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FromRusty Russell <>
SubjectRe: [PATCH] Lightweight userspace semaphores...
DateMon, 25 Feb 2002 12:10:34 +1100
In message <Pine.LNX.4.33.0202241543550.28708-100000@home.transmeta.com> you wr
ite:
> 
> On Mon, 25 Feb 2002, Rusty Russell wrote:
> > >
> > >   sys_sem_create()
> > >   sys_sem_destroy()
> >
> > There is no create and destroy (init is purely userspace).  There is
> > "this is a semapore: up it".  This is a feature.
> 
> You have to realize that there are architectures that need special
> initialization and page allocation for semaphores: they need special flags
> in the TLB for "careful access", for example (sometimes the careful access
> ends up being non-cached).

Bugger.  How about:

	sys_sem_area(void *pagestart, size_t len)
	sys_unsem_area(void *pagestart, size_t len)

Is that sufficient?  Is sys_unsem_area required at all?

TDB has an arbitrary number of semaphores in the mmap file...
Rusty.
--
  Anyone who quotes me in their sig is an idiot. -- Rusty Russell.
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