Re: [patch V2 16/17] init: Introduce SYSTEM_SCHEDULING state

Mark Rutland
2017-05-17T10:59:35Z

On Tue, May 16, 2017 at 08:42:47PM +0200, Thomas Gleixner wrote:
> might_sleep() debugging and smp_processor_id() debugging should be active
> right after the scheduler starts working. The init task can invoke
> smp_processor_id() from preemptible context as it is pinned on the boot cpu
> until sched_smp_init() removes the pinning and lets it schedule on all non
> isolated cpus.
>
> Add a new state which allows to enable those checks earlier and add it to
> the xen do_poweroff() function.
>
> No functional change.
>
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
> Cc: Juergen Gross <jgross@suse.com>
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Makes sense to me. FWIW:

Acked-by: Mark Rutland <mark.rutland@arm.com>

Mark.

> ---
>
> V2: Use only one intermediate state and document that state order matters.
>
> drivers/xen/manage.c | 1 +
> include/linux/kernel.h | 6 +++++-
> 2 files changed, 6 insertions(+), 1 deletion(-)
>
> --- a/drivers/xen/manage.c
> +++ b/drivers/xen/manage.c
> @@ -190,6 +190,7 @@ static void do_poweroff(void)
> {
> switch (system_state) {
> case SYSTEM_BOOTING:
> + case SYSTEM_SCHEDULING:
> orderly_poweroff(true);
> break;
> case SYSTEM_RUNNING:
> --- a/include/linux/kernel.h
> +++ b/include/linux/kernel.h
> @@ -490,9 +490,13 @@ extern int root_mountflags;
>
> extern bool early_boot_irqs_disabled;
>
> -/* Values used for system_state */
> +/*
> + * Values used for system_state. Ordering of the states must not be changed
> + * as code checks for <, <=, >, >= STATE.
> + */
> extern enum system_states {
> SYSTEM_BOOTING,
> + SYSTEM_SCHEDULING,
> SYSTEM_RUNNING,
> SYSTEM_HALT,
> SYSTEM_POWER_OFF,
>
>