Re: The disappearing sys_call_table export.

Alan Cox
2003-05-05T12:02:59Z

On Llu, 2003-05-05 at 10:33, Terje Eggestad wrote:
> 1. performance is everything.

Then you can live with building custom patched kernels

> 2. We're making a MPI library, and as such we don't have any control
> with the application.

LD_PRELOAD

> 3c. It's therefore necessary for HW to access user pages.

Like TV cards do. That isnt hard

> 4. In order to to 3, the user pages must be pinned down.
> 5. the way MPI is written, it's not using a special malloc() to allocate
> the send receive buffers. It can't since it would break language binding
> to fortran. Thus ANY writeable user page may be used.

Well not all the pages are guaranteed DMAable, so I guess you already
lost.

> 10. kernel patches are impractical, I must be able to do this with std
> stock, redhat, AND suse kernels.

So you want every vendor to screw up their kernels and the base kernel
for an obscure (but fun) corner case. Thats not a rational choice is it.
You want "performance is everything" you pay the price, don't make
everyone suffer.