From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756357Ab3H3MlN (ORCPT ); Fri, 30 Aug 2013 08:41:13 -0400 Received: from e8.ny.us.ibm.com ([32.97.182.138]:43227 "EHLO e8.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756321Ab3H3MlL (ORCPT ); Fri, 30 Aug 2013 08:41:11 -0400 From: "Srivatsa S. Bhat" Subject: [RFC PATCH v3 09/35] mm: Track the freepage migratetype of pages accurately To: akpm@linux-foundation.org, mgorman@suse.de, hannes@cmpxchg.org, tony.luck@intel.com, matthew.garrett@nebula.com, dave@sr71.net, riel@redhat.com, arjan@linux.intel.com, srinivas.pandruvada@linux.intel.com, willy@linux.intel.com, kamezawa.hiroyu@jp.fujitsu.com, lenb@kernel.org, rjw@sisk.pl Cc: gargankita@gmail.com, paulmck@linux.vnet.ibm.com, amit.kachhap@linaro.org, svaidy@linux.vnet.ibm.com, andi@firstfloor.org, isimatu.yasuaki@jp.fujitsu.com, santosh.shilimkar@ti.com, kosaki.motohiro@gmail.com, srivatsa.bhat@linux.vnet.ibm.com, linux-pm@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Date: Fri, 30 Aug 2013 18:07:01 +0530 Message-ID: <20130830123655.24352.97744.stgit@srivatsabhat.in.ibm.com> In-Reply-To: <20130830123303.24352.18732.stgit@srivatsabhat.in.ibm.com> References: <20130830123303.24352.18732.stgit@srivatsabhat.in.ibm.com> User-Agent: StGIT/0.14.3 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-TM-AS-MML: No X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13083012-0320-0000-0000-000000D83793 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Due to the region-wise ordering of the pages in the buddy allocator's free lists, whenever we want to delete a free pageblock from a free list (for ex: when moving blocks of pages from one list to the other), we need to be able to tell the buddy allocator exactly which migratetype it belongs to. For that purpose, we can use the page's freepage migratetype (which is maintained in the page's ->index field). So, while splitting up higher order pages into smaller ones as part of buddy operations, keep the new head pages updated with the correct freepage migratetype information (because we depend on tracking this info accurately, as outlined above). Signed-off-by: Srivatsa S. Bhat --- mm/page_alloc.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 398b62c..b4b1275 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -947,6 +947,13 @@ static inline void expand(struct zone *zone, struct page *page, add_to_freelist(&page[size], &area->free_list[migratetype]); area->nr_free++; set_page_order(&page[size], high); + + /* + * Freepage migratetype is tracked using the index field of the + * first page of the block. So we need to update the new first + * page, when changing the page order. + */ + set_freepage_migratetype(&page[size], migratetype); } }