From: Paul E. McKenney Date: Mon, 29 Oct 2012 14:29:20 +0000 (-0700) Subject: rcu: Separate accounting of callbacks from callback-free CPUs X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=c635a4e1c24e9396db10ed7424b2084908b32252;p=deliverable%2Flinux.git rcu: Separate accounting of callbacks from callback-free CPUs Currently, callback invocations from callback-free CPUs are accounted to the CPU that registered the callback, but using the same field that is used for normal callbacks. This makes it impossible to determine from debugfs output whether callbacks are in fact being diverted. This commit therefore adds a separate ->n_nocbs_invoked field in the rcu_data structure in which diverted callback invocations are counted. RCU's debugfs tracing still displays normal callback invocations using ci=, but displayed diverted callbacks with nci=. Signed-off-by: Paul E. McKenney Signed-off-by: Paul E. McKenney --- diff --git a/kernel/rcutree.h b/kernel/rcutree.h index 488f2ec6b663..4b69291b093d 100644 --- a/kernel/rcutree.h +++ b/kernel/rcutree.h @@ -287,6 +287,7 @@ struct rcu_data { long qlen_last_fqs_check; /* qlen at last check for QS forcing */ unsigned long n_cbs_invoked; /* count of RCU cbs invoked. */ + unsigned long n_nocbs_invoked; /* count of no-CBs RCU cbs invoked. */ unsigned long n_cbs_orphaned; /* RCU cbs orphaned by dying CPU */ unsigned long n_cbs_adopted; /* RCU cbs adopted from dying CPU */ unsigned long n_force_qs_snap; diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h index 6cdc372de34c..f6e5ec2932b4 100644 --- a/kernel/rcutree_plugin.h +++ b/kernel/rcutree_plugin.h @@ -2406,7 +2406,7 @@ static int rcu_nocb_kthread(void *arg) trace_rcu_batch_end(rdp->rsp->name, c, !!list, 0, 0, 1); ACCESS_ONCE(rdp->nocb_p_count) -= c; ACCESS_ONCE(rdp->nocb_p_count_lazy) -= cl; - rdp->n_cbs_invoked += c; + rdp->n_nocbs_invoked += c; } return 0; } diff --git a/kernel/rcutree_trace.c b/kernel/rcutree_trace.c index 3189f9aa3e84..0d095dcaa670 100644 --- a/kernel/rcutree_trace.c +++ b/kernel/rcutree_trace.c @@ -148,8 +148,9 @@ static void print_one_rcu_data(struct seq_file *m, struct rcu_data *rdp) per_cpu(rcu_cpu_kthread_loops, rdp->cpu) & 0xffff); #endif /* #ifdef CONFIG_RCU_BOOST */ seq_printf(m, " b=%ld", rdp->blimit); - seq_printf(m, " ci=%lu co=%lu ca=%lu\n", - rdp->n_cbs_invoked, rdp->n_cbs_orphaned, rdp->n_cbs_adopted); + seq_printf(m, " ci=%lu nci=%lu co=%lu ca=%lu\n", + rdp->n_cbs_invoked, rdp->n_nocbs_invoked, + rdp->n_cbs_orphaned, rdp->n_cbs_adopted); } static int show_rcudata(struct seq_file *m, void *v)