diff options
| author | KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> | 2010-09-09 16:38:01 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-09-09 18:57:24 -0700 |
| commit | 0dcc48c15f63ee86c2fcd33968b08d651f0360a5 (patch) | |
| tree | d182a43200204be2fea04bcb80b824c6f4941267 /mm/memory_hotplug.c | |
| parent | bc6930457460788e14b2c0808ed4632a1592bd61 (diff) | |
memory hotplug: fix next block calculation in is_removable
next_active_pageblock() is for finding next _used_ freeblock. It skips
several blocks when it finds there are a chunk of free pages lager than
pageblock. But it has 2 bugs.
1. We have no lock. page_order(page) - pageblock_order can be minus.
2. pageblocks_stride += is wrong. it should skip page_order(p) of pages.
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/memory_hotplug.c')
| -rw-r--r-- | mm/memory_hotplug.c | 16 |
1 files changed, 8 insertions, 8 deletions
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index a4cfcdc00455..dd186c1a5d53 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -584,19 +584,19 @@ static inline int pageblock_free(struct page *page) /* Return the start of the next active pageblock after a given page */ static struct page *next_active_pageblock(struct page *page) { - int pageblocks_stride; - /* Ensure the starting page is pageblock-aligned */ BUG_ON(page_to_pfn(page) & (pageblock_nr_pages - 1)); - /* Move forward by at least 1 * pageblock_nr_pages */ - pageblocks_stride = 1; - /* If the entire pageblock is free, move to the end of free page */ - if (pageblock_free(page)) - pageblocks_stride += page_order(page) - pageblock_order; + if (pageblock_free(page)) { + int order; + /* be careful. we don't have locks, page_order can be changed.*/ + order = page_order(page); + if ((order < MAX_ORDER) && (order >= pageblock_order)) + return page + (1 << order); + } - return page + (pageblocks_stride * pageblock_nr_pages); + return page + pageblock_nr_pages; } /* Checks if this range of memory is likely to be hot-removable. */ |