Merge tag 'trace-v4.7' of git://git.kernel.org/pub/scm/linux/kernel/g…

…it/rostedt/linux-trace

Pull tracing updates from Steven Rostedt:
 "This includes two new updates for the ftrace infrastructure.

   - With the changing of the code for filtering events by pid, from a
     list of pids to a bitmask, we can now easily implement following
     forks.  With a new tracing option "event-fork" which, when set,
     will have tasks with pids in set_event_pid, when they fork, to have
     their child pids added to set_event_pid and the child will be
     traced as well.

     Note, if "event-fork" is set and a task with its pid in
     set_event_pid exits, its pid will be removed from set_event_pid

   - The addition of Tom Zanussi's hist triggers.  This includes a very
     thorough documentatino on how to use the hist triggers with events.
     This introduces a quick and easy way to get histogram data from
     events and their fields.

  Some other cleanups and updates were added as well.  Like Masami
  Hiramatsu added test cases for the event trigger and hist triggers.
  Also I added a speed up of filtering by using a temp buffer when
  filters are set"

* tag 'trace-v4.7' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (45 commits)
  tracing: Use temp buffer when filtering events
  tracing: Remove TRACE_EVENT_FL_USE_CALL_FILTER logic
  tracing: Remove unused function trace_current_buffer_lock_reserve()
  tracing: Remove one use of trace_current_buffer_lock_reserve()
  tracing: Have trace_buffer_unlock_commit() call the _regs version with NULL
  tracing: Remove unused function trace_current_buffer_discard_commit()
  tracing: Move trace_buffer_unlock_commit{_regs}() to local header
  tracing: Fold filter_check_discard() into its only user
  tracing: Make filter_check_discard() local
  tracing: Move event_trigger_unlock_commit{_regs}() to local header
  tracing: Don't use the address of the buffer array name in copy_from_user
  tracing: Handle tracing_map_alloc_elts() error path correctly
  tracing: Add check for NULL event field when creating hist field
  tracing: checking for NULL instead of IS_ERR()
  tracing: Do not inherit event-fork option for instances
  tracing: Fix unsigned comparison to zero in hist trigger code
  kselftests/ftrace: Add a test for log2 modifier of hist trigger
  tracing: Add hist trigger 'log2' modifier
  kselftests/ftrace: Add hist trigger testcases
  kselftests/ftrace : Add event trigger testcases
  ...

Documentation/trace/ftrace.txt

@@ -210,6 +210,11 @@ of ftrace. Here is a list of some of the key files:
 	Note, sched_switch and sched_wake_up will also trace events
 	listed in this file.
 
+	To have the PIDs of children of tasks with their PID in this file
+	added on fork, enable the "event-fork" option. That option will also
+	cause the PIDs of tasks to be removed from this file when the task
+	exits.
+
   set_graph_function:
 
 	Set a "trigger" function where tracing should start
@@ -725,24 +730,25 @@ noraw
 nohex
 nobin
 noblock
-nostacktrace
 trace_printk
-noftrace_preempt
 nobranch
 annotate
 nouserstacktrace
 nosym-userobj
 noprintk-msg-only
 context-info
-latency-format
+nolatency-format
 sleep-time
 graph-time
 record-cmd
 overwrite
 nodisable_on_free
 irq-info
 markers
+noevent-fork
 function-trace
+nodisplay-graph
+nostacktrace
 
 To disable one of the options, echo in the option prepended with
 "no".
@@ -796,11 +802,6 @@ Here are the available options:
 
   block - When set, reading trace_pipe will not block when polled.
 
-  stacktrace - This is one of the options that changes the trace
-	       itself. When a trace is recorded, so is the stack
-	       of functions. This allows for back traces of
-	       trace sites.
-
   trace_printk - Can disable trace_printk() from writing into the buffer.
 
   branch - Enable branch tracing with the tracer.
@@ -897,15 +898,28 @@ x494] <- /root/a.out[+0x4a8] <- /lib/libc-2.7.so[+0x1e1a6]
   	    When disabled, the trace_marker will error with EINVAL
 	    on write.
 
