Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756175Ab3IYXX5 (ORCPT ); Wed, 25 Sep 2013 19:23:57 -0400 Received: from e28smtp07.in.ibm.com ([122.248.162.7]:41651 "EHLO e28smtp07.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755215Ab3IYXXz (ORCPT ); Wed, 25 Sep 2013 19:23:55 -0400 From: "Srivatsa S. Bhat" Subject: [RFC PATCH v4 26/40] mm: Connect Page Allocator(PA) to Region Allocator(RA); add PA <= RA flow 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 04:49:41 +0530 Message-ID: <20130925231939.26184.88534.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: 13092523-8878-0000-0000-000008FD521F Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2686 Lines: 72 Now that we have built up an infrastructure that forms a "Memory Region Allocator", connect it with the page allocator. To entities requesting memory, the page allocator will function as a front-end, whereas the region allocator will act as a back-end to the page allocator. (Analogy: page allocator is like free cash, whereas region allocator is like a bank). Implement the flow of freepages from the region allocator to the page allocator. When __rmqueue_smallest() comes out empty handed, try to get freepages from the region allocator. If that fails, only then fallback to an allocation from a different migratetype. This helps significantly in avoiding mixing of allocations of different migratetypes in a single region. Thus it helps in keeping entire memory regions homogeneous with respect to the type of allocations. Simplification: We assume that the freepages of a memory region can be completely represented by a set of MAX_ORDER-1 pages. That is, we only need to consider the buddy freelists corresponding to MAX_ORDER-1, while interacting with the region allocator. Furthermore, we assume that pageblock_order == MAX_ORDER-1. (These assumptions are used to ease the implementation, so that one can quickly evaluate the benefits of the overall design without getting bogged down by too many corner cases and constraints. Of course future implementations will handle more scenarios and will have reduced dependence on such simplifying assumptions.) Signed-off-by: Srivatsa S. Bhat --- mm/page_alloc.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index d08bc91..0d73134 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1703,10 +1703,18 @@ static struct page *__rmqueue(struct zone *zone, unsigned int order, { struct page *page; -retry_reserve: +retry: page = __rmqueue_smallest(zone, order, migratetype); if (unlikely(!page) && migratetype != MIGRATE_RESERVE) { + + /* + * Try to get a region from the region allocator before falling + * back to an allocation from a different migratetype. + */ + if (!del_from_region_allocator(zone, MAX_ORDER-1, migratetype)) + goto retry; + page = __rmqueue_fallback(zone, order, migratetype); /* @@ -1716,7 +1724,7 @@ retry_reserve: */ if (!page) { migratetype = MIGRATE_RESERVE; - goto retry_reserve; + goto retry; } } -- 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/