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,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 3CC36C433E0 for ; Tue, 16 Feb 2021 11:52:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E11D364DA5 for ; Tue, 16 Feb 2021 11:52:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230394AbhBPLwG (ORCPT ); Tue, 16 Feb 2021 06:52:06 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:26651 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230280AbhBPLuF (ORCPT ); Tue, 16 Feb 2021 06:50:05 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1613476119; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=coH4C7xdrmgBE3/XsHGmHJNC7rb47IS/kJchI+NLx3A=; b=PZu8BxFFewks0etlybQeiktQl+i6Xz/jRF/+xQTJ7TjNDaEArVTpxtScVkmwoRkNdlkzHQ 6aVfHudJJ986oTWKbTmeSN4HUFUhPAaWFVTnt2Br6njEN/AnRnbnTiLUDwwr96iUltiG4k TaolSFXKZWu2V5aKBlhS7XeZ5f0yl70= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-349-jKcmJhrLMwullgSDWVKkPg-1; Tue, 16 Feb 2021 06:48:35 -0500 X-MC-Unique: jKcmJhrLMwullgSDWVKkPg-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id B44BE801977; Tue, 16 Feb 2021 11:48:32 +0000 (UTC) Received: from warthog.procyon.org.uk (ovpn-119-68.rdu2.redhat.com [10.10.119.68]) by smtp.corp.redhat.com (Postfix) with ESMTP id EDB605C1B4; Tue, 16 Feb 2021 11:48:24 +0000 (UTC) Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 From: David Howells In-Reply-To: <20210216103215.GB27714@lst.de> References: <20210216103215.GB27714@lst.de> <161340385320.1303470.2392622971006879777.stgit@warthog.procyon.org.uk> <161340389201.1303470.14353807284546854878.stgit@warthog.procyon.org.uk> To: Christoph Hellwig , "Matthew Wilcox (Oracle)" Cc: dhowells@redhat.com, Trond Myklebust , Anna Schumaker , Steve French , Dominique Martinet , Alexander Viro , linux-mm@kvack.org, linux-cachefs@redhat.com, linux-afs@lists.infradead.org, linux-nfs@vger.kernel.org, linux-cifs@vger.kernel.org, ceph-devel@vger.kernel.org, v9fs-developer@lists.sourceforge.net, linux-fsdevel@vger.kernel.org, Jeff Layton , David Wysochanski , linux-kernel@vger.kernel.org Subject: Re: [PATCH 03/33] mm: Implement readahead_control pageset expansion MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-ID: <1429174.1613476104.1@warthog.procyon.org.uk> Date: Tue, 16 Feb 2021 11:48:24 +0000 Message-ID: <1429175.1613476104@warthog.procyon.org.uk> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Precedence: bulk List-ID: X-Mailing-List: linux-cifs@vger.kernel.org Christoph Hellwig wrote: > On Mon, Feb 15, 2021 at 03:44:52PM +0000, David Howells wrote: > > Provide a function, readahead_expand(), that expands the set of pages > > specified by a readahead_control object to encompass a revised area with a > > proposed size and length. > ... > So looking at linux-next this seems to have a user, but that user is > dead wood given that nothing implements ->expand_readahead. Interesting question. Code on my fscache-iter branch does implement this, but I was asked to split the patchset up, so that's not in this subset. > Looking at the code structure I think netfs_readahead and > netfs_rreq_expand is a complete mess and needs to be turned upside > down, that is instead of calling back from netfs_readahead to the > calling file system, split it into a few helpers called by the > caller. > > But even after this can't we just expose the cache granule boundary > to the VM so that the read-ahead request gets setup correctly from > the very beginning? You need to argue this one with Willy. In my opinion, the VM should ask the filesystem and the expansion be done before ->readahead() is called. Willy disagrees, however. David