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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id D4334C77B73 for ; Sat, 6 May 2023 10:38:34 +0000 (UTC) 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:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=olRTclD1EErWMuJrQtEJ8ef+Vk1U2SBCNeurbpuxczE=; b=ofbm68F48lM47c UhCmWyG7ohDzY78nXlf5ONylYuu/E0etV1vdb2SvTTIHxP0CjvEzfxbcBhSkUh5SCc+4nd+jELmDh hOKpYSSM+1DyRiWM5YD127XmexQ/GRpnNs+dK7gq2bE93LAvYqMpDY36pPNEXNcVs9fp4oyZ9OUQo KoCl5K6NsZgM1Kqnp+Cmf7e0bfZmcV+6qp7JjFbQgJ9gOtp/RoRMW5BTW9FWwoMn3F+LYVoMt/hNm IIJrsmbd24jHjLZLB0/DopyQY7qTdn0st3QD2GnL1MW9bdram4AYrp6q5m+8dLqRFYa/9o4x3uEBS ZlA+pnqv/gsVFgKDKuow==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1pvFIO-00D6KD-24; Sat, 06 May 2023 10:37:44 +0000 Received: from pandora.armlinux.org.uk ([2001:4d48:ad52:32c8:5054:ff:fe00:142]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1pvFIL-00D6B1-2T for linux-arm-kernel@lists.infradead.org; Sat, 06 May 2023 10:37:43 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=armlinux.org.uk; s=pandora-2019; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=Ij+1FzzEw0ym9IbkYj6bEJ+/bJ6G7Dj6d3TKP9aE6jo=; b=WIjEsXlFHZ1WekLHRfCNWc8M6g DxA2APOp5AQ+giFx4VMXtU+rtZFa89Hz8mMCXPQMgSKQ+pYlQnU+VK9hFhUtD6gk0nEz2aNABNTII yEd0iIqRVLL3Lp9Gs4MtwHT3VfqzTkJ9CwxOcZXxQhCfQWaU0WwSkR/3WBWLnpNI6evh+9XCf7kLo wcQ71htCvigcqR6zXCoJUbPbN7S0BgpGdEQNQP+2k2yw8NAnrvenjAK+Gq7bp4+mGRr20AS78ZqKz 7Ci/tWEEUaDhfEXy8NdU09jUiNm1yhKxGu9Ag2t9HO+5r/HGXxh9n4u7Qo0QXrKXL84HjpzRLLMQ9 zxRZqnmQ==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:59408) by pandora.armlinux.org.uk with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1pvFGI-0007hM-6H; Sat, 06 May 2023 11:35:34 +0100 Received: from linux by shell.armlinux.org.uk with local (Exim 4.94.2) (envelope-from ) id 1pvFGG-0004yS-5s; Sat, 06 May 2023 11:35:32 +0100 Date: Sat, 6 May 2023 11:35:32 +0100 From: "Russell King (Oracle)" To: ye.xingchen@zte.com.cn Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] ARM: mm: use bitmap_zero() API Message-ID: References: <202305061635221161194@zte.com.cn> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <202305061635221161194@zte.com.cn> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230506_033741_804333_CF5093EB X-CRM114-Status: GOOD ( 11.11 ) 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, May 06, 2023 at 04:35:22PM +0800, ye.xingchen@zte.com.cn wrote: > From: Ye Xingchen > > bitmap_zero() is faster than bitmap_clear(), so use bitmap_zero() > instead of bitmap_clear(). Maybe in theory, but as NUM_USER_ASIDS is a power of two (256), and therefore both start and nbits are aigned to BITMAP_MEM_ALIGNMENT, bitmap_clear() will call memset(). The only difference between the two are that bitmap_zero() doesn't involve the compiler working out that it can call memset() (which will be worked out at compile time not run time). So, I doubt that this change makes any difference what so ever to the generated code, and thus this change is just for change sake. In other words, it's just useless churn. Thanks anyway. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last! _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel