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 9AFCFC67871 for ; Mon, 24 Oct 2022 19:43:39 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 3FA2D940009; Mon, 24 Oct 2022 15:43:39 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 3AA60940007; Mon, 24 Oct 2022 15:43:39 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 29A6F940009; Mon, 24 Oct 2022 15:43:39 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id 1A97D940007 for ; Mon, 24 Oct 2022 15:43:39 -0400 (EDT) Received: from smtpin13.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id D432F140495 for ; Mon, 24 Oct 2022 19:43:38 +0000 (UTC) X-FDA: 80056867716.13.C628CDA Received: from mail-qv1-f47.google.com (mail-qv1-f47.google.com [209.85.219.47]) by imf17.hostedemail.com (Postfix) with ESMTP id 851B04001C for ; Mon, 24 Oct 2022 19:43:38 +0000 (UTC) Received: by mail-qv1-f47.google.com with SMTP id j6so2712972qvn.12 for ; Mon, 24 Oct 2022 12:43:38 -0700 (PDT) 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=JBAZHyd5XgygP1+md+qYdTHi+gwkM0InAuquo+/p7pw=; b=WBTb2zVyYxNOefcbYu3yHqG/UB1C+xJGDwXHwakVh38aS5ZuDINwt8jsxNEAQqvkEi XrcSmdHK+SpPVQiz7c1X4aBcmHBv21rx1vohljqxcxvdc1TQj/sdvazdSXaHo0IYXHLv 2TH61pa0fSCvroXIW67FQ2PDONkPgzt3hTCwY= 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=JBAZHyd5XgygP1+md+qYdTHi+gwkM0InAuquo+/p7pw=; b=c5ogPVtk3FZcPATft4UrIZjNH6VknpNkgCZ7XYCG1sge8i5tPZQRxpPG1QNADyfp4H 17M7Ts05WhEHRJNPBlVAfzXXqtA8gShEeeZaIa9duhZxBdN8uqSdfkN7f73YrAwNjMQ4 CYc55P3YJ5xEUbvXnJdzfjjJIBHtmz0RQzazDNrFXLASA+nC6/qv/LqU142Y5OES112H n1ztYQoxVVnKmB/tt/Se5vUsQOFYtBlE/CWR5zyhANUkjwLByYZ9FxKC8x2FzZaVOxDW KB5pKUto1vya+AVg7a/x/+IptjhTN2CzY40kaIXLsuo5mJimkVwwjaUmxTyozFH7OKTh tF4Q== X-Gm-Message-State: ACrzQf1GoQcV4zeDLJHp21oO+t2SvwnCX7nB6g5vy1Ln3u1vKz4l/JKK J8DeEuoxamPMFbgmKXvotGCPAHUfteIdOg== X-Google-Smtp-Source: AMsMyM7xxApV806PVXtFa0vJt8qwPTUFrGN2J9Ygw4FEgGsjKhc8iD2VszLWOKTHkYxHQM1X33r19Q== X-Received: by 2002:a0c:b69a:0:b0:4bb:86ec:b8a4 with SMTP id u26-20020a0cb69a000000b004bb86ecb8a4mr956901qvd.86.1666640617566; Mon, 24 Oct 2022 12:43:37 -0700 (PDT) Received: from mail-yw1-f180.google.com (mail-yw1-f180.google.com. [209.85.128.180]) by smtp.gmail.com with ESMTPSA id a138-20020ae9e890000000b006ced196a73fsm456567qkg.135.2022.10.24.12.43.36 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 24 Oct 2022 12:43:36 -0700 (PDT) Received: by mail-yw1-f180.google.com with SMTP id 00721157ae682-36d2188004bso33878137b3.4 for ; Mon, 24 Oct 2022 12:43:36 -0700 (PDT) X-Received: by 2002:a81:2544:0:b0:360:c270:15a1 with SMTP id l65-20020a812544000000b00360c27015a1mr29252227ywl.67.1666640616299; Mon, 24 Oct 2022 12:43:36 -0700 (PDT) MIME-Version: 1.0 References: <6350a5f07bae2_6be12944c@dwillia2-xfh.jf.intel.com.notmuch> In-Reply-To: From: Linus Torvalds Date: Mon, 24 Oct 2022 12:43:20 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: writeback completion soft lockup BUG in folio_wake_bit() To: Tim Chen Cc: Dan Williams , Matthew Wilcox , Brian Foster , Linux-MM , linux-fsdevel , linux-xfs , Hugh Dickins Content-Type: text/plain; charset="UTF-8" ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1666640618; a=rsa-sha256; cv=none; b=ariRm3WtZ4Ab0XiLxxUEcSAnqMTtjbba+FOw5mevz8YjvE4vOR6E/cNHzPlyv8GMlwzZXC sh1t6stqg4KomV7YR4MAcsnSJX+OXY/1Q5Wdv4NYI3YoNRshX/cwhkXsnS/Y90hIriXPz5 jknkxBYAoII7a0chiD/Fgaz+mY6qpUs= ARC-Authentication-Results: i=1; imf17.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=google header.b=WBTb2zVy; dmarc=none; spf=pass (imf17.hostedemail.com: domain of torvalds@linuxfoundation.org designates 209.85.219.47 as permitted sender) smtp.mailfrom=torvalds@linuxfoundation.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1666640618; 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=JBAZHyd5XgygP1+md+qYdTHi+gwkM0InAuquo+/p7pw=; b=YdrIkhzeUNok/93Z5+A75SaGXOTCNw6hF5DjHsaKZK+Ajubff4SQJZsnCyCkFqjqLnEbGs ZuIkXbTmUePNayGmX7PTBJs6il3NuwzrLx0YXRzOdRt+CPjmQ0KHLovXCNHFB8MfXz1EV4 Tpwa+ZMeUAgvGthRf03IJ7I7CyZVfaM= X-Rspam-User: Authentication-Results: imf17.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=google header.b=WBTb2zVy; dmarc=none; spf=pass (imf17.hostedemail.com: domain of torvalds@linuxfoundation.org designates 209.85.219.47 as permitted sender) smtp.mailfrom=torvalds@linuxfoundation.org X-Rspamd-Server: rspam11 X-Stat-Signature: 7zii4j19pzi8y9cde4nr18c9rk5guuhe X-Rspamd-Queue-Id: 851B04001C X-HE-Tag: 1666640618-273073 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: On Mon, Oct 24, 2022 at 12:39 PM Tim Chen wrote: > > I do think that the original locked page on migration problem was fixed > by commit 9a1ea439b16b. Unfortunately the customer did not respond to > us when we asked them to test their workload when that patch went > into the mainline. Oh well. > I don't have objection to Matthew's fix to remove the bookmark code, > now that it is causing problems with this scenario that I didn't > anticipate in my original code. I'd really like to avoid *another* "we can't actually verify that this helps" change in this area, so I'm hoping that the reporter that Dan was talking to could test that patch. Otherwise we're kind of going back-and-forth based on "this might fix things", which just feels really fragile and reminds me of the bad old days when we had the "one step forward, two steps back" dance with some of the suspend/resume issues. I realize that this code needs some extreme loads (and likely pretty special hardware too) to actually become problematic, so testing is _always_ going to be a bit of a problem, but still... Linus