From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A36EF4749D5; Tue, 4 Aug 2026 18:56:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785869765; cv=none; b=BUMAij6vabqoI9EiSLXlCS1ea/ldadXDwD9Ixjtzcuuu3he98WJsXFkoY/j/U4/nQQnfOf8IpzMiXD1a2exprx8sVdFas3wh6kNi1yrv2v+5EgcBSipRXDhumsE1ViQ0/fv3Ue3K1fN1H75nf7juYvLeQzpdCEyBTgB1iw8ljyc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785869765; c=relaxed/simple; bh=5V1tMilXrp8eNkgdSpdNcHwYprpQGpRkHB0+SIPanAE=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=GanUzSHZqJSG1QZi+mRZOeXehtt+TV1moC1oizzwnUqjNvbBhkJqFqUtqTrKfEK9VWC1xHy2IpjjWuCP5RqXI4Y/FVd0jkUhsj5pW4ZQ2ek9rCGFiWlpWMkhrCcacUHLdgD/QeohgBqsA3rzs0bd2POdSTRJC8qVM6yGZFBqKhc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=SHEa/nwq; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="SHEa/nwq" Received: by smtp.kernel.org (Postfix) with UTF8SMTPSA id 1E5241F000E9; Tue, 4 Aug 2026 18:56:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1785869764; bh=nFk6R/B/BKxw+kr+MboqGD+mfukfGOz2/GgStRKasCc=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=SHEa/nwq8r2kvOtxBoue7o7cfuRCShIJ4uDViRyPz3GjLxNsyGRBt5ITQ+c1xLxWd W8VSDB5WxQuUpV1UASJ4jDc+gspz8sMZTEKtZuDcmIjudDMoLsYKw+ra/WT/ppzS97 wF9IcCtTdylxCYWTO0q2ZgggUKP935iq0t+TMbHz2ioVcpwJDYBVYRQaP84DDp3nHu 9JeimgeUsic3VQFPGqSqlrypSpDF4mpXUVCJiiERgHpCT+3Eq060NZSYmzx9qzcSbe 9cKMHCDsDyftSezqsFvw05wQcY4FsdoOVOvAdGbU9A3mQlWEMVQd4YRKq1kMlMqdyZ he3Tp/rp1XbOA== Date: Tue, 4 Aug 2026 11:56:03 -0700 From: "Darrick J. Wong" To: Matthew Wilcox Cc: Andrey Albershteyn , linux-xfs@vger.kernel.org, fsverity@lists.linux.dev, linux-fsdevel@vger.kernel.org, ebiggers@kernel.org, hch@lst.de, linux-ext4@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-btrfs@vger.kernel.org Subject: Re: [PATCH v14 05/21] fsverity: improve flushing performance of fsverity_fill_zerohash Message-ID: <20260804185603.GP3556460@frogsfrogsfrogs> References: <20260803200820.393203-1-aalbersh@kernel.org> <20260803200820.393203-6-aalbersh@kernel.org> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Tue, Aug 04, 2026 at 07:46:03PM +0100, Matthew Wilcox wrote: > On Mon, Aug 03, 2026 at 10:07:55PM +0200, Andrey Albershteyn wrote: > > The current version calls flush_dcache_folio(), in memcpy_to_folio(), to > > flush whole folio on every digest (which is 128 for 4k) on the HIGHMEM > > systems. Open code folio mapping and flushing to copy all digests at > > once. > > Have you looked at the implementations of flush_dcache_folio()? On > any architecture we actually care about, all it does is set one bit > in folio->flags noting that the folio will need to be flushed if > it's going to be accessed by userspace. > > But, um, do we support mapping folios containing fsverity data into > userspace? Can't we just delete the calls to flush_dcache_folio()? I don't think programs are allowed to mmap the fsverity data, right? I know there's an ioctl that effectively allows read()ing it. --D 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 lists.sourceforge.net (lists.sourceforge.net [216.105.38.7]) (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 084E0C55184 for ; Tue, 4 Aug 2026 18:56:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.sourceforge.net; s=beta; h=Content-Transfer-Encoding:Content-Type:Cc: Reply-To:From:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:Subject:In-Reply-To:MIME-Version:References: Message-ID:To:Date:Sender:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=CCdOo+sVfo3o1fm0ip4S+pjvxSkhiCVBQ9KDsdMYn6A=; b=Kauyr5GH83FDAtBOOpBb7F4WZ3 InaCIejLHuEISVbsIZ/ehMBwZDm6OYobfAxhtrsFe9m0Xqp86Qrs7bk8oFU0N3OVG1VKaKaXL4TPs baAI5BXsMEv+OjWL8OukKlxCwPsuKi8jG3B0fGiwFTnmihk3OsRlCgIsHdVAzpvQrZEU=; Received: from [127.0.0.1] (helo=sfs-ml-1.v29.lw.sourceforge.com) by sfs-ml-1.v29.lw.sourceforge.com with esmtp (Exim 4.95) (envelope-from ) id 1wrKJD-00050R-HU; Tue, 04 Aug 2026 18:56:13 +0000 Received: from [172.30.29.66] (helo=mx.sourceforge.net) by