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Globally disabling preemption
- Date: Fri, 09 Nov 2007 15:32:03 +0000
- From: kjrobert at alumni.uwaterloo.ca (Keith Robertson)
- Subject: Globally disabling preemption
The rtems user guide states: "If preemption is disabled for a task
(RTEMS_NO_PREEMPT), then the task will not relinquish control of the
processor until it terminates, blocks, or re-enables preemption."
Given an RTEMS_NO_PREEMPT thread A, I'd like to clarify what happens if
A is interrupted (as interrupts are still on). When the scheduler runs
at the end of an isr, what happens? Will A always be rescheduled? Or
will the normal scheduling algorithm run and A may or may not be selected.
I suspect it's the later. If this is the case, is there a recommended
way of globally disabling preemption so as to have the effect of the
former? That is, A is interrupted, but is always rescheduled after the