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 82489C3600C for ; Thu, 3 Apr 2025 05:58:31 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id C4F70280003; Thu, 3 Apr 2025 01:58:29 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id BFDC5280001; Thu, 3 Apr 2025 01:58:29 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id AEE12280003; Thu, 3 Apr 2025 01:58:29 -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 91A5F280001 for ; Thu, 3 Apr 2025 01:58:29 -0400 (EDT) Received: from smtpin18.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 753DA16171A for ; Thu, 3 Apr 2025 05:58:30 +0000 (UTC) X-FDA: 83291677980.18.0F1B895 Received: from out-176.mta1.migadu.com (out-176.mta1.migadu.com [95.215.58.176]) by imf27.hostedemail.com (Postfix) with ESMTP id 86CF040007 for ; Thu, 3 Apr 2025 05:58:28 +0000 (UTC) Authentication-Results: imf27.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=xayL+XCw; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf27.hostedemail.com: domain of ye.liu@linux.dev designates 95.215.58.176 as permitted sender) smtp.mailfrom=ye.liu@linux.dev ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1743659908; a=rsa-sha256; cv=none; b=8cpPL+K3uXRZgRce5M5TXcQpZUGpRE4G/yX7Z6qn0itYyFiCLylOAZM5aKIkB7OJSYI+vd ETLogmcKfhqJ5Zian6QIRu61P0ZSKvLZTSLXNIzLK0MolnRZYSsA7Urroc+rLG5EAJ0JVc PrPZwmCPLawDXpcWM/JPwCv5uAL7fWA= ARC-Authentication-Results: i=1; imf27.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=xayL+XCw; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf27.hostedemail.com: domain of ye.liu@linux.dev designates 95.215.58.176 as permitted sender) smtp.mailfrom=ye.liu@linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1743659908; 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=z4j7PhN7Wup2fYwx3gBiSsMabuOB6a6FQW9/Vz5nkMk=; b=wQ4HBIY2paMAmbd1MWa1cNvtJjp0bvD4NUeuniXYGKHkoTwcYhvaV3+wML1zvKj2nhnfPV Iq6hrDEJEd9VbbDuN7CPMxCZOVHcEVgOPmH/QYHIJFrRkpU23aYB38vRfrz58y5Ll+hjDd L2piUaBdyQ19NNJ8HlmC/5pYaZW+65M= Message-ID: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1743659906; 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=z4j7PhN7Wup2fYwx3gBiSsMabuOB6a6FQW9/Vz5nkMk=; b=xayL+XCw9AqSEOzvQvWTAwKzx9GstCLM1h1BXL2Si7vcCmNaWQRJEKCzJc+Q/EATqCRgbD IB1w1EilAXBTs2x0toxWhPVLZXX2c+vUAfHwf8fnwLu4Z9DmiA64soBZkmeHuhUYhoLfVz ZmsGloM3c0IbrAzzfcePV6eOuSQTi8I= Date: Thu, 3 Apr 2025 13:58:10 +0800 MIME-Version: 1.0 Subject: Re: [PATCH v4] mm/page_alloc: Consolidate unlikely handling in page_expected_state To: "Vishal Moola (Oracle)" Cc: Matthew Wilcox , akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Markus.Elfring@web.de, Ye Liu , Sidhartha Kumar , Anshuman Khandual References: <20250328014757.1212737-1-ye.liu@linux.dev> <8720c775-c0fb-4fbf-a1a8-409fef2b67ad@linux.dev> <6cd78595-f9d3-4f26-8ca3-d1a0bf4e8dff@linux.dev> Content-Language: en-US X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Ye Liu In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Rspam-User: X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: 86CF040007 X-Stat-Signature: ypdq8dg3fafu4nr5w8x5ya3kthe9zdfb X-HE-Tag: 1743659908-402514 X-HE-Meta: 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 uWh9iHmQ FWtQyPCRTPVBEcWrN4YaqVZDP42EEAVqe48O2Aot+EDbAZaAujDDEE3tRiDshIzi/bVRCHfCIAglTSMvDkyVJ8aTk/DXFSUKL+tepc0KI0zQ8Aw4rc+FJVX1SOu7jKnRlJDTMQJ191QlynlNifYq+Q2ou8OUFvjYX0CrfXKf4bUhb+iTizA2jYbNEQiUMDMCmLuLBtRj8iHr3Vi7ojTNXn12byr3imYwSeNSlvCHJEpTrl6c+/RHmpPXkYa21A4tZNMZ0J3Wh9xWBz35vlUB1iqLnUHEKIk5p6Zlmjwct3UNjyVM93q19EC/J/wTqvT+LehNZ8Vq7rPCArYU= 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: List-Subscribe: List-Unsubscribe: 在 2025/4/3 11:55, Vishal Moola (Oracle) 写道: > On Wed, Apr 02, 2025 at 10:49:17AM +0800, Ye Liu wrote: >> 在 2025/3/31 23:59, Matthew Wilcox 写道: >>> On Mon, Mar 31, 2025 at 08:08:01PM +0800, Ye Liu wrote: >>>> 在 2025/3/28 22:29, Matthew Wilcox 写道: >>>>> On Fri, Mar 28, 2025 at 09:47:57AM +0800, Ye Liu wrote: >>>>>> Consolidate the handling of unlikely conditions in the >>>>>> page_expected_state() function to reduce code duplication and improve >>>>>> readability. >>>>> I don't think this is an equivalent transformation. >>>> Could you explain it in detail? >>> page_expected_state() is called both at free and alloc. I think >>> the correct behaviour on encountering a HWPOISON page should be >>> different at alloc and free, don't you? >> In the alloc process, this patch does not modify the code behavior. >> Regarding the free process, the if (unlikely(PageHWPoison(page)) && !order) >> code handles the case where order is 0. When order is not 0, it does not >> matter if __ClearPageBuddy is used to process the last page of the compound >> page, because page->flags &= ~PAGE_FLAGS_CHECK_AT_PREP; will also clear it. >> Is that right?                                                              > I believe a page's "Buddy" flag is stored in page->type, so maybe this > won't do what you expect? Got it, thanks! I originally thought that page->page_type would also be cleared in the free process, meaning the free behavior wouldn't change, but that’s not actually the case. I need to look into what impact it would have if __ClearPageBuddy is also executed in the free process.    Thanks, Ye Liu