[lkml]   [2005]   [Aug]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
Patch in this message
Subject[PATCH 1/1] block: CFQ refcounting fix

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

Signed-off-by: Brian King <>

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
More majordomo info at
Please read the FAQ at
 \ /
  Last update: 2005-08-31 00:43    [W:0.040 / U:1.856 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site