On Tue, Nov 12, 2024 at 10:12:40AM +0530, Neeraj Upadhyay wrote:
> On 10/15/2024 9:41 PM, Paul E. McKenney wrote:
> > This commit adds an rcutorture.reader_flavor parameter whose bits
> > correspond to reader flavors. For example, SRCU's readers are 0x1 for
> > normal and 0x2 for NMI-safe.
> >
> > Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
> > Cc: Alexei Starovoitov <ast@xxxxxxxxxx>
> > Cc: Andrii Nakryiko <andrii@xxxxxxxxxx>
> > Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> > Cc: Kent Overstreet <kent.overstreet@xxxxxxxxx>
> > Cc: <bpf@xxxxxxxxxxxxxxx>
> > ---
> > .../admin-guide/kernel-parameters.txt | 8 +++++
> > kernel/rcu/rcutorture.c | 30 ++++++++++++++-----
> > 2 files changed, 30 insertions(+), 8 deletions(-)
> >
> > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> > index 1518343bbe223..52922727006fc 100644
> > --- a/Documentation/admin-guide/kernel-parameters.txt
> > +++ b/Documentation/admin-guide/kernel-parameters.txt
> > @@ -5426,6 +5426,14 @@
> > The delay, in seconds, between successive
> > read-then-exit testing episodes.
> >
> > + rcutorture.reader_flavor= [KNL]
> > + A bit mask indicating which readers to use.
> > + If there is more than one bit set, the readers
> > + are entered from low-order bit up, and are
> > + exited in the opposite order. For SRCU, the
> > + 0x1 bit is normal readers and the 0x2 bit is
> > + for NMI-safe readers.
> > +
> > rcutorture.shuffle_interval= [KNL]
> > Set task-shuffle interval (s). Shuffling tasks
> > allows some CPUs to go into dyntick-idle mode
> > diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
> > index f96ab98f8182f..405decec33677 100644
> > --- a/kernel/rcu/rcutorture.c
> > +++ b/kernel/rcu/rcutorture.c
> > @@ -111,6 +111,7 @@ torture_param(int, nocbs_nthreads, 0, "Number of NOCB toggle threads, 0 to disab
> > torture_param(int, nocbs_toggle, 1000, "Time between toggling nocb state (ms)");
> > torture_param(int, read_exit_delay, 13, "Delay between read-then-exit episodes (s)");
> > torture_param(int, read_exit_burst, 16, "# of read-then-exit bursts per episode, zero to disable");
> > +torture_param(int, reader_flavor, 0x1, "Reader flavors to use, one per bit.");
> > torture_param(int, shuffle_interval, 3, "Number of seconds between shuffles");
> > torture_param(int, shutdown_secs, 0, "Shutdown time (s), <= zero to disable.");
> > torture_param(int, stall_cpu, 0, "Stall duration (s), zero to disable.");
> > @@ -644,10 +645,20 @@ static void srcu_get_gp_data(int *flags, unsigned long *gp_seq)
> >
> > static int srcu_torture_read_lock(void)
> > {
> > - if (cur_ops == &srcud_ops)
> > - return srcu_read_lock_nmisafe(srcu_ctlp);
> > - else
> > - return srcu_read_lock(srcu_ctlp);
> > + int idx;
> > + int ret = 0;
> > +
> > + if ((reader_flavor & 0x1) || !(reader_flavor & 0x7)) {
>
> Minor: Maybe use macros in place of 0x1, 0x2, 0x7 as a cleanup later.
Hmmm...
I could move SRCU_READ_FLAVOR_* to include/linux/srcu.h and make
rcutorture use those. Plus have a combined mask for the instances of 0x7.
Or is there a better way?
Thanx, Paul
> - Neeraj
>
> > + idx = srcu_read_lock(srcu_ctlp);
> > + WARN_ON_ONCE(idx & ~0x1);
> > + ret += idx;
> > + }
> > + if (reader_flavor & 0x2) {
> > + idx = srcu_read_lock_nmisafe(srcu_ctlp);
> > + WARN_ON_ONCE(idx & ~0x1);
> > + ret += idx << 1;
> > + }
> > + return ret;
> > }
> >
>
