From 264bbd32a31ba80e634bec5c1df8514c0e97fe7e Mon Sep 17 00:00:00 2001 From: Boqun Feng Date: Tue, 4 Aug 2026 09:14:33 -0700 Subject: [PATCH] arm64: sched/preempt: Enable HAS_SEPARATE_PREEMPT_RESCHED_BITS Arm64 already uses 64-bit preempt count and the need reschedule bit is maintained in a separate 32-bit word from the preempt count. Therefore preempt count has enough bits to represent 16 levels 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 Signed-off-by: Peter Zijlstra (Intel) Link: https://patch.msgid.link/20260804161447.84806-12-boqun@kernel.org --- arch/arm64/Kconfig | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index b3afe0688919..349c3533cd1e 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -247,6 +247,7 @@ config ARM64 select PCI_SYSCALL if PCI select POWER_RESET select POWER_SUPPLY + select HAS_SEPARATE_PREEMPT_RESCHED_BITS select SPARSE_IRQ select SWIOTLB select SYSCTL_EXCEPTION_TRACE