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 X-Spam-Level: X-Spam-Status: No, score=-6.5 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 161A3C5518A for ; Wed, 22 Apr 2020 07:44:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E1DAE206E9 for ; Wed, 22 Apr 2020 07:44:31 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="nB6Trxxb" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726363AbgDVHob (ORCPT ); Wed, 22 Apr 2020 03:44:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39086 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1726077AbgDVHoa (ORCPT ); Wed, 22 Apr 2020 03:44:30 -0400 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:e::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A997CC03C1A6 for ; Wed, 22 Apr 2020 00:44:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=Vb8WfOWxjm/MnaPsL9+qBHJ7m7UkiiF7A/1WuSmoehQ=; b=nB6TrxxbQTqxLF5B0N1QGMH7hG JnJatWxU+DRoPVQufO2OrfkyqKD3UldhS15OhvCZYRbjlDd2+vPnuTpJV9V8v01tSq7W6UprQrVuV HsCJ4HPKoVThhuZOoabk3f/M5N+5kqBULHmez6VPQQuBZ7wQRdOUyAWEHSewmg1Sl6xd+KRjNpQSe F14wd7uuU72dlOyl2hhozvCnSOTn9mlkXKorGX30H0vWa8bTGl4AyIFJFP0vK5fJpxkznyF4YcJKQ +D3LGbgp9zr8QVpCAMIZ7PCB9/zizqOUSYQ0/nfDsXIn5HfU0ByQHQ4mWCvobuhWa9W8rnaFplNvV aors5CRA==; Received: from hch by bombadil.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1jRA3T-0003kL-Ho; Wed, 22 Apr 2020 07:44:23 +0000 Date: Wed, 22 Apr 2020 00:44:23 -0700 From: Christoph Hellwig To: js1304@gmail.com Cc: Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Vlastimil Babka , Laura Abbott , "Aneesh Kumar K . V" , Mel Gorman , Michal Hocko , Johannes Weiner , Roman Gushchin , Minchan Kim , Rik van Riel , Christian Koenig , Huang Rui , Eric Biederman , "Rafael J . Wysocki" , Pavel Machek , Joonsoo Kim Subject: Re: [PATCH 03/10] mm/migrate: separate PageHighMem() and PageHighMemZone() use case Message-ID: <20200422074423.GA12288@infradead.org> References: <1587369582-3882-1-git-send-email-iamjoonsoo.kim@lge.com> <1587369582-3882-4-git-send-email-iamjoonsoo.kim@lge.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1587369582-3882-4-git-send-email-iamjoonsoo.kim@lge.com> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Apr 20, 2020 at 04:59:35PM +0900, js1304@gmail.com wrote: > From: Joonsoo Kim > > Until now, PageHighMem() is used for two different cases. One is to check > if there is a direct mapping for this page or not. The other is to check > the zone of this page, that is, weather it is the highmem type zone or not. > > Now, we have separate functions, PageHighMem() and PageHighMemZone() for > each cases. Use appropriate one. > > Note that there are some rules to determine the proper macro. > > 1. If PageHighMem() is called for checking if the direct mapping exists > or not, use PageHighMem(). > 2. If PageHighMem() is used to predict the previous gfp_flags for > this page, use PageHighMemZone(). The zone of the page is related to > the gfp_flags. > 3. If purpose of calling PageHighMem() is to count highmem page and > to interact with the system by using this count, use PageHighMemZone(). > This counter is usually used to calculate the available memory for an > kernel allocation and pages on the highmem zone cannot be available > for an kernel allocation. > 4. Otherwise, use PageHighMemZone(). It's safe since it's implementation > is just copy of the previous PageHighMem() implementation and won't > be changed. > > I apply the rule #2 for this patch. > > Signed-off-by: Joonsoo Kim > --- > include/linux/migrate.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/include/linux/migrate.h b/include/linux/migrate.h > index 3e546cb..9a57766 100644 > --- a/include/linux/migrate.h > +++ b/include/linux/migrate.h > @@ -47,7 +47,7 @@ static inline struct page *new_page_nodemask(struct page *page, > order = HPAGE_PMD_ORDER; > } > > - if (PageHighMem(page) || (zone_idx(page_zone(page)) == ZONE_MOVABLE)) > + if (PageHighMemZone(page) || zone_idx(page_zone(page)) == ZONE_MOVABLE) > gfp_mask |= __GFP_HIGHMEM; I think this would be much cleaner if you open coded PageHighMemZone here. E.g. int zone = page_zone(page); if (is_highmem_idx(zone) || zone_idx(zone) == ZONE_MOVABLE)