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 4B028C433B4 for ; Thu, 13 May 2021 13:38:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 244F8613AA for ; Thu, 13 May 2021 13:38:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234142AbhEMNjn (ORCPT ); Thu, 13 May 2021 09:39:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60126 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234106AbhEMNjY (ORCPT ); Thu, 13 May 2021 09:39:24 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3AC79C061574; Thu, 13 May 2021 06:38:14 -0700 (PDT) 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=7qdcsekCpDC0XbH1OXVUDI58yFo8Z7At/i6/i0XMALI=; b=tfkCjdPhG2JWyiamQqLUcVIUaa XIAK/k2n62tt+Wbf/46OEwAYMQmA+a7bxfjCQNJeofqSoJn1tx8g09UAvpof8TiISSa9sOFxVSN8w nCvW92rZta0Ztby0RSYVTKYOkyXuxIu5khMZE9L+bS3UvMSj+aeeIUOr7y/BZ0s3moMIBGnmRaaSy 08Fy6gD4Ww+T7IVNTy+9uiKfwl9bw9+Ie3saiCuYJSsI+W//LBbl1U4U9o+0MyqTusGI62zeRBaCe sAGJMylp/ZwrTaXz1ygWi77JLYrKiU3A1rF9dV6x19gN9MMMDWs8rVF6qFAXnGsUza3T3lvP2KglO Sl13Etjw==; Received: from willy by casper.infradead.org with local (Exim 4.94 #2 (Red Hat Linux)) id 1lhBU3-009Sko-72; Thu, 13 May 2021 13:35:00 +0000 Date: Thu, 13 May 2021 14:34:35 +0100 From: Matthew Wilcox To: Steve French Cc: linux-nfs , CIFS , v9fs-developer@lists.sourceforge.net, linux-fsdevel Subject: Re: Removing readpages aop Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-cifs@vger.kernel.org On Wed, May 12, 2021 at 02:28:41PM -0500, Steve French wrote: > I don't have any objections as long as: > - we see at least mild performance benefit (or at least we are > confident that no performance loss) Nobody's complained of a performance loss in the other ~30 filesystems which have already been converted (some almost a year ago). And CIFS has one of the more convoluted readpages implementation, so I'd expect a higher likelihood of a performance gain from CIFS. > - it passes regression tests (the usual xfstest bucket) > - it doesn't complicate the code too much (sounds like it actually > might simplify it, but needs a little more work) > - make sure that the usual tuning parms still work (e.g. "rsize" and > "rasize" mount options) or we can figure out a sane way to autotune > readhead so those wouldn't be needed for any workload One of the enhancements added as part of the recent netfs merge was readahead_expand(). Take a look at it and see if it works for you. > But currently since we get the most benefit from multichannel (as that > allows even better parallelization of i/o) ... I have been focused on > various multichannel issues (low credit situations, reconnect, fall > back to different channels when weird errors, adjusting channels > dynamically when server adds or removes adapters on the fly) for the > short term Understood. Only so many hours in the day. I think https://lore.kernel.org/linux-fsdevel/1794123.1605713481@warthog.procyon.org.uk/ is the most recent version, but as Dave notes, it needs attention from somebody who knows the CIFS code better.