Commit 3dbe43f6 authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

Merge branches 'doc.2015.07.15a' and 'torture.2015.07.15a' into HEAD 

doc.2015.07.15a: Documentation updates.
torture.2015.07.15a: Torture-test updates.
parents 8ff4fbfd 96d7744e d6a8c6d3

Documentation/RCU/rcu_dereference.txt

+1 −1
Original line number Diff line number Diff line
@@ -28,7 +28,7 @@ o You must use one of the rcu_dereference() family of primitives 
o	Avoid cancellation when using the "+" and "-" infix arithmetic

	operators.  For example, for a given variable "x", avoid

	"(x-x)".  There are similar arithmetic pitfalls from other

	arithmetic operatiors, such as "(x*0)", "(x/(x+1))" or "(x%1)".

	arithmetic operators, such as "(x*0)", "(x/(x+1))" or "(x%1)".

	The compiler is within its rights to substitute zero for all of

	these expressions, so that subsequent accesses no longer depend

	on the rcu_dereference(), again possibly resulting in bugs due

Documentation/kernel-parameters.txt

+24 −11
Original line number Diff line number Diff line
@@ -3135,22 +3135,35 @@ bytes respectively. Such letter suffixes can also be entirely omitted. 
			in a given burst of a callback-flood test.



	rcutorture.fqs_duration= [KNL]

			Set duration of force_quiescent_state bursts.

			Set duration of force_quiescent_state bursts

			in microseconds.



	rcutorture.fqs_holdoff= [KNL]

			Set holdoff time within force_quiescent_state bursts.

			Set holdoff time within force_quiescent_state bursts

			in microseconds.



	rcutorture.fqs_stutter= [KNL]

			Set wait time between force_quiescent_state bursts.

			Set wait time between force_quiescent_state bursts

			in seconds.



	rcutorture.gp_cond= [KNL]

			Use conditional/asynchronous update-side

			primitives, if available.



	rcutorture.gp_exp= [KNL]

			Use expedited update-side primitives.

			Use expedited update-side primitives, if available.



	rcutorture.gp_normal= [KNL]

			Use normal (non-expedited) update-side primitives.

			If both gp_exp and gp_normal are set, do both.

			If neither gp_exp nor gp_normal are set, still

			do both.

			Use normal (non-expedited) asynchronous

			update-side primitives, if available.



	rcutorture.gp_sync= [KNL]

			Use normal (non-expedited) synchronous

			update-side primitives, if available.  If all

			of rcutorture.gp_cond=, rcutorture.gp_exp=,

			rcutorture.gp_normal=, and rcutorture.gp_sync=

			are zero, rcutorture acts as if is interpreted

			they are all non-zero.



	rcutorture.n_barrier_cbs= [KNL]

			Set callbacks/threads for rcu_barrier() testing.
@@ -3177,9 +3190,6 @@ bytes respectively. Such letter suffixes can also be entirely omitted. 
			Set time (s) between CPU-hotplug operations, or

			zero to disable CPU-hotplug testing.



	rcutorture.torture_runnable= [BOOT]

			Start rcutorture running at boot time.



	rcutorture.shuffle_interval= [KNL]

			Set task-shuffle interval (s).  Shuffling tasks

			allows some CPUs to go into dyntick-idle mode
@@ -3220,6 +3230,9 @@ bytes respectively. Such letter suffixes can also be entirely omitted. 
			Test RCU's dyntick-idle handling.  See also the

			rcutorture.shuffle_interval parameter.



	rcutorture.torture_runnable= [BOOT]

			Start rcutorture running at boot time.



	rcutorture.torture_type= [KNL]

			Specify the RCU implementation to test.

Documentation/memory-barriers.txt

+184 −175

File changed.

