reverted them from my 2.6.33.2 kernel. Here's my list of commits I reverted that seemed to improve performance locally running a 2.6.33.2 kernel. cb723ba5d03bf719dbc7409b4d67572d4472ef8b (this one you suspected) block: fix bio_add_page for non trivial merge_bvec_fn case b2ea8cb9c8f1937cb80b9beb50548a05bfc37819 vmscan: do not evict inactive pages when skipping an active list scan e4dd8ca5be771aa706b0797b3284328bb595bfa1 fasync: split 'fasync_helper()' into separate add/remove functions Though, I was hoping you guys could identify which one of these is the real culprit. > -- > 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/ > > > -- 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/