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| author | Paul E. McKenney <paulmck@kernel.org> | 2021-11-08 23:14:43 +0100 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@kernel.org> | 2021-12-08 01:26:57 +0100 |
| commit | b14fb4fbbcd8ff62f1a7aa2c6e2603424c117943 (patch) | |
| tree | 01b2773292f10bbc17eb26509442788bf3f22e12 /kernel | |
| parent | rcu-tasks: Introduce ->percpu_enqueue_shift for dynamic queue selection (diff) | |
| download | linux-b14fb4fbbcd8ff62f1a7aa2c6e2603424c117943.tar.xz linux-b14fb4fbbcd8ff62f1a7aa2c6e2603424c117943.zip | |
rcu-tasks: Convert grace-period counter to grace-period sequence number
This commit moves the rcu_tasks structure's ->n_gps grace-period-counter
field to a ->task_gp_seq grce-period sequence number in order to enable
use of the rcu_segcblist structure for the callback lists. This in turn
permits CPUs to lag behind the RCU Tasks grace-period sequence number
without suffering long-term slowdowns in callback invocation.
Reported-by: Martin Lau <kafai@fb.com>
Cc: Neeraj Upadhyay <neeraj.iitr10@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/rcu/tasks.h | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h index 2a5fe3e04b36..ed84d59b6dbf 100644 --- a/kernel/rcu/tasks.h +++ b/kernel/rcu/tasks.h @@ -42,7 +42,7 @@ struct rcu_tasks_percpu { * @init_fract: Initial backoff sleep interval. * @gp_jiffies: Time of last @gp_state transition. * @gp_start: Most recent grace-period start in jiffies. - * @n_gps: Number of grace periods completed since boot. + * @tasks_gp_seq: Number of grace periods completed since boot. * @n_ipis: Number of IPIs sent to encourage grace periods to end. * @n_ipis_fails: Number of IPI-send failures. * @pregp_func: This flavor's pre-grace-period function (optional). @@ -64,7 +64,7 @@ struct rcu_tasks { int init_fract; unsigned long gp_jiffies; unsigned long gp_start; - unsigned long n_gps; + unsigned long tasks_gp_seq; unsigned long n_ipis; unsigned long n_ipis_fails; struct task_struct *kthread_ptr; @@ -273,8 +273,9 @@ static int __noreturn rcu_tasks_kthread(void *arg) // Wait for one grace period. set_tasks_gp_state(rtp, RTGS_WAIT_GP); rtp->gp_start = jiffies; + rcu_seq_start(&rtp->tasks_gp_seq); rtp->gp_func(rtp); - rtp->n_gps++; + rcu_seq_end(&rtp->tasks_gp_seq); /* Invoke the callbacks. */ set_tasks_gp_state(rtp, RTGS_INVOKE_CBS); @@ -335,7 +336,7 @@ static void show_rcu_tasks_generic_gp_kthread(struct rcu_tasks *rtp, char *s) rtp->kname, tasks_gp_state_getname(rtp), data_race(rtp->gp_state), jiffies - data_race(rtp->gp_jiffies), - data_race(rtp->n_gps), + data_race(rcu_seq_current(&rtp->tasks_gp_seq)), data_race(rtp->n_ipis_fails), data_race(rtp->n_ipis), ".k"[!!data_race(rtp->kthread_ptr)], ".C"[!!data_race(rtpcp->cbs_head)], |