Commit 5de62ea8 authored Sep 21, 2021 by Peter Zijlstra

sched,livepatch: Use wake_up_if_idle()



Make sure to prod idle CPUs so they call klp_update_patch_state().

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Vasily Gorbik <gor@linux.ibm.com>
Tested-by: Petr Mladek <pmladek@suse.com>
Tested-by: Vasily Gorbik <gor@linux.ibm.com> # on s390
Link: https://lkml.kernel.org/r/20210929151723.162004989@infradead.org

parent 8850cb66

include/linux/sched/idle.h

+4 −0

Original line number	Diff line number	Diff line
		@@ -11,7 +11,11 @@ enum cpu_idle_type {
		CPU_MAX_IDLE_TYPES
		};

		#ifdef CONFIG_SMP
		extern void wake_up_if_idle(int cpu);
		#else
		static inline void wake_up_if_idle(int cpu) { }
		#endif

		/*
		* Idle thread specific functions to determine the need_resched

kernel/livepatch/transition.c

+4 −1

Original line number	Diff line number	Diff line
		@@ -413,8 +413,11 @@ void klp_try_complete_transition(void)
		for_each_possible_cpu(cpu) {
		task = idle_task(cpu);
		if (cpu_online(cpu)) {
		if (!klp_try_switch_task(task))
		if (!klp_try_switch_task(task)) {
		complete = false;
		/* Make idle task go through the main loop. */
		wake_up_if_idle(cpu);
		}
		} else if (task->patch_state != klp_target_state) {
		/* offline idle tasks can be switched immediately */
		clear_tsk_thread_flag(task, TIF_PATCH_PENDING);