+  event-fork - When set, tasks with PIDs listed in set_event_pid will have
+	       the PIDs of their children added to set_event_pid when those
+	       tasks fork. Also, when tasks with PIDs in set_event_pid exit,
+	       their PIDs will be removed from the file.
 
   function-trace - The latency tracers will enable function tracing
   	    if this option is enabled (default it is). When
 	    it is disabled, the latency tracers do not trace
 	    functions. This keeps the overhead of the tracer down
 	    when performing latency tests.
 
- Note: Some tracers have their own options. They only appear
-       when the tracer is active.
+  display-graph - When set, the latency tracers (irqsoff, wakeup, etc) will
+	          use function graph tracing instead of function tracing.
+
+  stacktrace - This is one of the options that changes the trace
+	       itself. When a trace is recorded, so is the stack
+	       of functions. This allows for back traces of
+	       trace sites.
+
+ Note: Some tracers have their own options. They only appear in this
+       file when the tracer is active. They always appear in the
+       options directory.
 
 
 

include/linux/trace_events.h

@@ -154,21 +154,6 @@ trace_event_buffer_lock_reserve(struct ring_buffer **current_buffer,
 				struct trace_event_file *trace_file,
 				int type, unsigned long len,
 				unsigned long flags, int pc);
-struct ring_buffer_event *
-trace_current_buffer_lock_reserve(struct ring_buffer **current_buffer,
-				  int type, unsigned long len,
-				  unsigned long flags, int pc);
-void trace_buffer_unlock_commit(struct trace_array *tr,
-				struct ring_buffer *buffer,
-				struct ring_buffer_event *event,
-				unsigned long flags, int pc);
-void trace_buffer_unlock_commit_regs(struct trace_array *tr,
-				     struct ring_buffer *buffer,
-				     struct ring_buffer_event *event,
-				     unsigned long flags, int pc,
-				     struct pt_regs *regs);
-void trace_current_buffer_discard_commit(struct ring_buffer *buffer,
-					 struct ring_buffer_event *event);
 
 void tracing_record_cmdline(struct task_struct *tsk);
 
@@ -229,7 +214,6 @@ enum {
 	TRACE_EVENT_FL_NO_SET_FILTER_BIT,
 	TRACE_EVENT_FL_IGNORE_ENABLE_BIT,
 	TRACE_EVENT_FL_WAS_ENABLED_BIT,
-	TRACE_EVENT_FL_USE_CALL_FILTER_BIT,
 	TRACE_EVENT_FL_TRACEPOINT_BIT,
 	TRACE_EVENT_FL_KPROBE_BIT,
 	TRACE_EVENT_FL_UPROBE_BIT,
@@ -244,7 +228,6 @@ enum {
  *  WAS_ENABLED   - Set and stays set when an event was ever enabled
  *                    (used for module unloading, if a module event is enabled,
  *                     it is best to clear the buffers that used it).
- *  USE_CALL_FILTER - For trace internal events, don't use file filter
  *  TRACEPOINT    - Event is a tracepoint
  *  KPROBE        - Event is a kprobe
  *  UPROBE        - Event is a uprobe
@@ -255,7 +238,6 @@ enum {
 	TRACE_EVENT_FL_NO_SET_FILTER	= (1 << TRACE_EVENT_FL_NO_SET_FILTER_BIT),
 	TRACE_EVENT_FL_IGNORE_ENABLE	= (1 << TRACE_EVENT_FL_IGNORE_ENABLE_BIT),
 	TRACE_EVENT_FL_WAS_ENABLED	= (1 << TRACE_EVENT_FL_WAS_ENABLED_BIT),
-	TRACE_EVENT_FL_USE_CALL_FILTER	= (1 << TRACE_EVENT_FL_USE_CALL_FILTER_BIT),
 	TRACE_EVENT_FL_TRACEPOINT	= (1 << TRACE_EVENT_FL_TRACEPOINT_BIT),
 	TRACE_EVENT_FL_KPROBE		= (1 << TRACE_EVENT_FL_KPROBE_BIT),
 	TRACE_EVENT_FL_UPROBE		= (1 << TRACE_EVENT_FL_UPROBE_BIT),
@@ -407,16 +389,12 @@ enum event_trigger_type {
 	ETT_SNAPSHOT		= (1 << 1),
 	ETT_STACKTRACE		= (1 << 2),
 	ETT_EVENT_ENABLE	= (1 << 3),
+	ETT_EVENT_HIST		= (1 << 4),
+	ETT_HIST_ENABLE		= (1 << 5),
 };
 
