From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Srivatsa S. Bhat" Subject: [RFC PATCH v3 17/35] mm: Add aggressive bias to prefer lower regions during page allocation Date: Fri, 30 Aug 2013 18:49:05 +0530 Message-ID: <20130830131902.4947.17975.stgit@srivatsabhat.in.ibm.com> References: <20130830131221.4947.99764.stgit@srivatsabhat.in.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20130830131221.4947.99764.stgit@srivatsabhat.in.ibm.com> Sender: owner-linux-mm@kvack.org 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 List-Id: linux-pm@vger.kernel.org While allocating pages from buddy freelists, there could be situations in which we have a ready freepage of the required order in a *higher* numbered memory region, and there also exists a freepage of a higher page order in a *lower* numbered memory region. To make the consolidation logic more aggressive, try to split up the higher order buddy page of a lower numbered region and allocate it, rather than allocating pages from a higher numbered region. This ensures that we spill over to a new region only when we truly don't have enough contiguous memory in any lower numbered region to satisfy that allocation request. Signed-off-by: Srivatsa S. Bhat --- mm/page_alloc.c | 44 ++++++++++++++++++++++++++++++++++---------- 1 file changed, 34 insertions(+), 10 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 6e711b9..0cc2a3e 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1210,8 +1210,9 @@ static inline struct page *__rmqueue_smallest(struct zone *zone, unsigned int order, int migratetype) { - unsigned int current_order; - struct free_area * area; + unsigned int current_order, alloc_order; + struct free_area *area, *other_area; + int alloc_region, other_region; struct page *page; /* Find a page of the appropriate size in the preferred list */ @@ -1220,17 +1221,40 @@ struct page *__rmqueue_smallest(struct zone *zone, unsigned int order, if (list_empty(&area->free_list[migratetype].list)) continue; - page = list_entry(area->free_list[migratetype].list.next, - struct page, lru); - rmqueue_del_from_freelist(page, &area->free_list[migratetype], - current_order); - rmv_page_order(page); - area->nr_free--; - expand(zone, page, order, current_order, area, migratetype); - return page; + alloc_order = current_order; + alloc_region = area->free_list[migratetype].next_region - + area->free_list[migratetype].mr_list; + current_order++; + goto try_others; } return NULL; + +try_others: + /* Try to aggressively prefer lower numbered regions for allocations */ + for ( ; current_order < MAX_ORDER; ++current_order) { + other_area = &(zone->free_area[current_order]); + if (list_empty(&other_area->free_list[migratetype].list)) + continue; + + other_region = other_area->free_list[migratetype].next_region - + other_area->free_list[migratetype].mr_list; + + if (other_region < alloc_region) { + alloc_region = other_region; + alloc_order = current_order; + } + } + + area = &(zone->free_area[alloc_order]); + page = list_entry(area->free_list[migratetype].list.next, struct page, + lru); + rmqueue_del_from_freelist(page, &area->free_list[migratetype], + alloc_order); + rmv_page_order(page); + area->nr_free--; + expand(zone, page, order, alloc_order, area, migratetype); + return page; } -- 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