From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pb0-f41.google.com (mail-pb0-f41.google.com [209.85.160.41]) by kanga.kvack.org (Postfix) with ESMTP id 7B4B36B0088 for ; Wed, 25 Sep 2013 19:24:19 -0400 (EDT) Received: by mail-pb0-f41.google.com with SMTP id rp2so313643pbb.14 for ; Wed, 25 Sep 2013 16:24:19 -0700 (PDT) Received: from /spool/local by e28smtp05.in.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 26 Sep 2013 04:54:14 +0530 Received: from d28relay05.in.ibm.com (d28relay05.in.ibm.com [9.184.220.62]) by d28dlp02.in.ibm.com (Postfix) with ESMTP id DE7D5394004D for ; Thu, 26 Sep 2013 04:53:55 +0530 (IST) Received: from d28av01.in.ibm.com (d28av01.in.ibm.com [9.184.220.63]) by d28relay05.in.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id r8PNO97q47317180 for ; Thu, 26 Sep 2013 04:54:09 +0530 Received: from d28av01.in.ibm.com (localhost [127.0.0.1]) by d28av01.in.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id r8PNOAJV020557 for ; Thu, 26 Sep 2013 04:54:11 +0530 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 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> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: 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 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, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org