Commit 6a153efc authored Aug 19, 2019 by Andy Ross Committed by Anas Nashif Sep 26, 2019

kernel/timeout: Fix timeslicing edge case in SMP



The timeout code has an optimization where it refuses to send a new
timeout to the driver unless it is sooner than one already scheduled.
This won't work on SMP, though, because the timeout value when
timeslicing is enabled depends on the current thread, and on SMP the
decision as to the next thread will not be made until later (when we
swap, or exit an interrupt).

Signed-off-by: Andy Ross <andrew.j.ross@intel.com>

parent 11bd67db

kernel/timeout.c

+5 −1

Original line number	Diff line number	Diff line
		@@ -168,8 +168,12 @@ void z_set_timeout_expiry(s32_t ticks, bool idle)
		* one is about to expire: drivers have internal logic
		* that will bump the timeout to the "next" tick if
		* it's not considered to be settable as directed.
		* SMP can't use this optimization though: we don't
		* know when context switches happen until interrupt
		* exit and so can't get the timeslicing clamp folded
		* in.
		*/
		if (sooner && !imminent) {
		if (!imminent && (sooner \|\| IS_ENABLED(CONFIG_SMP))) {
		z_clock_set_timeout(ticks, idle);
		}
		}

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