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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id A8857C7EE25 for ; Fri, 24 Feb 2023 16:06:40 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id EE6696B0071; Fri, 24 Feb 2023 11:06:39 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id E96F66B0073; Fri, 24 Feb 2023 11:06:39 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D5DD16B0074; Fri, 24 Feb 2023 11:06:39 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id C5BEF6B0071 for ; Fri, 24 Feb 2023 11:06:39 -0500 (EST) Received: from smtpin09.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id 95C0C803BE for ; Fri, 24 Feb 2023 16:06:39 +0000 (UTC) X-FDA: 80502663318.09.B748385 Received: from mail-ed1-f41.google.com (mail-ed1-f41.google.com [209.85.208.41]) by imf06.hostedemail.com (Postfix) with ESMTP id 87AD3180014 for ; Fri, 24 Feb 2023 16:06:36 +0000 (UTC) Authentication-Results: imf06.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=google header.b=ROuAwM4t; spf=pass (imf06.hostedemail.com: domain of torvalds@linuxfoundation.org designates 209.85.208.41 as permitted sender) smtp.mailfrom=torvalds@linuxfoundation.org; dmarc=none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1677254796; h=from:from:sender: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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=p1FN9nq7chgygC5NWZzWMsQda297W5OS4KEAh+SuMus=; b=ZmRG/Kv365T+Ff+Af/Sdwtz6CHXdjy41H4SkAtATjjZaNMfnpoVzcOSHzyIKPchApPOajb Rctzsln5hqtsyKk+/saikLFLKMpWUIYqlJrkUBOO0E9awe7ZdwStZwnBCQYDfXnTgDQiM5 dfM9H9gkEtPyY+AuMGHhIT5mWaxa+8o= ARC-Authentication-Results: i=1; imf06.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=google header.b=ROuAwM4t; spf=pass (imf06.hostedemail.com: domain of torvalds@linuxfoundation.org designates 209.85.208.41 as permitted sender) smtp.mailfrom=torvalds@linuxfoundation.org; dmarc=none ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1677254796; a=rsa-sha256; cv=none; b=Ptk9sJRRtPrSBW1YeKzeKUjKzk4xs/RmF7SpBQbIGUYGFYz488fYwpNM8qeCDyQ4HEKtax 6AdFDoUy+WoJOq1vtZjLrVXre34hT+64uteSCFMyN0q9S9DhJ0UD2AaCGpOYOuGQEoqkei M15Y3/jg90wZypS+Wnfalga6kfN+AX8= Received: by mail-ed1-f41.google.com with SMTP id h16so56813660edz.10 for ; Fri, 24 Feb 2023 08:06:36 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=google; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc:subject:date:message-id:reply-to; bh=p1FN9nq7chgygC5NWZzWMsQda297W5OS4KEAh+SuMus=; b=ROuAwM4tAg+0iPPS4RRwf6U41AYovrmQQIr053RV82OWjRNJcwmgCd6EQZWBUDcuGl /YVUiED8jw7JQASfhrW9ek4MlJhqfPYCZ1uL7j8YbV641zREe/AnXkbLos/4aIYT+sxu AZKf48FLhcgz6ZmoERs6q2Q6vFuFae0IFc4mo= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=p1FN9nq7chgygC5NWZzWMsQda297W5OS4KEAh+SuMus=; b=HxbEU3FDM0T4KfWL+dmbilXwhW0+viJWE4pkAR4DSecR3L4SJr/yOpuIq7AZBiEXvB qCagp+uyfu6KmbmerNcSaTrARRAlgTCswXEGiL4gjJF/1LQau4WXhXa2ZH/yFoHLJu2+ 