Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932820AbbBBHVE (ORCPT ); Mon, 2 Feb 2015 02:21:04 -0500 Received: from mail-pa0-f46.google.com ([209.85.220.46]:42305 "EHLO mail-pa0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932617AbbBBHUv (ORCPT ); Mon, 2 Feb 2015 02:20:51 -0500 From: Joonsoo Kim X-Google-Original-From: Joonsoo Kim To: Andrew Morton Cc: Mel Gorman , David Rientjes , Rik van Riel , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Zhang Yanfei , Joonsoo Kim Subject: [RFC PATCH v3 2/3] mm/page_alloc: factor out fallback freepage checking Date: Mon, 2 Feb 2015 16:15:47 +0900 Message-Id: <1422861348-5117-2-git-send-email-iamjoonsoo.kim@lge.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1422861348-5117-1-git-send-email-iamjoonsoo.kim@lge.com> References: <1422861348-5117-1-git-send-email-iamjoonsoo.kim@lge.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5925 Lines: 187 This is preparation step to use page allocator's anti fragmentation logic in compaction. This patch just separates fallback freepage checking part from fallback freepage management part. Therefore, there is no functional change. Signed-off-by: Joonsoo Kim --- mm/page_alloc.c | 128 +++++++++++++++++++++++++++++++++----------------------- 1 file changed, 76 insertions(+), 52 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index e64b260..6cb18f8 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1142,14 +1142,26 @@ static void change_pageblock_range(struct page *pageblock_page, * as fragmentation caused by those allocations polluting movable pageblocks * is worse than movable allocations stealing from unmovable and reclaimable * pageblocks. - * - * If we claim more than half of the pageblock, change pageblock's migratetype - * as well. */ -static void try_to_steal_freepages(struct zone *zone, struct page *page, - int start_type, int fallback_type) +static bool can_steal_fallback(unsigned int order, int start_mt) +{ + if (order >= pageblock_order) + return true; + + if (order >= pageblock_order / 2 || + start_mt == MIGRATE_RECLAIMABLE || + start_mt == MIGRATE_UNMOVABLE || + page_group_by_mobility_disabled) + return true; + + return false; +} + +static void steal_suitable_fallback(struct zone *zone, struct page *page, + int start_type) { int current_order = page_order(page); + int pages; /* Take ownership for orders >= pageblock_order */ if (current_order >= pageblock_order) { @@ -1157,19 +1169,39 @@ static void try_to_steal_freepages(struct zone *zone, struct page *page, return; } - if (current_order >= pageblock_order / 2 || - start_type == MIGRATE_RECLAIMABLE || - start_type == MIGRATE_UNMOVABLE || - page_group_by_mobility_disabled) { - int pages; + pages = move_freepages_block(zone, page, start_type); - pages = move_freepages_block(zone, page, start_type); + /* Claim the whole block if over half of it is free */ + if (pages >= (1 << (pageblock_order-1)) || + page_group_by_mobility_disabled) + set_pageblock_migratetype(page, start_type); +} - /* Claim the whole block if over half of it is free */ - if (pages >= (1 << (pageblock_order-1)) || - page_group_by_mobility_disabled) - set_pageblock_migratetype(page, start_type); +static int find_suitable_fallback(struct free_area *area, unsigned int order, + int migratetype, bool *can_steal) +{ + int i; + int fallback_mt; + + if (area->nr_free == 0) + return -1; + + *can_steal = false; + for (i = 0;; i++) { + fallback_mt = fallbacks[migratetype][i]; + if (fallback_mt == MIGRATE_RESERVE) + break; + + if (list_empty(&area->free_list[fallback_mt])) + continue; + + if (can_steal_fallback(order, migratetype)) + *can_steal = true; + + return i; } + + return -1; } /* Remove an element from the buddy allocator from the fallback list */ @@ -1179,53 +1211,45 @@ __rmqueue_fallback(struct zone *zone, unsigned int order, int start_migratetype) struct free_area *area; unsigned int current_order; struct page *page; + int fallback_mt; + bool can_steal; /* Find the largest possible block of pages in the other list */ for (current_order = MAX_ORDER-1; current_order >= order && current_order <= MAX_ORDER-1; --current_order) { - int i; - for (i = 0;; i++) { - int migratetype = fallbacks[start_migratetype][i]; - int buddy_type = start_migratetype; - - /* MIGRATE_RESERVE handled later if necessary */ - if (migratetype == MIGRATE_RESERVE) - break; - - area = &(zone->free_area[current_order]); - if (list_empty(&area->free_list[migratetype])) - continue; - - page = list_entry(area->free_list[migratetype].next, - struct page, lru); - area->nr_free--; + area = &(zone->free_area[current_order]); + fallback_mt = find_suitable_fallback(area, current_order, + start_migratetype, &can_steal); + if (fallback_mt == -1) + continue; - try_to_steal_freepages(zone, page, start_migratetype, - migratetype); + page = list_entry(area->free_list[fallback_mt].next, + struct page, lru); + if (can_steal) + steal_suitable_fallback(zone, page, start_migratetype); - /* Remove the page from the freelists */ - list_del(&page->lru); - rmv_page_order(page); - - expand(zone, page, order, current_order, area, - buddy_type); + /* Remove the page from the freelists */ + area->nr_free--; + list_del(&page->lru); + rmv_page_order(page); - /* - * The freepage_migratetype may differ from pageblock's - * migratetype depending on the decisions in - * try_to_steal_freepages(). This is OK as long as it - * does not differ for MIGRATE_CMA pageblocks. For CMA - * we need to make sure unallocated pages flushed from - * pcp lists are returned to the correct freelist. - */ - set_freepage_migratetype(page, buddy_type); + expand(zone, page, order, current_order, area, + start_migratetype); + /* + * The freepage_migratetype may differ from pageblock's + * migratetype depending on the decisions in + * try_to_steal_freepages(). This is OK as long as it + * does not differ for MIGRATE_CMA pageblocks. For CMA + * we need to make sure unallocated pages flushed from + * pcp lists are returned to the correct freelist. + */ + set_freepage_migratetype(page, start_migratetype); - trace_mm_page_alloc_extfrag(page, order, current_order, - start_migratetype, migratetype); + trace_mm_page_alloc_extfrag(page, order, current_order, + start_migratetype, fallback_mt); - return page; - } + return page; } return NULL; -- 1.9.1 -- 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/