 extern int filter_match_preds(struct event_filter *filter, void *rec);
 
-extern int filter_check_discard(struct trace_event_file *file, void *rec,
-				struct ring_buffer *buffer,
-				struct ring_buffer_event *event);
-extern int call_filter_check_discard(struct trace_event_call *call, void *rec,
-				     struct ring_buffer *buffer,
-				     struct ring_buffer_event *event);
 extern enum event_trigger_type event_triggers_call(struct trace_event_file *file,
 						   void *rec);
 extern void event_triggers_post_call(struct trace_event_file *file,
@@ -450,100 +428,6 @@ trace_trigger_soft_disabled(struct trace_event_file *file)
 	return false;
 }
 
-/*
- * Helper function for event_trigger_unlock_commit{_regs}().
- * If there are event triggers attached to this event that requires
- * filtering against its fields, then they wil be called as the
- * entry already holds the field information of the current event.
- *
- * It also checks if the event should be discarded or not.
- * It is to be discarded if the event is soft disabled and the
- * event was only recorded to process triggers, or if the event
- * filter is active and this event did not match the filters.
- *
- * Returns true if the event is discarded, false otherwise.
- */
-static inline bool
-__event_trigger_test_discard(struct trace_event_file *file,
-			     struct ring_buffer *buffer,
-			     struct ring_buffer_event *event,
-			     void *entry,
-			     enum event_trigger_type *tt)
-{
-	unsigned long eflags = file->flags;
-
-	if (eflags & EVENT_FILE_FL_TRIGGER_COND)
-		*tt = event_triggers_call(file, entry);
-
-	if (test_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags))
-		ring_buffer_discard_commit(buffer, event);
-	else if (!filter_check_discard(file, entry, buffer, event))
-		return false;
-
-	return true;
-}
-
-/**
- * event_trigger_unlock_commit - handle triggers and finish event commit
- * @file: The file pointer assoctiated to the event
- * @buffer: The ring buffer that the event is being written to
- * @event: The event meta data in the ring buffer
- * @entry: The event itself
- * @irq_flags: The state of the interrupts at the start of the event
- * @pc: The state of the preempt count at the start of the event.
- *
- * This is a helper function to handle triggers that require data
- * from the event itself. It also tests the event against filters and
- * if the event is soft disabled and should be discarded.
- */
-static inline void
-event_trigger_unlock_commit(struct trace_event_file *file,
-			    struct ring_buffer *buffer,
-			    struct ring_buffer_event *event,
-			    void *entry, unsigned long irq_flags, int pc)
-{
-	enum event_trigger_type tt = ETT_NONE;
-
-	if (!__event_trigger_test_discard(file, buffer, event, entry, &tt))
-		trace_buffer_unlock_commit(file->tr, buffer, event, irq_flags, pc);
-
-	if (tt)
-		event_triggers_post_call(file, tt, entry);
-}
-
-/**
- * event_trigger_unlock_commit_regs - handle triggers and finish event commit
- * @file: The file pointer assoctiated to the event
- * @buffer: The ring buffer that the event is being written to
- * @event: The event meta data in the ring buffer
- * @entry: The event itself
- * @irq_flags: The state of the interrupts at the start of the event
- * @pc: The state of the preempt count at the start of the event.
- *
- * This is a helper function to handle triggers that require data
- * from the event itself. It also tests the event against filters and
- * if the event is soft disabled and should be discarded.
- *
- * Same as event_trigger_unlock_commit() but calls
- * trace_buffer_unlock_commit_regs() instead of trace_buffer_unlock_commit().
- */
-static inline void
-event_trigger_unlock_commit_regs(struct trace_event_file *file,
-				 struct ring_buffer *buffer,
-				 struct ring_buffer_event *event,
-				 void *entry, unsigned long irq_flags, int pc,
-				 struct pt_regs *regs)
-{
-	enum event_trigger_type tt = ETT_NONE;
-
-	if (!__event_trigger_test_discard(file, buffer, event, entry, &tt))
-		trace_buffer_unlock_commit_regs(file->tr, buffer, event,
-						irq_flags, pc, regs);
-
-	if (tt)
-		event_triggers_post_call(file, tt, entry);
-}
-
 #ifdef CONFIG_BPF_EVENTS
 unsigned int trace_call_bpf(struct bpf_prog *prog, void *ctx);
 #else

