From: Ankur Arora ankur.a.arora@oracle.com
ARCH_HAS_CPU_RELAX is defined on architectures that provide an primitive (via cpu_relax()) that can be used as part of a polling mechanism -- one that would be cheaper than spinning in a tight loop.
However, recent changes in poll_idle() mean that a higher level primitive -- smp_cond_load_relaxed() is used for polling. This would in-turn use cpu_relax() or an architecture specific implementation. On ARM64 in particular this turns into a WFE which waits on a store to a cacheline instead of a busy poll.
Accordingly condition the polling drivers on ARCH_HAS_OPTIMIZED_POLL instead of ARCH_HAS_CPU_RELAX. While at it, make both intel-idle and cpuidle-haltpoll explicitly depend on ARCH_HAS_CPU_RELAX.
Suggested-by: Will Deacon will@kernel.org Signed-off-by: Ankur Arora ankur.a.arora@oracle.com Signed-off-by: lishusen lishusen2@huawei.com --- arch/x86/Kconfig | 2 +- drivers/acpi/processor_idle.c | 4 ++-- drivers/cpuidle/Kconfig | 2 +- drivers/cpuidle/Makefile | 2 +- drivers/idle/Kconfig | 1 + include/linux/cpuidle.h | 2 +- 6 files changed, 7 insertions(+), 6 deletions(-)
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 9be87b701f0f..0ee350a21f3a 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -370,7 +370,7 @@ config ARCH_MAY_HAVE_PC_FDC config GENERIC_CALIBRATE_DELAY def_bool y
-config ARCH_HAS_CPU_RELAX +config ARCH_HAS_OPTIMIZED_POLL def_bool y
config ARCH_HIBERNATION_POSSIBLE diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c index 831fa4a12159..44096406d65d 100644 --- a/drivers/acpi/processor_idle.c +++ b/drivers/acpi/processor_idle.c @@ -35,7 +35,7 @@ #include <asm/cpu.h> #endif
-#define ACPI_IDLE_STATE_START (IS_ENABLED(CONFIG_ARCH_HAS_CPU_RELAX) ? 1 : 0) +#define ACPI_IDLE_STATE_START (IS_ENABLED(CONFIG_ARCH_HAS_OPTIMIZED_POLL) ? 1 : 0)
static unsigned int max_cstate __read_mostly = ACPI_PROCESSOR_MAX_POWER; module_param(max_cstate, uint, 0400); @@ -782,7 +782,7 @@ static int acpi_processor_setup_cstates(struct acpi_processor *pr) if (max_cstate == 0) max_cstate = 1;
- if (IS_ENABLED(CONFIG_ARCH_HAS_CPU_RELAX)) { + if (IS_ENABLED(CONFIG_ARCH_HAS_OPTIMIZED_POLL)) { cpuidle_poll_state_init(drv); count = 1; } else { diff --git a/drivers/cpuidle/Kconfig b/drivers/cpuidle/Kconfig index cac5997dca50..75f6e176bbc8 100644 --- a/drivers/cpuidle/Kconfig +++ b/drivers/cpuidle/Kconfig @@ -73,7 +73,7 @@ endmenu
config HALTPOLL_CPUIDLE tristate "Halt poll cpuidle driver" - depends on X86 && KVM_GUEST + depends on X86 && KVM_GUEST && ARCH_HAS_OPTIMIZED_POLL select CPU_IDLE_GOV_HALTPOLL default y help diff --git a/drivers/cpuidle/Makefile b/drivers/cpuidle/Makefile index d103342b7cfc..f29dfd1525b0 100644 --- a/drivers/cpuidle/Makefile +++ b/drivers/cpuidle/Makefile @@ -7,7 +7,7 @@ obj-y += cpuidle.o driver.o governor.o sysfs.o governors/ obj-$(CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED) += coupled.o obj-$(CONFIG_DT_IDLE_STATES) += dt_idle_states.o obj-$(CONFIG_DT_IDLE_GENPD) += dt_idle_genpd.o -obj-$(CONFIG_ARCH_HAS_CPU_RELAX) += poll_state.o +obj-$(CONFIG_ARCH_HAS_OPTIMIZED_POLL) += poll_state.o obj-$(CONFIG_HALTPOLL_CPUIDLE) += cpuidle-haltpoll.o
################################################################################## diff --git a/drivers/idle/Kconfig b/drivers/idle/Kconfig index 6707d2539fc4..6f9b1d48fede 100644 --- a/drivers/idle/Kconfig +++ b/drivers/idle/Kconfig @@ -4,6 +4,7 @@ config INTEL_IDLE depends on CPU_IDLE depends on X86 depends on CPU_SUP_INTEL + depends on ARCH_HAS_OPTIMIZED_POLL help Enable intel_idle, a cpuidle driver that includes knowledge of native Intel hardware idle features. The acpi_idle driver diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h index 3183aeb7f5b4..7e7e58a17b07 100644 --- a/include/linux/cpuidle.h +++ b/include/linux/cpuidle.h @@ -275,7 +275,7 @@ static inline void cpuidle_coupled_parallel_barrier(struct cpuidle_device *dev, } #endif
-#if defined(CONFIG_CPU_IDLE) && defined(CONFIG_ARCH_HAS_CPU_RELAX) +#if defined(CONFIG_CPU_IDLE) && defined(CONFIG_ARCH_HAS_OPTIMIZED_POLL) void cpuidle_poll_state_init(struct cpuidle_driver *drv); #else static inline void cpuidle_poll_state_init(struct cpuidle_driver *drv) {}