From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761992Ab0J2Usc (ORCPT ); Fri, 29 Oct 2010 16:48:32 -0400 Received: from mail3.caviumnetworks.com ([12.108.191.235]:9064 "EHLO mail3.caviumnetworks.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758328Ab0J2Usb (ORCPT ); Fri, 29 Oct 2010 16:48:31 -0400 Message-ID: <4CCB331F.6070507@caviumnetworks.com> Date: Fri, 29 Oct 2010 13:48:31 -0700 From: David Daney User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.12) Gecko/20100907 Fedora/3.0.7-1.fc12 Thunderbird/3.0.7 MIME-Version: 1.0 To: David Miller CC: rostedt@goodmis.org, linux-kernel@vger.kernel.org, mingo@elte.hu, akpm@linux-foundation.org, fweisbec@gmail.com, jbaron@redhat.com Subject: Re: [PATCH 4/8] jump label: Make arch_jump_label_text_poke_early() optional References: <20101028135548.055490014@goodmis.org> <20101028135647.822609872@goodmis.org> <20101029.133759.48489968.davem@davemloft.net> In-Reply-To: <20101029.133759.48489968.davem@davemloft.net> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 29 Oct 2010 20:49:01.0402 (UTC) FILETIME=[B75333A0:01CB77AA] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/29/2010 01:37 PM, David Miller wrote: > From: Steven Rostedt > Date: Thu, 28 Oct 2010 09:55:52 -0400 > >> From: David Daney >> >> For the forthcoming MIPS jump label support, >> arch_jump_label_text_poke_early() is unneeded as the MIPS NOP >> instruction is already optimal. >> >> Supply a default implementation that does nothing. Flag x86 and SPARC >> as having arch_jump_label_text_poke_early(). >> >> Cc: Jason Baron >> Cc: David Miller >> Signed-off-by: David Daney >> LKML-Reference:<1286218615-24011-2-git-send-email-ddaney@caviumnetworks.com> >> Signed-off-by: Steven Rostedt > > On the SPARC side, it's not that the nop isn't optimal, on sparc it's > always 0x01000000. That's what I thought. You could remove your arch_jump_label_text_poke_early() function to no determent. > The issue is that when written an I-cache flush is > necessary using a 'flushi' instruction. > > Does MIPS not need a flush when poking instructions? Yes, it does. > I find this hard to believe, although it's been some time since I > last touched that architecture :-) I just looked at my patch again. I am indeed flushing the I cache after patching the code, so I don't really know what you are talking about. David Daney