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=-3.5 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS 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 A44AAC33CAE for ; Tue, 14 Jan 2020 00:41:55 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 752E9217BA; Tue, 14 Jan 2020 00:41:55 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=sourceforge.net header.i=@sourceforge.net header.b="Z442teTG"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=sf.net header.i=@sf.net header.b="dXLop1vJ" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 752E9217BA Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=mit.edu Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linux-f2fs-devel-bounces@lists.sourceforge.net Received: from [127.0.0.1] (helo=sfs-ml-2.v29.lw.sourceforge.com) by sfs-ml-2.v29.lw.sourceforge.com with esmtp (Exim 4.90_1) (envelope-from ) id 1irAHK-00013G-81; Tue, 14 Jan 2020 00:41:54 +0000 Received: from [172.30.20.202] (helo=mx.sourceforge.net) by sfs-ml-2.v29.lw.sourceforge.com with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.90_1) (envelope-from ) id 1irAHJ-000139-17 for linux-f2fs-devel@lists.sourceforge.net; Tue, 14 Jan 2020 00:41:53 +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=rNLA2aIsg2KWijZTSC3EgL5aU50anHJ4KTrPKnTDJhQ=; b=Z442teTG/p4eyaOJIHtGvufHGK TS1JhwYU6K/QJjnEIwm8kA5jVoO3AA96E3Dk3MDGzqahz95iKpMdd5DswM4Bun7eXIsaUnGwpau5G MivweCd08QqvAhyXDvIaeu5SkNzi6GzxNu7BICGbbnNgBfca0iSXW28xN3s46qL9CpsY=; 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=rNLA2aIsg2KWijZTSC3EgL5aU50anHJ4KTrPKnTDJhQ=; b=dXLop1vJ84ppWz1vCgow5iRLI8 BHqxA1UxeKKFhzo1kIj2S/wJcAIhEFmOautzdLK4vLEnkZs5QT2qK49V6BLH3qulERqvhhPd61/IZ 4VFPMWtVyVdOrz8ZCzmaSOwLFT1WLHE3cc3knJ45qaAlZ/wuY/kL+jQxk8iGXJlvWZIE=; Received: from outgoing-auth-1.mit.edu ([18.9.28.11] helo=outgoing.mit.edu) by sfi-mx-4.v28.lw.sourceforge.com with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.92.2) id 1irAHH-001l8f-Gh for linux-f2fs-devel@lists.sourceforge.net; Tue, 14 Jan 2020 00:41:52 +0000 Received: from callcc.thunk.org (guestnat-104-133-0-111.corp.google.com [104.133.0.111] (may be forged)) (authenticated bits=0) (User authenticated as tytso@ATHENA.MIT.EDU) by outgoing.mit.edu (8.14.7/8.12.4) with ESMTP id 00E0fbEI006931 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 13 Jan 2020 19:41:38 -0500 Received: by callcc.thunk.org (Postfix, from userid 15806) id 5C3A54207DF; Mon, 13 Jan 2020 19:41:37 -0500 (EST) Date: Mon, 13 Jan 2020 19:41:37 -0500 From: "Theodore Y. Ts'o" To: Eric Biggers Message-ID: <20200114004137.GQ76141@mit.edu> References: <20200106205410.136707-1-ebiggers@kernel.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200106205410.136707-1-ebiggers@kernel.org> X-Headers-End: 1irAHH-001l8f-Gh Subject: Re: [f2fs-dev] [PATCH v3] fs-verity: implement readahead for FS_IOC_ENABLE_VERITY 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: linux-fsdevel@vger.kernel.org, linux-fscrypt@vger.kernel.org, linux-ext4@vger.kernel.org, Victor Hsieh , linux-f2fs-devel@lists.sourceforge.net Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-f2fs-devel-bounces@lists.sourceforge.net On Mon, Jan 06, 2020 at 12:54:10PM -0800, Eric Biggers wrote: > From: Eric Biggers > > When it builds the first level of the Merkle tree, FS_IOC_ENABLE_VERITY > sequentially reads each page of the file using read_mapping_page(). > This works fine if the file's data is already in pagecache, which should > normally be the case, since this ioctl is normally used immediately > after writing out the file. > > But in any other case this implementation performs very poorly, since > only one page is read at a time. > > Fix this by implementing readahead using the functions from > mm/readahead.c. > > This improves performance in the uncached case by about 20x, as seen in > the following benchmarks done on a 250MB file (on x86_64 with SHA-NI): > > FS_IOC_ENABLE_VERITY uncached (before) 3.299s > FS_IOC_ENABLE_VERITY uncached (after) 0.160s > FS_IOC_ENABLE_VERITY cached 0.147s > sha256sum uncached 0.191s > sha256sum cached 0.145s > > Note: we could instead switch to kernel_read(). But that would mean > we'd no longer be hashing the data directly from the pagecache, which is > a nice optimization of its own. And using kernel_read() would require > allocating another temporary buffer, hashing the data and tree pages > separately, and explicitly zero-padding the last page -- so it wouldn't > really be any simpler than direct pagecache access, at least for now. > > Signed-off-by: Eric Biggers Looks good, feel free to add: Reviewed-by: Theodore Ts'o _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel