The scheduling policy for RESCHED_lazy (TIF_NEED_RESCHED_LAZY) is to let anything running in the kernel run to completion. Accordingly, while deciding whether to call preempt_schedule_irq() narrow the check to tif_need_resched(RESCHED_eager). Also add a comment about why we need to check at all, given that we have aleady checked the preempt_count(). Signed-off-by: Ankur Arora <ankur.a.arora@xxxxxxxxxx> --- kernel/entry/common.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/kernel/entry/common.c b/kernel/entry/common.c index 0d055c39690b..6433e6c77185 100644 --- a/kernel/entry/common.c +++ b/kernel/entry/common.c @@ -384,7 +384,15 @@ void irqentry_exit_cond_resched(void) rcu_irq_exit_check_preempt(); if (IS_ENABLED(CONFIG_DEBUG_ENTRY)) WARN_ON_ONCE(!on_thread_stack()); - if (need_resched()) + + /* + * If the scheduler really wants us to preempt while returning + * to kernel, it would set TIF_NEED_RESCHED. + * On some archs the flag gets folded in preempt_count, and + * thus would be covered in the conditional above, but not all + * archs do that, so check explicitly. + */ + if (tif_need_resched(RESCHED_eager)) preempt_schedule_irq(); } } -- 2.31.1
