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 <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>
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 1243241..46ab2c0 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -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 @@
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 @@
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 9260314..2c6523a 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 @@
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 @@
BUG_ON(ret);
out:
- unlock_system_sleep();
+ unlock_memory_hotplug();
return ret;
}
@@ -516,7 +533,7 @@
struct resource *res;
int ret;
- lock_system_sleep();
+ lock_memory_hotplug();
res = register_memory_resource(start, size);
ret = -EEXIST;
@@ -563,7 +580,7 @@
release_memory_resource(res);
out:
- unlock_system_sleep();
+ unlock_memory_hotplug();
return ret;
}
EXPORT_SYMBOL_GPL(add_memory);
@@ -791,7 +808,7 @@
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 @@
writeback_set_ratelimit();
memory_notify(MEM_OFFLINE, &arg);
- unlock_system_sleep();
+ unlock_memory_hotplug();
return 0;
failed_removal:
@@ -891,7 +908,7 @@
undo_isolate_page_range(start_pfn, end_pfn);
out:
- unlock_system_sleep();
+ unlock_memory_hotplug();
return ret;
}
