Re: [PATCH] ipw2200 stack reduction

[Jens Axboe <axboe@suse.de>]

On Thu, Dec 29 2005, Zhu Yi wrote:
> On Wed, 2005-12-28 at 22:29 +0100, Jens Axboe wrote:
> > The reason is the host_cmd structure is large (500 bytes). All other
> > functions currently using ipw_send_cmd() suffer from the same problem.
> > This patch introduces ipw_send_cmd_simple() for commands with no data
> > transfer, and ipw_send_cmd_pdu() for commands with a data payload.
> 
> Hi Jens,
> 
> Thanks for point this out and provide the patch. One comment:
> 
> > +static struct host_cmd *ipw_host_cmd_get(u8 command, u8 len)
> >  {
> > ...
> > +       cmd = kzalloc(sizeof(*cmd), GFP_KERNEL);
> 
> This will still alloc 500 bytes for each command. I think if we want to
> dynamically alloc the struct, we can split the struct to head and
> payload and alloc the payload according to the real size.

Well you could do that if you wanted, but 500 bytes of dynamic
allocation is not a big issue. But it could be an optimization on top of
this patch, indeed. The downside is that you then have to do 2
allocations for each command, so whether it would be a win or not I
don't know.

-- 
Jens Axboe