sfs-ml-1.v29.lw.sourceforge.com with esmtps (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.95) (envelope-from ) id 1wrKJC-00050K-5o for linux-f2fs-devel@lists.sourceforge.net; Tue, 04 Aug 2026 18:56:11 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sourceforge.net; s=x; h=In-Reply-To:Content-Type:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Sender: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=nFk6R/B/BKxw+kr+MboqGD+mfukfGOz2/GgStRKasCc=; b=m0MHHfwuyzWtRZk5VcQrydzV5k mU3iqHxbFFrGQgtJy++B+Kv8QSr+q2uT6Ik/h0tmT3d3Oa/iXqeu9dGPl3OrJ81O4yJnM4pyaLAiq 5LKphr97nF2lfDwAIh6wlDwH90skINlp4gvGYJx5p46gQzdRXWChBTJA3UcTG408ekEo=; DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sf.net; s=x ; h=In-Reply-To:Content-Type:MIME-Version:References:Message-ID:Subject:Cc:To :From:Date:Sender: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=nFk6R/B/BKxw+kr+MboqGD+mfukfGOz2/GgStRKasCc=; b=ahI0v1JK5YeeruVJiORalvBfOg OoYRE32YFIbZR0Cephqt9WgCzfePk8l1UPQh4DKupovIH/SLaPnQClXc42tCFA6rVDV7e4eNdAvKP dzyu42afZ7NP+uPSz6gNsNZWl+Olbo5SqV+Z6jUwG6c2KAkJ82sWMZ0WWgUbWNlka4UM=; Received: from tor.source.kernel.org ([172.105.4.254]) by sfi-mx-1.v28.lw.sourceforge.com with esmtps (TLS1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.95) id 1wrKJB-0001ps-RW for linux-f2fs-devel@lists.sourceforge.net; Tue, 04 Aug 2026 18:56:11 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with UTF8SMTP id 83ACC60A78; Tue, 4 Aug 2026 18:56:04 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with UTF8SMTPSA id 1E5241F000E9; Tue, 4 Aug 2026 18:56:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1785869764; bh=nFk6R/B/BKxw+kr+MboqGD+mfukfGOz2/GgStRKasCc=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=SHEa/nwq8r2kvOtxBoue7o7cfuRCShIJ4uDViRyPz3GjLxNsyGRBt5ITQ+c1xLxWd W8VSDB5WxQuUpV1UASJ4jDc+gspz8sMZTEKtZuDcmIjudDMoLsYKw+ra/WT/ppzS97 wF9IcCtTdylxCYWTO0q2ZgggUKP935iq0t+TMbHz2ioVcpwJDYBVYRQaP84DDp3nHu 9JeimgeUsic3VQFPGqSqlrypSpDF4mpXUVCJiiERgHpCT+3Eq060NZSYmzx9qzcSbe 9cKMHCDsDyftSezqsFvw05wQcY4FsdoOVOvAdGbU9A3mQlWEMVQd4YRKq1kMlMqdyZ he3Tp/rp1XbOA== Date: Tue, 4 Aug 2026 11:56:03 -0700 To: Matthew Wilcox Message-ID: <20260804185603.GP3556460@frogsfrogsfrogs> References: <20260803200820.393203-1-aalbersh@kernel.org> <20260803200820.393203-6-aalbersh@kernel.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-Headers-End: 1wrKJB-0001ps-RW Subject: Re: [f2fs-dev] [PATCH v14 05/21] fsverity: improve flushing performance of fsverity_fill_zerohash X-BeenThere: linux-f2fs-devel@lists.sourceforge.net X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , From: "Darrick J. Wong via Linux-f2fs-devel" Reply-To: "Darrick J. Wong" Cc: fsverity@lists.linux.dev, ebiggers@kernel.org, Andrey Albershteyn , linux-f2fs-devel@lists.sourceforge.net, linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org, hch@lst.de, linux-btrfs@vger.kernel.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-f2fs-devel-bounces@lists.sourceforge.net On Tue, Aug 04, 2026 at 07:46:03PM +0100, Matthew Wilcox wrote: > On Mon, Aug 03, 2026 at 10:07:55PM +0200, Andrey Albershteyn wrote: > > The current version calls flush_dcache_folio(), in memcpy_to_folio(), to > > flush whole folio on every digest (which is 128 for 4k) on the HIGHMEM > > systems. Open code folio mapping and flushing to copy all digests at > > once. > > Have you looked at the implementations of flush_dcache_folio()? On > any architecture we actually care about, all it does is set one bit > in folio->flags noting that the folio will need to be flushed if > it's going to be accessed by userspace. > > But, um, do we support mapping folios containing fsverity data into > userspace? Can't we just delete the calls to flush_dcache_folio()? I don't think programs are allowed to mmap the fsverity data, right? I know there's an ioctl that effectively allows read()ing it. --D _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel