Merge tag 'trace-v5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing updates from Steven Rostedt:

 - simplify the Kconfig use of FTRACE and TRACE_IRQFLAGS_SUPPORT

 - bootconfig can now start histograms

 - bootconfig supports group/all enabling

 - histograms now can put values in linear size buckets

 - execnames can be passed to synthetic events

 - introduce "event probes" that attach to other events and can retrieve
   data from pointers of fields, or record fields as different types (a
   pointer to a string as a string instead of just a hex number)

 - various fixes and clean ups

* tag 'trace-v5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (35 commits)
  tracing/doc: Fix table format in histogram code
  selftests/ftrace: Add selftest for testing duplicate eprobes and kprobes
  selftests/ftrace: Add selftest for testing eprobe events on synthetic events
  selftests/ftrace: Add test case to test adding and removing of event probe
  selftests/ftrace: Fix requirement check of README file
  selftests/ftrace: Add clear_dynamic_events() to test cases
  tracing: Add a probe that attaches to trace events
  tracing/probes: Reject events which have the same name of existing one
  tracing/probes: Have process_fetch_insn() take a void * instead of pt_regs
  tracing/probe: Change traceprobe_set_print_fmt() to take a type
  tracing/probes: Use struct_size() instead of defining custom macros
  tracing/probes: Allow for dot delimiter as well as slash for system names
  tracing/probe: Have traceprobe_parse_probe_arg() take a const arg
  tracing: Have dynamic events have a ref counter
  tracing: Add DYNAMIC flag for dynamic events
  tracing: Replace deprecated CPU-hotplug functions.
  MAINTAINERS: Add an entry for os noise/latency
  tracepoint: Fix kerneldoc comments
  bootconfig/tracing/ktest: Update ktest example for boot-time tracing
  tools/bootconfig: Use per-group/all enable option in ftrace2bconf script
  ...

2 files changed, 175 insertions, 20 deletions

diff --git a/Documentation/trace/boottime-trace.rst b/Documentation/trace/boottime-trace.rst
index 8053898cfeb4..6dcfbc64014d 100644
--- a/Documentation/trace/boottime-trace.rst
+++ b/Documentation/trace/boottime-trace.rst
@@ -125,6 +125,71 @@ Note that kprobe and synthetic event definitions can be written under
 instance node, but those are also visible from other instances. So please
 take care for event name conflict.
 
+Ftrace Histogram Options
+------------------------
+
+Since it is too long to write a histogram action as a string for per-event
+action option, there are tree-style options under per-event 'hist' subkey
+for the histogram actions. For the detail of the each parameter,
+please read the event histogram document [3]_.
+
+.. [3] See :ref:`Documentation/trace/histogram.rst <histogram>`
+
+ftrace.[instance.INSTANCE.]event.GROUP.EVENT.hist.[N.]keys = KEY1[, KEY2[...]]
+  Set histogram key parameters. (Mandatory)
+  The 'N' is a digit string for the multiple histogram. You can omit it
+  if there is one histogram on the event.
+
+ftrace.[instance.INSTANCE.]event.GROUP.EVENT.hist.[N.]values = VAL1[, VAL2[...]]
+  Set histogram value parameters.
+
+ftrace.[instance.INSTANCE.]event.GROUP.EVENT.hist.[N.]sort = SORT1[, SORT2[...]]
+  Set histogram sort parameter options.
+
+ftrace.[instance.INSTANCE.]event.GROUP.EVENT.hist.[N.]size = NR_ENTRIES
+  Set histogram size (number of entries).
+
+ftrace.[instance.INSTANCE.]event.GROUP.EVENT.hist.[N.]name = NAME
+  Set histogram name.
+
+ftrace.[instance.INSTANCE.]event.GROUP.EVENT.hist.[N.]var.VARIABLE = EXPR
+  Define a new VARIABLE by EXPR expression.
+
+ftrace.[instance.INSTANCE.]event.GROUP.EVENT.hist.[N.]<pause|continue|clear>
+  Set histogram control parameter. You can set one of them.
+
+ftrace.[instance.INSTANCE.]event.GROUP.EVENT.hist.[N.]onmatch.[M.]event = GROUP.EVENT
+  Set histogram 'onmatch' handler matching event parameter.
+  The 'M' is a digit string for the multiple 'onmatch' handler. You can omit it
+  if there is one 'onmatch' handler on this histogram.
+
+ftrace.[instance.INSTANCE.]event.GROUP.EVENT.hist.[N.]onmatch.[M.]trace = EVENT[, ARG1[...]]
+  Set histogram 'trace' action for 'onmatch'.
+  EVENT must be a synthetic event name, and ARG1... are parameters
+  for that event. Mandatory if 'onmatch.event' option is set.
+
+ftrace.[instance.INSTANCE.]event.GROUP.EVENT.hist.[N.]onmax.[M.]var = VAR
+  Set histogram 'onmax' handler variable parameter.
+
+ftrace.[instance.INSTANCE.]event.GROUP.EVENT.hist.[N.]onchange.[M.]var = VAR
+  Set histogram 'onchange' handler variable parameter.
+
+ftrace.[instance.INSTANCE.]event.GROUP.EVENT.hist.[N.]<onmax|onchange>.[M.]save = ARG1[, ARG2[...]]
+  Set histogram 'save' action parameters for 'onmax' or 'onchange' handler.
+  This option or below 'snapshot' option is mandatory if 'onmax.var' or
+  'onchange.var' option is set.
+
+ftrace.[instance.INSTANCE.]event.GROUP.EVENT.hist.[N.]<onmax|onchange>.[M.]snapshot
+  Set histogram 'snapshot' action for 'onmax' or 'onchange' handler.
+  This option or above 'save' option is mandatory if 'onmax.var' or
+  'onchange.var' option is set.
+
+ftrace.[instance.INSTANCE.]event.GROUP.EVENT.hist.filter = FILTER_EXPR
+  Set histogram filter expression. You don't need 'if' in the FILTER_EXPR.
+
+Note that this 'hist' option can conflict with the per-event 'actions'
+option if the 'actions' option has a histogram action.
+
 
