Messages in this thread Patch in this message | | | From | Frederic Weisbecker <> | Subject | [PATCH 5/7] cpuidle: Introduce CPUIDLE_FLAG_POLLING_HARD | Date | Fri, 24 Nov 2023 23:32:24 +0100 |
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From: Peter Zijlstra <peterz@infradead.org>
Provide a way to tell the cpuidle core about states polling/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 polling 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_POLLING_HARD]
Not-yet-signed-off-by: Peter Zijlstra <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 | 3 ++- 3 files changed, 9 insertions(+), 2 deletions(-)
diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c index 3a34a8c425fe..a77a4d4b0dad 100644 --- a/drivers/acpi/processor_idle.c +++ b/drivers/acpi/processor_idle.c @@ -814,6 +814,9 @@ static int acpi_processor_setup_cstates(struct acpi_processor *pr) if (cx->type != ACPI_STATE_C3) drv->safe_state_index = count; } + + if (cx->entry_method == ACPI_CSTATE_FFH) + state->flags |= CPUIDLE_FLAG_POLLING_HARD; /* * 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 3e01a6b23e75..bc56624fe0b5 100644 --- a/drivers/idle/intel_idle.c +++ b/drivers/idle/intel_idle.c @@ -1563,7 +1563,8 @@ 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_POLLING_HARD; + if (cx->type > ACPI_STATE_C2) state->flags |= CPUIDLE_FLAG_TLB_FLUSHED; @@ -1836,6 +1837,8 @@ 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_POLLING_HARD; + 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 66b59868622c..873fdf200dc3 100644 --- a/include/linux/cpuidle.h +++ b/include/linux/cpuidle.h @@ -78,13 +78,14 @@ struct cpuidle_state { /* Idle State Flags */ #define CPUIDLE_FLAG_NONE (0x00) -#define CPUIDLE_FLAG_POLLING_SOFT BIT(0) /* polling state */ +#define CPUIDLE_FLAG_POLLING_SOFT BIT(0) /* software need_resched() polling state */ #define CPUIDLE_FLAG_COUPLED BIT(1) /* state applies to multiple cpus */ #define CPUIDLE_FLAG_TIMER_STOP BIT(2) /* timer is stopped on this state */ #define CPUIDLE_FLAG_UNUSABLE BIT(3) /* avoid using this 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_POLLING_HARD BIT(7) /* hardware need_resched() polling state */ struct cpuidle_device_kobj; struct cpuidle_state_kobj; -- 2.42.1
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