From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 65831C282DA for ; Fri, 1 Feb 2019 08:49:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3FBB0218FC for ; Fri, 1 Feb 2019 08:49:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729324AbfBAItp (ORCPT ); Fri, 1 Feb 2019 03:49:45 -0500 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:56158 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727614AbfBAItm (ORCPT ); Fri, 1 Feb 2019 03:49:42 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 20B45A78; Fri, 1 Feb 2019 00:49:42 -0800 (PST) Received: from [10.1.197.45] (e112298-lin.cambridge.arm.com [10.1.197.45]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 3EE583F71E; Fri, 1 Feb 2019 00:49:40 -0800 (PST) Subject: Re: [RFC PATCH 2/3] ARM: entry: Remove unneeded need_resched() loop To: Valentin Schneider , linux-kernel@vger.kernel.org Cc: Russell King , Thomas Gleixner , Will Deacon , linux-arm-kernel@lists.infradead.org References: <20190131182339.9835-1-valentin.schneider@arm.com> <20190131182339.9835-3-valentin.schneider@arm.com> From: Julien Thierry Message-ID: Date: Fri, 1 Feb 2019 08:49:37 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 MIME-Version: 1.0 In-Reply-To: <20190131182339.9835-3-valentin.schneider@arm.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Valentin, On 31/01/2019 18:23, Valentin Schneider wrote: > Since the enabling and disabling of IRQs within preempt_schedule_irq() > is contained in a need_resched() loop, we don't need the outer arch > code loop. > > Signed-off-by: Valentin Schneider > Cc: Russell King > Cc: Thomas Gleixner > Cc: Will Deacon > Cc: Julien Thierry > Cc: linux-arm-kernel@lists.infradead.org Reviewed-by: Julien Thierry Cheers, > --- > arch/arm/kernel/entry-armv.S | 12 +----------- > 1 file changed, 1 insertion(+), 11 deletions(-) > > diff --git a/arch/arm/kernel/entry-armv.S b/arch/arm/kernel/entry-armv.S > index e85a3af9ddeb..a7ac22e09bb2 100644 > --- a/arch/arm/kernel/entry-armv.S > +++ b/arch/arm/kernel/entry-armv.S > @@ -220,7 +220,7 @@ __irq_svc: > teq r8, #0 @ if preempt count != 0 > movne r0, #0 @ force flags to 0 > tst r0, #_TIF_NEED_RESCHED > - blne svc_preempt > + blne preempt_schedule_irq @ irq en/disable is done inside > #endif > > svc_exit r5, irq = 1 @ return from exception > @@ -229,16 +229,6 @@ ENDPROC(__irq_svc) > > .ltorg > > -#ifdef CONFIG_PREEMPT > -svc_preempt: > - mov r8, lr > -1: bl preempt_schedule_irq @ irq en/disable is done inside > - ldr r0, [tsk, #TI_FLAGS] @ get new tasks TI_FLAGS > - tst r0, #_TIF_NEED_RESCHED > - reteq r8 @ go again > - b 1b > -#endif > - > __und_fault: > @ Correct the PC such that it is pointing at the instruction > @ which caused the fault. If the faulting instruction was ARM > -- Julien Thierry