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=-15.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable 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 3AAA4C433DB for ; Wed, 17 Mar 2021 10:06:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E65F264E27 for ; Wed, 17 Mar 2021 10:06:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230327AbhCQKFi (ORCPT ); Wed, 17 Mar 2021 06:05:38 -0400 Received: from mx2.suse.de ([195.135.220.15]:35036 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229767AbhCQKF1 (ORCPT ); Wed, 17 Mar 2021 06:05:27 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 0D497AC1F; Wed, 17 Mar 2021 10:05:26 +0000 (UTC) Date: Wed, 17 Mar 2021 11:05:23 +0100 From: Oscar Salvador To: David Hildenbrand Cc: Andrew Morton , Vlastimil Babka , Michal Hocko , Muchun Song , Mike Kravetz , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Anshuman Khandual Subject: Re: [PATCH v4 0/4] Make alloc_contig_range handle Hugetlb pages Message-ID: <20210317100518.GA16479@linux> References: <20210310150853.13541-1-osalvador@suse.de> <01d2ee6a-f0aa-4580-b1f4-f0e8a2ded4f8@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <01d2ee6a-f0aa-4580-b1f4-f0e8a2ded4f8@redhat.com> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Mar 17, 2021 at 10:48:31AM +0100, David Hildenbrand wrote: > > I was preparing v5, and I wanted to be sure I understood you here. > > > > Right you are that the in-use page check can be dropped, as those pages > > can > > be migrated away, and the Hugetlb page check can also be dropped since > > isolate_migratepages_range is now capable of dealing with those kind of > > pages. > > > > > b) Similarly, check for gigantic pages and/or movability/migratability. > > > > I lost you here. > > > > isolate_or_dissolve_huge_page() already bails out on hugetlb-gigantic > > pages. > > > > Or do you mean to place an upfront check here? (hstate_is_gigantic())? > > Yes. But I prefer a) and keeping it simple here -- just doing basic sanity > checks (online, zone, PageReserved()) that are absolutely necessary. Ok, I am probably dense as I understood as if you were lean towards having a) + b). That is what I have as the last patch of the patchset: >From e97175b7d4970cbdcbafcf8c398f72a571e817b0 Mon Sep 17 00:00:00 2001 From: Oscar Salvador Date: Thu, 18 Mar 2021 05:03:18 +0100 Subject: [PATCH] mm,page_alloc: Drop unnecesary checks from pfn_range_valid_contig pfn_range_valid_contig() bails out when it finds an in-use page or a hugetlb page, among other things. We can drop the in-use page check since __alloc_contig_pages can migrate away those pages, and the hugetlb page check can go too since isolate_migratepages_range is now capable of dealing with hugetlb pages. Signed-off-by: Oscar Salvador --- mm/page_alloc.c | 6 ------ 1 file changed, 6 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 4cb455355f6d..50d73e68b79e 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -8685,12 +8685,6 @@ static bool pfn_range_valid_contig(struct zone *z, unsigned long start_pfn, if (PageReserved(page)) return false; - - if (page_count(page) > 0) - return false; - - if (PageHuge(page)) - return false; } return true; } -- Oscar Salvador SUSE L3