This doesn't change functionality at all, but I've misread this code
so many times that I want to make it a bit more obvious.
Signed-off-by: Andy Lutomirski <l...@amacapital.net>
---
kernel/sched/idle.c | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)
diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c
index 25b9423..2ec9f47 100644
--- a/kernel/sched/idle.c
+++ b/kernel/sched/idle.c
@@ -67,6 +67,10 @@ void __weak arch_cpu_idle(void)
* cpuidle_idle_call - the main idle function
*
* NOTE: no locks or semaphores should be used here
+ *
+ * On archs that support TIF_POLLING_NRFLAG, is called with polling
+ * set, and it returns with polling set. If it ever stops polling, it
+ * must clear the polling bit.
*/
static void cpuidle_idle_call(void)
{
@@ -178,7 +182,14 @@ exit_idle:
*/
static void cpu_idle_loop(void)
{
+ __current_set_polling();
+
while (1) {
+ /*
+ * Invariant: polling is set here (assuming that the arch
+ * has a polling bit.
+ */
+
tick_nohz_idle_enter();
while (!need_resched()) {
@@ -239,7 +250,6 @@ void cpu_startup_entry(enum cpuhp_state state)
*/
boot_init_stack_canary();
#endif
- __current_set_polling();
arch_cpu_idle_prepare();
cpu_idle_loop();
}
--
1.9.3
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