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=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_PASS 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 A55F2C43381 for ; Thu, 14 Feb 2019 09:52:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 80630222D2 for ; Thu, 14 Feb 2019 09:52:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388241AbfBNJwK (ORCPT ); Thu, 14 Feb 2019 04:52:10 -0500 Received: from mx2.suse.de ([195.135.220.15]:59322 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S2387579AbfBNJwK (ORCPT ); Thu, 14 Feb 2019 04:52:10 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 2349EADF1; Thu, 14 Feb 2019 09:52:08 +0000 (UTC) Subject: Re: [PATCH v2] hugetlb: allow to free gigantic pages regardless of the configuration To: Dave Hansen , Alexandre Ghiti , Catalin Marinas , Will Deacon , Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Martin Schwidefsky , Heiko Carstens , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H . Peter Anvin" , x86@kernel.org, Dave Hansen , Andy Lutomirski , Peter Zijlstra , Alexander Viro , Mike Kravetz , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org References: <20190213192610.17265-1-alex@ghiti.fr> From: Vlastimil Babka Openpgp: preference=signencrypt Message-ID: Date: Thu, 14 Feb 2019 10:52:06 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On 2/13/19 8:30 PM, Dave Hansen wrote: >> -#if (defined(CONFIG_MEMORY_ISOLATION) && defined(CONFIG_COMPACTION)) || defined(CONFIG_CMA) >> +#ifdef CONFIG_COMPACTION_CORE >> static __init int gigantic_pages_init(void) >> { >> /* With compaction or CMA we can allocate gigantic pages at runtime */ >> diff --git a/fs/Kconfig b/fs/Kconfig >> index ac474a61be37..8fecd3ea5563 100644 >> --- a/fs/Kconfig >> +++ b/fs/Kconfig >> @@ -207,8 +207,9 @@ config HUGETLB_PAGE >> config MEMFD_CREATE >> def_bool TMPFS || HUGETLBFS >> >> -config ARCH_HAS_GIGANTIC_PAGE >> +config COMPACTION_CORE >> bool >> + default y if (MEMORY_ISOLATION && MIGRATION) || CMA > > This takes a hard dependency (#if) and turns it into a Kconfig *default* > that can be overridden. That seems like trouble. > > Shouldn't it be: > > config COMPACTION_CORE > def_bool y > depends on (MEMORY_ISOLATION && MIGRATION) || CMA Agreed. Also I noticed that it now depends on MIGRATION instead of COMPACTION. That intention is correct IMHO, but will fail to compile/link when both COMPACTION and CMA are disabled, and would need more changes in mm/internal.h and mm/compaction.c (possibly just replacing CMA in all "if defined CONFIG_COMPACTION || defined CONFIG_CMA" instances with COMPACTION_CORE, but there might be more problems, wanna try? :) Also, I realized that COMPACTION_CORE is a wrong name, sorry about that. What the config really provides is alloc_contig_range(), so it should be named either CONFIG_CMA_CORE (as it provides contiguous memory allocation, but not the related reservation and accounting), or something like CONFIG_CONTIG_ALLOC. I would also move it from fs/Kconfig to mm/Kconfig. Thanks!