From: Borislav Petkov <bp@xxxxxxx> The CONFIG_NO_HZ_IDLE paragraph is using "dyntick-idle mode" before having defined it while the definition comes a couple of paragraphs later. That is leaving the reader with scratching head what that dyntick-idle mode might be. Pull its definition up so that it is clear. Signed-off-by: Borislav Petkov <bp@xxxxxxx> --- Documentation/timers/no_hz.rst | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/Documentation/timers/no_hz.rst b/Documentation/timers/no_hz.rst index 6cadad7c3aad..20ad23a6c618 100644 --- a/Documentation/timers/no_hz.rst +++ b/Documentation/timers/no_hz.rst @@ -70,6 +70,10 @@ interrupt. After all, the primary purpose of a scheduling-clock interrupt is to force a busy CPU to shift its attention among multiple duties, and an idle CPU has no duties to shift its attention among. +An idle CPU that is not receiving scheduling-clock interrupts is said to +be "dyntick-idle", "in dyntick-idle mode", "in nohz mode", or "running +tickless". The remainder of this document will use "dyntick-idle mode". + The CONFIG_NO_HZ_IDLE=y Kconfig option causes the kernel to avoid sending scheduling-clock interrupts to idle CPUs, which is critically important both to battery-powered devices and to highly virtualized mainframes. @@ -91,10 +95,6 @@ Therefore, systems with aggressive real-time response constraints often run CONFIG_HZ_PERIODIC=y kernels (or CONFIG_NO_HZ=n for older kernels) in order to avoid degrading from-idle transition latencies. -An idle CPU that is not receiving scheduling-clock interrupts is said to -be "dyntick-idle", "in dyntick-idle mode", "in nohz mode", or "running -tickless". The remainder of this document will use "dyntick-idle mode". - There is also a boot parameter "nohz=" that can be used to disable dyntick-idle mode in CONFIG_NO_HZ_IDLE=y kernels by specifying "nohz=off". By default, CONFIG_NO_HZ_IDLE=y kernels boot with "nohz=on", enabling -- 2.29.2
