| Message ID | 20241206130408.18690-3-frederic@kernel.org |
|---|---|
| State | New |
| Headers | show |
| Series | cpuidle: Handle TIF_NR_POLLING on behalf of polling idle states v2 | expand |
On Fri, Dec 06, 2024 at 02:04:05PM +0100, Frederic Weisbecker wrote: > From: Peter Zijlstra <peterz@infradead.org> > > Provide a way to tell the cpuidle core about states monitoring > TIF_NEED_RESCHED on the hardware level, monitor/mwait users being the > only examples in use. > > This will allow cpuidle core to manage TIF_NR_POLLING on behalf of all > kinds of TIF_NEED_RESCHED watching states while keeping a necessary > distinction for the governors between software loops polling on > TIF_NEED_RESCHED and hardware monitored writes to thread flags. > > [fweisbec: _ Initialize flag from acpi_processor_setup_cstates() instead > of acpi_processor_setup_lpi_states(), as the latter seem to > be about arm64... > _ Rename CPUIDLE_FLAG_NO_IPI to CPUIDLE_FLAG_MWAIT] > > Not-yet-signed-off-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> > Signed-off-by: Frederic Weisbecker <frederic@kernel.org> > --- > drivers/acpi/processor_idle.c | 3 +++ > drivers/idle/intel_idle.c | 5 ++++- > include/linux/cpuidle.h | 1 + > 3 files changed, 8 insertions(+), 1 deletion(-) > > diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c > index 698897b29de2..66cb5536d91e 100644 > --- a/drivers/acpi/processor_idle.c > +++ b/drivers/acpi/processor_idle.c > @@ -806,6 +806,9 @@ static int acpi_processor_setup_cstates(struct acpi_processor *pr) > if (cx->type == ACPI_STATE_C1 || cx->type == ACPI_STATE_C2) > drv->safe_state_index = count; > > + if (cx->entry_method == ACPI_CSTATE_FFH) > + state->flags |= CPUIDLE_FLAG_MWAIT; > + > /* > * Halt-induced C1 is not good for ->enter_s2idle, because it > * re-enables interrupts on exit. Moreover, C1 is generally not > diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c > index ac4d8faa3886..d52723fbeb04 100644 > --- a/drivers/idle/intel_idle.c > +++ b/drivers/idle/intel_idle.c > @@ -1787,7 +1787,8 @@ static void __init intel_idle_init_cstates_acpi(struct cpuidle_driver *drv) > if (cx->type > ACPI_STATE_C1) > state->target_residency *= 3; > > - state->flags = MWAIT2flg(cx->address); > + state->flags = MWAIT2flg(cx->address) | CPUIDLE_FLAG_MWAIT; > + > if (cx->type > ACPI_STATE_C2) > state->flags |= CPUIDLE_FLAG_TLB_FLUSHED; > > @@ -2072,6 +2073,8 @@ static bool __init intel_idle_verify_cstate(unsigned int mwait_hint) > > static void state_update_enter_method(struct cpuidle_state *state, int cstate) > { > + state->flags |= CPUIDLE_FLAG_MWAIT; > + > if (state->flags & CPUIDLE_FLAG_INIT_XSTATE) { > /* > * Combining with XSTATE with IBRS or IRQ_ENABLE flags > diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h > index a9ee4fe55dcf..b8084617aa27 100644 > --- a/include/linux/cpuidle.h > +++ b/include/linux/cpuidle.h > @@ -85,6 +85,7 @@ struct cpuidle_state { > #define CPUIDLE_FLAG_OFF BIT(4) /* disable this state by default */ > #define CPUIDLE_FLAG_TLB_FLUSHED BIT(5) /* idle-state flushes TLBs */ > #define CPUIDLE_FLAG_RCU_IDLE BIT(6) /* idle-state takes care of RCU */ > +#define CPUIDLE_FLAG_MWAIT BIT(7) /* hardware need_resched() monitoring */ > > struct cpuidle_device_kobj; > struct cpuidle_state_kobj; > -- > 2.46.0 >
diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c index 698897b29de2..66cb5536d91e 100644 --- a/drivers/acpi/processor_idle.c +++ b/drivers/acpi/processor_idle.c @@ -806,6 +806,9 @@ static int acpi_processor_setup_cstates(struct acpi_processor *pr) if (cx->type == ACPI_STATE_C1 || cx->type == ACPI_STATE_C2) drv->safe_state_index = count; + if (cx->entry_method == ACPI_CSTATE_FFH) + state->flags |= CPUIDLE_FLAG_MWAIT; + /* * Halt-induced C1 is not good for ->enter_s2idle, because it * re-enables interrupts on exit. Moreover, C1 is generally not diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c index ac4d8faa3886..d52723fbeb04 100644 --- a/drivers/idle/intel_idle.c +++ b/drivers/idle/intel_idle.c @@ -1787,7 +1787,8 @@ static void __init intel_idle_init_cstates_acpi(struct cpuidle_driver *drv) if (cx->type > ACPI_STATE_C1) state->target_residency *= 3; - state->flags = MWAIT2flg(cx->address); + state->flags = MWAIT2flg(cx->address) | CPUIDLE_FLAG_MWAIT; + if (cx->type > ACPI_STATE_C2) state->flags |= CPUIDLE_FLAG_TLB_FLUSHED; @@ -2072,6 +2073,8 @@ static bool __init intel_idle_verify_cstate(unsigned int mwait_hint) static void state_update_enter_method(struct cpuidle_state *state, int cstate) { + state->flags |= CPUIDLE_FLAG_MWAIT; + if (state->flags & CPUIDLE_FLAG_INIT_XSTATE) { /* * Combining with XSTATE with IBRS or IRQ_ENABLE flags diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h index a9ee4fe55dcf..b8084617aa27 100644 --- a/include/linux/cpuidle.h +++ b/include/linux/cpuidle.h @@ -85,6 +85,7 @@ struct cpuidle_state { #define CPUIDLE_FLAG_OFF BIT(4) /* disable this state by default */ #define CPUIDLE_FLAG_TLB_FLUSHED BIT(5) /* idle-state flushes TLBs */ #define CPUIDLE_FLAG_RCU_IDLE BIT(6) /* idle-state takes care of RCU */ +#define CPUIDLE_FLAG_MWAIT BIT(7) /* hardware need_resched() monitoring */ struct cpuidle_device_kobj; struct cpuidle_state_kobj;