Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753414Ab3HFBwJ (ORCPT ); Mon, 5 Aug 2013 21:52:09 -0400 Received: from e28smtp09.in.ibm.com ([122.248.162.9]:48082 "EHLO e28smtp09.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753223Ab3HFBwI (ORCPT ); Mon, 5 Aug 2013 21:52:08 -0400 From: "Aneesh Kumar K.V" To: Naoya Horiguchi Cc: Andrew Morton , linux-mm@kvack.org, Mel Gorman , Hugh Dickins , KOSAKI Motohiro , Andi Kleen , Hillf Danton , Michal Hocko , Rik van Riel , Wanpeng Li , linux-kernel@vger.kernel.org, Naoya Horiguchi Subject: Re: [PATCH 8/8] prepare to remove /proc/sys/vm/hugepages_treat_as_movable In-Reply-To: <1375411396-bw4cbhso-mutt-n-horiguchi@ah.jp.nec.com> References: <1374728103-17468-1-git-send-email-n-horiguchi@ah.jp.nec.com> <1374728103-17468-9-git-send-email-n-horiguchi@ah.jp.nec.com> <87k3k7q4ox.fsf@linux.vnet.ibm.com> <1375302249-scfvftrh-mutt-n-horiguchi@ah.jp.nec.com> <87vc3qvtmc.fsf@linux.vnet.ibm.com> <1375411396-bw4cbhso-mutt-n-horiguchi@ah.jp.nec.com> User-Agent: Notmuch/0.15.2+167~g5306b2b (http://notmuchmail.org) Emacs/24.3.50.1 (x86_64-unknown-linux-gnu) Date: Tue, 06 Aug 2013 07:22:02 +0530 Message-ID: <87haf3oabh.fsf@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain X-TM-AS-MML: No X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13080601-2674-0000-0000-00000A1DA302 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1085 Lines: 28 Naoya Horiguchi writes: >> >> Considering that we have architectures that won't support migrating >> explicit hugepages with this patch series, is it ok to use >> GFP_HIGHUSER_MOVABLE for hugepage allocation ? > > Originally this parameter was introduced to make hugepage pool on ZONE_MOVABLE. > The benefit is that we can extend the hugepage pool more easily, > because external fragmentation less likely happens than other zone type > by rearranging fragmented pages with page migration/reclaim. > > So I think using ZONE_MOVABLE for hugepage allocation by default makes sense > even on the architectures which don't support hugepage migration. But allocating hugepages from ZONE_MOVABLE means we have pages in that zone which we can't migrate. Doesn't that impact other features like hotplug ? -aneesh -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/