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 47BE4EDB7DC for ; Tue, 7 Apr 2026 09:42:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To: Content-Transfer-Encoding:Content-Type: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=M7O1tGSn16rF+cgNylrwNR4YR9bgxfhy4/q1KWy/S2Q=; b=S75RZPx2vKVfEp/t4L56gpbnlB sWm0exu9di5G4zObucWmAghnrH8aOTDlm4fqzbLkHVCMu3B2iixXoyYcyGRiJgqsx50rPGDm+6mty +ZUwpHSuVLNBUdnmoIvcKpZKiINdRm3u40G+pqnPLSX8bU4W4eEWzq5JqpbEulLRjM2xxxhv9heNX 9mTWkRp2wbwSNglOPptHfKzMkCCdHfu7I64Iwz+dICML0kJqckm0kWehqHmn64aD2yi+rrWCFvUFs vKCIxiWBq1LZRSouBEab2UV0gtAamjAsCJhOF5xIOM+367X4CUxYYFRu1ozhZTSjSYV1oD/mEBt/h rEdBYmYg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1wA2wm-00000006ErD-3c7z; Tue, 07 Apr 2026 09:42:12 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1wA2wk-00000006Eqs-1YxK for linux-arm-kernel@lists.infradead.org; Tue, 07 Apr 2026 09:42:11 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id D2DCC1AED; Tue, 7 Apr 2026 02:42:02 -0700 (PDT) Received: from arm.com (usa-sjc-mx-foss1.foss.arm.com [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 343DD3F7D8; Tue, 7 Apr 2026 02:42:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1775554928; bh=QVk2QexSDpe+HZEkpL5txOUhT8aKVmwKMv7KrU8GZYw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=HeitlxxqEEoi85H89/Tmtj+HglpzvFQbeg676fzYA2REer9MbUo2rw03SiyfWhKDG 5lJlvZvIcBdZoAZfgEzfclew8VklDpARacR/KV5jdVPRUNUAZmanmXdQD32keuWyVn khMGOW4mOujv7+8+GoDRwxy5Yl7QutLWQ0sMktms= Date: Tue, 7 Apr 2026 10:42:00 +0100 From: Catalin Marinas To: Linus Walleij Cc: Will Deacon , Marc Zyngier , Oliver Upton , Joey Gouly , Suzuki K Poulose , Zenghui Yu , linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev Subject: Re: [PATCH] arm64: clear_page[s] using memset Message-ID: References: <20260306-aarch64-clear-pages-c-v1-1-77c1bb0f1c21@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260407_024210_452981_83EF31DF X-CRM114-Status: GOOD ( 23.62 ) 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: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, Apr 07, 2026 at 11:25:55AM +0200, Linus Walleij wrote: > On Thu, Apr 2, 2026 at 10:57 PM Catalin Marinas wrote: > > On Fri, Mar 06, 2026 at 09:57:50AM +0100, Linus Walleij wrote: > > > There is no need to try to second-guess the compiler when > > > clearing memory. Just call memset() like everyone else. > > > > Hmm, that "like everyone else" made me think - why not move this to > > generic code and only the 1-2 platforms that need their own should > > override it? Could we do the same with copy_page()? > > > > Sorry, more work all of a sudden ;). > > I actually had that planned, I just wanted to know if this would > be fine for arm64 first so that there is a user. > > It seems you are on board so I will send a 2-patch series > next. We might as well merge the arm64 patch first and do the cross-arch cleanup separately, queued via akpm's tree. > > > While at it, implement the shorthand for directly calling > > > the new prototype clear_pages() for larger page chunks. > > > > > > No performance regressions can be seen, the fastpath > > > benchmarks differences are in the noise. > > > > I assume the benchmarks ran on real hardware (had to ask, last time you > > mentioned qemu ;)). > > Quoting my own commit message hehe: > > > No performance regressions can be seen, the fastpath > > benchmarks differences are in the noise. > > This was tested on hardware with Ryan Robert's fastpath tool. It wasn't clear to me where the fastpath tool ran ;). Thanks. -- Catalin