Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756379AbZJATxR (ORCPT ); Thu, 1 Oct 2009 15:53:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753612AbZJATxQ (ORCPT ); Thu, 1 Oct 2009 15:53:16 -0400 Received: from e36.co.us.ibm.com ([32.97.110.154]:50258 "EHLO e36.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752822AbZJATxQ (ORCPT ); Thu, 1 Oct 2009 15:53:16 -0400 Date: Thu, 1 Oct 2009 14:53:11 -0500 From: Robert Jennings To: Mel Gorman Cc: Ingo Molnar , Badari Pulavarty , Brian King , Robert Jennings , Benjamin Herrenschmidt , Paul Mackerras , Martin Schwidefsky , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linuxppc-dev@ozlabs.org Subject: [PATCH 1/2] mm: add notifier in pageblock isolation for balloon drivers Message-ID: <20091001195311.GA16667@austin.ibm.com> Mail-Followup-To: Mel Gorman , Ingo Molnar , Badari Pulavarty , Brian King , Benjamin Herrenschmidt , Paul Mackerras , Martin Schwidefsky , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linuxppc-dev@ozlabs.org MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.17+20080114 (2008-01-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6153 Lines: 189 Memory balloon drivers can allocate a large amount of memory which is not movable but could be freed to accommodate memory hotplug remove. Prior to calling the memory hotplug notifier chain the memory in the pageblock is isolated. If the migrate type is not MIGRATE_MOVABLE the isolation will not proceed, causing the memory removal for that page range to fail. Rather than immediately failing pageblock isolation if the the migrateteype is not MIGRATE_MOVABLE, this patch checks if all of the pages in the pageblock are owned by a registered balloon driver using a notifier chain. If all of the non-movable pages are owned by a balloon, they can be freed later through the memory notifier chain and the range can still be isolated in set_migratetype_isolate(). Signed-off-by: Robert Jennings --- drivers/base/memory.c | 19 +++++++++++++++++++ include/linux/memory.h | 22 ++++++++++++++++++++++ mm/page_alloc.c | 49 +++++++++++++++++++++++++++++++++++++++++-------- 3 files changed, 82 insertions(+), 8 deletions(-) Index: b/drivers/base/memory.c =================================================================== --- a/drivers/base/memory.c +++ b/drivers/base/memory.c @@ -63,6 +63,20 @@ void unregister_memory_notifier(struct n } EXPORT_SYMBOL(unregister_memory_notifier); +static BLOCKING_NOTIFIER_HEAD(memory_isolate_chain); + +int register_memory_isolate_notifier(struct notifier_block *nb) +{ + return blocking_notifier_chain_register(&memory_isolate_chain, nb); +} +EXPORT_SYMBOL(register_memory_isolate_notifier); + +void unregister_memory_isolate_notifier(struct notifier_block *nb) +{ + blocking_notifier_chain_unregister(&memory_isolate_chain, nb); +} +EXPORT_SYMBOL(unregister_memory_isolate_notifier); + /* * register_memory - Setup a sysfs device for a memory block */ @@ -157,6 +171,11 @@ int memory_notify(unsigned long val, voi return blocking_notifier_call_chain(&memory_chain, val, v); } +int memory_isolate_notify(unsigned long val, void *v) +{ + return blocking_notifier_call_chain(&memory_isolate_chain, val, v); +} + /* * MEMORY_HOTPLUG depends on SPARSEMEM in mm/Kconfig, so it is * OK to have direct references to sparsemem variables in here. Index: b/include/linux/memory.h =================================================================== --- a/include/linux/memory.h +++ b/include/linux/memory.h @@ -50,6 +50,14 @@ struct memory_notify { int status_change_nid; }; +#define MEM_ISOLATE_COUNT (1<<0) + +struct memory_isolate_notify { + unsigned long start_addr; + unsigned int nr_pages; + unsigned int pages_found; +}; + struct notifier_block; struct mem_section; @@ -76,14 +84,28 @@ static inline int memory_notify(unsigned { return 0; } +static inline int register_memory_isolate_notifier(struct notifier_block *nb) +{ + return 0; +} +static inline void unregister_memory_isolate_notifier(struct notifier_block *nb) +{ +} +static inline int memory_isolate_notify(unsigned long val, void *v) +{ + return 0; +} #else extern int register_memory_notifier(struct notifier_block *nb); extern void unregister_memory_notifier(struct notifier_block *nb); +extern int register_memory_isolate_notifier(struct notifier_block *nb); +extern void unregister_memory_isolate_notifier(struct notifier_block *nb); extern int register_new_memory(int, struct mem_section *); extern int unregister_memory_section(struct mem_section *); extern int memory_dev_init(void); extern int remove_memory_block(unsigned long, struct mem_section *, int); extern int memory_notify(unsigned long val, void *v); +extern int memory_isolate_notify(unsigned long val, void *v); extern struct memory_block *find_memory_block(struct mem_section *); #define CONFIG_MEM_BLOCK_SIZE (PAGES_PER_SECTION< #include #include +#include #include #include @@ -4985,23 +4986,55 @@ void set_pageblock_flags_group(struct pa int set_migratetype_isolate(struct page *page) { struct zone *zone; - unsigned long flags; + unsigned long flags, pfn, iter; + long immobile = 0; + struct memory_isolate_notify arg; + int notifier_ret; int ret = -EBUSY; int zone_idx; zone = page_zone(page); zone_idx = zone_idx(zone); + + pfn = page_to_pfn(page); + arg.start_addr = (unsigned long)page_address(page); + arg.nr_pages = pageblock_nr_pages; + arg.pages_found = 0; + spin_lock_irqsave(&zone->lock, flags); /* * In future, more migrate types will be able to be isolation target. */ - if (get_pageblock_migratetype(page) != MIGRATE_MOVABLE && - zone_idx != ZONE_MOVABLE) - goto out; - set_pageblock_migratetype(page, MIGRATE_ISOLATE); - move_freepages_block(zone, page, MIGRATE_ISOLATE); - ret = 0; -out: + do { + if (get_pageblock_migratetype(page) == MIGRATE_MOVABLE && + zone_idx == ZONE_MOVABLE) { + ret = 0; + break; + } + + /* + * If all of the pages in a zone are used by a balloon, + * the range can be still be isolated. The balloon will + * free these pages from the memory notifier chain. + */ + notifier_ret = memory_isolate_notify(MEM_ISOLATE_COUNT, &arg); + notifier_ret = notifier_to_errno(ret); + if (notifier_ret || !arg.pages_found) + break; + + for (iter = pfn; iter < (pfn + pageblock_nr_pages); iter++) + if (page_count(pfn_to_page(iter))) + immobile++; + + if (arg.pages_found == immobile) + ret = 0; + } while (0); + + if (!ret) { + set_pageblock_migratetype(page, MIGRATE_ISOLATE); + move_freepages_block(zone, page, MIGRATE_ISOLATE); + } + spin_unlock_irqrestore(&zone->lock, flags); if (!ret) drain_all_pages(); -- 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/