From af98603dad87e393d2fc57117fe8a2aa6d620a0c Mon Sep 17 00:00:00 2001 From: Catalin Marinas Date: Thu, 27 Aug 2009 14:29:12 +0100 Subject: kmemleak: Allow rescheduling during an object scanning 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 --- mm/kmemleak.c | 21 +++++++++++++++++---- 1 file changed, 17 insertions(+), 4 deletions(-) diff --git a/mm/kmemleak.c b/mm/kmemleak.c index 487267310a8..6debe0d80e6 100644 --- a/mm/kmemleak.c +++ b/mm/kmemleak.c @@ -107,6 +107,7 @@ #define SECS_FIRST_SCAN 60 /* delay before the first scan */ #define SECS_SCAN_WAIT 600 /* subsequent auto scanning delay */ #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 *) @@ -642,6 +643,7 @@ static void make_black_object(unsigned long ptr) spin_lock_irqsave(&object->lock, flags); object->min_count = -1; + object->flags |= OBJECT_NO_SCAN; spin_unlock_irqrestore(&object->lock, flags); put_object(object); } @@ -949,10 +951,21 @@ static void scan_object(struct kmemleak_object *object) if (!(object->flags & OBJECT_ALLOCATED)) /* already freed object */ goto out; - if (hlist_empty(&object->area_list)) - scan_block((void *)object->pointer, - (void *)(object->pointer + object->size), object, 0); - else + if (hlist_empty(&object->area_list)) { + void *start = (void *)object->pointer; + void *end = (void *)(object->pointer + object->size); + + 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) scan_block((void *)(object->pointer + area->offset), (void *)(object->pointer + area->offset -- cgit v1.2.3