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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 BB482C67863 for ; Fri, 19 Oct 2018 02:02:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 65B8020645 for ; Fri, 19 Oct 2018 02:02:33 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 65B8020645 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ah.jp.nec.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726702AbeJSKGY convert rfc822-to-8bit (ORCPT ); Fri, 19 Oct 2018 06:06:24 -0400 Received: from tyo161.gate.nec.co.jp ([114.179.232.161]:41526 "EHLO tyo161.gate.nec.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726463AbeJSKGY (ORCPT ); Fri, 19 Oct 2018 06:06:24 -0400 Received: from mailgate02.nec.co.jp ([114.179.233.122]) by tyo161.gate.nec.co.jp (8.15.1/8.15.1) with ESMTPS id w9J21umX007134 (version=TLSv1.2 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Fri, 19 Oct 2018 11:01:56 +0900 Received: from mailsv02.nec.co.jp (mailgate-v.nec.co.jp [10.204.236.94]) by mailgate02.nec.co.jp (8.15.1/8.15.1) with ESMTP id w9J21uZb028123; Fri, 19 Oct 2018 11:01:56 +0900 Received: from mail02.kamome.nec.co.jp (mail02.kamome.nec.co.jp [10.25.43.5]) by mailsv02.nec.co.jp (8.15.1/8.15.1) with ESMTP id w9J21Ame003402; Fri, 19 Oct 2018 11:01:56 +0900 Received: from bpxc99gp.gisp.nec.co.jp ([10.38.151.147] [10.38.151.147]) by mail01b.kamome.nec.co.jp with ESMTP id BT-MMP-4688595; Fri, 19 Oct 2018 10:59:32 +0900 Received: from BPXM23GP.gisp.nec.co.jp ([10.38.151.215]) by BPXC19GP.gisp.nec.co.jp ([10.38.151.147]) with mapi id 14.03.0319.002; Fri, 19 Oct 2018 10:59:31 +0900 From: Naoya Horiguchi To: Anshuman Khandual CC: "linux-mm@kvack.org" , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "suzuki.poulose@arm.com" , "punit.agrawal@arm.com" , "will.deacon@arm.com" , "Steven.Price@arm.com" , "steve.capper@arm.com" , "catalin.marinas@arm.com" , "mhocko@kernel.org" , "akpm@linux-foundation.org" , "mike.kravetz@oracle.com" Subject: Re: [PATCH V2 2/5] mm/hugetlb: Distinguish between migratability and movability Thread-Topic: [PATCH V2 2/5] mm/hugetlb: Distinguish between migratability and movability Thread-Index: AQHUYeAhh+l78BzFeEGRzFlmEYQ+5aUlRB+A Date: Fri, 19 Oct 2018 01:59:31 +0000 Message-ID: <20181019015931.GA18973@hori1.linux.bs1.fc.nec.co.jp> References: <1539316799-6064-1-git-send-email-anshuman.khandual@arm.com> <1539316799-6064-3-git-send-email-anshuman.khandual@arm.com> In-Reply-To: <1539316799-6064-3-git-send-email-anshuman.khandual@arm.com> Accept-Language: en-US, ja-JP Content-Language: ja-JP X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.51.8.80] Content-Type: text/plain; charset="iso-2022-jp" Content-ID: <0D6086D1CF56CC48B332AC9789ACCB2B@gisp.nec.co.jp> Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 X-TM-AS-MML: disable Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Oct 12, 2018 at 09:29:56AM +0530, Anshuman Khandual wrote: > During huge page allocation it's migratability is checked to determine if > it should be placed under movable zones with GFP_HIGHUSER_MOVABLE. But the > movability aspect of the huge page could depend on other factors than just > migratability. Movability in itself is a distinct property which should not > be tied with migratability alone. > > This differentiates these two and implements an enhanced movability check > which also considers huge page size to determine if it is feasible to be > placed under a movable zone. At present it just checks for gigantic pages > but going forward it can incorporate other enhanced checks. (nitpicking...) The following code just checks hugepage_migration_supported(), so maybe s/Movability/Migratability/ is expected in the comment? static int unmap_and_move_huge_page(...) { ... /* * Movability of hugepages depends on architectures and hugepage size. * This check is necessary because some callers of hugepage migration * like soft offline and memory hotremove don't walk through page * tables or check whether the hugepage is pmd-based or not before * kicking migration. */ if (!hugepage_migration_supported(page_hstate(hpage))) { Thanks, Naoya Horiguchi > > Suggested-by: Michal Hocko > Signed-off-by: Anshuman Khandual > --- > include/linux/hugetlb.h | 30 ++++++++++++++++++++++++++++++ > mm/hugetlb.c | 2 +- > 2 files changed, 31 insertions(+), 1 deletion(-) > > diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h > index 9c1b77f..456cb60 100644 > --- a/include/linux/hugetlb.h > +++ b/include/linux/hugetlb.h > @@ -493,6 +493,31 @@ static inline bool hugepage_migration_supported(struct hstate *h) > #endif > } > > +/* > + * Movability check is different as compared to migration check. > + * It determines whether or not a huge page should be placed on > + * movable zone or not. Movability of any huge page should be > + * required only if huge page size is supported for migration. > + * There wont be any reason for the huge page to be movable if > + * it is not migratable to start with. Also the size of the huge > + * page should be large enough to be placed under a movable zone > + * and still feasible enough to be migratable. Just the presence > + * in movable zone does not make the migration feasible. > + * > + * So even though large huge page sizes like the gigantic ones > + * are migratable they should not be movable because its not > + * feasible to migrate them from movable zone. > + */ > +static inline bool hugepage_movable_supported(struct hstate *h) > +{ > + if (!hugepage_migration_supported(h)) > + return false; > + > + if (hstate_is_gigantic(h)) > + return false; > + return true; > +} > + > static inline spinlock_t *huge_pte_lockptr(struct hstate *h, > struct mm_struct *mm, pte_t *pte) > { > @@ -589,6 +614,11 @@ static inline bool hugepage_migration_supported(struct hstate *h) > return false; > } > > +static inline bool hugepage_movable_supported(struct hstate *h) > +{ > + return false; > +} > + > static inline spinlock_t *huge_pte_lockptr(struct hstate *h, > struct mm_struct *mm, pte_t *pte) > { > diff --git a/mm/hugetlb.c b/mm/hugetlb.c > index 3c21775..a5a111d 100644 > --- a/mm/hugetlb.c > +++ b/mm/hugetlb.c > @@ -919,7 +919,7 @@ static struct page *dequeue_huge_page_nodemask(struct hstate *h, gfp_t gfp_mask, > /* Movability of hugepages depends on migration support. */ > static inline gfp_t htlb_alloc_mask(struct hstate *h) > { > - if (hugepage_migration_supported(h)) > + if (hugepage_movable_supported(h)) > return GFP_HIGHUSER_MOVABLE; > else > return GFP_HIGHUSER; > -- > 2.7.4 > >