On Fri, Mar 02, 2018 at 04:39:12PM +0900, Byungchul Park wrote:
> Commit ae91aa0adb14(rcu: Remove debugfs tracing) removed the RCU debugfs
> tracing code, and left deprecated code.
>
> Because exp_workdone{0,1,2,3} won't be used anymore since the commit,
> it's better to remove code to do with those variables. Remove it.
>
> Signed-off-by: Byungchul Park <byungchul.p...@lge.com>
Good catch, queued for testing and review, thank you!
Thanx, Paul
> ---
> kernel/rcu/tree.h | 4 ----
> kernel/rcu/tree_exp.h | 13 +++++--------
> 2 files changed, 5 insertions(+), 12 deletions(-)
>
> diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h
> index 9dd0ea7..cfeb351 100644
> --- a/kernel/rcu/tree.h
> +++ b/kernel/rcu/tree.h
> @@ -234,10 +234,6 @@ struct rcu_data {
> #ifdef CONFIG_RCU_FAST_NO_HZ
> struct rcu_head oom_head;
> #endif /* #ifdef CONFIG_RCU_FAST_NO_HZ */
> - atomic_long_t exp_workdone0; /* # done by workqueue. */
> - atomic_long_t exp_workdone1; /* # done by others #1. */
> - atomic_long_t exp_workdone2; /* # done by others #2. */
> - atomic_long_t exp_workdone3; /* # done by others #3. */
> int exp_dynticks_snap; /* Double-check need for IPI. */
>
> /* 6) Callback offloading. */
> diff --git a/kernel/rcu/tree_exp.h b/kernel/rcu/tree_exp.h
> index 73e1d3d..f8e4571 100644
> --- a/kernel/rcu/tree_exp.h
> +++ b/kernel/rcu/tree_exp.h
> @@ -248,14 +248,12 @@ static void rcu_report_exp_rdp(struct rcu_state *rsp,
> struct rcu_data *rdp,
> }
>
> /* Common code for synchronize_{rcu,sched}_expedited() work-done checking. */
> -static bool sync_exp_work_done(struct rcu_state *rsp, atomic_long_t *stat,
> - unsigned long s)
> +static bool sync_exp_work_done(struct rcu_state *rsp, unsigned long s)
> {
> if (rcu_exp_gp_seq_done(rsp, s)) {
> trace_rcu_exp_grace_period(rsp->name, s, TPS("done"));
> /* Ensure test happens before caller kfree(). */
> smp_mb__before_atomic(); /* ^^^ */
> - atomic_long_inc(stat);
> return true;
> }
> return false;
> @@ -289,7 +287,7 @@ static bool exp_funnel_lock(struct rcu_state *rsp,
> unsigned long s)
> * promoting locality and is not strictly needed for correctness.
> */
> for (; rnp != NULL; rnp = rnp->parent) {
> - if (sync_exp_work_done(rsp, &rdp->exp_workdone1, s))
> + if (sync_exp_work_done(rsp, s))
> return true;
>
> /* Work not done, either wait here or go up. */
> @@ -302,8 +300,7 @@ static bool exp_funnel_lock(struct rcu_state *rsp,
> unsigned long s)
> rnp->grplo, rnp->grphi,
> TPS("wait"));
> wait_event(rnp->exp_wq[rcu_seq_ctr(s) & 0x3],
> - sync_exp_work_done(rsp,
> - &rdp->exp_workdone2, s));
> + sync_exp_work_done(rsp, s));
> return true;
> }
> rnp->exp_seq_rq = s; /* Followers can wait on us. */
> @@ -313,7 +310,7 @@ static bool exp_funnel_lock(struct rcu_state *rsp,
> unsigned long s)
> }
> mutex_lock(&rsp->exp_mutex);
> fastpath:
> - if (sync_exp_work_done(rsp, &rdp->exp_workdone3, s)) {
> + if (sync_exp_work_done(rsp, s)) {
> mutex_unlock(&rsp->exp_mutex);
> return true;
> }
> @@ -661,7 +658,7 @@ static void _synchronize_rcu_expedited(struct rcu_state
> *rsp,
> rdp = per_cpu_ptr(rsp->rda, raw_smp_processor_id());
> rnp = rcu_get_root(rsp);
> wait_event(rnp->exp_wq[rcu_seq_ctr(s) & 0x3],
> - sync_exp_work_done(rsp, &rdp->exp_workdone0, s));
> + sync_exp_work_done(rsp, s));
> smp_mb(); /* Workqueue actions happen before return. */
>
> /* Let the next expedited grace period start. */
> --
> 1.9.1
>
