I've some questions about the preemption of the kernel. In the Linux 2.2 and 2.4, there are a lot of spin_lock_irqsave to disable interrupt like :
spin_lock_irqsave() ;
CRITICAL SECTION
spin_lock_irqrestore() ;
In a non preemptive kernel, the critical section is executed as an atomic operation that's sure. But in a preemptive kernel, the kernel can be interrupted by a process. So the kernel has a timeslice and if the timeslice finishes in the CRITICAL section, there's a problem.
And this code in SMP environment doesn't work neither, does it ? It only protects the interrupts of 1 processor no ?
Just some thoughts about synchronization :)
Thx :p
Eric
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