From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754148Ab1GEHl6 (ORCPT ); Tue, 5 Jul 2011 03:41:58 -0400 Received: from mailout4.w1.samsung.com ([210.118.77.14]:46886 "EHLO mailout4.w1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754047Ab1GEHl4 (ORCPT ); Tue, 5 Jul 2011 03:41:56 -0400 MIME-version: 1.0 Content-transfer-encoding: 7BIT Content-type: TEXT/PLAIN Date: Tue, 05 Jul 2011 09:41:44 +0200 From: Marek Szyprowski Subject: [PATCH 2/8] mm: alloc_contig_freed_pages() added In-reply-to: <1309851710-3828-1-git-send-email-m.szyprowski@samsung.com> To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-media@vger.kernel.org, linux-mm@kvack.org, linaro-mm-sig@lists.linaro.org Cc: Michal Nazarewicz , Marek Szyprowski , Kyungmin Park , Andrew Morton , KAMEZAWA Hiroyuki , Ankita Garg , Daniel Walker , Mel Gorman , Arnd Bergmann , Jesse Barker , Jonathan Corbet , Chunsang Jeong Message-id: <1309851710-3828-3-git-send-email-m.szyprowski@samsung.com> X-Mailer: git-send-email 1.7.2.5 References: <1309851710-3828-1-git-send-email-m.szyprowski@samsung.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: KAMEZAWA Hiroyuki This commit introduces alloc_contig_freed_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 this function, a free_contig_pages() function is provided which frees all (or a subset of) pages allocated with alloc_contig_free_pages(). Michal Nazarewicz has modified the function to make it easier to allocate not MAX_ORDER_NR_PAGES aligned pages by making it return pfn of one-past-the-last allocated page. Signed-off-by: KAMEZAWA Hiroyuki Signed-off-by: Michal Nazarewicz Signed-off-by: Kyungmin Park Signed-off-by: Marek Szyprowski CC: Michal Nazarewicz --- include/linux/page-isolation.h | 3 ++ mm/page_alloc.c | 44 ++++++++++++++++++++++++++++++++++++++++ 2 files changed, 47 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 4e8985a..00e9b24 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -5600,6 +5600,50 @@ 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(start)); + zone = page_zone(pfn_to_page(start)); + + spin_lock_irq(&zone->lock); + + page = pfn_to_page(pfn); + 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. -- 1.7.1.569.g6f426