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]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 9BB39CD484A for ; Mon, 11 May 2026 13:05:52 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id CE0636B00B0; Mon, 11 May 2026 09:05:51 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id C90F16B00B1; Mon, 11 May 2026 09:05:51 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B80266B00B2; Mon, 11 May 2026 09:05:51 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id A3DFF6B00B0 for ; Mon, 11 May 2026 09:05:51 -0400 (EDT) Received: from smtpin23.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay06.hostedemail.com (Postfix) with ESMTP id 2E6C31C05F9 for ; Mon, 11 May 2026 13:05:51 +0000 (UTC) X-FDA: 84755161302.23.0B5F8E5 Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf21.hostedemail.com (Postfix) with ESMTP id 570E81C0005 for ; Mon, 11 May 2026 13:05:49 +0000 (UTC) Authentication-Results: imf21.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=tDDYWlLU; spf=pass (imf21.hostedemail.com: domain of david@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=david@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1778504749; 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:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=HmvNkne3o759PCjy6fQT+2QRCqCgKE98+uXhfCTILYY=; b=LVLoEpaqBZ+HcRAFMbkueKOVJhsqCCrVfasno7aHh5EcNA5r+oSNEhOjQhoz38kW0CMrBW 94bBvA1xlvu++Oh/abjAm6NTEftd0ffhOZH0FcW5SzlIvsGpfRDrVEHBMoUUUlCAM9JUF/ 8xrbbFaMAjd9nj7nL504jY4K+ReDfpI= ARC-Authentication-Results: i=1; imf21.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=tDDYWlLU; spf=pass (imf21.hostedemail.com: domain of david@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=david@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1778504749; a=rsa-sha256; cv=none; b=5psIIMHgy6SK1+hkEjrESM3pk6+ByEfwohQJOStjPar9zjyjdohQIlypc4URsctPNg0fSD imCTQcyEckQZd7QnqHtq7B/dZ6k5kPQdilCye6OZ2IucnWsaPMKk7111nSGW5dlQQbUtvP mpoE1DAQHiVANolhPTXL7NOCNe20Mys= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id 36C87418D6; Mon, 11 May 2026 13:05:48 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A3B48C2BCB0; Mon, 11 May 2026 13:05:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1778504748; bh=D4TZ2PDbQ1D4kjvzq/nrJ+Uq6CeX3FneZzCQz8PjBeo=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=tDDYWlLU6lMBmIRR99eo79X8GJzcf/TVADyvfp3K4/zs7YokACeF1tOsC947D162J JNxZC0BnVx4IZGnIM6dL4UXmE7Tz5c36rdrkb/pNiRKxHojvEMS1JGVEaOI95wPXJq Wro67TeQLzRvccM4SvXngRjGeZBKPxYJo2Xj7Q2BUYV0pn3korL6Kt3FVaei9ghdyL +HHzQhYKaltX2xrJVj4JO3KPWQOgYdInXEw5NFY0kdbel72ut0cPRW4/8iTaBuHVPs +Q0dH/8Bou1kJbS2k4a/5b7K2yaPpCmv56aTRPnYuOAduo5DX4oxCOPyhH4RvV5Qpp uxo6JudqRrdHA== Message-ID: <4df23f32-c538-4755-a1c9-be8559a103a3@kernel.org> Date: Mon, 11 May 2026 15:05:44 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v1 2/3] mm: process_mrelease: skip LRU movement for exclusive file folios To: "Liam R. Howlett" Cc: Michal Hocko , Minchan Kim , Suren Baghdasaryan , akpm@linux-foundation.org, hca@linux.ibm.com, linux-s390@vger.kernel.org, brauner@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, timmurray@google.com, "Liam R. Howlett" References: <7f98f461-62a7-455d-a7a8-cb8928465946@kernel.org> <4a612d63-2838-40f5-ab67-79bf35dd3a56@kernel.org> <7g5g57jbll5joujbwjb4osqhdwqd4yzc54wmoi7ftx4a4chuax@xtxyljtqaodp> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; keydata= xsFNBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzS5EYXZpZCBIaWxk ZW5icmFuZCAoQ3VycmVudCkgPGRhdmlkQGtlcm5lbC5vcmc+wsGQBBMBCAA6AhsDBQkmWAik AgsJBBUKCQgCFgICHgUCF4AWIQQb2cqtc1xMOkYN/MpN3hD3AP+DWgUCaYJt/AIZAQAKCRBN 3hD3AP+DWriiD/9BLGEKG+N8L2AXhikJg6YmXom9ytRwPqDgpHpVg2xdhopoWdMRXjzOrIKD g4LSnFaKneQD0hZhoArEeamG5tyo32xoRsPwkbpIzL0OKSZ8G6mVbFGpjmyDLQCAxteXCLXz ZI0VbsuJKelYnKcXWOIndOrNRvE5eoOfTt2XfBnAapxMYY2IsV+qaUXlO63GgfIOg8RBaj7x 3NxkI3rV0SHhI4GU9K6jCvGghxeS1QX6L/XI9mfAYaIwGy5B68kF26piAVYv/QZDEVIpo3t7 /fjSpxKT8plJH6rhhR0epy8dWRHk3qT5tk2P85twasdloWtkMZ7FsCJRKWscm1BLpsDn6EQ4 jeMHECiY9kGKKi8dQpv3FRyo2QApZ49NNDbwcR0ZndK0XFo15iH708H5Qja/8TuXCwnPWAcJ DQoNIDFyaxe26Rx3ZwUkRALa3iPcVjE0//TrQ4KnFf+lMBSrS33xDDBfevW9+Dk6IISmDH1R HFq2jpkN+FX/PE8eVhV68B2DsAPZ5rUwyCKUXPTJ/irrCCmAAb5Jpv11S7hUSpqtM/6oVESC 3z/7CzrVtRODzLtNgV4r5EI+wAv/3PgJLlMwgJM90Fb3CB2IgbxhjvmB1WNdvXACVydx55V7 LPPKodSTF29rlnQAf9HLgCphuuSrrPn5VQDaYZl4N/7zc2wcWM7BTQRVy5+RARAA59fefSDR 9nMGCb9LbMX+TFAoIQo/wgP5XPyzLYakO+94GrgfZjfhdaxPXMsl2+o8jhp/hlIzG56taNdt VZtPp3ih1AgbR8rHgXw1xwOpuAd5lE1qNd54ndHuADO9a9A0vPimIes78Hi1/yy+ZEEvRkHk /kDa6F3AtTc1m4rbbOk2fiKzzsE9YXweFjQvl9p+AMw6qd/iC4lUk9g0+FQXNdRs+o4o6Qvy iOQJfGQ4UcBuOy1IrkJrd8qq5jet1fcM2j4QvsW8CLDWZS1L7kZ5gT5EycMKxUWb8LuRjxzZ 3QY1aQH2kkzn6acigU3HLtgFyV1gBNV44ehjgvJpRY2cC8VhanTx0dZ9mj1YKIky5N+C0f21 zvntBqcxV0+3p8MrxRRcgEtDZNav+xAoT3G0W4SahAaUTWXpsZoOecwtxi74CyneQNPTDjNg azHmvpdBVEfj7k3p4dmJp5i0U66Onmf6mMFpArvBRSMOKU9DlAzMi4IvhiNWjKVaIE2Se9BY FdKVAJaZq85P2y20ZBd08ILnKcj7XKZkLU5FkoA0udEBvQ0f9QLNyyy3DZMCQWcwRuj1m73D sq8DEFBdZ5eEkj1dCyx+t/ga6x2rHyc8Sl86oK1tvAkwBNsfKou3v+jP/l14a7DGBvrmlYjO 59o3t6inu6H7pt7OL6u6BQj7DoMAEQEAAcLBfAQYAQgAJgIbDBYhBBvZyq1zXEw6Rg38yk3e