From 20d6c96b5f1cad5c5da4641945ec17a1d9a1afc8 Mon Sep 17 00:00:00 2001 From: KOSAKI Motohiro Date: Thu, 2 Dec 2010 14:31:19 -0800 Subject: [PATCH] mem-hotplug: introduce {un}lock_memory_hotplug() Presently hwpoison is using lock_system_sleep() to prevent a race with memory hotplug. However lock_system_sleep() is a no-op if CONFIG_HIBERNATION=n. Therefore we need a new lock. Signed-off-by: KOSAKI Motohiro Cc: Andi Kleen Cc: Kamezawa Hiroyuki Suggested-by: Hugh Dickins Acked-by: Hugh Dickins Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/memory_hotplug.h | 6 ++++++ mm/memory-failure.c | 8 ++++---- mm/memory_hotplug.c | 31 ++++++++++++++++++++++++------- 3 files changed, 34 insertions(+), 11 deletions(-) diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h index 4307231bd22..31c237a00c4 100644 --- a/include/linux/memory_hotplug.h +++ b/include/linux/memory_hotplug.h @@ -161,6 +161,9 @@ extern void register_page_bootmem_info_node(struct pglist_data *pgdat); extern void put_page_bootmem(struct page *page); #endif +void lock_memory_hotplug(void); +void unlock_memory_hotplug(void); + #else /* ! CONFIG_MEMORY_HOTPLUG */ /* * Stub functions for when hotplug is off @@ -192,6 +195,9 @@ static inline void register_page_bootmem_info_node(struct pglist_data *pgdat) { } +static inline void lock_memory_hotplug(void) {} +static inline void unlock_memory_hotplug(void) {} + #endif /* ! CONFIG_MEMORY_HOTPLUG */ #ifdef CONFIG_MEMORY_HOTREMOVE diff --git a/mm/memory-failure.c b/mm/memory-failure.c index 124324134ff..46ab2c044b0 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -51,6 +51,7 @@ #include #include #include +#include #include "internal.h" int sysctl_memory_failure_early_kill __read_mostly = 0; @@ -1230,11 +1231,10 @@ static int get_any_page(struct page *p, unsigned long pfn, int flags) return 1; /* - * The lock_system_sleep prevents a race with memory hotplug, - * because the isolation assumes there's only a single user. + * The lock_memory_hotplug prevents a race with memory hotplug. * This is a big hammer, a better would be nicer. */ - lock_system_sleep(); + lock_memory_hotplug(); /* * Isolate the page, so that it doesn't get reallocated if it @@ -1264,7 +1264,7 @@ static int get_any_page(struct page *p, unsigned long pfn, int flags) ret = 1; } unset_migratetype_isolate(p); - unlock_system_sleep(); + unlock_memory_hotplug(); return ret; } diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index 9260314a221..2c6523af547 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -34,6 +34,23 @@ #include "internal.h" +DEFINE_MUTEX(mem_hotplug_mutex); + +void lock_memory_hotplug(void) +{ + mutex_lock(&mem_hotplug_mutex); + + /* for exclusive hibernation if CONFIG_HIBERNATION=y */ + lock_system_sleep(); +} + +void unlock_memory_hotplug(void) +{ + unlock_system_sleep(); + mutex_unlock(&mem_hotplug_mutex); +} + + /* add this memory to iomem resource */ static struct resource *register_memory_resource(u64 start, u64 size) { @@ -493,7 +510,7 @@ int mem_online_node(int nid) pg_data_t *pgdat; int ret; - lock_system_sleep(); + lock_memory_hotplug(); pgdat = hotadd_new_pgdat(nid, 0); if (pgdat) { ret = -ENOMEM; @@ -504,7 +521,7 @@ int mem_online_node(int nid) BUG_ON(ret); out: - unlock_system_sleep(); + unlock_memory_hotplug(); return ret; } @@ -516,7 +533,7 @@ int __ref add_memory(int nid, u64 start, u64 size) struct resource *res; int ret; - lock_system_sleep(); + lock_memory_hotplug(); res = register_memory_resource(start, size); ret = -EEXIST; @@ -563,7 +580,7 @@ error: release_memory_resource(res); out: - unlock_system_sleep(); + unlock_memory_hotplug(); return ret; } EXPORT_SYMBOL_GPL(add_memory); @@ -791,7 +808,7 @@ static int offline_pages(unsigned long start_pfn, if (!test_pages_in_a_zone(start_pfn, end_pfn)) return -EINVAL; - lock_system_sleep(); + lock_memory_hotplug(); zone = page_zone(pfn_to_page(start_pfn)); node = zone_to_nid(zone); @@ -880,7 +897,7 @@ repeat: writeback_set_ratelimit(); memory_notify(MEM_OFFLINE, &arg); - unlock_system_sleep(); + unlock_memory_hotplug(); return 0; failed_removal: @@ -891,7 +908,7 @@ failed_removal: undo_isolate_page_range(start_pfn, end_pfn); out: - unlock_system_sleep(); + unlock_memory_hotplug(); return ret; } -- 2.20.1