| Message ID | 20220620221757.3839212-2-paulmck@kernel.org (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 71de1e34f1dfc31ab3cb052cdd7038950aae06e7 |
| Headers | show |
| Series | Documentation updates for v5.20 | expand |
On 6/21/2022 3:47 AM, Paul E. McKenney wrote: > This commit adds kernel-parameters.txt documentation for the > rcutree.rcu_divisor kernel boot parameter, which controls the softirq > callback-invocation batch limit. > > Cc: Eric Dumazet <edumazet@google.com> > Signed-off-by: Paul E. McKenney <paulmck@kernel.org> > --- Reviewed-by: Neeraj Upadhyay <quic_neeraju@quicinc.com> > Documentation/admin-guide/kernel-parameters.txt | 15 +++++++++++++++ > 1 file changed, 15 insertions(+) > > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > index 2522b11e593f2..bdf431bdbfdc4 100644 > --- a/Documentation/admin-guide/kernel-parameters.txt > +++ b/Documentation/admin-guide/kernel-parameters.txt > @@ -4666,6 +4666,21 @@ > When RCU_NOCB_CPU is set, also adjust the > priority of NOCB callback kthreads. > > + rcutree.rcu_divisor= [KNL] > + Set the shift-right count to use to compute > + the callback-invocation batch limit bl from > + the number of callbacks queued on this CPU. > + The result will be bounded below by the value of > + the rcutree.blimit kernel parameter. Every bl > + callbacks, the softirq handler will exit in > + order to allow the CPU to do other work. > + > + Please note that this callback-invocation batch > + limit applies only to non-offloaded callback > + invocation. Offloaded callbacks are instead > + invoked in the context of an rcuoc kthread, which > + scheduler will preempt as it does any other task. > + > rcutree.rcu_nocb_gp_stride= [KNL] > Set the number of NOCB callback kthreads in > each group, which defaults to the square root
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 2522b11e593f2..bdf431bdbfdc4 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -4666,6 +4666,21 @@ When RCU_NOCB_CPU is set, also adjust the priority of NOCB callback kthreads. + rcutree.rcu_divisor= [KNL] + Set the shift-right count to use to compute + the callback-invocation batch limit bl from + the number of callbacks queued on this CPU. + The result will be bounded below by the value of + the rcutree.blimit kernel parameter. Every bl + callbacks, the softirq handler will exit in + order to allow the CPU to do other work. + + Please note that this callback-invocation batch + limit applies only to non-offloaded callback + invocation. Offloaded callbacks are instead + invoked in the context of an rcuoc kthread, which + scheduler will preempt as it does any other task. + rcutree.rcu_nocb_gp_stride= [KNL] Set the number of NOCB callback kthreads in each group, which defaults to the square root
This commit adds kernel-parameters.txt documentation for the rcutree.rcu_divisor kernel boot parameter, which controls the softirq callback-invocation batch limit. Cc: Eric Dumazet <edumazet@google.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> --- Documentation/admin-guide/kernel-parameters.txt | 15 +++++++++++++++ 1 file changed, 15 insertions(+)