Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932427Ab2EaPMw (ORCPT ); Thu, 31 May 2012 11:12:52 -0400 Received: from e38.co.us.ibm.com ([32.97.110.159]:44913 "EHLO e38.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757850Ab2EaPMv (ORCPT ); Thu, 31 May 2012 11:12:51 -0400 Date: Thu, 31 May 2012 20:37:56 +0530 From: Srikar Dronamraju To: Peter Zijlstra Cc: Ingo Molnar , Linus Torvalds , Ananth N Mavinakayanahalli , LKML , Oleg Nesterov , Steven Rostedt , Arnaldo Carvalho de Melo , Masami Hiramatsu , Anton Arapov Subject: Re: [PATCH 1/3] uprobes/core: Remove redundant lock_page/unlock_page Message-ID: <20120531150756.GC24279@linux.vnet.ibm.com> Reply-To: Srikar Dronamraju References: <20120531114630.23691.33166.sendpatchset@srdronam.in.ibm.com> <1338465518.28384.55.camel@twins> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <1338465518.28384.55.camel@twins> User-Agent: Mutt/1.5.20 (2009-06-14) X-Content-Scanned: Fidelis XPS MAILER x-cbid: 12053115-5518-0000-0000-000004D00046 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 956 Lines: 27 * Peter Zijlstra [2012-05-31 13:58:38]: > On Thu, 2012-05-31 at 17:16 +0530, Srikar Dronamraju wrote: > > From: Srikar Dronamraju > > > > No need to lock the page when copying the opcode in read_opcode(). > > It would be good if the changelog said _why_ this is so :-) In read_opcode(), we have the reference for the page and we only are reading from the the page. i.e we are neither modifying the page contents, not the page attributes. Existing kernel code has enough examples where we read the contents of the page without taking the page lock. Further this was discussed here too https://lkml.org/lkml/2012/4/17/361. -- Thanks and Regards Srikar -- 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/