lkml.org 
[lkml]   [2022]   [May]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [RFC PATCH 4/4] cpuset: Support RCU-NOCB toggle on v2 root partitions
On Thu, May 26, 2022 at 12:10:55AM +0200, Frederic Weisbecker wrote:
> Introduce a new "isolation.rcu_nocb" file within a cgroup2/cpuset
> directory which provides support for a set of CPUs to either enable ("1")
> or disable ("0") RCU callbacks offloading (aka. RCU NOCB). This can
> overwrite previous boot settings towards "rcu_nocbs=" kernel parameter.
>
> The file is only writeable on "root" type partitions to exclude any
> overlap. The deepest root type partition has the highest priority.
> This means that given the following setting:
>
> Top cpuset (CPUs: 0-7)
> cpuset.isolation.rcu_nocb = 0
> |
> |
> Subdirectory A (CPUs: 5-7)
> cpuset.cpus.partition = root
> cpuset.isolation.rcu_nocb = 0
> |
> |
> Subdirectory B (CPUs: 7)
> cpuset.cpus.partition = root
> cpuset.isolation.rcu_nocb = 1
>
> the result is that only CPU 7 is in rcu_nocb mode.
>
> Note that "rcu_nocbs" kernel parameter must be passed on boot, even
> without a cpulist, so that nocb support is enabled.

Does it even make sense to make this hierarchical? What's wrong with a
cpumask under sys/ or proc/?

Thanks.

--
tejun

\
 
 \ /
  Last update: 2022-05-26 20:22    [W:0.180 / U:0.464 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site