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

From: Evgeniy Polyakov
Date: Fri Dec 14 2007 - 01:36:22 EST


On Thu, Dec 13, 2007 at 11:43:43PM +0300, Dmitry Monakhov (dmonakhov@xxxxx) wrote:
> On 14:47 Mon 10 Dec , Evgeniy Polyakov wrote:
> >
> > 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
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