Re: [PATCH 1/1] block: CFQ refcounting fix

[Brian King <brking@us.ibm.com>]

Jens Axboe wrote:
> On Tue, Aug 30 2005, brking@us.ibm.com wrote:
> 
>>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.
> 
> 
> Yeah, that actually looks like a dangling reference. I assume you tested
> this properly?

Yes. I applied the patch, booted my system (which was crashing on bootup before
due to out of memory errors due to the leak) ran the scan a few times and verified
/proc/meminfo didn't continually decrease like without it, and rebooted again.
If there is anything else you would like me to do, I would be happy to do so.

Thanks

Brian


-- 
Brian King
eServer Storage I/O
IBM Linux Technology Center