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 23DDBCDB46E for ; Thu, 12 Oct 2023 09:36:54 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 9A71F8D011D; Thu, 12 Oct 2023 05:36:53 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 957118D0002; Thu, 12 Oct 2023 05:36:53 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 8453B8D011D; Thu, 12 Oct 2023 05:36:53 -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 72F0A8D0002 for ; Thu, 12 Oct 2023 05:36:53 -0400 (EDT) Received: from smtpin19.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay03.hostedemail.com (Postfix) with ESMTP id 450C7A05D6 for ; Thu, 12 Oct 2023 09:36:53 +0000 (UTC) X-FDA: 81336305106.19.BD4048B Received: from out-207.mta1.migadu.com (out-207.mta1.migadu.com [95.215.58.207]) by imf21.hostedemail.com (Postfix) with ESMTP id 6DEBB1C0017 for ; Thu, 12 Oct 2023 09:36:51 +0000 (UTC) Authentication-Results: imf21.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=M2oWhf1W; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf21.hostedemail.com: domain of yajun.deng@linux.dev designates 95.215.58.207 as permitted sender) smtp.mailfrom=yajun.deng@linux.dev ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1697103411; a=rsa-sha256; cv=none; b=jBy4mgTxam67QvOiyeL7UNs4RbTpRnQiub9dsgs3U5hILJpTL7bbfWjxuixpgfkbOxQ3wC uSdSPBEX4etbd3IfhOJIWnRKBw7iYpy3szRZ4zt8WEK4BR1UVUIPqZ8a2k1DQObHiQYCOu K7EaiefOL1himwOdUpzBgslxHDrWkTA= ARC-Authentication-Results: i=1; imf21.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=M2oWhf1W; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf21.hostedemail.com: domain of yajun.deng@linux.dev designates 95.215.58.207 as permitted sender) smtp.mailfrom=yajun.deng@linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1697103411; 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=ZJ7Hvxze07BnW+iLsUmdQvphJeSNuEhC6cbejDQqx+I=; b=1Q1CoqXV3pNf/cMFCB71adiZh2lA1nLWvuo5t/CUM9Me/EzecrqIao04ha1k4vPMSev/Ib tWflAWTT2roNk1u8D3hJsQALhmuKZXuljoHiDLvAE5pozQ8WBud4qx5ffrSDFCG10hsFqt 6qAxRfivv6xSG7KXujqpo8MhbNcx5QA= Message-ID: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1697103409; h=from:from: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; bh=ZJ7Hvxze07BnW+iLsUmdQvphJeSNuEhC6cbejDQqx+I=; b=M2oWhf1WUsxDITd54dPtMLI0p3RWx+acBeFB5GSpNUhWhAGw1KPbjcG2VQrdbLyqgBC0gH KJS7kna6ZLAum46fmEE7Xp+j/LMMue+3QAAseUsK71VQEKViOAeqaiHh/4w8KAoWAa5wtc dKqc2eV2+sFyCv1qemE4x1zsTydVCuE= Date: Thu, 12 Oct 2023 17:36:40 +0800 MIME-Version: 1.0 Subject: Re: [PATCH v4 2/2] mm: Init page count in reserve_bootmem_region when MEMINIT_EARLY Content-Language: en-US To: Mike Rapoport Cc: David Hildenbrand , akpm@linux-foundation.org, mike.kravetz@oracle.com, muchun.song@linux.dev, willy@infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <15233624-f32e-172e-b2f6-7ca7bffbc96d@linux.dev> <20231001185934.GX3303@kernel.org> <90342474-432a-9fe3-2f11-915a04f0053f@linux.dev> <20231002084708.GZ3303@kernel.org> <20231002111051.GA3303@kernel.org> <3057dab3-19f2-99ca-f125-e91a094975ed@redhat.com> <8c9ee3bd-6d71-4111-8f4e-91bc52b42ed4@linux.dev> <20231005050619.GB3303@kernel.org> <6545ac4c-1205-6c09-49ea-e00c24d1a2ff@linux.dev> <20231012091906.GQ3303@kernel.org> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Yajun Deng In-Reply-To: <20231012091906.GQ3303@kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Rspam-User: X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 6DEBB1C0017 X-Stat-Signature: k7hgmchiwd7picwankzkrmweqzoy7zx6 X-HE-Tag: 1697103411-732317 X-HE-Meta: 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 r7AZ1iwb FtQ8eX7rNTiHyGwLiFrmsyO5390w6+Vg+LEHTWMNWi27wEs64RJqlgm7hJl57KhKTg94odv5dIB1MZQI/GmwgYxrWWev+jT92Q33nS0NyGYdRK9kv4D/RgtgUIsMrHvNgj7+W 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 2023/10/12 17:19, Mike Rapoport wrote: > On Thu, Oct 05, 2023 at 10:04:28PM +0800, Yajun Deng wrote: >>>>>>>> That 'if' breaks the invariant that __free_pages_core is >>>>>>>> always called for pages with initialized page count. Adding >>>>>>>> it may lead to subtle bugs and random memory corruption so we >>>>>>>> don't want to add it at the first place. >>>>>>> As long as we have to special-case memory hotplug, we know that >>>>>>> we are always coming via generic_online_page() in that case. We >>>>>>> could either move some logic over there, or let >>>>>>> __free_pages_core() know what it should do. >>>>>> Looks like the patch rather special cases MEMINIT_EARLY, although >>>>>> I didn't check throughfully other code paths. Anyway, relying on >>>>>> page_count() to be correct in different ways for different >>>>>> callers of __free_pages_core() does not sound right to me. >>>>> Absolutely agreed. >>>>> >>>> I already sent v5  a few days ago. Comments, please... >>> Does it address all the feedback from this thread? >> Except hotplug. > Please reread carefully the last comments from me and from David above. > I replied in another thread about that 'if' statement. David just replied to me, let's discuss in another thread.