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 6A81CC433FE for ; Wed, 26 Oct 2022 09:25:36 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id E28178E0002; Wed, 26 Oct 2022 05:25:35 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id DD7DD8E0001; Wed, 26 Oct 2022 05:25:35 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id CC6B48E0002; Wed, 26 Oct 2022 05:25:35 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id BFF638E0001 for ; Wed, 26 Oct 2022 05:25:35 -0400 (EDT) Received: from smtpin17.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id 9B4D2120EF9 for ; Wed, 26 Oct 2022 09:25:35 +0000 (UTC) X-FDA: 80062567830.17.06002BC Received: from outbound-smtp24.blacknight.com (outbound-smtp24.blacknight.com [81.17.249.192]) by imf02.hostedemail.com (Postfix) with ESMTP id EF0AB8000B for ; Wed, 26 Oct 2022 09:25:34 +0000 (UTC) Received: from mail.blacknight.com (pemlinmail01.blacknight.ie [81.17.254.10]) by outbound-smtp24.blacknight.com (Postfix) with ESMTPS id ECAB6C0FA1 for ; Wed, 26 Oct 2022 10:25:31 +0100 (IST) Received: (qmail 23250 invoked from network); 26 Oct 2022 09:25:31 -0000 Received: from unknown (HELO techsingularity.net) (mgorman@techsingularity.net@[84.203.198.246]) by 81.17.254.9 with ESMTPSA (AES256-SHA encrypted, authenticated); 26 Oct 2022 09:25:31 -0000 Date: Wed, 26 Oct 2022 10:25:29 +0100 From: Mel Gorman To: Hugh Dickins Cc: Tvrtko Ursulin , "Matthew Wilcox (Oracle)" , Linux MM , Matthew Auld , Andrew Morton , "Intel-gfx@lists.freedesktop.org" Subject: Re: mm/huge_memory: do not clobber swp_entry_t during THP split Message-ID: <20221026092529.xia2nug2b2yijfws@techsingularity.net> References: <1596edbb-02ad-6bdf-51b8-15c2d2e08b76@linux.intel.com> <20221024142321.f2etddxtqa47bib7@techsingularity.net> <8d9517cc-6fba-ede0-a95f-e9b036e75ceb@linux.intel.com> <20221025100338.zcvqyji5gwiuj3nj@techsingularity.net> <831c3f2f-97c6-608d-9d16-1742c447c7e@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <831c3f2f-97c6-608d-9d16-1742c447c7e@google.com> ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1666776335; 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; bh=CFGa1vAsDxQqNdFK2HR4WMZmQVrp0vBFdvo8FNwrFXI=; b=VUj7ZiKX1W1/BSyzyj3pOG+sF2x0VQBc5vvgXRb19nwsbOxaVQ5fwQ6CHoE7tBePJwYd3n k7D09M1L142X6pAMq7WKLckFULcC8yfd4+6ZAI48lR1D2Sg8KeWnWoj8wdvRl2h+trRXiI ewVp5DxUHF1ib9nQS5W/k3JBfrmN2m8= ARC-Authentication-Results: i=1; imf02.hostedemail.com; dkim=none; dmarc=none; spf=pass (imf02.hostedemail.com: domain of mgorman@techsingularity.net designates 81.17.249.192 as permitted sender) smtp.mailfrom=mgorman@techsingularity.net ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1666776335; a=rsa-sha256; cv=none; b=hQbqCkBxkrEQvuHnYfggFzxJBf1tiwQA/i2qcGvoKRDX4uyXMj2dFbCNbh9FMAR/oj8QPN TOOFy7EvfrlZGNxFIA0NeX62LO67Ps4iqWkHC0euwRfQPxXN99/goyRkDzkHjMfYRG69Ke jYYu2oFRrCAeGiiKAb5fc3S8AgwscYk= X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: EF0AB8000B X-Rspam-User: Authentication-Results: imf02.hostedemail.com; dkim=none; dmarc=none; spf=pass (imf02.hostedemail.com: domain of mgorman@techsingularity.net designates 81.17.249.192 as permitted sender) smtp.mailfrom=mgorman@techsingularity.net X-Stat-Signature: htwnbnkn1xom5zskkspaz7m3co1d1gs3 X-HE-Tag: 1666776334-768436 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 Tue, Oct 25, 2022 at 08:26:06AM -0700, Hugh Dickins wrote: > > > > > If so I > > > can temporarily put it in until it arrives via the next rc - assuming that > > > would be the flow from upstream pov? > > The right thing for now is for GregKH to drop Mel's from 6.0.4: > I've just sent a mail asking for that (I would have asked yesterday, > but mistook that GregKH was not in Cc). > Thanks for catching that, I only saw the mail this morning that it had been picked up as a stable candidate and was internally screaming "no no no" until I saw your mail :P. I added the warning thinking "we have almost a full rc cycle to catch any additional fallout". > Of course Mel's fix is much more important than the harmless > (unless panic on warn) warning, but let's delay it a few more days, > it just flowed into stable too quickly. > > Thanks Mel: I never knowingly hit the THP_SWAP issue which your patch > is fixing, but it now looks like it was also responsible for mysterious > occasional OOM kills that I had been chasing for weeks. > I'm glad it helped! I worried that the additional warning would trigger an excessive number of new bugs but it served its intended purpose -- catch fallout from clobbering page->private causing subtle bugs later that are hard to debug. -- Mel Gorman SUSE Labs