Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756218Ab3IYXYT (ORCPT ); Wed, 25 Sep 2013 19:24:19 -0400 Received: from e28smtp06.in.ibm.com ([122.248.162.6]:47697 "EHLO e28smtp06.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756205Ab3IYXYP (ORCPT ); Wed, 25 Sep 2013 19:24:15 -0400 From: "Srivatsa S. Bhat" Subject: [RFC PATCH v4 28/40] mm: Provide a mechanism to check if a given page is in the region allocator To: akpm@linux-foundation.org, mgorman@suse.de, dave@sr71.net, hannes@cmpxchg.org, tony.luck@intel.com, matthew.garrett@nebula.com, 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, 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: Thu, 26 Sep 2013 04:50:04 +0530 Message-ID: <20130925232002.26184.73188.stgit@srivatsabhat.in.ibm.com> In-Reply-To: <20130925231250.26184.31438.stgit@srivatsabhat.in.ibm.com> References: <20130925231250.26184.31438.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: 13092523-9574-0000-0000-000009CD0C51 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2047 Lines: 60 With the introduction of the region allocator, a freepage can be either in one of the buddy freelists or in the region allocator. In cases where we want to move freepages to a given migratetype's freelists, we will need to know where they were originally located. So provide a helper to distinguish whether the freepage resides in the region allocator or the buddy freelists. Signed-off-by: Srivatsa S. Bhat --- mm/page_alloc.c | 31 +++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index ca7b959..ac04b45 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1048,6 +1048,37 @@ static int del_from_region_allocator(struct zone *zone, unsigned int order, } /* + * Return 1 if the page is in the region allocator, else return 0 + * (which usually means that the page is in the buddy freelists). + */ +static int page_in_region_allocator(struct page *page) +{ + struct region_allocator *reg_alloc; + struct free_area_region *reg_area; + int order, region_id; + + /* We keep only MAX_ORDER-1 pages in the region allocator */ + order = page_order(page); + if (order != MAX_ORDER-1) + return 0; + + /* + * It is sufficient to check if (any of) the pages belonging to + * that region are in the region allocator, because a page resides + * in the region allocator if and only if all the pages of that + * region are also in the region allocator. + */ + region_id = page_zone_region_id(page); + reg_alloc = &page_zone(page)->region_allocator; + reg_area = ®_alloc->region[region_id].region_area[order]; + + if (reg_area->nr_free) + return 1; + + return 0; +} + +/* * Freeing function for a buddy system allocator. * * The concept of a buddy system is to maintain direct-mapped table -- 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/