Commit 61370792 authored by Uladzislau Rezki (Sony)'s avatar Uladzislau Rezki (Sony) Committed by Paul E. McKenney
Browse files

rcu: Add a trace event for kfree_rcu() use of kfree_bulk() 



The event is given three parameters, first one is the name
of RCU flavour, second one is the number of elements in array
for free and last one is an address of the array holding
pointers to be freed by the kfree_bulk() function.

To enable the trace event your kernel has to be build with
CONFIG_RCU_TRACE=y, after that it is possible to track the
events using ftrace subsystem.

Signed-off-by: default avatarUladzislau Rezki (Sony) <urezki@gmail.com>
Signed-off-by: default avatarPaul E. McKenney <paulmck@kernel.org>
parent 34c88174

include/trace/events/rcu.h

+28 −0
Original line number Diff line number Diff line
@@ -623,6 +623,34 @@ TRACE_EVENT_RCU(rcu_invoke_kfree_callback, 
		  __entry->rcuname, __entry->rhp, __entry->offset)

);



/*

 * Tracepoint for the invocation of a single RCU callback of the special

 * kfree_bulk() form. The first argument is the RCU flavor, the second

 * argument is a number of elements in array to free, the third is an

 * address of the array holding nr_records entries.

 */

TRACE_EVENT_RCU(rcu_invoke_kfree_bulk_callback,



	TP_PROTO(const char *rcuname, unsigned long nr_records, void **p),



	TP_ARGS(rcuname, nr_records, p),



	TP_STRUCT__entry(

		__field(const char *, rcuname)

		__field(unsigned long, nr_records)

		__field(void **, p)

	),



	TP_fast_assign(

		__entry->rcuname = rcuname;

		__entry->nr_records = nr_records;

		__entry->p = p;

	),



	TP_printk("%s bulk=0x%p nr_records=%lu",

		__entry->rcuname, __entry->p, __entry->nr_records)

);



/*

 * Tracepoint for exiting rcu_do_batch after RCU callbacks have been

 * invoked.  The first argument is the name of the RCU flavor,

kernel/rcu/tree.c

+3 −0
Original line number Diff line number Diff line
@@ -2792,6 +2792,9 @@ static void kfree_rcu_work(struct work_struct *work) 
		debug_rcu_head_unqueue_bulk(bhead->head_free_debug);



		rcu_lock_acquire(&rcu_callback_map);

		trace_rcu_invoke_kfree_bulk_callback(rcu_state.name,

			bhead->nr_records, bhead->records);



		kfree_bulk(bhead->nr_records, bhead->records);

		rcu_lock_release(&rcu_callback_map);

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