On 4/21/2025 1:47 PM, Joel Fernandes wrote: > Currently, the ->gpwrap is not tested (at all per my testing) due to the > requirement of a large delta between a CPU's rdp->gp_seq and its node's > rnp->gpseq. > > This results in no testing of ->gpwrap being set. This patch by default > adds 5 minutes of testing with ->gpwrap forced by lowering the delta > between rdp->gp_seq and rnp->gp_seq to just 8 GPs. All of this is > configurable, including the active time for the setting and a full > testing cycle. > > By default, the first 25 minutes of a test will have the _default_ > behavior there is right now (ULONG_MAX / 4) delta. Then for 5 minutes, > we switch to a smaller delta causing 1-2 wraps in 5 minutes. I believe > this is reasonable since we at least add a little bit of testing for > usecases where ->gpwrap is set. > > Tested-by: Paul E. McKenney <paulmck@xxxxxxxxxx> > Signed-off-by: Joel Fernandes <joelagnelf@xxxxxxxxxx> > --- > v4->v5 > - Added gpwrap_lag torture param to turn off entire test. > - replaced references to 'ovf' with 'gpwrap lag'. > > Will move this to my rcu/torture-for-6.16 and update my rcu/for-next branches. > > .../admin-guide/kernel-parameters.txt | 5 ++ > kernel/rcu/rcu.h | 4 ++ > kernel/rcu/rcutorture.c | 72 ++++++++++++++++++- > kernel/rcu/tree.c | 34 ++++++++- > kernel/rcu/tree.h | 1 + > 5 files changed, 113 insertions(+), 3 deletions(-) > > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > index 76e538c77e31..e1d11b6595fd 100644 > --- a/Documentation/admin-guide/kernel-parameters.txt > +++ b/Documentation/admin-guide/kernel-parameters.txt > @@ -5657,6 +5657,11 @@ > are zero, rcutorture acts as if is interpreted > they are all non-zero. > > + rcutorture.gpwrap_lag= [KNL] > + Enable grace-period wrap lag testing. Setting > + to false prevents the gpwrap lag test from > + running. > + FYI, I added docs for the additional params here as well: + rcutorture.gpwrap_lag= [KNL] + Enable grace-period wrap lag testing. Setting + to false prevents the gpwrap lag test from + running. + + rcutorture.gpwrap_lag_gps= [KNL] + Set the value for grace-period wrap lag during + active lag testing periods. This controls how many + grace periods differences we tolerate between + rdp and rnp's gp_seq before setting overflow flag. + + rcutorture.gpwrap_lag_cycle_mins= [KNL] + Set the total cycle duration for gpwrap lag + testing in minutes. This is the total time for + one complete cycle of active and inactive + testing periods. Default is 30 minutes. + + rcutorture.gpwrap_lag_active_mins= [KNL] + Set the duration for which gpwrap lag is active + within each cycle, in minutes. During this time, + the grace-period wrap lag will be set to the + value specified by gpwrap_lag_gps. Default is + 5 minutes. + Will push this to my rcu/torture-for-6.16 and also update my rcu/for-next branch. - Joel
