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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6616FEB64DC for ; Wed, 12 Jul 2023 03:23:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230150AbjGLDXT (ORCPT ); Tue, 11 Jul 2023 23:23:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34882 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229742AbjGLDXS (ORCPT ); Tue, 11 Jul 2023 23:23:18 -0400 X-Greylist: delayed 413 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Tue, 11 Jul 2023 20:23:16 PDT Received: from out-33.mta1.migadu.com (out-33.mta1.migadu.com [95.215.58.33]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E7A61CA for ; Tue, 11 Jul 2023 20:23:16 -0700 (PDT) Message-ID: <605b8001-2d93-9214-814e-0abd91f61a69@linux.dev> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1689131779; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=UVJ3OHyeN/LH6c0no72u5Xee/3/cvZ6pqHiGoR3aXRw=; b=r40zbl+4ZYMuk92ay+97Rot0SVcWSPlUhSmntRkkxft4/InPfXXn24bN8hCGzCm1ZC5/Sc huxOhNSyKJXh81S0fnM2+YSoKo+PC9EUixs/hlx6tGLftiQE8Ew7QW1pdxcUHOCOwZlJkZ uBGKzRJA+ic06GaKVyTM7aOB+FFQGWo= Date: Wed, 12 Jul 2023 11:16:10 +0800 MIME-Version: 1.0 Subject: Re: [PATCH v3 0/3] io_uring getdents Content-Language: en-US To: Jens Axboe , Dominique Martinet Cc: Dave Chinner , io-uring@vger.kernel.org, Pavel Begunkov , Christian Brauner , Alexander Viro , Stefan Roesch , Clay Harris , linux-fsdevel@vger.kernel.org, Wanpeng Li References: <20230711114027.59945-1-hao.xu@linux.dev> <5264f776-a5fd-4878-1b4c-7fe9f9a61b51@kernel.dk> <26b22ded-d6bc-97d6-75d8-22ff778d66ac@kernel.dk> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Hao Xu In-Reply-To: <26b22ded-d6bc-97d6-75d8-22ff778d66ac@kernel.dk> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org Hi, On 7/12/23 08:56, Jens Axboe wrote: > On 7/11/23 6:53 PM, Dominique Martinet wrote: >> Jens Axboe wrote on Tue, Jul 11, 2023 at 05:51:46PM -0600: >>>> So what filesystem actually uses this new NOWAIT functionality? >>>> Unless I'm blind (quite possibly) I don't see any filesystem >>>> implementation of this functionality in the patch series. >> >> I had implemented this for kernfs and libfs (so sysfs, debugfs, possibly >> tmpfs/proc?) in v2 >> >> The patch as of v2's mail has a bug, but my branch has it fixed as of >> https://github.com/martinetd/linux/commits/io_uring_getdents >> >> (I guess these aren't "real" enough though) > > No, I definitely think those are real and valid. But would be nice with > a "real" file system as well. > >>>> I know I posted a prototype for XFS to use it, and I expected that >>>> it would become part of this patch series to avoid the "we don't add >>>> unused code to the kernel" problem. i.e. the authors would take the >>>> XFS prototype, make it work, add support into for the new io_uring >>>> operation to fsstress in fstests and then use that to stress test >>>> the new infrastructure before it gets merged.... >>>> >>>> But I don't see any of this? >>> >>> That would indeed be great if we could get NOWAIT, that might finally >>> convince me that it's worth plumbing up! Do you have a link to that >>> prototype? That seems like what should be the base for this, and be an >>> inspiration for other file systems to get efficient getdents via this >>> (rather than io-wq punt, which I'm not a huge fan of...). >> >> the xfs poc was in this mail: >> https://lore.kernel.org/all/20230501071603.GE2155823@dread.disaster.area/ >> >> I never spent time debugging it, but it should definitely be workable > > If either you or Hao wants to take a stab at it and see how it goes, > I think that would be hugely beneficial for this patchset. > I can take the xfs and kernfs part if Dominique doesn't mind. Regards, Hao