 When to Start
 =============
@@ -159,13 +224,23 @@ below::
         }
         synthetic.initcall_latency {
                 fields = "unsigned long func", "u64 lat"
-                actions = "hist:keys=func.sym,lat:vals=lat:sort=lat"
+                hist {
+                        keys = func.sym, lat
+                        values = lat
+                        sort = lat
+                }
         }
-        initcall.initcall_start {
-                actions = "hist:keys=func:ts0=common_timestamp.usecs"
+        initcall.initcall_start.hist {
+                keys = func
+                var.ts0 = common_timestamp.usecs
         }
-        initcall.initcall_finish {
-                actions = "hist:keys=func:lat=common_timestamp.usecs-$ts0:onmatch(initcall.initcall_start).initcall_latency(func,$lat)"
+        initcall.initcall_finish.hist {
+                keys = func
+                var.lat = common_timestamp.usecs - $ts0
+                onmatch {
+                        event = initcall.initcall_start
+                        trace = initcall_latency, func, $lat
+                }
         }
   }
 
diff --git a/Documentation/trace/histogram.rst b/Documentation/trace/histogram.rst
index f99be8062bc8..533415644c54 100644
--- a/Documentation/trace/histogram.rst
+++ b/Documentation/trace/histogram.rst
@@ -70,15 +70,16 @@ Documentation written by Tom Zanussi
   modified by appending any of the following modifiers to the field
   name:
 
-	=========== ==========================================
-        .hex        display a number as a hex value
-	.sym        display an address as a symbol
-	.sym-offset display an address as a symbol and offset
-	.syscall    display a syscall id as a system call name
-	.execname   display a common_pid as a program name
-	.log2       display log2 value rather than raw number
-	.usecs      display a common_timestamp in microseconds
-	=========== ==========================================
+	=============  =================================================
+        .hex           display a number as a hex value
+	.sym           display an address as a symbol
+	.sym-offset    display an address as a symbol and offset
+	.syscall       display a syscall id as a system call name
+	.execname      display a common_pid as a program name
+	.log2          display log2 value rather than raw number
+	.buckets=size  display grouping of values rather than raw number
+	.usecs         display a common_timestamp in microseconds
+	=============  =================================================
 
   Note that in general the semantics of a given field aren't
   interpreted when applying a modifier to it, but there are some
@@ -228,7 +229,7 @@ Extended error information
   that lists the total number of bytes requested for each function in
   the kernel that made one or more calls to kmalloc::
 
-    # echo 'hist:key=call_site:val=bytes_req' > \
+    # echo 'hist:key=call_site:val=bytes_req.buckets=32' > \
             /sys/kernel/debug/tracing/events/kmem/kmalloc/trigger
 
   This tells the tracing system to create a 'hist' trigger using the
@@ -1823,20 +1824,99 @@ and variables defined on other events (see Section 2.2.3 below on
 how that is done using hist trigger 'onmatch' action). Once that is
 done, the 'wakeup_latency' synthetic event instance is created.
 
-A histogram can now be defined for the new synthetic event::
-
-  # echo 'hist:keys=pid,prio,lat.log2:sort=pid,lat' >> \
-        /sys/kernel/debug/tracing/events/synthetic/wakeup_latency/trigger
-
 The new event is created under the tracing/events/synthetic/ directory
 and looks and behaves just like any other event::
 
   # ls /sys/kernel/debug/tracing/events/synthetic/wakeup_latency
         enable  filter  format  hist  id  trigger
 
+A histogram can now be defined for the new synthetic event::
+
+  # echo 'hist:keys=pid,prio,lat.log2:sort=lat' >> \
+        /sys/kernel/debug/tracing/events/synthetic/wakeup_latency/trigger
+
+The above shows the latency "lat" in a power of 2 grouping.
+
 Like any other event, once a histogram is enabled for the event, the
 output can be displayed by reading the event's 'hist' file.
 
+  # cat /sys/kernel/debug/tracing/events/synthetic/wakeup_latency/hist
+
+  # event histogram
+  #
+  # trigger info: hist:keys=pid,prio,lat.log2:vals=hitcount:sort=lat.log2:size=2048 [active]
+  #
+
+  { pid:       2035, prio:          9, lat: ~ 2^2  } hitcount:         43
+  { pid:       2034, prio:          9, lat: ~ 2^2  } hitcount:         60
+  { pid:       2029, prio:          9, lat: ~ 2^2  } hitcount:        965
+  { pid:       2034, prio:        120, lat: ~ 2^2  } hitcount:          9
+  { pid:       2033, prio:        120, lat: ~ 2^2  } hitcount:          5
+  { pid:       2030, prio:          9, lat: ~ 2^2  } hitcount:        335
+  { pid:       2030, prio:        120, lat: ~ 2^2  } hitcount:         10
+  { pid:       2032, prio:        120, lat: ~ 2^2  } hitcount:          1
+  { pid:       2035, prio:        120, lat: ~ 2^2  } hitcount:          2
+  { pid:       2031, prio:          9, lat: ~ 2^2  } hitcount:        176
+  { pid:       2028, prio:        120, lat: ~ 2^2  } hitcount:         15
+  { pid:       2033, prio:          9, lat: ~ 2^2  } hitcount:         91
+  { pid:       2032, prio:          9, lat: ~ 2^2  } hitcount:        125
+  { pid:       2029, prio:        120, lat: ~ 2^2  } hitcount:          4
+  { pid:       2031, prio:        120, lat: ~ 2^2  } hitcount:          3
+  { pid:       2029, prio:        120, lat: ~ 2^3  } hitcount:          2
+  { pid:       2035, prio:          9, lat: ~ 2^3  } hitcount:         41
+  { pid:       2030, prio:        120, lat: ~ 2^3  } hitcount:          1
+  { pid:       2032, prio:          9, lat: ~ 2^3  } hitcount:         32
+  { pid:       2031, prio:          9, lat: ~ 2^3  } hitcount:         44
+  { pid:       2034, prio:          9, lat: ~ 2^3  } hitcount:         40
+  { pid:       2030, prio:          9, lat: ~ 2^3  } hitcount:         29
+  { pid:       2033, prio:          9, lat: ~ 2^3  } hitcount:         31
+  { pid:       2029, prio:          9, lat: ~ 2^3  } hitcount:         31
+  { pid:       2028, prio:        120, lat: ~ 2^3  } hitcount:         18
+  { pid:       2031, prio:        120, lat: ~ 2^3  } hitcount:          2
+  { pid:       2028, prio:        120, lat: ~ 2^4  } hitcount:          1
+  { pid:       2029, prio:          9, lat: ~ 2^4  } hitcount:          4
+  { pid:       2031, prio:        120, lat: ~ 2^7  } hitcount:          1
+  { pid:       2032, prio:        120, lat: ~ 2^7  } hitcount:          1
+
+  Totals:
+      Hits: 2122
+      Entries: 30
+      Dropped: 0
+
+
+The latency values can also be grouped linearly by a given size with
+the ".buckets" modifier and specify a size (in this case groups of 10).
+
+  # echo 'hist:keys=pid,prio,lat.buckets=10:sort=lat' >> \
+        /sys/kernel/debug/tracing/events/synthetic/wakeup_latency/trigger
+
+  # event histogram
+  #
+  # trigger info: hist:keys=pid,prio,lat.buckets=10:vals=hitcount:sort=lat.buckets=10:size=2048 [active]
+  #
+
+  { pid:       2067, prio:          9, lat: ~ 0-9 } hitcount:        220
+  { pid:       2068, prio:          9, lat: ~ 0-9 } hitcount:        157
+  { pid:       2070, prio:          9, lat: ~ 0-9 } hitcount:        100
+  { pid:       2067, prio:        120, lat: ~ 0-9 } hitcount:          6
+  { pid:       2065, prio:        120, lat: ~ 0-9 } hitcount:          2
+  { pid:       2066, prio:        120, lat: ~ 0-9 } hitcount:          2
+  { pid:       2069, prio:          9, lat: ~ 0-9 } hitcount:        122
+  { pid:       2069, prio:        120, lat: ~ 0-9 } hitcount:          8
+  { pid:       2070, prio:        120, lat: ~ 0-9 } hitcount:          1
+  { pid:       2068, prio:        120, lat: ~ 0-9 } hitcount:          7
+  { pid:       2066, prio:          9, lat: ~ 0-9 } hitcount:        365
+  { pid:       2064, prio:        120, lat: ~ 0-9 } hitcount:         35
+  { pid:       2065, prio:          9, lat: ~ 0-9 } hitcount:        998
+  { pid:       2071, prio:          9, lat: ~ 0-9 } hitcount:         85
+  { pid:       2065, prio:          9, lat: ~ 10-19 } hitcount:          2
+  { pid:       2064, prio:        120, lat: ~ 10-19 } hitcount:          2
+
+  Totals:
+      Hits: 2112
+      Entries: 16
+      Dropped: 0
+
 2.2.3 Hist trigger 'handlers' and 'actions'
 -------------------------------------------