From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oi1-f197.google.com (mail-oi1-f197.google.com [209.85.167.197]) by kanga.kvack.org (Postfix) with ESMTP id A4B706B0006 for ; Thu, 18 Oct 2018 22:32:34 -0400 (EDT) Received: by mail-oi1-f197.google.com with SMTP id o6-v6so22231050oib.9 for ; Thu, 18 Oct 2018 19:32:34 -0700 (PDT) Received: from foss.arm.com (usa-sjc-mx-foss1.foss.arm.com. [217.140.101.70]) by mx.google.com with ESMTP id t88-v6si10666867oij.53.2018.10.18.19.32.33 for ; Thu, 18 Oct 2018 19:32:33 -0700 (PDT) Subject: Re: [PATCH V2 2/5] mm/hugetlb: Distinguish between migratability and movability References: <1539316799-6064-1-git-send-email-anshuman.khandual@arm.com> <1539316799-6064-3-git-send-email-anshuman.khandual@arm.com> <20181019015931.GA18973@hori1.linux.bs1.fc.nec.co.jp> From: Anshuman Khandual Message-ID: Date: Fri, 19 Oct 2018 08:02:26 +0530 MIME-Version: 1.0 In-Reply-To: <20181019015931.GA18973@hori1.linux.bs1.fc.nec.co.jp> Content-Type: text/plain; charset=iso-2022-jp Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Naoya Horiguchi 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" On 10/19/2018 07:29 AM, Naoya Horiguchi wrote: > 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))) { > Sure, will update this patch only unless other changes are suggested.