RE: [PATCH v6 1/2] rcu: Add RCU stall diagnosis information

From: Elliott, Robert (Servers)
Date: Wed Nov 09 2022 - 12:09:01 EST




> -----Original Message-----
> From: Elliott, Robert (Servers)
> Sent: Wednesday, November 9, 2022 10:56 AM
> > b/Documentation/admin-guide/kernel-parameters.txt
> > index a465d5242774af8..2729f3ad11d108b 100644
> > --- a/Documentation/admin-guide/kernel-parameters.txt
> > +++ b/Documentation/admin-guide/kernel-parameters.txt
> > @@ -5082,6 +5082,12 @@
> > rcupdate.rcu_cpu_stall_timeout to be used (after
> > conversion from seconds to milliseconds).
> >
> > + rcupdate.rcu_cpu_stall_cputime= [KNL]
> > + Provide statistics on the cputime and count of
> > + interrupts and tasks during the sampling period. For
> > + multiple continuous RCU stalls, all sampling periods
> > + begin at half of the first RCU stall timeout.
>
> This description should start with:
> "In kernels built with CONFIG_RCU_CPU_STALL_TIME=y, "

Please ignore that comment - the module parameter is always
present (only subject to CONFIG_RCU_STALL_COMMON like the others).
The config option is just selecting the default value for
that module parameter.