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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, 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 B3FAFC433E9 for ; Wed, 20 Jan 2021 16:56:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8126C23358 for ; Wed, 20 Jan 2021 16:56:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389360AbhATQ4D (ORCPT ); Wed, 20 Jan 2021 11:56:03 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48882 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2403975AbhATQVd (ORCPT ); Wed, 20 Jan 2021 11:21:33 -0500 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8D1D2C061575; Wed, 20 Jan 2021 08:21:18 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; 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; bh=+TyaprsFFpe4D2IdPtCe/vGt+ZyBDLNGMTqOEUV0Y0Y=; b=ktIh2yT5awX/xT5bRccUykitbs zgufB8WSm9bC+xgIIJPaJjx3/ouKSRW3nr/780xlRnnsuVhmezcnEKPSCnUf6NgrDm1i8C9IyVjoe 7oN5VPb5AgfWo7DAV0yXTMSXo83+Chdgpq5voEK9+OvpiytpbBq4cDbpWzYwyPIIfrh8NPIRtcasX IdwcjrCl/q/UWPa2RP/B/Z5UOv0F/Uz7DvSTBayM8ImJyTMLoL/46+7yxjhhEIamoJqbq6PL3l4EE DSyKwogLbgvVPII5ePApUKii8KrZcUepI/RCyxl9cvXpGs0Dvc/qunL0M5/Yo9X99iONsZNQCHSdh QMoIJrwA==; Received: from hch by casper.infradead.org with local (Exim 4.94 #2 (Red Hat Linux)) id 1l2GDB-00FuBN-2r; Wed, 20 Jan 2021 16:20:12 +0000 Date: Wed, 20 Jan 2021 16:20:01 +0000 From: Christoph Hellwig To: Jan Kara Cc: linux-fsdevel@vger.kernel.org, Matthew Wilcox , linux-ext4@vger.kernel.org Subject: Re: [PATCH 2/3] mm: Provide address_space operation for filling pages for read Message-ID: <20210120162001.GB3790454@infradead.org> References: <20210120160611.26853-1-jack@suse.cz> <20210120160611.26853-3-jack@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210120160611.26853-3-jack@suse.cz> X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Wed, Jan 20, 2021 at 05:06:10PM +0100, Jan Kara wrote: > Provide an address_space operation for filling pages needed for read > into page cache. Filesystems can use this operation to seriealize > page cache filling with e.g. hole punching properly. Besides the impending rewrite of the area - having another indirection here is just horrible for performance. If we want locking in this area it should be in core code and common for multiple file systems.