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 A38CCC433EF for ; Mon, 4 Apr 2022 18:28:26 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 377FA6B0071; Mon, 4 Apr 2022 14:28:16 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 326E56B0073; Mon, 4 Apr 2022 14:28:16 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 215DF6B0074; Mon, 4 Apr 2022 14:28:16 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (relay.hostedemail.com [64.99.140.27]) by kanga.kvack.org (Postfix) with ESMTP id 135016B0071 for ; Mon, 4 Apr 2022 14:28:16 -0400 (EDT) Received: from smtpin15.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay13.hostedemail.com (Postfix) with ESMTP id C107160BA7 for ; Mon, 4 Apr 2022 18:28:05 +0000 (UTC) X-FDA: 79320030930.15.C24FFF6 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by imf20.hostedemail.com (Postfix) with ESMTP id 3D4C91C0017 for ; Mon, 4 Apr 2022 18:28:05 +0000 (UTC) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 717D360DB5; Mon, 4 Apr 2022 18:28:04 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 80607C3410F; Mon, 4 Apr 2022 18:28:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1649096883; bh=mXpgbaUOKADPld1qaxP9bMRmsQjHNjEPuGekcdbMNYY=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=v6bjHFt5uljyjHe+ez9sjYIqqF9fzyUmoRru/bYCu24+F2cohePUpzuei3TBWgy6s Pb1gDf6fBUp+xjB8SolqraUeA5F1Dv8BTB2C5BuPVlLsiPTLqtzR1Iu8DX3Yax0aTB HurUYiqNhieSdhd+mULt7cLJfDk7cC8cdUmeJEXA= Date: Mon, 4 Apr 2022 11:28:02 -0700 From: Andrew Morton To: Zi Yan Cc: Zi Yan , linux-mm@kvack.org, Matthew Wilcox , Michal Hocko , Naoya Horiguchi , linux-kernel@vger.kernel.org, Naoya Horiguchi Subject: Re: [PATCH] mm: migrate: use thp_order instead of HPAGE_PMD_ORDER for new page allocation. Message-Id: <20220404112802.4c07585b7b7e420342c9b0fb@linux-foundation.org> In-Reply-To: <20220404165325.1883267-1-zi.yan@sent.com> References: <20220404165325.1883267-1-zi.yan@sent.com> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.33; x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Stat-Signature: qstbxqhj6pzkhpx7he3hd71ptmw95ijg Authentication-Results: imf20.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=v6bjHFt5; dmarc=none; spf=pass (imf20.hostedemail.com: domain of akpm@linux-foundation.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org X-Rspam-User: X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 3D4C91C0017 X-HE-Tag: 1649096885-343495 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 Mon, 4 Apr 2022 12:53:25 -0400 Zi Yan wrote: > From: Zi Yan > > With folios support, it is possible to have other than HPAGE_PMD_ORDER > THPs, in the form of folios, in the system. Use thp_order() to correctly > determine the source page order during migration. Changelog doesn't describe the end user visible effects of the bug. And it really should, because > Link: https://lore.kernel.org/linux-mm/20220404132908.GA785673@u2004/ it fixes a kernel crash!