On Tue, Sep 15, 2020 at 12:32:01PM +0200, Peter Zijlstra wrote: > The C3 BusMaster idle code takes lock in a number of places, some deep > inside the ACPI code. Instead of wrapping it all in RCU_NONIDLE, have > the driver take over RCU-idle duty and avoid flipping RCU state back > and forth a lot. > > ( by marking 'C3 && bm_check' as RCU_IDLE, we _must_ call enter_bm() for > that combination, otherwise we'll loose RCU-idle, this requires > shuffling some code around ) > > Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> ia64:defconfig: ERROR: modpost: "rcu_idle_enter" [drivers/acpi/processor.ko] undefined! ERROR: modpost: "rcu_idle_exit" [drivers/acpi/processor.ko] undefined! I realize that this has already been reported more than a week ago, with no visible reaction. Another problem introduced in the same file, resulting in drivers/acpi/processor_idle.c: In function 'lapic_timer_needs_broadcast': drivers/acpi/processor_idle.c:179:1: warning: no return statement in function returning non-void may cause ia64 boot problems since a non-zero return value will trigger a function call. AFAICS that is not supposed to happen on ia64. This makes me wonder - if no one cares about buiding (much less running) ia64 images with the upstream kernel, is it possibly time to remove it ? Guenter
