Re: Linux 2.3.39 has 32bit uid. What about 32bit pid?

From: Chris Wedgwood (cw@f00f.org)
Date: Sat Jan 15 2000 - 16:01:47 EST


> Only few libc5 programs are affected in fact (one with IPC usage).

No, its worse sadly -- think fcntl(fd,F_SETOWN,&pid) sort of thing.
We will need a new F_SETOWN or esle the SIGIO stuff will break.

Its likely there are other such cases too.

> If program is created that way it's broken already :-)

> get_pid() and sheduler should be fixed of course. But they can be
> fixed later. It does not require ABI change :-)

> IMO it's way to go. We do not need more then 2000000000 processes even on
> 64bit platforms but who knows what will be done in next 20 years+ ?

Oh, I completely agree -- but perhaps we wanted to divide that 64-bit
space into bit-regions which had some intrinsic meaning? It may sound
really gross, but you never know.

The main reason I mentioned this, was I imagine for most 64-bit
platforms, accessing a 64-bit word as opposed to a 32-bit word is as
cheap or cheaper and may allow various atomic operations.

-cw

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