[PATCH 1/3] mem-hotplug: call isolate_lru_page with elevated refcount

Konstantin Khlebnikov
2011-04-21T13:12:43Z

isolate_lru_page() must be called only with stable reference to page.
So, let's grab normal page reference.

Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
---
mm/memory_hotplug.c | 4 +++-
1 files changed, 3 insertions(+), 1 deletions(-)

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 9ca1d60..0a19109 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -705,7 +705,7 @@ do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
if (!pfn_valid(pfn))
continue;
page = pfn_to_page(pfn);
- if (!page_count(page))
+ if (!get_page_unless_zero(page))
continue;
/*
* We can skip free pages. And we can only deal with pages on
@@ -713,6 +713,7 @@ do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
*/
ret = isolate_lru_page(page);
if (!ret) { /* Success */
+ put_page(page);
list_add_tail(&page->lru, &source);
move_pages--;
inc_zone_page_state(page, NR_ISOLATED_ANON +
@@ -724,6 +725,7 @@ do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
pfn);
dump_page(page);
#endif
+ put_page(page);
/* Because we don't have big zone->lock. we should
check this again here. */
if (page_count(page)) {