Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757267Ab0LML2p (ORCPT ); Mon, 13 Dec 2010 06:28:45 -0500 Received: from mailout4.w1.samsung.com ([210.118.77.14]:61457 "EHLO mailout4.w1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753967Ab0LML1G (ORCPT ); Mon, 13 Dec 2010 06:27:06 -0500 MIME-version: 1.0 Content-transfer-encoding: 7BIT Content-type: TEXT/PLAIN Date: Mon, 13 Dec 2010 12:26:46 +0100 From: Michal Nazarewicz Subject: [PATCHv7 05/10] mm: alloc_contig_free_pages() added In-reply-to: To: Michal Nazarewicz Cc: Andrew Morton , Ankita Garg , BooJin Kim , Daniel Walker , Johan MOSSBERG , KAMEZAWA Hiroyuki , Marek Szyprowski , Mel Gorman , "Paul E. McKenney" , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, linux-mm@kvack.org, Michal Nazarewicz , Kyungmin Park Message-id: X-Mailer: git-send-email 1.7.2.3 References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3264 Lines: 101 From: KAMEZAWA Hiroyuki This commit introduces alloc_contig_free_pages() function which allocates (ie. removes from buddy system) free pages in range. Caller has to guarantee that all pages in range are in buddy system. Along with alloc_contig_free_pages(), a free_contig_pages() function is provided which frees (or a subset of) pages allocated with alloc_contig_free_pages(). I, Michal Nazarewicz, have modified the alloc_contig_free_pages() function slightly from the original version, mostly to make it easier to allocate note MAX_ORDER aligned pages. This is done by making the function return a pfn of a page one past the one allocated which may be further then caller requested. Signed-off-by: KAMEZAWA Hiroyuki Signed-off-by: Michal Nazarewicz Signed-off-by: Kyungmin Park --- include/linux/page-isolation.h | 3 ++ mm/page_alloc.c | 42 ++++++++++++++++++++++++++++++++++++++++ 2 files changed, 45 insertions(+), 0 deletions(-) diff --git a/include/linux/page-isolation.h b/include/linux/page-isolation.h index 58cdbac..f1417ed 100644 --- a/include/linux/page-isolation.h +++ b/include/linux/page-isolation.h @@ -32,6 +32,9 @@ test_pages_isolated(unsigned long start_pfn, unsigned long end_pfn); */ extern int set_migratetype_isolate(struct page *page); extern void unset_migratetype_isolate(struct page *page); +extern unsigned long alloc_contig_freed_pages(unsigned long start, + unsigned long end, gfp_t flag); +extern void free_contig_pages(struct page *page, int nr_pages); /* * For migration. diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 826ba69..997f6c8 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -5425,6 +5425,48 @@ out: spin_unlock_irqrestore(&zone->lock, flags); } +unsigned long alloc_contig_freed_pages(unsigned long start, + unsigned long end, gfp_t flag) +{ + unsigned long pfn = start, count; + struct page *page; + struct zone *zone; + int order; + + VM_BUG_ON(!pfn_valid(pfn)); + page = pfn_to_page(pfn); + + zone = page_zone(page); + spin_lock_irq(&zone->lock); + for (;;) { + VM_BUG_ON(page_count(page) || !PageBuddy(page)); + list_del(&page->lru); + order = page_order(page); + zone->free_area[order].nr_free--; + rmv_page_order(page); + __mod_zone_page_state(zone, NR_FREE_PAGES, -(1UL << order)); + pfn += 1 << order; + if (pfn >= end) + break; + VM_BUG_ON(!pfn_valid(pfn)); + page += 1 << order; + } + spin_unlock_irq(&zone->lock); + + /* After this, pages in the range can be freed one be one */ + page = pfn_to_page(start); + for (count = pfn - start; count; --count, ++page) + prep_new_page(page, 0, flag); + + return pfn; +} + +void free_contig_pages(struct page *page, int nr_pages) +{ + for (; nr_pages; --nr_pages, ++page) + __free_page(page); +} + #ifdef CONFIG_MEMORY_HOTREMOVE /* * All pages in the range must be isolated before calling this. -- 1.7.2.3 -- 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/