Re: 2.6.17-rc5-mm1

[Andrew Morton]

On Wed, 7 Jun 2006 00:05:07 +0200
Ingo Molnar <mingo@xxxxxxx> wrote:

> 
> * Laurent Riffard <laurent.riffard@xxxxxxx> 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.

However there are no locks in the request struct, so lockdep hasn't
worsened that part of the stack usage.

There could be lock-heavy automatically-allocated structs lurking all over
the place - the least path of resistance here is to require 8k stacks for
lockdep.

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