From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) (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 58EEC3A9628; Fri, 24 Jul 2026 13:13:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=213.95.11.211 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784898799; cv=none; b=ZoeXV7WpzMs332O23aDorBjncg7UtM20gYcQJYNBRM7Fz1+2ADmeRQ72MmHSyVcs2+0PW5GCXksJFLfFqcD7eFnWBk8SR9ydzfqf11IZBOzVi1GJQMvGAMkX0CRb1S7q6/HOftOtgw1zJ8pi08Bn2KnqzMYidYTyBpdczKc+u8s= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784898799; c=relaxed/simple; bh=B2EJbs3TJ5XbxxR+DLc0pnnDadUKwE4zezEBIo5PGwI=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=JbucjbDV2eeJHpPWV6AGnJ0ut0NPX14jKx+iHCRUnqU+wHxGRDykyLhxqFGbd0UqDWN1GmRPKAl3hZ1n6uLruvJsbMF9fgEKPnAAffPfkVkE+8xwZ+r4Ljx5tXbS5WLrMRPwl2/JFKL7WO/q+V12ohXm6GFjTNHhzbDuscFR1gg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=lst.de; spf=pass smtp.mailfrom=lst.de; arc=none smtp.client-ip=213.95.11.211 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=lst.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=lst.de Received: by verein.lst.de (Postfix, from userid 2407) id 5216C68AFE; Fri, 24 Jul 2026 15:13:10 +0200 (CEST) Date: Fri, 24 Jul 2026 15:13:09 +0200 From: Christoph Hellwig To: Andrey Albershteyn Cc: 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, djwong@kernel.org Subject: Re: [PATCH v13 05/23] fsverity: improve flushing performance of fsverity_fill_zerohash Message-ID: <20260724131309.GA27878@lst.de> References: <20260721184346.416657-1-aalbersh@kernel.org> <20260721184346.416657-6-aalbersh@kernel.org> Precedence: bulk X-Mailing-List: linux-xfs@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: <20260721184346.416657-6-aalbersh@kernel.org> User-Agent: Mutt/1.5.17 (2007-11-01) On Tue, Jul 21, 2026 at 08:40:42PM +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). Open code folio > mapping and flushing to copy all digests at once. What is the point of this? flush_dcache_folio is a no-op on sane architectures, and this should not be a performance path, so avoiding all the kmap logic does seem benefitial. Or at least only opencode it for !highmem to avoid the worst part. 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 6FA05C531FA for ; Fri, 24 Jul 2026 15:41:23 +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: List-Subscribe:List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id: Subject:In-Reply-To:MIME-Version:References:Message-ID:To:From:Date:Sender: Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender :Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=0br3WpHphIXM/6XdcUc+udsKjwl1JENwF6gqF1VDiME=; b=OHX+QhIZ7xY/+fMYrwd9xrsZJr VL0WQoy/7i2CRyBjZmxPCIzPHSyYrgdTs8IQg5em2Kuv2dcXVBdaq8zwd0Mpah9GfYoPN+NU+A7j3 NURpmQeQFWakzE4LAB3A0YJPLvbHXHzXRzmrjRI+mZQyXjRfRlKFyn0RsvjU3XVjZ068=; Received: from [127.0.0.1] (helo=sfs-ml-3.v29.lw.sourceforge.com) by sfs-ml-3.v29.lw.sourceforge.com with esmtp (Exim 4.95) (envelope-from ) id 1wnI1Z-0006ej-Fc; Fri, 24 Jul 2026 15:41:22 +0000 Received: from [172.30.29.66] (helo=mx.sourceforge.net) by sfs-ml-3.v29.lw.sourceforge.com with esmtps (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.95) (envelope-from ) id 1wnI1Y-0006eb-FZ for linux-f2fs-devel@lists.sourceforge.net; Fri, 24 Jul 2026 15:41:21 +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=xiBePRu5pAxh3mf+wgKwHiXWgeATkzN4gVVwbCFjwOw=; b=K9Smmkzvr/dFdO8RXbeJdKRHSh KXir8DC0xl+f/bqrXXLaaLIUzFAo80kXdr50E0wOp/mgnWI5xIogiiJe+V9LvV9iQsjxVf0k+k+w0 W+XXjw2A+4IsTEAYeZRTvg08q/piCwt+Z38+s4cPqpl03NIAiCab6GssoBTxy/PygaK4=; 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=xiBePRu5pAxh3mf+wgKwHiXWgeATkzN4gVVwbCFjwOw=; b=HhzCmmE/DnLTk88szn0O3IgWkv yNtEV8XdJ3Aw7XfRfBqhnrt1BOgjAjXusF0C605JHzUnS0K7fUjKfX1NMrhBHSNFvqZ6XbMocXzbq Vb3cU1h8GTa+9yj8VdGjnHl/M9QzvpvjnpjNErwPghzkV6BDvBDKkZYuRL1rCnkOL2jg=; Received: from verein.lst.de ([213.95.11.211]) by sfi-mx-2.v28.lw.sourceforge.com with esmtps (TLS1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.95) id 1wnI1X-00081V-Ha for linux-f2fs-devel@lists.sourceforge.net; Fri, 24 Jul 2026 15:41:21 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id 5216C68AFE; Fri, 24 Jul 2026 15:13:10 +0200 (CEST) Date: Fri, 24 Jul 2026 15:13:09 +0200 From: Christoph Hellwig To: Andrey Albershteyn Message-ID: <20260724131309.GA27878@lst.de> References: <20260721184346.416657-1-aalbersh@kernel.org> <20260721184346.416657-6-aalbersh@kernel.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20260721184346.416657-6-aalbersh@kernel.org> User-Agent: Mutt/1.5.17 (2007-11-01) X-Headers-End: 1wnI1X-00081V-Ha Subject: Re: [f2fs-dev] [PATCH v13 05/23] 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: , Cc: fsverity@lists.linux.dev, ebiggers@kernel.org, djwong@kernel.org, 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, Jul 21, 2026 at 08:40:42PM +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). Open code folio > mapping and flushing to copy all digests at once. What is the point of this? flush_dcache_folio is a no-op on sane architectures, and this should not be a performance path, so avoiding all the kmap logic does seem benefitial. Or at least only opencode it for !highmem to avoid the worst part. _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel