diff options
| author | Paul E. McKenney <paulmck@kernel.org> | 2022-07-28 19:58:13 -0700 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@kernel.org> | 2022-08-31 05:08:07 -0700 |
| commit | 3fdefca9b42c8bebe3beea5c1a067c9718ca0fc7 (patch) | |
| tree | 3779c8a6228ed9d1eb214490a6020621e00e1322 /kernel/rcu/rcutorture.c | |
| parent | 91a967fd6934abc0c7e4b0d26728e38674278707 (diff) | |
rcu: Add full-sized polling for get_state()
The get_state_synchronize_rcu() API compresses the combined expedited and
normal grace-period states into a single unsigned long, which conserves
storage, but can miss grace periods in certain cases involving overlapping
normal and expedited grace periods. Missing the occasional grace period
is usually not a problem, but there are use cases that care about each
and every grace period.
This commit therefore adds the next member of the full-state RCU
grace-period polling API, namely the get_state_synchronize_rcu_full()
function. This uses up to three times the storage (rcu_gp_oldstate
structure instead of unsigned long), but is guaranteed not to miss
grace periods.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Diffstat (limited to 'kernel/rcu/rcutorture.c')
| -rw-r--r-- | kernel/rcu/rcutorture.c | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c index b31e6ed64d1b..4f196ebce7f2 100644 --- a/kernel/rcu/rcutorture.c +++ b/kernel/rcu/rcutorture.c @@ -335,6 +335,7 @@ struct rcu_torture_ops { bool (*poll_gp_state_exp)(unsigned long oldstate); void (*cond_sync_exp)(unsigned long oldstate); unsigned long (*get_gp_state)(void); + void (*get_gp_state_full)(struct rcu_gp_oldstate *rgosp); unsigned long (*get_gp_completed)(void); void (*get_gp_completed_full)(struct rcu_gp_oldstate *rgosp); unsigned long (*start_gp_poll)(void); @@ -504,6 +505,7 @@ static struct rcu_torture_ops rcu_ops = { .sync = synchronize_rcu, .exp_sync = synchronize_rcu_expedited, .get_gp_state = get_state_synchronize_rcu, + .get_gp_state_full = get_state_synchronize_rcu_full, .get_gp_completed = get_completed_synchronize_rcu, .get_gp_completed_full = get_completed_synchronize_rcu_full, .start_gp_poll = start_poll_synchronize_rcu, @@ -1293,12 +1295,12 @@ rcu_torture_writer(void *arg) break; case RTWS_EXP_SYNC: rcu_torture_writer_state = RTWS_EXP_SYNC; - if (cur_ops->get_gp_state && cur_ops->poll_gp_state) - cookie = cur_ops->get_gp_state(); + if (cur_ops->get_gp_state_full && cur_ops->poll_gp_state_full) + cur_ops->get_gp_state_full(&cookie_full); cur_ops->exp_sync(); cur_ops->exp_sync(); - if (cur_ops->get_gp_state && cur_ops->poll_gp_state) - WARN_ON_ONCE(!cur_ops->poll_gp_state(cookie)); + if (cur_ops->get_gp_state_full && cur_ops->poll_gp_state_full) + WARN_ON_ONCE(!cur_ops->poll_gp_state_full(&cookie_full)); rcu_torture_pipe_update(old_rp); break; case RTWS_COND_GET: |