From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <owner-linux-mm@kvack.org>
Received: from mail144.messagelabs.com (mail144.messagelabs.com [216.82.254.51])
	by kanga.kvack.org (Postfix) with ESMTP id 775B76B0012
	for <linux-mm@kvack.org>; Wed, 15 Jun 2011 17:15:28 -0400 (EDT)
Received: from d01relay07.pok.ibm.com (d01relay07.pok.ibm.com [9.56.227.147])
	by e2.ny.us.ibm.com (8.14.4/8.13.1) with ESMTP id p5FKsxJS029481
	for <linux-mm@kvack.org>; Wed, 15 Jun 2011 16:54:59 -0400
Received: from d01av01.pok.ibm.com (d01av01.pok.ibm.com [9.56.224.215])
	by d01relay07.pok.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id p5FLFQa51548542
	for <linux-mm@kvack.org>; Wed, 15 Jun 2011 17:15:26 -0400
Received: from d01av01.pok.ibm.com (loopback [127.0.0.1])
	by d01av01.pok.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id p5FLFILM029717
	for <linux-mm@kvack.org>; Wed, 15 Jun 2011 17:15:26 -0400
Date: Wed, 15 Jun 2011 14:15:17 -0700
From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Subject: Re: [GIT PULL] Re: REGRESSION: Performance regressions from
 switching anon_vma->lock to mutex
Message-ID: <20110615211517.GI2267@linux.vnet.ibm.com>
Reply-To: paulmck@linux.vnet.ibm.com
References: <1308097798.17300.142.camel@schen9-DESK>
 <1308134200.15315.32.camel@twins>
 <1308135495.15315.38.camel@twins>
 <BANLkTikt88KnxTy8TuGGVrBVnXvsnL7nMQ@mail.gmail.com>
 <20110615201216.GA4762@elte.hu>
 <35c0ff16-bd58-4b9c-9d9f-d1a4df2ae7b9@email.android.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <35c0ff16-bd58-4b9c-9d9f-d1a4df2ae7b9@email.android.com>
Sender: owner-linux-mm@kvack.org
List-ID: <linux-mm.kvack.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Ingo Molnar <mingo@elte.hu>, Peter Zijlstra <peterz@infradead.org>, Tim Chen <tim.c.chen@linux.intel.com>, Andrew Morton <akpm@linux-foundation.org>, Hugh Dickins <hughd@google.com>, KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>, Benjamin Herrenschmidt <benh@kernel.crashing.org>, David Miller <davem@davemloft.net>, Martin Schwidefsky <schwidefsky@de.ibm.com>, Russell King <rmk@arm.linux.org.uk>, Paul Mundt <lethal@linux-sh.org>, Jeff Dike <jdike@addtoit.com>, Richard Weinberger <richard@nod.at>, Tony Luck <tony.luck@intel.com>, KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>, Mel Gorman <mel@csn.ul.ie>, Nick Piggin <npiggin@kernel.dk>, Namhyung Kim <namhyung@gmail.com>, ak@linux.intel.com, shaohua.li@intel.com, alex.shi@intel.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, "Rafael J. Wysocki" <rjw@sisk.pl>

On Wed, Jun 15, 2011 at 02:05:46PM -0700, Linus Torvalds wrote:
> 
> 
> Ingo Molnar <mingo@elte.hu> wrote:
> >
> >I have this fix queued up currently:
> >
> >  09223371deac: rcu: Use softirq to address performance regression
> 
> I really don't think that is even close to enough.
> 
> It still does all the callbacks in the threads, and according to Peter, about half the rcu time in the threads remained..

I am putting together a patch that gets rid of the kthreads in the
!RCU_BOOST case.  The time will still be consumed, but in softirq
context, though of course with many fewer context switches.

							Thanx, Paul

--
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/ .
Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>