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authorPaul E. McKenney <paul.mckenney@linaro.org>2012-10-29 07:29:20 -0700
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2012-11-16 10:05:57 -0800
commitc635a4e1c24e9396db10ed7424b2084908b32252 (patch)
treeac1cced2e0c05d5edcd74af6d3493e15e99a7cec
parent3fbfbf7a3b66ec424042d909f14ba2ddf4372ea8 (diff)
downloadop-kernel-dev-c635a4e1c24e9396db10ed7424b2084908b32252.zip
op-kernel-dev-c635a4e1c24e9396db10ed7424b2084908b32252.tar.gz
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 <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
-rw-r--r--kernel/rcutree.h1
-rw-r--r--kernel/rcutree_plugin.h2
-rw-r--r--kernel/rcutree_trace.c5
3 files changed, 5 insertions, 3 deletions
diff --git a/kernel/rcutree.h b/kernel/rcutree.h
index 488f2ec..4b69291 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 6cdc372..f6e5ec2 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 3189f9a..0d095dc 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)
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