Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755065Ab2BCMWb (ORCPT ); Fri, 3 Feb 2012 07:22:31 -0500 Received: from mailout3.w1.samsung.com ([210.118.77.13]:14440 "EHLO mailout3.w1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754164Ab2BCMTI (ORCPT ); Fri, 3 Feb 2012 07:19:08 -0500 MIME-version: 1.0 Content-transfer-encoding: 7BIT Content-type: TEXT/PLAIN Date: Fri, 03 Feb 2012 13:18:47 +0100 From: Marek Szyprowski Subject: [PATCH 04/15] mm: compaction: introduce isolate_freepages_range() In-reply-to: <1328271538-14502-1-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 , Russell King , Andrew Morton , KAMEZAWA Hiroyuki , Daniel Walker , Mel Gorman , Arnd Bergmann , Jesse Barker , Jonathan Corbet , Shariq Hasnain , Chunsang Jeong , Dave Hansen , Benjamin Gaignard , Rob Clark , Ohad Ben-Cohen Message-id: <1328271538-14502-5-git-send-email-m.szyprowski@samsung.com> X-Mailer: git-send-email 1.7.7.3 References: <1328271538-14502-1-git-send-email-m.szyprowski@samsung.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6257 Lines: 194 From: Michal Nazarewicz This commit introduces isolate_freepages_range() function which generalises isolate_freepages_block() so that it can be used on arbitrary PFN ranges. isolate_freepages_block() is left with only minor changes. Signed-off-by: Michal Nazarewicz Signed-off-by: Marek Szyprowski Acked-by: Mel Gorman Tested-by: Rob Clark Tested-by: Ohad Ben-Cohen Tested-by: Benjamin Gaignard --- mm/compaction.c | 111 ++++++++++++++++++++++++++++++++++++++++++++++--------- 1 files changed, 93 insertions(+), 18 deletions(-) diff --git a/mm/compaction.c b/mm/compaction.c index 9bbcc53..9fef891 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -54,24 +54,20 @@ static unsigned long release_freepages(struct list_head *freelist) return count; } -/* Isolate free pages onto a private freelist. Must hold zone->lock */ -static unsigned long isolate_freepages_block(struct zone *zone, - unsigned long blockpfn, - struct list_head *freelist) +/* + * Isolate free pages onto a private freelist. Caller must hold zone->lock. + * If @strict is true, will abort returning 0 on any invalid PFNs or non-free + * pages inside of the pageblock (even though it may still end up isolating + * some pages). + */ +static unsigned long isolate_freepages_block(unsigned long blockpfn, + unsigned long end_pfn, + struct list_head *freelist, + bool strict) { - unsigned long zone_end_pfn, end_pfn; int nr_scanned = 0, total_isolated = 0; struct page *cursor; - /* Get the last PFN we should scan for free pages at */ - zone_end_pfn = zone->zone_start_pfn + zone->spanned_pages; - end_pfn = min(blockpfn + pageblock_nr_pages, zone_end_pfn); - - /* Find the first usable PFN in the block to initialse page cursor */ - for (; blockpfn < end_pfn; blockpfn++) { - if (pfn_valid_within(blockpfn)) - break; - } cursor = pfn_to_page(blockpfn); /* Isolate free pages. This assumes the block is valid */ @@ -79,15 +75,23 @@ static unsigned long isolate_freepages_block(struct zone *zone, int isolated, i; struct page *page = cursor; - if (!pfn_valid_within(blockpfn)) + if (!pfn_valid_within(blockpfn)) { + if (strict) + return 0; continue; + } nr_scanned++; - if (!PageBuddy(page)) + if (!PageBuddy(page)) { + if (strict) + return 0; continue; + } /* Found a free page, break it into order-0 pages */ isolated = split_free_page(page); + if (!isolated && strict) + return 0; total_isolated += isolated; for (i = 0; i < isolated; i++) { list_add(&page->lru, freelist); @@ -105,6 +109,73 @@ static unsigned long isolate_freepages_block(struct zone *zone, return total_isolated; } +/** + * isolate_freepages_range() - isolate free pages. + * @start_pfn: The first PFN to start isolating. + * @end_pfn: The one-past-last PFN. + * + * Non-free pages, invalid PFNs, or zone boundaries within the + * [start_pfn, end_pfn) range are considered errors, cause function to + * undo its actions and return zero. + * + * Otherwise, function returns one-past-the-last PFN of isolated page + * (which may be greater then end_pfn if end fell in a middle of + * a free page). + */ +static unsigned long +isolate_freepages_range(unsigned long start_pfn, unsigned long end_pfn) +{ + unsigned long isolated, pfn, block_end_pfn, flags; + struct zone *zone = NULL; + LIST_HEAD(freelist); + + if (pfn_valid(start_pfn)) + zone = page_zone(pfn_to_page(start_pfn)); + + for (pfn = start_pfn; pfn < end_pfn; pfn += isolated) { + if (!pfn_valid(pfn) || zone != page_zone(pfn_to_page(pfn))) + break; + + /* + * On subsequent iterations ALIGN() is actually not needed, + * but we keep it that we not to complicate the code. + */ + block_end_pfn = ALIGN(pfn + 1, pageblock_nr_pages); + block_end_pfn = min(block_end_pfn, end_pfn); + + spin_lock_irqsave(&zone->lock, flags); + isolated = isolate_freepages_block(pfn, block_end_pfn, + &freelist, true); + spin_unlock_irqrestore(&zone->lock, flags); + + /* + * In strict mode, isolate_freepages_block() returns 0 if + * there are any holes in the block (ie. invalid PFNs or + * non-free pages). + */ + if (!isolated) + break; + + /* + * If we managed to isolate pages, it is always (1 << n) * + * pageblock_nr_pages for some non-negative n. (Max order + * page may span two pageblocks). + */ + } + + /* split_free_page does not map the pages */ + map_pages(&freelist); + + if (pfn < end_pfn) { + /* Loop terminated early, cleanup. */ + release_freepages(&freelist); + return 0; + } + + /* We don't use freelists for anything. */ + return pfn; +} + /* Returns true if the page is within a block suitable for migration to */ static bool suitable_migration_target(struct page *page) { @@ -145,7 +216,7 @@ static void isolate_freepages(struct zone *zone, struct compact_control *cc) { struct page *page; - unsigned long high_pfn, low_pfn, pfn; + unsigned long high_pfn, low_pfn, pfn, zone_end_pfn, end_pfn; unsigned long flags; int nr_freepages = cc->nr_freepages; struct list_head *freelist = &cc->freepages; @@ -165,6 +236,8 @@ static void isolate_freepages(struct zone *zone, */ high_pfn = min(low_pfn, pfn); + zone_end_pfn = zone->zone_start_pfn + zone->spanned_pages; + /* * Isolate free pages until enough are available to migrate the * pages on cc->migratepages. We stop searching if the migrate @@ -201,7 +274,9 @@ static void isolate_freepages(struct zone *zone, isolated = 0; spin_lock_irqsave(&zone->lock, flags); if (suitable_migration_target(page)) { - isolated = isolate_freepages_block(zone, pfn, freelist); + end_pfn = min(pfn + pageblock_nr_pages, zone_end_pfn); + isolated = isolate_freepages_block(pfn, end_pfn, + freelist, false); nr_freepages += isolated; } spin_unlock_irqrestore(&zone->lock, flags); -- 1.7.1.569.g6f426 -- 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/