Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753454Ab2EVQwW (ORCPT ); Tue, 22 May 2012 12:52:22 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.122]:31576 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751387Ab2EVQwV (ORCPT ); Tue, 22 May 2012 12:52:21 -0400 X-Authority-Analysis: v=2.0 cv=cssZYiEi c=1 sm=0 a=ZycB6UtQUfgMyuk2+PxD7w==:17 a=XQbtiDEiEegA:10 a=huzqtivG31QA:10 a=5SG0PmZfjMsA:10 a=Q9fys5e9bTEA:10 a=meVymXHHAAAA:8 a=ayC55rCoAAAA:8 a=teaT499NlCQ6FntJr90A:9 a=1w2v0sI_Kxct7RhKtYQA:7 a=PUjeQqilurYA:10 a=ZycB6UtQUfgMyuk2+PxD7w==:117 X-Cloudmark-Score: 0 X-Originating-IP: 74.67.80.29 Message-ID: <1337705539.13348.81.camel@gandalf.stny.rr.com> Subject: Re: [RFC][PATCH RT] rwsem_rt: Another (more sane) approach to mulit reader rt locks From: Steven Rostedt To: Thomas Gleixner Cc: LKML , RT , Clark Williams , Peter Zijlstra Date: Tue, 22 May 2012 12:52:19 -0400 In-Reply-To: References: <1337090625.14207.304.camel@gandalf.stny.rr.com> <1337701801.13348.56.camel@gandalf.stny.rr.com> Content-Type: text/plain; charset="ISO-8859-15" X-Mailer: Evolution 3.2.2-1 Content-Transfer-Encoding: 7bit Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 962 Lines: 24 On Tue, 2012-05-22 at 18:40 +0200, Thomas Gleixner wrote: > > I'm all for benchmarks. But right now, making all readers pass through a > > single mutex is a huge bottle neck for a lot of loads. Yes, they are > > mostly Java loads, but for some strange reason, our customers seems to > > like to run Java on our RT kernel :-p > > I'm well aware that mmap_sem is a PITA but replacing one nightmare > with the next one is not the best approach. Perhaps we could just change the mmap_sem to use this approach. Create a new type of rwsem/lock for -rt that we can be picky about. Yeah, mmap_sem is a real PITA and it would be nice to have a solution that can be used until we can convert it to an RCU lock. -- Steve -- 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/