From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx111.postini.com [74.125.245.111]) by kanga.kvack.org (Postfix) with SMTP id 7F7BE6B0089 for ; Wed, 7 Aug 2013 05:21:25 -0400 (EDT) Date: Wed, 7 Aug 2013 18:21:28 +0900 From: Joonsoo Kim Subject: Re: [PATCH 0/2] hugepage: optimize page fault path locking Message-ID: <20130807092128.GE32449@lge.com> References: <1374848845-1429-1-git-send-email-davidlohr.bueso@hp.com> <20130729061820.GA4784@lge.com> <1375834084.2134.44.camel@buesod1.americas.hpqcorp.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1375834084.2134.44.camel@buesod1.americas.hpqcorp.net> Sender: owner-linux-mm@kvack.org List-ID: To: Davidlohr Bueso Cc: Davidlohr Bueso , Andrew Morton , Rik van Riel , Michel Lespinasse , Mel Gorman , Michal Hocko , "AneeshKumarK.V" , KAMEZAWA Hiroyuki , Hillf Danton , Hugh Dickins , David Gibson , Eric B Munson , Anton Blanchard , Konstantin Khlebnikov , linux-mm@kvack.org, linux-kernel@vger.kernel.org On Tue, Aug 06, 2013 at 05:08:04PM -0700, Davidlohr Bueso wrote: > On Mon, 2013-07-29 at 15:18 +0900, Joonsoo Kim wrote: > > On Fri, Jul 26, 2013 at 07:27:23AM -0700, Davidlohr Bueso wrote: > > > This patchset attempts to reduce the amount of contention we impose > > > on the hugetlb_instantiation_mutex by replacing the global mutex with > > > a table of mutexes, selected based on a hash. The original discussion can > > > be found here: http://lkml.org/lkml/2013/7/12/428 > > > > Hello, Davidlohr. > > > > I recently sent a patchset which remove the hugetlb_instantiation_mutex > > entirely ('mm, hugetlb: remove a hugetlb_instantiation_mutex'). > > This patchset can be found here: https://lkml.org/lkml/2013/7/29/54 > > > > If possible, could you review it and test it whether your problem is > > disappered with it or not? > > This patchset applies on top of https://lkml.org/lkml/2013/7/22/96 > "[PATCH v2 00/10] mm, hugetlb: clean-up and possible bug fix", right? > > AFAIK those changes are the ones Andrew picked up a few weeks ago and > are now in linux-next, right? I was able to apply those just fine, but > couldn't apply your 'remove a hugetlb_instantiation_mutex series' (IIRC > pach 1/18 failed). I guess you'll send out a v2 anyway so I'll wait > until then. > > In any case I'm not seeing an actual performance issue with the > hugetlb_instantiation_mutex, all I noticed was that under large DB > workloads that make use of hugepages, such as Oracle, this lock becomes > quite hot during the first few minutes of startup, which makes sense in > the fault path it is contended. So I'll try out your patches, but, in > this particular case, I just cannot compare with the lock vs without the > lock situations. Okay. I just want to know that lock contention is reduced by my patches in the first few minutes of startup. I will send v2 soon. Thanks. -- 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