Re: 2.6.17-rc5-mm1

[Jens Axboe <axboe@suse.de>]

On Tue, Jun 06 2006, Andrew Morton wrote:
> On Wed, 7 Jun 2006 00:05:07 +0200
> Ingo Molnar <mingo@elte.hu> wrote:
> 
> > 
> > * Laurent Riffard <laurent.riffard@free.fr> wrote:
> > 
> > > >> Results:
> > > >> - 2.6.17-rc4-mm3 with 4K stack works fine (this is the latest good 4K-kernel).
> > > >> - 2.6.17-rc5-mm3 with 4K stack crashes, the stack seems to be corrupted.
> > > > 
> > > > that's vanilla mm3, or mm3 patched with extra lockdep patches? If it's 
> > > > patched then you should try vanilla mm3 too.
> > > 
> > > It was vanilla mm3.
> > 
> > ok, i'll check the stack impact of the block_dev.c changes tomorrow.
> > 
> 
> Note that Laurent is also passing through ide_cdrom_packet(), which has a
> `struct request' on the stack.  The kernel does this in a lot of places,
> and at 168 bytes on x86, it'd really be best if we were to dynamically
> allocate these things.

That's an old peeve of mine, on-stack requests... It's nasty from
several angles, stack usage just being one of them. Perhaps I'll give it
a go for 2.6.18 and add checks for request being thrown at the block
layer which didn't originate from get_request().

-- 
Jens Axboe