rcu: Consolidate dumping of ftrace buffer

This commit consolidates a couple definitions and several calls for
single-shot ftrace-buffer dumping.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index 2657aff2725b4fdc8243e7beb836747bbd5817d6..45de591657a6f044ce1a3cd78d0f0fdfab4a730b 100644 (file)
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -1144,4 +1144,17 @@ static inline void rcu_sysidle_force_exit(void)
 #endif /* #else #ifdef CONFIG_NO_HZ_FULL_SYSIDLE */
 
 
+/*
+ * Dump the ftrace buffer, but only one time per callsite per boot.
+ */
+#define rcu_ftrace_dump(oops_dump_mode) \
+do { \
+       static atomic_t ___rfd_beenhere = ATOMIC_INIT(0); \
+       \
+       if (!atomic_read(&___rfd_beenhere) && \
+           !atomic_xchg(&___rfd_beenhere, 1)) \
+               ftrace_dump(oops_dump_mode); \
+} while (0)
+
+
 #endif /* __LINUX_RCUPDATE_H */

diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index 250ea67c1615bf1022056e7a01ef088414cc0c39..463867c432216466558d9fcbdadb60636ce0402f 100644 (file)
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -1082,17 +1082,6 @@ rcu_torture_fakewriter(void *arg)
        return 0;
 }
 
-static void rcutorture_trace_dump(void)
-{
-       static atomic_t beenhere = ATOMIC_INIT(0);
-
-       if (atomic_read(&beenhere))
-               return;
-       if (atomic_xchg(&beenhere, 1) != 0)
-               return;
-       ftrace_dump(DUMP_ALL);
-}
-
 /*
  * RCU torture reader from timer handler.  Dereferences rcu_torture_current,
  * incrementing the corresponding element of the pipeline array.  The
@@ -1142,7 +1131,7 @@ static void rcu_torture_timer(unsigned long unused)
        if (pipe_count > 1) {
                do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu, ts,
                                          started, completed);
-               rcutorture_trace_dump();
+               rcu_ftrace_dump(DUMP_ALL);
        }
        __this_cpu_inc(rcu_torture_count[pipe_count]);
        completed = completed - started;
@@ -1215,7 +1204,7 @@ rcu_torture_reader(void *arg)
                if (pipe_count > 1) {
                        do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu,
                                                  ts, started, completed);
-                       rcutorture_trace_dump();
+                       rcu_ftrace_dump(DUMP_ALL);
                }
                __this_cpu_inc(rcu_torture_count[pipe_count]);
                completed = completed - started;
@@ -1333,7 +1322,7 @@ rcu_torture_stats_print(void)
                         rcu_torture_writer_state,
                         gpnum, completed, flags);
                show_rcu_gp_kthreads();
-               rcutorture_trace_dump();
+               rcu_ftrace_dump(DUMP_ALL);
        }
        rtcv_snap = rcu_torture_current_version;
 }

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 9a535a86e7326b21dce28a002607370df4de4de4..531a328076bdd82c61bd6e4c509225c9d450d1c4 100644 (file)
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -637,7 +637,7 @@ static void rcu_eqs_enter_common(long long oldval, bool user)
                        idle_task(smp_processor_id());
 
                trace_rcu_dyntick(TPS("Error on entry: not idle task"), oldval, 0);
-               ftrace_dump(DUMP_ORIG);
+               rcu_ftrace_dump(DUMP_ORIG);
                WARN_ONCE(1, "Current pid: %d comm: %s / Idle pid: %d comm: %s",
                          current->pid, current->comm,
                          idle->pid, idle->comm); /* must be idle task! */
@@ -799,7 +799,7 @@ static void rcu_eqs_exit_common(long long oldval, int user)
 
                trace_rcu_dyntick(TPS("Error on exit: not idle task"),
                                  oldval, rdtp->dynticks_nesting);
-               ftrace_dump(DUMP_ORIG);
+               rcu_ftrace_dump(DUMP_ORIG);
                WARN_ONCE(1, "Current pid: %d comm: %s / Idle pid: %d comm: %s",
                          current->pid, current->comm,
                          idle->pid, idle->comm); /* must be idle task! */