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mem-hotplug: introduce {un}lock_memory_hotplug()

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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 <kosaki.motohiro@jp.fujitsu.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Suggested-by: Hugh Dickins <hughd@google.com>
Acked-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
KOSAKI Motohiro 2010-12-02 14:31:19 -08:00 committed by Linus Torvalds
parent 4fe65cab84
commit 20d6c96b5f
3 changed files with 34 additions and 11 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

6
include/linux/memory_hotplug.h
View file

@ -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

8
mm/memory-failure.c
View file

@ -51,6 +51,7 @@
#include <linux/slab.h>
#include <linux/swapops.h>
#include <linux/hugetlb.h>
#include <linux/memory_hotplug.h>
#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;
}

31
mm/memory_hotplug.c
View file

@ -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 @@ int __ref add_memory(int nid, u64 start, u64 size)
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 @@ static int offline_pages(unsigned long start_pfn,
writeback_set_ratelimit();
memory_notify(MEM_OFFLINE, &arg);
unlock_system_sleep();
unlock_memory_hotplug();
return 0;
failed_removal:
@ -891,7 +908,7 @@ static int offline_pages(unsigned long start_pfn,
undo_isolate_page_range(start_pfn, end_pfn);
out:
unlock_system_sleep();
unlock_memory_hotplug();
return ret;
}