0A95737CdTXPkcoxDxlzcQCpYv1fxP8UA8M2FPBOvavrDUa9yh92cA/kd2voXVGH5ZR5 LjthCwgk9311bcSXZpU9wThuS/BBqlfDAtcrdcuDtMJpycs/jBs3vzZrf/3wqN6NzGYc BupBOEe09wP1wUgVCZPmVPSiqxxBnwS58bNLrl9d+/w1hIQvmdfmDHkAwMrcqo4zmOJx /LNA== X-Gm-Message-State: AO0yUKWI/mS4eCb54US5/zvxxofJViu9Xe7epj/PApeK1pnrwIV00x4F i8X32EC+lpzaKkHbF9mv3JOAZbpTGrGAeZ0quDnb6A== X-Google-Smtp-Source: AK7set8IxoHOj7+YSEWfQT+ccHayEOWFfkzsJCxgtRpUMgFkxdmA4KogEn7Tmg75FPRc1dCPHMv6OQ== X-Received: by 2002:a17:906:ce38:b0:8b2:8876:6a3c with SMTP id sd24-20020a170906ce3800b008b288766a3cmr27007504ejb.29.1677254794697; Fri, 24 Feb 2023 08:06:34 -0800 (PST) Received: from mail-ed1-f41.google.com (mail-ed1-f41.google.com. [209.85.208.41]) by smtp.gmail.com with ESMTPSA id y15-20020a17090629cf00b008caaae1f1e1sm7342336eje.110.2023.02.24.08.06.33 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 24 Feb 2023 08:06:33 -0800 (PST) Received: by mail-ed1-f41.google.com with SMTP id ec43so56109964edb.8 for ; Fri, 24 Feb 2023 08:06:33 -0800 (PST) X-Received: by 2002:a50:9fae:0:b0:4ab:4d34:9762 with SMTP id c43-20020a509fae000000b004ab4d349762mr7669709edf.5.1677254793184; Fri, 24 Feb 2023 08:06:33 -0800 (PST) MIME-Version: 1.0 References: <2009825.1677229488@warthog.procyon.org.uk> <20230220135225.91b0f28344c01d5306c31230@linux-foundation.org> <2134430.1677240738@warthog.procyon.org.uk> <2213409.1677249075@warthog.procyon.org.uk> In-Reply-To: <2213409.1677249075@warthog.procyon.org.uk> From: Linus Torvalds Date: Fri, 24 Feb 2023 08:06:16 -0800 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [RFC][PATCH] cifs: Fix cifs_writepages_region() To: David Howells Cc: Steve French , Vishal Moola , Andrew Morton , Jan Kara , Paulo Alcantara , Matthew Wilcox , Huang Ying , Baolin Wang , Xin Hao , linux-mm@kvack.org, mm-commits@vger.kernel.org, linux-kernel@vger.kernel.org Content-Type: multipart/mixed; boundary="00000000000025890805f57450f3" X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 87AD3180014 X-Stat-Signature: phybs54buw4mpjmj6i7niyhcctusetfd X-Rspam-User: X-HE-Tag: 1677254796-272175 X-HE-Meta: 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 5naKm94U 1XVyPSB8guoVorPEM7fQfppVXAKYnt2sE5bw26Xfh64qcvPizJAlZzvE5kzwrRegsvS2/rO3b3/wX0RIb0ElJzS37P+3AdG7XtyOS1RtcsZWI1uPoBEcvkO5fIaaf+If+gzqYDIz5WlSwcUmAD8Xuoa+7sbiSBgjmDZvrRITBJrbt0kUW/Q6YR25jc7tbgmROZJatnuigdQvCmAJtWDNNemMquEhs0Dj0E6vsJt6GjvTgoFCcZgIlTQa4/mMt3dqMgm6Y8uc4rIay6lwpCiQzFepAtelGfaI6zXGLFIsuXEvnGCuE2OdKReUl4svj4EsK90WmY7PqqqxGda2X80QG/pkl/QyqarSegPR3gMqGnwBLWC26jDWlDfmESH+TixLX+WyXkmNaXs4uhqnXM1xUe++J91dYnwOtnYN2z1r3aGkB8ZHs34HcEDN8tHGK43jZVptfEcmf5582cKniSY0Es/Pca2EO9m7GG79laSkMWmOA47N8uxx4UsGWam3DZk+Xiu54z0alT+SUG/vyPnQYy0keJctTMcjV43sxCIt5JoUVecb1zfXrnvPw1xClfOJ8xzfA6hXh2SVorD+1og62O0Jk3QaiRYmX8W/9a42nLXk5xkeIJQtm+iBfKQFw793Qyv4Wa5pa7I3YBdpQ4eG15tpnAZfwfSari64m5ucBmduGCwlnyRHwJsg8ZBykI78HI9wbFYwUTPC97h23jQanEqRZEE071OAUJ6e5msqTKAhZqVUrlraezbglZnwNE3eqjHOMMxcksY/tOR1pL6sQIE/vg80XoG/itPy7/n+01T3f9huqle23n27LyeMKRB1baSChXHFXHLU5fN9gTSA6s5Ieuv3li65uQcJ/xkdpW/L0SciA304vocFA69LSsW8qhUvx