kernel/trace/Kconfig

@@ -528,6 +528,32 @@ config MMIOTRACE
 	  See Documentation/trace/mmiotrace.txt.
 	  If you are not helping to develop drivers, say N.
 
+config TRACING_MAP
+	bool
+	depends on ARCH_HAVE_NMI_SAFE_CMPXCHG
+	help
+	  tracing_map is a special-purpose lock-free map for tracing,
+	  separated out as a stand-alone facility in order to allow it
+	  to be shared between multiple tracers.  It isn't meant to be
+	  generally used outside of that context, and is normally
+	  selected by tracers that use it.
+
+config HIST_TRIGGERS
+	bool "Histogram triggers"
+	depends on ARCH_HAVE_NMI_SAFE_CMPXCHG
+	select TRACING_MAP
+	default n
+	help
+	  Hist triggers allow one or more arbitrary trace event fields
+	  to be aggregated into hash tables and dumped to stdout by
+	  reading a debugfs/tracefs file.  They're useful for
+	  gathering quick and dirty (though precise) summaries of
+	  event activity as an initial guide for further investigation
+	  using more advanced tools.
+
+	  See Documentation/trace/events.txt.
+	  If in doubt, say N.
+
 config MMIOTRACE_TEST
 	tristate "Test module for mmiotrace"
 	depends on MMIOTRACE && m

kernel/trace/Makefile

@@ -31,6 +31,7 @@ obj-$(CONFIG_TRACING) += trace_output.o
 obj-$(CONFIG_TRACING) += trace_seq.o
 obj-$(CONFIG_TRACING) += trace_stat.o
 obj-$(CONFIG_TRACING) += trace_printk.o
+obj-$(CONFIG_TRACING_MAP) += tracing_map.o
 obj-$(CONFIG_CONTEXT_SWITCH_TRACER) += trace_sched_switch.o
 obj-$(CONFIG_FUNCTION_TRACER) += trace_functions.o
 obj-$(CONFIG_IRQSOFF_TRACER) += trace_irqsoff.o
@@ -53,6 +54,7 @@ obj-$(CONFIG_EVENT_TRACING) += trace_event_perf.o
 endif
 obj-$(CONFIG_EVENT_TRACING) += trace_events_filter.o
 obj-$(CONFIG_EVENT_TRACING) += trace_events_trigger.o
+obj-$(CONFIG_HIST_TRIGGERS) += trace_events_hist.o
 obj-$(CONFIG_BPF_EVENTS) += bpf_trace.o
 obj-$(CONFIG_KPROBE_EVENT) += trace_kprobe.o
 obj-$(CONFIG_TRACEPOINTS) += power-traces.o