Re: [Lse-tech] Re: [PATCH for 2.5] preemptible kernel

Paul McKenney (Paul.McKenney@us.ibm.com)
Sun, 22 Apr 2001 06:38:37 -0700


> > But if you are suppressing preemption in all read-side critical
sections,
> > then wouldn't any already-preempted tasks be guaranteed to -not- be in
> > a read-side critical section, and therefore be guaranteed to be
unaffected
> > by the update (in other words, wouldn't such tasks not need to be
waited
> > for)?
>
> Ah, if you want to inc and dec all the time, yes. But even if the
> performance isn't hurt, it's unneccessary, and something else people
> have to remember to do.

I must admit that free is a very good price.

> Simplicity is very nice. And in the case of module unload, gives us
> the ability to avoid the distinction between "am I calling into a
> module?" and "is this fixed in the kernel?" at runtime. A very good
> thing 8)

Is it also desireable to avoid the distinction between "the currently
executing code is in a module" and "the currently executing code is
fixed in the kernel"?

> Rusty.

Thanx, Paul

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