From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933376Ab1JDSR5 (ORCPT ); Tue, 4 Oct 2011 14:17:57 -0400 Received: from mx1.redhat.com ([209.132.183.28]:10288 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932853Ab1JDSR4 (ORCPT ); Tue, 4 Oct 2011 14:17:56 -0400 Date: Tue, 4 Oct 2011 20:13:57 +0200 From: Oleg Nesterov To: Linus Torvalds Cc: Peter Zijlstra , Matt Fleming , Tejun Heo , linux-kernel@vger.kernel.org, Tony Luck , Thomas Gleixner Subject: Re: [RFC][PATCH 0/5] Signal scalability series Message-ID: <20111004181357.GA6822@redhat.com> References: <1317395577-14091-1-git-send-email-matt@console-pimps.org> <20110930165206.GA22048@redhat.com> <1317412823.3375.34.camel@mfleming-mobl1.ger.corp.intel.com> <20110930235625.GD2658@mtj.dyndns.org> <1317464192.3375.57.camel@mfleming-mobl1.ger.corp.intel.com> <1317474209.12973.15.camel@twins> <20111003130701.GB25952@redhat.com> <1317655320.20367.25.camel@twins> <20111004171437.GA3489@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/04, Linus Torvalds wrote: > > On Tue, Oct 4, 2011 at 10:14 AM, Oleg Nesterov wrote: > > > > Whatever we do with the locking, this can't remove O(nr_threads), > > although read_lock() could help to reduce the contention. > > Read locks often make things worse. Yes, yes, I see, thanks. I meant that probably "more concurrency" was the reason for rwlock this series adds. Oleg.