X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: --00000000000025890805f57450f3 Content-Type: text/plain; charset="UTF-8" On Fri, Feb 24, 2023 at 6:31 AM David Howells wrote: > > Here's the simplest fix for cifs_writepages_region() that gets it to work. Hmm. The commit message for this is wrong. > Fix the cifs_writepages_region() to just skip over members of the batch that > have been cleaned up rather than retrying them. It never retried them. The "skip_write" code did that same start += folio_size(folio); continue; that your patch does, but it *also* had that if (skips >= 5 || need_resched()) { thing to just stop writing entirely. > I'm not entirely sure why it fixes it, though. Yes. Strange. Because it does the exact same thing as the "Oh, the trylock worked, but it was still under writeback or fscache" did. I just merged all the "skip write" cases. But the code is clearly (a) not working and (b) the whole skip count and need_resched() logic is a bit strange to begin with. Can you humor me, and try if just removing that skip count thing instead? IOW, this attached patch? Because that whole "let's stop writing if we need to reschedule" sounds truly odd (we have a cond_resched(), although it's per folio batch, not per-folio), and the skip count logic doesn't make much sense to me either. SteveF? Linus --00000000000025890805f57450f3 Content-Type: text/x-patch; charset="US-ASCII"; name="patch.diff" Content-Disposition: attachment; filename="patch.diff" Content-Transfer-Encoding: base64 Content-ID: X-Attachment-Id: f_leiq6lh00 IGZzL2NpZnMvZmlsZS5jIHwgMTIgLS0tLS0tLS0tLS0tCiAxIGZpbGUgY2hhbmdlZCwgMTIgZGVs ZXRpb25zKC0pCgpkaWZmIC0tZ2l0IGEvZnMvY2lmcy9maWxlLmMgYi9mcy9jaWZzL2ZpbGUuYwpp bmRleCA1MzY1YTMyOTkwODguLjcwNjFkMjYzMzE1ZCAxMDA2NDQKLS0tIGEvZnMvY2lmcy9maWxl LmMKKysrIGIvZnMvY2lmcy9maWxlLmMKQEAgLTI4NTgsNyArMjg1OCw2IEBAIHN0YXRpYyBpbnQg Y2lmc193cml0ZXBhZ2VzX3JlZ2lvbihzdHJ1Y3QgYWRkcmVzc19zcGFjZSAqbWFwcGluZywKIAkJ CQkgIGxvZmZfdCBzdGFydCwgbG9mZl90IGVuZCwgbG9mZl90ICpfbmV4dCkKIHsKIAlzdHJ1Y3Qg Zm9saW9fYmF0Y2ggZmJhdGNoOwotCWludCBza2lwcyA9IDA7CiAKIAlmb2xpb19iYXRjaF9pbml0 KCZmYmF0Y2gpOwogCWRvIHsKQEAgLTI5MjcsMTcgKzI5MjYsNiBAQCBzdGF0aWMgaW50IGNpZnNf d3JpdGVwYWdlc19yZWdpb24oc3RydWN0IGFkZHJlc3Nfc3BhY2UgKm1hcHBpbmcsCiAJCQlyZXR1 cm4gcmV0OwogCiBza2lwX3dyaXRlOgotCQkJLyoKLQkJCSAqIFRvbyBtYW55IHNraXBwZWQgd3Jp dGVzLCBvciBuZWVkIHRvIHJlc2NoZWR1bGU/Ci0JCQkgKiBUcmVhdCBpdCBhcyBhIHdyaXRlIGVy cm9yIHdpdGhvdXQgYW4gZXJyb3IgY29kZS4KLQkJCSAqLwotCQkJaWYgKHNraXBzID49IDUgfHwg bmVlZF9yZXNjaGVkKCkpIHsKLQkJCQlyZXQgPSAwOwotCQkJCWdvdG8gd3JpdGVfZXJyb3I7Ci0J CQl9Ci0KLQkJCS8qIE90aGVyd2lzZSwganVzdCBza2lwIHRoYXQgZm9saW8gYW5kIGdvIG9uIHRv IHRoZSBuZXh0ICovCi0JCQlza2lwcysrOwogCQkJc3RhcnQgKz0gZm9saW9fc2l6ZShmb2xpbyk7 CiAJCQljb250aW51ZTsKIAkJfQo= --00000000000025890805f57450f3--