Re: Preemptive linux

many driver are wrote for UP before, such as a global variable is
accessed without lock.

David Schwartz wrote:
Binary wrote:

Will this challenge the driver developer, such as reentrant function
handling.

Any comments?

It rarely makes much difference because the issues with pre-emption are
more or less identical to the issues with SMP.

Imagine if you write some code that first does X, then does Y. There is
some other code, Z, that has issues if it runs between X and Y. How is
a single CPU doing "X, pre-empt to Z, then Y" any different from
another CPU doing Z after you finish X but before you start Y?

There are differences at low-level, of course. But Linux already takes
care of that in its code for things like spinlocks.

DS

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