Add architectural support for the cpuidle-haltpoll driver by defining arch_haltpoll_*(). Also select ARCH_HAS_OPTIMIZED_POLL since we have an optimized polling mechanism via smp_cond_load*(). Add the configuration option, ARCH_CPUIDLE_HALTPOLL to allow cpuidle-haltpoll to be selected. Note that we limit cpuidle-haltpoll support to when the event-stream is available. This is necessary because polling via smp_cond_load_relaxed() uses WFE to wait for a store which might not happen for an prolonged period of time. So, ensure the event-stream is around to provide a terminating condition. Signed-off-by: Ankur Arora <ankur.a.arora@xxxxxxxxxx> --- arch/arm64/Kconfig | 10 ++++++++++ arch/arm64/include/asm/cpuidle_haltpoll.h | 21 +++++++++++++++++++++ 2 files changed, 31 insertions(+) create mode 100644 arch/arm64/include/asm/cpuidle_haltpoll.h diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 7b11c98b3e84..6f2df162b10e 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -34,6 +34,7 @@ config ARM64 select ARCH_HAS_MEMBARRIER_SYNC_CORE select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE + select ARCH_HAS_OPTIMIZED_POLL select ARCH_HAS_PTE_DEVMAP select ARCH_HAS_PTE_SPECIAL select ARCH_HAS_HW_PTE_YOUNG @@ -2331,6 +2332,15 @@ config ARCH_HIBERNATION_HEADER config ARCH_SUSPEND_POSSIBLE def_bool y +config ARCH_CPUIDLE_HALTPOLL + bool "Enable selection of the cpuidle-haltpoll driver" + default n + help + cpuidle-haltpoll allows for adaptive polling based on + current load before entering the idle state. + + Some virtualized workloads benefit from using it. + endmenu # "Power management options" menu "CPU Power Management" diff --git a/arch/arm64/include/asm/cpuidle_haltpoll.h b/arch/arm64/include/asm/cpuidle_haltpoll.h new file mode 100644 index 000000000000..a79bdec7f516 --- /dev/null +++ b/arch/arm64/include/asm/cpuidle_haltpoll.h @@ -0,0 +1,21 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ASM_HALTPOLL_H +#define _ASM_HALTPOLL_H + +static inline void arch_haltpoll_enable(unsigned int cpu) +{ +} + +static inline void arch_haltpoll_disable(unsigned int cpu) +{ +} + +static inline bool arch_haltpoll_supported(void) +{ + /* + * Ensure the event stream is available to provide a terminating + * condition to the WFE in the poll loop. + */ + return arch_timer_evtstrm_available(); +} +#endif -- 2.39.3