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 3CD1EC98314 for ; Thu, 24 Sep 2026 07:31:55 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 4EC0E6B0099; Thu, 24 Sep 2026 03:31:54 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 4C55D6B009B; Thu, 24 Sep 2026 03:31:54 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3DA596B009D; Thu, 24 Sep 2026 03:31:54 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id 156D96B0099 for ; Thu, 24 Sep 2026 03:31:54 -0400 (EDT) Received: from smtpin04.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay02.hostedemail.com (Postfix) with ESMTP id 95638120253 for ; Thu, 24 Sep 2026 07:31:53 +0000 (UTC) X-FDA: 85247836506.04.19030B4 Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf18.hostedemail.com (Postfix) with ESMTP id CA16E1C000B for ; Thu, 24 Sep 2026 07:31:51 +0000 (UTC) Authentication-Results: imf18.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=hkx27hRc; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf18.hostedemail.com: domain of david@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=david@kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1790235111; 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=+8q2JgeXQNfzhUF8cZaw85JDPDtRQeG2PJ5xPgrb8xI=; b=nbmj3Jb30RPo4gyw6o/yv4ny/SbPw3lfe/LpsZabXHJ1KSom8gXKo0SwMBPrXtwqU2+DFU LDfVJFKiBJsZfvXiURhd2zIToLmXefJ2dj2BcJjN7JkTObagycZ2yL8oZO1F6BoNdS9NNh Jg9nIBsqRcZbLQinVbcpovSQmVZo8cc= ARC-Authentication-Results: i=1; imf18.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=hkx27hRc; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf18.hostedemail.com: domain of david@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=david@kernel.org ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1790235111; b=VgsxM4JoODUXKG/MRxjAXo+cXfPKuW8f9mmOFYBhqZumI7NEBMop3S0Uo/NW+sBnrS6YBI BjfFVaCycQ52v1eY3aLM4lNq75ybvtbzkSZEaMhsM2tmUsjDGAm2pC4m19cotD4HAA3XSa VGpYTi6mjHnlojFIWSDGcr3k2KzqaFY= Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id BC4A0409E6; Thu, 24 Sep 2026 07:31:50 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C62DE1F000FF; Thu, 24 Sep 2026 07:31:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790235110; bh=+8q2JgeXQNfzhUF8cZaw85JDPDtRQeG2PJ5xPgrb8xI=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=hkx27hRcSqTkoEnzeb7acRmFdXIjYpNTSJf289b+3leAYFv0xoj8yCI+7A9tt1aGO 5zUX9PNaPjpswp6VGyERjPAepkP8JW73ehHI0SPXMdm19L5Ov4jT9S9odhmdmuvsne aroBirTZFHgD+lnRpGxqGpd1ugvrnLNQx4kH012ASoytHEuxkGxr8f9HMg4xH5CUTl OYgx+qvEXaLDLgmHR/xEYTuJS/M55xcSxMCO/jQcZdT/vdEOyjkXXeDYJIt5N97GX0 rfvvVC6ySnjb+Cmog48Wm1J1qL9NAh+u8Giy9slS3U9fKyht66lWK/iKJ1rKtKAA6I uMGfGGKVZDAFg== Message-ID: <65b94694-d503-46c5-9f13-f0f7f8bba8d8@kernel.org> Date: Thu, 24 Sep 2026 09:31:40 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] mm: don't defer freeing kernel page tables while booting To: Mikhail Gavrilov Cc: Andrew Morton , Dave Hansen , Lorenzo Stoakes , "Liam R . Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Vishal Moola , Ingo Molnar , Lu Baolu , Jason Gunthorpe , Steven Rostedt , x86@kernel.org, linux-mm@kvack.org, regressions@lists.linux.dev, linux-kernel@vger.kernel.org References: <41a59ba9-039e-454f-8d31-f647db802ada@kernel.org> <20260924072819.33277-1-mikhail.v.gavrilov@gmail.com> 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: <20260924072819.33277-1-mikhail.v.gavrilov@gmail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Stat-Signature: 6fis9n1obhptoajf1dtzde6aeuswwi1b X-Rspam-User: X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: CA16E1C000B X-HE-Tag: 1790235111-507245 X-HE-Meta: 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 EqXeet44 +3z8hFshUSL+zaoub+3kaA8vtAymaEaZqqBQoxqSoq3Ze6znHWmCGWQp7aJfSqsFiqviOP2sa7DYkUqELmbX4Jhu+mQefEd06Rm+8p8M8rEYJgYZ8QKJsgU/dZdspkXAGUz6Z7xCN3pq2ne944mmsVNfBiYodW8tNaV+BXlEyiD5tfp0fTPi2EAcZOEpyLaOU6VvNM/URH4WVyI362qrsAdyElVa9Fhc/OCruYNeanwzLWp0WKnC16rhtVrS0nqnXqTBSa9AbT3dzApb8AuYUqTl1vUw33/oB+tEYJKOGFIcvPIBt5xURKKFwylRLxLUMMjb+aW0e0+BFfm60JJVcN9Z0Pg== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 9/24/26 09:28, Mikhail Gavrilov wrote: > On 9/24/26 09:07, David Hildenbrand (Arm) wrote: >> Should we instead simply skip the >> >> schedule_work(&kernel_pgtable_work.work); >> >> and rely on anybody freeing stuff later to just free that one alongside? >> >> That avoids throwing in more freeing handling. > > Yes, that is simpler, and the early table then goes through the same > IOMMU flush as every other one, so there is no need to reason about > what an IOMMU can see during boot. The only cost is that it waits on > the list until the next kernel page table is freed after boot. If we're worried about that actually causing problems we could drain the list at a later part during the boot stage. I'd suspect we free something else later already and simply drain the list ... -- Cheers, David