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kmemleak: Allow rescheduling during an object scanning

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If the object size is bigger than a predefined value (4K in this case),
release the object lock during scanning and call cond_resched().
Re-acquire the lock after rescheduling and test whether the object is
still valid.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
Catalin Marinas
2009-08-27 14:29:12 +01:00
parent 1e23502cc5
commit af98603dad
1 changed files with 17 additions and 4 deletions
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21
mm/kmemleak.c
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@@ -107,6 +107,7 @@
#define SECS_FIRST_SCAN 60 /* delay before the first scan */ #define SECS_FIRST_SCAN 60 /* delay before the first scan */
#define SECS_SCAN_WAIT 600 /* subsequent auto scanning delay */ #define SECS_SCAN_WAIT 600 /* subsequent auto scanning delay */
#define GRAY_LIST_PASSES 25 /* maximum number of gray list scans */ #define GRAY_LIST_PASSES 25 /* maximum number of gray list scans */
#define MAX_SCAN_SIZE 4096 /* maximum size of a scanned block */
#define BYTES_PER_POINTER sizeof(void *) #define BYTES_PER_POINTER sizeof(void *)
@@ -642,6 +643,7 @@ static void make_black_object(unsigned long ptr)
spin_lock_irqsave(&object->lock, flags); spin_lock_irqsave(&object->lock, flags);
object->min_count = -1; object->min_count = -1;
object->flags |= OBJECT_NO_SCAN;
spin_unlock_irqrestore(&object->lock, flags); spin_unlock_irqrestore(&object->lock, flags);
put_object(object); put_object(object);
} }
@@ -949,10 +951,21 @@ static void scan_object(struct kmemleak_object *object)
if (!(object->flags & OBJECT_ALLOCATED)) if (!(object->flags & OBJECT_ALLOCATED))
/* already freed object */ /* already freed object */
goto out; goto out;
if (hlist_empty(&object->area_list)) if (hlist_empty(&object->area_list)) {
scan_block((void *)object->pointer, void *start = (void *)object->pointer;
(void *)(object->pointer + object->size), object, 0); void *end = (void *)(object->pointer + object->size);
else
while (start < end && (object->flags & OBJECT_ALLOCATED) &&
!(object->flags & OBJECT_NO_SCAN)) {
scan_block(start, min(start + MAX_SCAN_SIZE, end),
object, 0);
start += MAX_SCAN_SIZE;
spin_unlock_irqrestore(&object->lock, flags);
cond_resched();
spin_lock_irqsave(&object->lock, flags);
}
} else
hlist_for_each_entry(area, elem, &object->area_list, node) hlist_for_each_entry(area, elem, &object->area_list, node)
scan_block((void *)(object->pointer + area->offset), scan_block((void *)(object->pointer + area->offset),
(void *)(object->pointer + area->offset (void *)(object->pointer + area->offset