Preview size limit exceeded, changes collapsed.

kernel/rcu/rcutorture.c

+27 −13
Original line number Diff line number Diff line
@@ -686,10 +686,20 @@ static struct rcu_torture_ops tasks_ops = { 


#define RCUTORTURE_TASKS_OPS &tasks_ops,



static bool __maybe_unused torturing_tasks(void)

{

	return cur_ops == &tasks_ops;

}



#else /* #ifdef CONFIG_TASKS_RCU */



#define RCUTORTURE_TASKS_OPS



static bool torturing_tasks(void)

{

	return false;

}



#endif /* #else #ifdef CONFIG_TASKS_RCU */



/*
@@ -825,9 +835,7 @@ rcu_torture_cbflood(void *arg) 
	}

	if (err) {

		VERBOSE_TOROUT_STRING("rcu_torture_cbflood disabled: Bad args or OOM");

		while (!torture_must_stop())

			schedule_timeout_interruptible(HZ);

		return 0;

		goto wait_for_stop;

	}

	VERBOSE_TOROUT_STRING("rcu_torture_cbflood task started");

	do {
@@ -846,6 +854,7 @@ rcu_torture_cbflood(void *arg) 
		stutter_wait("rcu_torture_cbflood");

	} while (!torture_must_stop());

	vfree(rhp);

wait_for_stop:

	torture_kthread_stopping("rcu_torture_cbflood");

	return 0;

}
@@ -1090,7 +1099,8 @@ static void rcu_torture_timer(unsigned long unused) 
	p = rcu_dereference_check(rcu_torture_current,

				  rcu_read_lock_bh_held() ||

				  rcu_read_lock_sched_held() ||

				  srcu_read_lock_held(srcu_ctlp));

				  srcu_read_lock_held(srcu_ctlp) ||

				  torturing_tasks());

	if (p == NULL) {

		/* Leave because rcu_torture_writer is not yet underway */

		cur_ops->readunlock(idx);
@@ -1164,7 +1174,8 @@ rcu_torture_reader(void *arg) 
		p = rcu_dereference_check(rcu_torture_current,

					  rcu_read_lock_bh_held() ||

					  rcu_read_lock_sched_held() ||

					  srcu_read_lock_held(srcu_ctlp));

					  srcu_read_lock_held(srcu_ctlp) ||

					  torturing_tasks());

		if (p == NULL) {

			/* Wait for rcu_torture_writer to get underway */

			cur_ops->readunlock(idx);
@@ -1509,7 +1520,7 @@ static int rcu_torture_barrier_init(void) 
	int i;

	int ret;



	if (n_barrier_cbs == 0)

	if (n_barrier_cbs <= 0)

		return 0;

	if (cur_ops->call == NULL || cur_ops->cb_barrier == NULL) {

		pr_alert("%s" TORTURE_FLAG
@@ -1788,13 +1799,16 @@ rcu_torture_init(void) 
					  writer_task);

	if (firsterr)

		goto unwind;

	fakewriter_tasks = kzalloc(nfakewriters * sizeof(fakewriter_tasks[0]),

	if (nfakewriters > 0) {

		fakewriter_tasks = kzalloc(nfakewriters *

					   sizeof(fakewriter_tasks[0]),

					   GFP_KERNEL);

		if (fakewriter_tasks == NULL) {

			VERBOSE_TOROUT_ERRSTRING("out of memory");

			firsterr = -ENOMEM;

			goto unwind;

		}

	}

	for (i = 0; i < nfakewriters; i++) {

		firsterr = torture_create_kthread(rcu_torture_fakewriter,

						  NULL, fakewriter_tasks[i]);
@@ -1820,7 +1834,7 @@ rcu_torture_init(void) 
		if (firsterr)

			goto unwind;

	}

	if (test_no_idle_hz) {

	if (test_no_idle_hz && shuffle_interval > 0) {

		firsterr = torture_shuffle_init(shuffle_interval * HZ);

		if (firsterr)

			goto unwind;

tools/testing/selftests/rcutorture/configs/rcu/TASKS01

+2 −2
Original line number Diff line number Diff line
@@ -5,6 +5,6 @@ CONFIG_PREEMPT_NONE=n 
CONFIG_PREEMPT_VOLUNTARY=n

CONFIG_PREEMPT=y

CONFIG_DEBUG_LOCK_ALLOC=y

CONFIG_PROVE_LOCKING=n

#CHECK#CONFIG_PROVE_RCU=n

CONFIG_PROVE_LOCKING=y

#CHECK#CONFIG_PROVE_RCU=y

CONFIG_RCU_EXPERT=y