The patch titled
memory hotplug: fix next block calculation in is_removable
has been added to the -mm tree. Its filename is
memory-hotplug-fix-next-block-calculation-in-is_removable.patch
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------------------------------------------------------
Subject: memory hotplug: fix next block calculation in is_removable
From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
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@xxxxxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxx>
Cc: Wu Fengguang <fengguang.wu@xxxxxxxxx>
Cc: Mel Gorman <mel@xxxxxxxxx>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memory_hotplug.c | 16 ++++++++--------
1 file changed, 8 insertions(+), 8 deletions(-)
diff -puN mm/memory_hotplug.c~memory-hotplug-fix-next-block-calculation-in-is_removable mm/memory_hotplug.c
--- a/mm/memory_hotplug.c~memory-hotplug-fix-next-block-calculation-in-is_removable
+++ a/mm/memory_hotplug.c
@@ -584,19 +584,19 @@ static inline int pageblock_free(struct
/* 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. */
_
Patches currently in -mm which might be from kamezawa.hiroyu@xxxxxxxxxxxxxx are
linux-next.patch
memory-hotplug-fix-next-block-calculation-in-is_removable.patch
swap-revert-special-hibernation-allocation.patch
swap-prevent-reuse-during-hibernation.patch
vmstat-update-zone-stat-threshold-when-onlining-a-cpu.patch
mm-page-allocator-update-free-page-counters-after-pages-are-placed-on-the-free-list.patch
mm-page-allocator-update-free-page-counters-after-pages-are-placed-on-the-free-list-fix.patch
mm-page-allocator-drain-per-cpu-lists-after-direct-reclaim-allocation-fails.patch
vfs-introduce-fmode_neg_offset-for-allowing-negative-f_pos.patch
vmscan-do-not-writeback-filesystem-pages-in-direct-reclaim.patch
vmscan-kick-flusher-threads-to-clean-pages-when-reclaim-is-encountering-dirty-pages.patch
oom-add-per-mm-oom-disable-count.patch
oom-avoid-killing-a-task-if-a-thread-sharing-its-mm-cannot-be-killed.patch
oom-kill-all-threads-sharing-oom-killed-tasks-mm.patch
oom-kill-all-threads-sharing-oom-killed-tasks-mm-fix.patch
oom-kill-all-threads-sharing-oom-killed-tasks-mm-fix-fix.patch
oom-rewrite-error-handling-for-oom_adj-and-oom_score_adj-tunables.patch
oom-fix-locking-for-oom_adj-and-oom_score_adj.patch
memory-hotplug-fix-notifiers-return-value-check.patch
memory-hotplug-unify-is_removable-and-offline-detection-code.patch
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