context-tracking: Introduce CONFIG_HAVE_TIF_NOHZ

[mirror_ubuntu-jammy-kernel.git] / arch / Kconfig

diff --git a/arch/Kconfig b/arch/Kconfig
index 98de654b79b312eca4737efff9b6b1460cb94f37..dbf420a9f87b9f9f64c05e21106aaf65a401f857 100644 (file)
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -540,11 +540,17 @@ config HAVE_CONTEXT_TRACKING
        help
          Provide kernel/user boundaries probes necessary for subsystems
          that need it, such as userspace RCU extended quiescent state.
-         Syscalls need to be wrapped inside user_exit()-user_enter() through
-         the slow path using TIF_NOHZ flag. Exceptions handlers must be
-         wrapped as well. Irqs are already protected inside
-         rcu_irq_enter/rcu_irq_exit() but preemption or signal handling on
-         irq exit still need to be protected.
+         Syscalls need to be wrapped inside user_exit()-user_enter(), either
+         optimized behind static key or through the slow path using TIF_NOHZ
+         flag. Exceptions handlers must be wrapped as well. Irqs are already
+         protected inside rcu_irq_enter/rcu_irq_exit() but preemption or signal
+         handling on irq exit still need to be protected.
+
+config HAVE_TIF_NOHZ
+       bool
+       help
+         Arch relies on TIF_NOHZ and syscall slow path to implement context
+         tracking calls to user_enter()/user_exit().
 
 config HAVE_VIRT_CPU_ACCOUNTING
        bool