EPcA/4NaBQJonNqrBQkmWAihAAoJEE3eEPcA/4NaKtMQALAJ8PzprBEXbXcEXwDKQu+P/vts IfUb1UNMfMV76BicGa5NCZnJNQASDP/+bFg6O3gx5NbhHHPeaWz/VxlOmYHokHodOvtL0WCC 8A5PEP8tOk6029Z+J+xUcMrJClNVFpzVvOpb1lCbhjwAV465Hy+NUSbbUiRxdzNQtLtgZzOV Zw7jxUCs4UUZLQTCuBpFgb15bBxYZ/BL9MbzxPxvfUQIPbnzQMcqtpUs21CMK2PdfCh5c4gS sDci6D5/ZIBw94UQWmGpM/O1ilGXde2ZzzGYl64glmccD8e87OnEgKnH3FbnJnT4iJchtSvx yJNi1+t0+qDti4m88+/9IuPqCKb6Stl+s2dnLtJNrjXBGJtsQG/sRpqsJz5x1/2nPJSRMsx9 5YfqbdrJSOFXDzZ8/r82HgQEtUvlSXNaXCa95ez0UkOG7+bDm2b3s0XahBQeLVCH0mw3RAQg r7xDAYKIrAwfHHmMTnBQDPJwVqxJjVNr7yBic4yfzVWGCGNE4DnOW0vcIeoyhy9vnIa3w1uZ 3iyY2Nsd7JxfKu1PRhCGwXzRw5TlfEsoRI7V9A8isUCoqE2Dzh3FvYHVeX4Us+bRL/oqareJ CIFqgYMyvHj7Q06kTKmauOe4Nf0l0qEkIuIzfoLJ3qr5UyXc2hLtWyT9Ir+lYlX9efqh7mOY qIws/H2t In-Reply-To: <7g5g57jbll5joujbwjb4osqhdwqd4yzc54wmoi7ftx4a4chuax@xtxyljtqaodp> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Stat-Signature: zt1rnbb4jgt4ipdbgknadtfraewszo75 X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 570E81C0005 X-Rspam-User: X-HE-Tag: 1778504749-493372 X-HE-Meta: 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 wnDZQkjh YYNtA0C4dSxzqfNJsbldayzJNFW9oZupsgzd6HPpMSdIWoU6z9nhRFfiNDjwcdJvZXh7iZ8ngyNFkNplNr32FunfgrJ+wi3iR0J0tJOrmse9hrz2UtKozbsm42VKTklfx8fArrNOUnQCbNuc7nY8FLHFHdb9NhexrmTGp8izGpl+ALOLruJ7gMpcJqPd6ef9oVBhK1lnOXWwudllHe3hkNF1p3iWr0CfdzKeDuVayJVO2qnz9oER26wBtgtx70gj9spsvuSRl67hLZr6oUmPX8EjGkCUhMrkdh14ntRre4gbtJ7jii5Ybyo9I2A== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: >> >> But we'd have to learn from Liam :) > > Yes, it will be a zero entry tree now. > > I left the flag to indicate that it's an unstable mm, not for faulting > in but to be skipped in OOM events and process_mrelease since neither > should bother doing anything in the window between the dup_mm() failure > and the exit_mmap() window where the write lock was dropped. > > We can safely drop the flag now if you want to, because everything has > to deal with an empty vma tree anyways - a race can occur between a call > to unmap everything and the task seg faulting. Thanks for confirming! > >> >> >>> >>> The bottom line is the same. Make sure PF fails rather than silently >>> provide potentially corrupted data. >>> >>> >>> Ohh, you mean to add a new flag, right? >> >> We could do that as well, if it's of any help. > > I really think this goes back to the life cycle of the mm being somewhat > difficult to figure out. Agreed. > I'm fine with another flag. Right, alternatively we could just turn the unstable flag into a "OOM is hiding in the bushes to reap this MM". -- Cheers, David