ARM64 already uses 64bit preempt count and the need reschedule bit is maintained in a separate 32bit than the preempt count. Therefore preempt count has enough bits to represent 16 level of NMI nesting, hence enable it for ARM64. This saves a per-CPU variable and additional instructions in the NMI path.
Signed-off-by: Boqun Feng <[email protected]> --- arch/arm64/Kconfig | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index fe60738e5943..1ed5173872fc 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -248,6 +248,7 @@ config ARM64 select PCI_SYSCALL if PCI select POWER_RESET select POWER_SUPPLY + select PREEMPT_COUNT_64BIT select SPARSE_IRQ select SWIOTLB select SYSCTL_EXCEPTION_TRACE -- 2.50.1 (Apple Git-155)
