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 3AF8FE92703 for ; Thu, 5 Oct 2023 14:06:12 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id A548E8D00BA; Thu, 5 Oct 2023 10:06:11 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id A04BA8D0008; Thu, 5 Oct 2023 10:06:11 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 8CBBE8D00BA; Thu, 5 Oct 2023 10:06:11 -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 7C5CE8D0008 for ; Thu, 5 Oct 2023 10:06:11 -0400 (EDT) Received: from smtpin03.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id 4C7488020E for ; Thu, 5 Oct 2023 14:06:11 +0000 (UTC) X-FDA: 81311582142.03.10E8892 Received: from out-205.mta0.migadu.com (out-205.mta0.migadu.com [91.218.175.205]) by imf10.hostedemail.com (Postfix) with ESMTP id 6F184C0125 for ; Thu, 5 Oct 2023 14:04:39 +0000 (UTC) Authentication-Results: imf10.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=plmD0wnA; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf10.hostedemail.com: domain of yajun.deng@linux.dev designates 91.218.175.205 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=1696514680; 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=czgSb+pm6uNjMEiZ+zLe1URTxhscF82iKhFuHMluZ1o=; b=ROgDy2o8PMlIUrdCNeWcTp/y8AO87jz3PtKiKkf50IeX8m9CwCyVFtcd21zH7yWsVjeYWz 8OCHi1Qn5FFw2mAQgXENHEYbe8brC4oEMmCU5VduY6v13lX+FMq218nwERnFsjohsfd1Ha BPq9WpdtdL1KBTjg2TgW2XnG2OdLuxw= ARC-Authentication-Results: i=1; imf10.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=plmD0wnA; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf10.hostedemail.com: domain of yajun.deng@linux.dev designates 91.218.175.205 as permitted sender) smtp.mailfrom=yajun.deng@linux.dev ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1696514680; a=rsa-sha256; cv=none; b=zLQGcgztD4wxbty+mpiEvnAeuokvWNCAh52FYpHuuFjNacRIbu2Bo2w0osabASKiYQXClh Z7U5ndS4lUFCOaYpJCPY5I89OHroAf1e+8BnzX9pkmbX9d93eRaQF6dF1m8wca+FDt3tLR ZDueZgWdk9QhsZk5Ug4xif1rPEBWqqk= Message-ID: <6545ac4c-1205-6c09-49ea-e00c24d1a2ff@linux.dev> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1696514677; 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=czgSb+pm6uNjMEiZ+zLe1URTxhscF82iKhFuHMluZ1o=; b=plmD0wnAyGVVn6u1f6DP2PD1OQ3xfBXTH2n1KSVIw0vTM9wlyerdB3V9BDsRd7ixuIkh3k waXcprzA8Z/ok/W19GBjZhG28HLF19G97VFOoWwdwCtbepWjT8dt4hz4WJWZDx4qNjr+yZ +5pQBkVsTHH8zmsgKUz0xQacKA9wjoI= Date: Thu, 5 Oct 2023 22:04:28 +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: <20230929100252.GW3303@kernel.org> <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> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Yajun Deng In-Reply-To: <20231005050619.GB3303@kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Rspamd-Queue-Id: 6F184C0125 X-Rspam-User: X-Rspamd-Server: rspam05 X-Stat-Signature: o8pjhfk3gf6jxt59acafngg3fpxy8km7 X-HE-Tag: 1696514679-225562 X-HE-Meta: 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 OYjC64A+ qzFqWXPzInd3I5zhKYWaUb9FQt7avJeZf+N5yADcngsuyrHd6D6sJsANfIyoc/VWwWjS4qHJqvwE6nBgOrJrpV8K4DcEdP5OKYrt9gaLLqnGF7kwR4Qx4/AD+hYtKKyEQ1rfpmymqkDhuBnc= 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 2023/10/5 13:06, Mike Rapoport wrote: > On Tue, Oct 03, 2023 at 10:38:09PM +0800, Yajun Deng wrote: >> On 2023/10/2 19:25, David Hildenbrand wrote: >>> On 02.10.23 13:10, Mike Rapoport 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. As far as I konw, we only clear page count in MEMINIT_EARLY and all tail pages in compound page. So adding 'if (page_count(page))' will have no actual effect for other case. According to previous data, it didn't become slower in hotplug.