Messages in this thread | | | Date | Thu, 16 Nov 2023 15:09:05 +0800 | Subject | Re: [PATCH] LoongArch: Implement stable timer shutdown interface | From | WANG Xuerui <> |
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Hi,
Sorry for the late review but here we go:
On 11/14/23 19:46, Bibo Mao wrote: > When cpu is hotplug out, cpu is in idle state and function "When a CPU is hot-unplugged, it is put into idle state and the function ... is called" > arch_cpu_idle_dead is called. Timer interrupt for this processor should > be disabled, else there will be timer interrupt for the dead cpu. Also > this prevents vcpu to schedule out during halt-polling flow when system > is running in vm mode, since there is pending timer interrupt.
The logical relationship is a bit unclear, is my paraphrasing correct in your opinion?
"Timer interrupt for this processor should be disabled, else a pending timer interrupt will prevent the vCPU from scheduling out during the halt-polling flow when system is running in VM mode"
(I don't immediately know what a "schedule out" is. Is that a translation artifact or some KVM jargon?)
> > This patch adds detailed implementation for timer shutdown interface, so > that timer will be disabled when cpu is plug-out.
Missing some definite articles too.
"This patch implements the timer shutdown interface so that the timer will be properly disabled when a CPU is hot-unplugged"
Is this version better?
> > Signed-off-by: Bibo Mao <maobibo@loongson.cn> > --- > arch/loongarch/kernel/time.c | 9 ++------- > 1 file changed, 2 insertions(+), 7 deletions(-) > > diff --git a/arch/loongarch/kernel/time.c b/arch/loongarch/kernel/time.c > index 3064af94db9c..2920770e30a9 100644 > --- a/arch/loongarch/kernel/time.c > +++ b/arch/loongarch/kernel/time.c > @@ -58,7 +58,7 @@ static int constant_set_state_oneshot(struct clock_event_device *evt) > return 0; > } > > -static int constant_set_state_oneshot_stopped(struct clock_event_device *evt) > +static int constant_set_state_shutdown(struct clock_event_device *evt) > { > unsigned long timer_config; > > @@ -90,11 +90,6 @@ static int constant_set_state_periodic(struct clock_event_device *evt) > return 0; > } > > -static int constant_set_state_shutdown(struct clock_event_device *evt) > -{ > - return 0; > -} > - > static int constant_timer_next_event(unsigned long delta, struct clock_event_device *evt) > { > unsigned long timer_config; > @@ -161,7 +156,7 @@ int constant_clockevent_init(void) > cd->rating = 320; > cd->cpumask = cpumask_of(cpu); > cd->set_state_oneshot = constant_set_state_oneshot; > - cd->set_state_oneshot_stopped = constant_set_state_oneshot_stopped; > + cd->set_state_oneshot_stopped = constant_set_state_shutdown; > cd->set_state_periodic = constant_set_state_periodic; > cd->set_state_shutdown = constant_set_state_shutdown; > cd->set_next_event = constant_timer_next_event; > > base-commit: 9bacdd8996c77c42ca004440be610692275ff9d0
Otherwise LGTM (regarding the renaming of constant_set_state_oneshot_stopped, both it and the removed constant_set_state_shutdown only has one usage respectively, and looking at the function body it's arguably more appropriate to let it take the "shutdown" name: it's just clearing the enable bit from the CSR.TCFG and nothing else).
With the nits addressed:
Reviewed-by: WANG Xuerui <git@xen0n.name>
-- WANG "xen0n" Xuerui
Linux/LoongArch mailing list: https://lore.kernel.org/loongarch/
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