Re: [3/4] DST: Network state machine.

On Thu, Dec 13, 2007 at 11:43:43PM +0300, Dmitry Monakhov (dmonakhov@sw.ru) wrote:

On 14:47 Mon 10 Dec     , Evgeniy Polyakov wrote:

quoted

Network state machine.

Includes network async processing state machine and related tasks.

Hi, I've tried to play a little bit with DST and discover huge memory
leak. Every read request from remote node result in bio + bio's pages leak.

Data flow:
->kst_export_ready 		## prepare and submit bio 
  ->generic_make_request(bio) 	## submit it

->kst_export_read_end_io	## block layer call bio_end_io callback

->kst_thread_process_state	## process ready requests
  ->kst_data_callback
     ->kst_data_process_bio	## submit pages to network layer
  ->kst_complete_req
     ->kst_bio_endio
       ->kst_export_read_end_io ## WoW we calling the same bio_end_io 
				## callback twice 
     ->dst_free_request(req);   ## request will be destroyed but it's bio
				## and all bio's pages wasn't released.
We may release bio's pages after it was sent to network, it is safe because
sendpage() already called get_page(). I've attached simple patch which 
this this.

Yes, your patch looks good.
Thanks a lot, Dmitry.

-- 
	Evgeniy Polyakov