Currently Linux register ghes_poll_func with TIMER_DEFERRABLE flag, because of which it is serviced when the CPU eventually wakes up with a subsequent non-deferrable timer and not at the configured polling interval. For polling mode, the polling interval configured by firmware should not be exceeded as per ACPI_6_3 spec[refer Table 18-394], So Timer need to be configured in non-deferrable mode by removing TIMER_DEFERRABLE flag. With NO_HZ enabled and timer callback being configured in non-deferrable mode, timer callback will get called exactly after polling interval. Impact of removing TIMER_DEFFERABLE flag - With NO_HZ enabled, additional timer ticks and unnecessary wakeups of the cpu happens exactly after polling interval. - If polling interval is too small than polling function will be called too frequently which may stall the cpu. Signed-off-by: Bhaskar Upadhaya <bupadhaya@xxxxxxxxxxx> --- drivers/acpi/apei/ghes.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c index 777f6f7122b4..c8f9230f69fb 100644 --- a/drivers/acpi/apei/ghes.c +++ b/drivers/acpi/apei/ghes.c @@ -1181,7 +1181,7 @@ static int ghes_probe(struct platform_device *ghes_dev) switch (generic->notify.type) { case ACPI_HEST_NOTIFY_POLLED: - timer_setup(&ghes->timer, ghes_poll_func, TIMER_DEFERRABLE); + timer_setup(&ghes->timer, ghes_poll_func, 0); ghes_add_timer(ghes); break; case ACPI_HEST_NOTIFY_EXTERNAL: -- 2.17.1