Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751407AbbGaJZN (ORCPT ); Fri, 31 Jul 2015 05:25:13 -0400 Received: from mail-pd0-f178.google.com ([209.85.192.178]:34890 "EHLO mail-pd0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750804AbbGaJZK (ORCPT ); Fri, 31 Jul 2015 05:25:10 -0400 Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 8.2 \(2098\)) Subject: Re: [RFC] arm64:change jump_label to use branch instruction, not use NOP instr From: yalin wang In-Reply-To: <20150731075259.GR25159@twins.programming.kicks-ass.net> Date: Fri, 31 Jul 2015 17:25:02 +0800 Cc: Catalin Marinas , Will Deacon , Ingo Molnar , anton@samba.org, mark.rutland@arm.com, linux-arm-kernel@lists.infradead.org, open list , jbaron@akamai.com Content-Transfer-Encoding: 7bit Message-Id: <8F6A71B0-C7DB-4505-BEE2-79967FC91A8F@gmail.com> References: <94E2034B-9DE4-4ADF-8B2F-197D38A363CF@gmail.com> <20150731075259.GR25159@twins.programming.kicks-ass.net> To: Peter Zijlstra X-Mailer: Apple Mail (2.2098) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1195 Lines: 30 > On Jul 31, 2015, at 15:52, Peter Zijlstra wrote: > > On Fri, Jul 31, 2015 at 03:41:37PM +0800, yalin wang wrote: >> This change a little arch_static_branch(), use b . + 4 for false >> return, why? According to aarch64 TRM, if both source and dest >> instr are branch instr, can patch the instr directly, don't need >> all cpu to do ISB for sync, this means we can call >> aarch64_insn_patch_text_nosync() during patch_text(), >> will improve the performance when change a static_key. > > This doesn't parse.. What? > > Also, this conflicts with the jump label patches I've got. this is arch depend , you can see aarch64_insn_patch_text( ) for more info, if aarch64_insn_hotpatch_safe() is true, will patch the text directly. what is your git branch base? i make the patch based on linux-next branch, maybe a little delay than yours , could you share your branch git address? i can make a new based on yours . Thanks -- 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/