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 A1F2BD2ECF9 for ; Tue, 20 Jan 2026 07:35:53 +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=DTJA2YFmVg0Jk6L3LTmHuyQwz/l15rrcPTyKZbH1Q5Q=; b=X30ynsmdKOo9bIZ0j9a3uMGORq pTn4DEv3Gk/E9hDsc0khA98fOwWcJd4ClgPMJulBir8evgr3cJ0IaxUTpaIVAlAj6X5QDO9mPtEiT MoM4o7VqFcKnHg7xS2j9iVY+AUd3+BRROcCwaSn9OXGrVsG2+rveYJZkhB1SUa6IJXzs=; 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 1vi6HJ-00084t-7W; Tue, 20 Jan 2026 07:35:53 +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 1vi6HI-00084l-Ca for linux-f2fs-devel@lists.sourceforge.net; Tue, 20 Jan 2026 07:35:52 +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=qujE1lOQ/jcNmX3qKnt9ptIV5Nw0gyj2cNV3EDymq40=; b=SIyUAEAgZxkoh93Kl2yTI3BG4e QavP8mgt3Kzc+XWxeMrx96wQpianGBGblrhVXqnuDNzK4v6M87mItSEAg8elCKU4OpjVDrszzZ4cH RJpDUQdtcFz4oaTa5p/Q7HGWy8vwtOKRvVja7BQ6uDBk9UbfOlKqQbyTSq3zQWSZgDUw=; 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=qujE1lOQ/jcNmX3qKnt9ptIV5Nw0gyj2cNV3EDymq40=; b=NxEWcgsyfLUShD3rCbdEBUk/LQ 8NI+DGiB81Ht3vFX3qXw2VdizKm46A+lYoOZyrt8VXL1NsgaUVXOfvIRfDDiufuEoySHY/vI7zXxF m1AfkSmSJGYL3J+t6Vj9Hq9UPMf/8WCcCe+8ppvh0a2nrLqPxGtiPqkBps1fPqoueeOk=; 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 1vi6HH-0007wn-Ov for linux-f2fs-devel@lists.sourceforge.net; Tue, 20 Jan 2026 07:35:52 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id 64B75227AA8; Tue, 20 Jan 2026 08:35:38 +0100 (CET) Date: Tue, 20 Jan 2026 08:35:38 +0100 From: Christoph Hellwig To: Eric Biggers Message-ID: <20260120073538.GA6956@lst.de> References: <20260119062250.3998674-1-hch@lst.de> <20260119062250.3998674-5-hch@lst.de> <20260119190536.GA13800@sol> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20260119190536.GA13800@sol> User-Agent: Mutt/1.5.17 (2007-11-01) X-Headers-End: 1vi6HH-0007wn-Ov Subject: Re: [f2fs-dev] [PATCH 4/6] fsverity: use a hashtable to find the fsverity_info 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, Christian Brauner , Theodore Ts'o , Andrey Albershteyn , willy@infradead.org, linux-f2fs-devel@lists.sourceforge.net, linux-fsdevel@vger.kernel.org, Al Viro , Jaegeuk Kim , David Sterba , Jan Kara , linux-ext4@vger.kernel.org, Christoph Hellwig , 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 Mon, Jan 19, 2026 at 11:05:36AM -0800, Eric Biggers wrote: > On Mon, Jan 19, 2026 at 07:22:45AM +0100, Christoph Hellwig wrote: > > Use the kernel's resizable hash table to find the fsverity_info. This > > way file systems that want to support fsverity don't have to bloat > > every inode in the system with an extra pointer. The tradeoff is that > > looking up the fsverity_info is a bit more expensive now, but the main > > operations are still dominated by I/O and hashing overhead. > > > > Signed-off-by: Christoph Hellwig > > Has anything changed from my last feedback at > https://lore.kernel.org/linux-fsdevel/20250810170311.GA16624@sol/ ? > > Any additional data on the cycles and icache footprint added to data > verification? The preliminary results didn't look all that good to me. Nothing has changed, as as expected by then and now the lookup overhead is completely dwarfed by other parts of the read, even when the data and hashes are already cached. Of course if you look into the lookup in itself, any kind of data structure will be significantly more expensive than a pointer dereference and nothing will change that. > It also seems odd to put this in an "fsverity optimzations and speedups" > patchset, given that it's the opposite. It optimizes the memory usage and doesn't require bloating the inode for new file systems adding fsverity support. size of the inode is a major concern, and is even more so for a feature that is not commonly used and then not for most files. _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel