On 10/12/2015 04:40 AM, yalin wang wrote:
Remove unlikely(order), because we are sure order is not zero if
code reach here, also add if (page == NULL), only allocate page again if
__rmqueue_smallest() failed or alloc_flags & ALLOC_HARDER == 0
The second mentioned change is actually more important as it removes a
memory leak! Thanks for catching this. The problem is in patch
mm-page_alloc-reserve-pageblocks-for-high-order-atomic-allocations-on-demand.patch
and seems to have been due to a change in the last submitted version to
make sure the tracepoint is called.
Signed-off-by: yalin wang <yalin.wang2010@xxxxxxxxx>
---
mm/page_alloc.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 0d6f540..de82e2c 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2241,13 +2241,13 @@ struct page *buffered_rmqueue(struct zone *preferred_zone,
spin_lock_irqsave(&zone->lock, flags);
page = NULL;
- if (unlikely(order) && (alloc_flags & ALLOC_HARDER)) {
+ if (alloc_flags & ALLOC_HARDER) {
page = __rmqueue_smallest(zone, order, MIGRATE_HIGHATOMIC);
if (page)
trace_mm_page_alloc_zone_locked(page, order, migratetype);
}
-
- page = __rmqueue(zone, order, migratetype, gfp_flags);
+ if (page == NULL)
"if (!page)" is more common and already used below.
We could skip the check for !page in case we don't go through the
ALLOC_HARDER branch, but I guess it's not worth the goto, and hopefully
the compiler is smart enough anyway...
+ page = __rmqueue(zone, order, migratetype, gfp_flags);
spin_unlock(&zone->lock);
if (!page)
goto failed;
--
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