[PATCH 11/11] arm64: sched/preempt: Enable PREEMPT_COUNT_64BIT

[Boqun Feng]

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 <boqun@xxxxxxxxxx>
---
 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)