Polling in idle with poll_idle() needs TIF_POLLING_NRFLAG support, and a cheap mechanism to do the actual polling via smp_cond_load_relaxed_timeout(). Both of these are present on arm64. So, select ARCH_HAS_OPTIMIZED_POLL to enable it. Enabling this should help reduce the cost of remote wakeups, since if the target sets TIF_POLLING_NRFLAG (as it does while polling in idle), the scheduler does those just by setting the need-resched bit. This contrasts with sending an IPI, and incurring the cost of handling the interrupt on the receiver. Signed-off-by: Ankur Arora <ankur.a.arora@xxxxxxxxxx> --- arch/arm64/Kconfig | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index fd9df6dcc593..43762c68e357 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -38,6 +38,7 @@ config ARM64 select ARCH_HAS_MEM_ENCRYPT 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 -- 2.43.5
