[PATCH] memory hotplug locking: zone span seqlock
See the "fixup bad_range()" patch for more information, but this actually
creates a the lock to protect things making assumptions about a zone's size
staying constant at runtime.
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 32fad6d..817635f 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -33,6 +33,7 @@
#include <linux/sysctl.h>
#include <linux/cpu.h>
#include <linux/cpuset.h>
+#include <linux/memory_hotplug.h>
#include <linux/nodemask.h>
#include <linux/vmalloc.h>
@@ -80,12 +81,19 @@
static int page_outside_zone_boundaries(struct zone *zone, struct page *page)
{
- if (page_to_pfn(page) >= zone->zone_start_pfn + zone->spanned_pages)
- return 1;
- if (page_to_pfn(page) < zone->zone_start_pfn)
- return 1;
+ int ret = 0;
+ unsigned seq;
+ unsigned long pfn = page_to_pfn(page);
- return 0;
+ do {
+ seq = zone_span_seqbegin(zone);
+ if (pfn >= zone->zone_start_pfn + zone->spanned_pages)
+ ret = 1;
+ else if (pfn < zone->zone_start_pfn)
+ ret = 1;
+ } while (zone_span_seqretry(zone, seq));
+
+ return ret;
}
static int page_is_consistent(struct zone *zone, struct page *page)
@@ -1980,6 +1988,7 @@
zone->name = zone_names[j];
spin_lock_init(&zone->lock);
spin_lock_init(&zone->lru_lock);
+ zone_seqlock_init(zone);
zone->zone_pgdat = pgdat;
zone->free_pages = 0;