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=-4.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=no 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 8D290C48BCF for ; Sat, 12 Jun 2021 11:12:21 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 43D8C61376 for ; Sat, 12 Jun 2021 11:12:21 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 43D8C61376 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Subject:Cc:To:From:Message-ID:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=6Hr7mCr+wHm6T/xw/w1h18f8T1L103pV9Pao6KXLhbQ=; b=HV1u9hLgTzTNfT BQN9XtbhhrgcA6LxZxyEx60Kjw1CHaPaoWvKwnJxJwdpcM7g6tN9Gk2dpyaX0U3sNFjXwon83EUQv ukuwt2t6WYCptUDwaEc1VVe39r/ta+IU0GEQcc9V5YKHJhX/bgcOPKRQzP2TibRC21Nh4jBvJhJm5 EgofILvKvt3bxA5cIm96MU75dtFM0hBC0YKMch4zEzyQPRAeADnmWR0tpnnfEV27+DYYc85jh8mz8 4CYZ2xCRTKRV+HMpJvgvhB1FWjF9fj6XsD8ojtb8ynt0rbZP4z107K64DR8SCvrqo/xplFQlNT936 /bnKlZe8UUrVFk3mEwoQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1ls1XO-008M2e-DT; Sat, 12 Jun 2021 11:10:50 +0000 Received: from mail.kernel.org ([198.145.29.99]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1ls1XL-008M2C-DT for linux-arm-kernel@lists.infradead.org; Sat, 12 Jun 2021 11:10:48 +0000 Received: from disco-boy.misterjones.org (disco-boy.misterjones.org [51.254.78.96]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 4BB3261376; Sat, 12 Jun 2021 11:10:46 +0000 (UTC) Received: from [185.219.108.64] (helo=wait-a-minute.misterjones.org) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1ls1XI-0079Gc-6h; Sat, 12 Jun 2021 12:10:44 +0100 Date: Sat, 12 Jun 2021 12:10:43 +0100 Message-ID: <87eed7tk24.wl-maz@kernel.org> From: Marc Zyngier To: Austin Kim Cc: james.morse@arm.com, alexandru.elisei@arm.com, suzuki.poulose@arm.com, catalin.marinas@arm.com, will@kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org, austin.kim@lge.com Subject: Re: [PATCH] KVM: arm64: vgic: declear local variable 'flags' before for loop starts In-Reply-To: <20210612110014.GA1211@raspberrypi> References: <20210612110014.GA1211@raspberrypi> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM-LB/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL-LB/10.8 EasyPG/1.0.0 Emacs/27.1 (x86_64-pc-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: austindh.kim@gmail.com, james.morse@arm.com, alexandru.elisei@arm.com, suzuki.poulose@arm.com, catalin.marinas@arm.com, will@kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org, austin.kim@lge.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210612_041047_498157_7389B96D X-CRM114-Status: GOOD ( 15.65 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Sat, 12 Jun 2021 12:00:14 +0100, Austin Kim wrote: > > From: Austin Kim > > Normally local variable 'flags' is defined out of for loop, > when 'flags' is used as the second parameter in a call to > spinlock_irq[save/restore] function. > > So it had better declear local variable 'flags' ahead of for loop. Why better? Reducing the scope of a variable is in general good practice. Do you see any material advantage in moving this variable out of the loop? Does the compiler generate better code? Thanks, M. -- Without deviation from the norm, progress is not possible. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel