[PATCH 1/1] block: CFQ refcounting fix

brking_at_us.ibm.com
Date: 08/31/05

  • Next message: Daniel Walker: "[PATCH] PREEMPT_RT vermagic" 
    To: axboe@suse.de
Date:	Tue, 30 Aug 2005 17:41:07 -0500

    I ran across a memory leak related to the cfq scheduler. The cfq
    init function increments the refcnt of the associated request_queue.
    This refcount gets decremented in cfq's exit function. Since blk_cleanup_queue
    only calls the elevator exit function when its refcnt goes to zero, the
    request_q never gets cleaned up. It didn't look like other io schedulers were
    incrementing this refcnt, so I removed the refcnt increment and it fixed the
    memory leak for me.

    To reproduce the problem, simply use cfq and use the scsi_host scan sysfs
    attribute to scan "- - -" repeatedly on a scsi host and watch the memory
    vanish.

    Signed-off-by: Brian King <brking@us.ibm.com> 

    ---
 linux-2.6-bjking1/drivers/block/cfq-iosched.c |    1 -
 1 files changed, 1 deletion(-)
diff -puN drivers/block/cfq-iosched.c~cfq_refcnt_fix drivers/block/cfq-iosched.c
--- linux-2.6/drivers/block/cfq-iosched.c~cfq_refcnt_fix	2005-08-30 17:26:55.000000000 -0500
+++ linux-2.6-bjking1/drivers/block/cfq-iosched.c	2005-08-30 17:26:55.000000000 -0500
@@ -2318,7 +2318,6 @@ static int cfq_init_queue(request_queue_
 	e->elevator_data = cfqd;
 
 	cfqd->queue = q;
-	atomic_inc(&q->refcnt);
 
 	cfqd->max_queued = q->nr_requests / 4;
 	q->nr_batching = cfq_queued;
_
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/
  • Next message: Daniel Walker: "[PATCH] PREEMPT_RT vermagic"

    Relevant Pages