From 925cc71e512a29e2594bcc17dc58d0a0e9c4d524 Mon Sep 17 00:00:00 2001 From: Robert Jennings Date: Thu, 17 Dec 2009 14:44:38 +0000 Subject: mm: Add notifier in pageblock isolation for balloon drivers Memory balloon drivers can allocate a large amount of memory which is not movable but could be freed to accomodate memory hotplug remove. Prior to calling the memory hotplug notifier chain the memory in the pageblock is isolated. Currently, 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 failing pageblock isolation if the migrateteype is not MIGRATE_MOVABLE, this patch checks if all of the pages in the pageblock, and not on the LRU, are owned by a registered balloon driver (or other entity) 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 Cc: Mel Gorman Cc: Ingo Molnar Cc: Brian King Cc: Paul Mackerras Cc: Martin Schwidefsky Cc: Gerald Schaefer Cc: KAMEZAWA Hiroyuki Cc: Benjamin Herrenschmidt Signed-off-by: Andrew Morton Signed-off-by: Benjamin Herrenschmidt --- drivers/base/memory.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) (limited to 'drivers') diff --git a/drivers/base/memory.c b/drivers/base/memory.c index c4c8f2e1dd1..d7d77d4a402 100644 --- a/drivers/base/memory.c +++ b/drivers/base/memory.c @@ -63,6 +63,20 @@ void unregister_memory_notifier(struct notifier_block *nb) } EXPORT_SYMBOL(unregister_memory_notifier); +static ATOMIC_NOTIFIER_HEAD(memory_isolate_chain); + +int register_memory_isolate_notifier(struct notifier_block *nb) +{ + return atomic_notifier_chain_register(&memory_isolate_chain, nb); +} +EXPORT_SYMBOL(register_memory_isolate_notifier); + +void unregister_memory_isolate_notifier(struct notifier_block *nb) +{ + atomic_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, void *v) return blocking_notifier_call_chain(&memory_chain, val, v); } +int memory_isolate_notify(unsigned long val, void *v) +{ + return atomic_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. -- cgit v1.2.3