The following commit has been merged into the core/rcu branch of tip: Commit-ID: e816d56fad57ba9817cef6606b12f5e14647c3bf Gitweb: https://git.kernel.org/tip/e816d56fad57ba9817cef6606b12f5e14647c3bf Author: Paul E. McKenney <paulmck@xxxxxxxxxx> AuthorDate: Fri, 01 May 2020 16:49:48 -07:00 Committer: Paul E. McKenney <paulmck@xxxxxxxxxx> CommitterDate: Mon, 29 Jun 2020 11:58:49 -07:00 rcu: Add callbacks-invoked counters This commit adds a count of the callbacks invoked to the per-CPU rcu_data structure. This count is printed by the show_rcu_gp_kthreads() that is invoked by rcutorture and the RCU CPU stall-warning code. It is also intended for use by drgn. Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx> --- kernel/rcu/tree.c | 1 + kernel/rcu/tree.h | 1 + kernel/rcu/tree_stall.h | 3 +++ 3 files changed, 5 insertions(+) diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index bef1dc9..874c831 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -2443,6 +2443,7 @@ static void rcu_do_batch(struct rcu_data *rdp) local_irq_save(flags); rcu_nocb_lock(rdp); count = -rcl.len; + rdp->n_cbs_invoked += count; trace_rcu_batch_end(rcu_state.name, count, !!rcl.head, need_resched(), is_idle_task(current), rcu_is_callbacks_kthread()); diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h index 43991a4..9c6f734 100644 --- a/kernel/rcu/tree.h +++ b/kernel/rcu/tree.h @@ -171,6 +171,7 @@ struct rcu_data { /* different grace periods. */ long qlen_last_fqs_check; /* qlen at last check for QS forcing */ + unsigned long n_cbs_invoked; /* # callbacks invoked since boot. */ unsigned long n_force_qs_snap; /* did other CPU force QS recently? */ long blimit; /* Upper limit on a processed batch */ diff --git a/kernel/rcu/tree_stall.h b/kernel/rcu/tree_stall.h index 54a6dba..2768ce6 100644 --- a/kernel/rcu/tree_stall.h +++ b/kernel/rcu/tree_stall.h @@ -649,6 +649,7 @@ static void check_cpu_stall(struct rcu_data *rdp) */ void show_rcu_gp_kthreads(void) { + unsigned long cbs = 0; int cpu; unsigned long j; unsigned long ja; @@ -690,9 +691,11 @@ void show_rcu_gp_kthreads(void) } for_each_possible_cpu(cpu) { rdp = per_cpu_ptr(&rcu_data, cpu); + cbs += data_race(rdp->n_cbs_invoked); if (rcu_segcblist_is_offloaded(&rdp->cblist)) show_rcu_nocb_state(rdp); } + pr_info("RCU callbacks invoked since boot: %lu\n", cbs); show_rcu_tasks_gp_kthreads(); } EXPORT_SYMBOL_GPL(show_rcu_gp_kthreads);
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