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Bhat" Subject: [RFC PATCH v3 30/35] mm: Provide a mechanism to check if a given page is in the region allocator 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, 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 18:53:31 +0530 Message-ID: <20130830132329.4947.99949.stgit@srivatsabhat.in.ibm.com> In-Reply-To: <20130830131221.4947.99764.stgit@srivatsabhat.in.ibm.com> References: <20130830131221.4947.99764.stgit@srivatsabhat.in.ibm.com> User-Agent: StGIT/0.14.3 MIME-Version: 1.0 X-TM-AS-MML: No X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13083013-4834-0000-0000-00000A99548D Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org X-Spam-Status: No, score=-9.0 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP 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(+) -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/mm/page_alloc.c b/mm/page_alloc.c index a62730b..3f49ca8 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1047,6 +1047,37 @@ 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