Merge branch 'for-mingo-rcu' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu

Pull RCU updates from Paul E. McKenney:

- Documentation updates.

- Miscellaneous fixes.

- kfree_rcu() updates: Addition of mem_dump_obj() to provide allocator return
  addresses to more easily locate bugs.  This has a couple of RCU-related commits,
  but is mostly MM.  Was pulled in with akpm's agreement.

- Per-callback-batch tracking of numbers of callbacks,
  which enables better debugging information and smarter
  reactions to large numbers of callbacks.

- The first round of changes to allow CPUs to be runtime switched from and to
  callback-offloaded state.

- CONFIG_PREEMPT_RT-related changes.

- RCU CPU stall warning updates.
- Addition of polling grace-period APIs for SRCU.

- Torture-test and torture-test scripting updates, including a "torture everything"
  script that runs rcutorture, locktorture, scftorture, rcuscale, and refscale.
  Plus does an allmodconfig build.

Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 18 insertions, 5 deletions

diff --git a/kernel/rcu/refscale.c b/kernel/rcu/refscale.c
index 23ff36a66f97..02dd9767b559 100644
--- a/kernel/rcu/refscale.c
+++ b/kernel/rcu/refscale.c
@@ -46,6 +46,18 @@
 #define VERBOSE_SCALEOUT(s, x...) \
 	do { if (verbose) pr_alert("%s" SCALE_FLAG s, scale_type, ## x); } while (0)
 
+static atomic_t verbose_batch_ctr;
+
+#define VERBOSE_SCALEOUT_BATCH(s, x...)							\
+do {											\
+	if (verbose &&									\
+	    (verbose_batched <= 0 ||							\
+	     !(atomic_inc_return(&verbose_batch_ctr) % verbose_batched))) {		\
+		schedule_timeout_uninterruptible(1);					\
+		pr_alert("%s" SCALE_FLAG s, scale_type, ## x);				\
+	}										\
+} while (0)
+
 #define VERBOSE_SCALEOUT_ERRSTRING(s, x...) \
 	do { if (verbose) pr_alert("%s" SCALE_FLAG "!!! " s, scale_type, ## x); } while (0)
 
@@ -57,6 +69,7 @@ module_param(scale_type, charp, 0444);
 MODULE_PARM_DESC(scale_type, "Type of test (rcu, srcu, refcnt, rwsem, rwlock.");
 
 torture_param(int, verbose, 0, "Enable verbose debugging printk()s");
+torture_param(int, verbose_batched, 0, "Batch verbose debugging printk()s");
 
 // Wait until there are multiple CPUs before starting test.
 torture_param(int, holdoff, IS_BUILTIN(CONFIG_RCU_REF_SCALE_TEST) ? 10 : 0,
@@ -368,14 +381,14 @@ ref_scale_reader(void *arg)
 	u64 start;
 	s64 duration;
 
-	VERBOSE_SCALEOUT("ref_scale_reader %ld: task started", me);
+	VERBOSE_SCALEOUT_BATCH("ref_scale_reader %ld: task started", me);
 	set_cpus_allowed_ptr(current, cpumask_of(me % nr_cpu_ids));
 	set_user_nice(current, MAX_NICE);
 	atomic_inc(&n_init);
 	if (holdoff)
 		schedule_timeout_interruptible(holdoff * HZ);
 repeat:
-	VERBOSE_SCALEOUT("ref_scale_reader %ld: waiting to start next experiment on cpu %d", me, smp_processor_id());
+	VERBOSE_SCALEOUT_BATCH("ref_scale_reader %ld: waiting to start next experiment on cpu %d", me, smp_processor_id());
 
 	// Wait for signal that this reader can start.
 	wait_event(rt->wq, (atomic_read(&nreaders_exp) && smp_load_acquire(&rt->start_reader)) ||
@@ -392,7 +405,7 @@ repeat:
 		while (atomic_read_acquire(&n_started))
 			cpu_relax();
 
-	VERBOSE_SCALEOUT("ref_scale_reader %ld: experiment %d started", me, exp_idx);
+	VERBOSE_SCALEOUT_BATCH("ref_scale_reader %ld: experiment %d started", me, exp_idx);
 
 
 	// To reduce noise, do an initial cache-warming invocation, check
@@ -421,8 +434,8 @@ repeat:
 	if (atomic_dec_and_test(&nreaders_exp))
 		wake_up(&main_wq);
 
-	VERBOSE_SCALEOUT("ref_scale_reader %ld: experiment %d ended, (readers remaining=%d)",
-			me, exp_idx, atomic_read(&nreaders_exp));
+	VERBOSE_SCALEOUT_BATCH("ref_scale_reader %ld: experiment %d ended, (readers remaining=%d)",
+				me, exp_idx, atomic_read(&nreaders_exp));
 
 	if (!torture_must_stop())
 		goto repeat;