zephyr/arch
Benjamin Walsh 168695c7ef kernel/arch: inspect prio/sched_locked together for preemptibility
These two fields in the thread structure control the preemptibility of a
thread.

sched_locked is decremented when the scheduler gets locked, which means
that the scheduler is locked for values 0xff to 0x01, since it can be
locked recursively. A thread is coop if its priority is negative, thus
if the prio field value is 0x80 to 0xff when looked at as an unsigned
value.

By putting them end-to-end, this means that a thread is non-preemptible
if the bundled value is greater than or equal to 0x0080. This is the
only thing the interrupt exit code has to check to decide to try a
reschedule or not.

Change-Id: I902d36c14859d0d7a951a6aa1bea164613821aca
Signed-off-by: Benjamin Walsh <benjamin.walsh@windriver.com>
2017-01-09 20:52:25 +00:00
..
arc kernel/arch: inspect prio/sched_locked together for preemptibility 2017-01-09 20:52:25 +00:00
arm kernel/arch: inspect prio/sched_locked together for preemptibility 2017-01-09 20:52:25 +00:00
nios2 kernel/arch: inspect prio/sched_locked together for preemptibility 2017-01-09 20:52:25 +00:00
x86 kernel/arch: inspect prio/sched_locked together for preemptibility 2017-01-09 20:52:25 +00:00
Kconfig kernel: rename NANOKERNEL_TICKLESS_IDLE_SUPPORTED 2016-12-19 19:58:35 +00:00
Makefile arch/Makefile: simplify 2016-04-27 21:40:19 +00:00