Commit Graph

22249 Commits

Author SHA1 Message Date
Steven Rostedt (Red Hat)
a9fe48dcde tracing: Remove unused function trace_current_buffer_discard_commit()
The function trace_current_buffer_discard_commit() has no callers, remove
it.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-04-29 16:14:13 -04:00
Steven Rostedt (Red Hat)
fa66ddb870 tracing: Move trace_buffer_unlock_commit{_regs}() to local header
The functions trace_buffer_unlock_commit() and the _regs() version are only
used within the kernel/trace directory. Move them to the local header and
remove the export as well.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-04-29 16:14:12 -04:00
Steven Rostedt (Red Hat)
9cbb1506ab tracing: Fold filter_check_discard() into its only user
The function filter_check_discard() is small and only called by one user,
its code can be folded into that one caller and make the code a bit less
comlplex.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-04-29 16:14:08 -04:00
Steven Rostedt (Red Hat)
65da9a0a3b tracing: Make filter_check_discard() local
Nothing outside of the tracing directory calls filter_check_discard() or
check_filter_check_discard(). They should not be called by modules. Move
their prototypes into the local tracing header and remove their
EXPORT_SYMBOL() macros.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-04-27 10:13:46 -04:00
Steven Rostedt (Red Hat)
dad56ee742 tracing: Move event_trigger_unlock_commit{_regs}() to local header
The functions event_trigger_unlock_commit() and
event_trigger_unlock_commit_regs() are no longer used outside the tracing
system. Move them out of the generic headers and into the local one.

Along with __event_trigger_test_discard() that is only used by them.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-04-26 21:24:53 -04:00
Wang Xiaoqiang
4afe6495e5 tracing: Don't use the address of the buffer array name in copy_from_user
With the following code snippet:

    ...
    char buf[64];
    ...
    if (copy_from_user(&buf, ubuf, cnt))
    ...

Even though the value of "&buf" equals "buf", but there is no need
to get the address of the "buf" again. Use "buf" instead of "&buf".

Link: http://lkml.kernel.org/r/20160418152329.18b72bea@debian

Signed-off-by: Wang Xiaoqiang <wangxq10@lzu.edu.cn>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-04-26 14:42:03 -04:00
Tom Zanussi
6e4cf657de tracing: Handle tracing_map_alloc_elts() error path correctly
If tracing_map_elt_alloc() fails, it will return ERR_PTR() instead of
NULL, so change the check to IS_ERROR().  We also need to set the
failed entry in the map->elts array to NULL instead of ERR_PTR() so
tracing_map_free_elts() doesn't try freeing an ERR_PTR().

tracing_map_free_elts() should also zero out what it frees so a
reentrant call won't find previously freed elements.

Link: http://lkml.kernel.org/r/f29d03b00bce3aac8cf151a8a30e6c83e5fee66d.1461610073.git.tom.zanussi@linux.intel.com

Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-04-26 09:40:30 -04:00
Tom Zanussi
432480c582 tracing: Add check for NULL event field when creating hist field
Smatch flagged create_hist_field() as possibly being able to
dereference a NULL pointer, although the current code exits in all
cases where the event field could be NULL, so it's not actually a
problem.

Still, to prevent future changes to the code from overlooking new
cases, make the NULL pointer check explicit and warn once in that
case.

Link: http://lkml.kernel.org/r/cfbc003f534a3e441b4313272fd412310aba6336.1461610073.git.tom.zanussi@linux.intel.com

Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-04-26 09:40:29 -04:00
Dan Carpenter
4812952f9c tracing: checking for NULL instead of IS_ERR()
tracing_map_elt_alloc() returns ERR_PTRs on error, never NULL.

Fixes: 08d43a5fa0 ('tracing: Add lock-free tracing_map')
Link: http://lkml.kernel.org/r/20160423102347.GA11136@mwanda

Acked-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-04-26 09:40:20 -04:00
Steven Rostedt (Red Hat)
205506228b tracing: Do not inherit event-fork option for instances
As the event-fork option requires doing work when enabled and disabled, it
can not be passed down to created instances. The instance must clear this
flag when it is created, and must clear it when its removed.

As more options may be created with this need, a macro ZEROED_TRACE_FLAGS is
created that holds the flags that must not be inherited by the top level
instance, and must be cleared on removal of instances.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-04-25 22:40:12 -04:00
Steven Rostedt (Red Hat)
d50c744ecd tracing: Fix unsigned comparison to zero in hist trigger code
Fengguang Wu's bot found two comparisons of unsigned integers to zero. These
were real bugs, as it would miss error conditions returned to zero.

trace_events_hist.c:426:6-9: WARNING: Unsigned expression compared with zero: idx < 0
trace_events_hist.c:568:5-14: WARNING: Unsigned expression compared with zero: n_entries < 0

Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-04-19 18:56:05 -04:00
Namhyung Kim
4b94f5b7b4 tracing: Add hist trigger 'log2' modifier
Allow users to have numeric fields displayed as log2 values in case
value range is very wide by appending '.log2' to field names.

For example,

  # echo 'hist:key=bytes_req' > kmalloc/trigger
  # cat kmalloc/hist

  { bytes_req:        504 } hitcount:          1
  { bytes_req:         11 } hitcount:          1
  { bytes_req:        104 } hitcount:          1
  { bytes_req:         48 } hitcount:          1
  { bytes_req:       2048 } hitcount:          1
  { bytes_req:       4096 } hitcount:          1
  { bytes_req:        240 } hitcount:          1
  { bytes_req:        392 } hitcount:          1
  { bytes_req:         13 } hitcount:          1
  { bytes_req:         28 } hitcount:          1
  { bytes_req:         12 } hitcount:          1
  { bytes_req:         64 } hitcount:          2
  { bytes_req:        128 } hitcount:          2
  { bytes_req:         32 } hitcount:          2
  { bytes_req:          8 } hitcount:         11
  { bytes_req:         10 } hitcount:         13
  { bytes_req:         24 } hitcount:         25
  { bytes_req:        160 } hitcount:         29
  { bytes_req:         16 } hitcount:         33
  { bytes_req:         80 } hitcount:         36

When using '.log2' modifier, the output looks like:

  # echo 'hist:key=bytes_req.log2' > kmalloc/trigger
  # cat kmalloc/hist

  { bytes_req: ~ 2^12 } hitcount:          1
  { bytes_req: ~ 2^11 } hitcount:          1
  { bytes_req: ~ 2^9  } hitcount:          2
  { bytes_req: ~ 2^6  } hitcount:          3
  { bytes_req: ~ 2^3  } hitcount:         13
  { bytes_req: ~ 2^5  } hitcount:         19
  { bytes_req: ~ 2^8  } hitcount:         49
  { bytes_req: ~ 2^7  } hitcount:         57
  { bytes_req: ~ 2^4  } hitcount:         74

Link: http://lkml.kernel.org/r/7ff396b246c6a881f46b979735fddf05a0d6c71a.1457029949.git.tom.zanussi@linux.intel.com

Cc: Tom Zanussi <tom.zanussi@linux.intel.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-04-19 18:56:03 -04:00
Tom Zanussi
5463bfda32 tracing: Add support for named hist triggers
Allow users to define 'named' hist triggers.  All triggers created
with the same 'name=xxx' option will update the same shared histogram
data.

This expands the hist trigger syntax from this:

    # echo hist:keys=xxx ... [ if filter] > event/trigger

to this:

    # echo hist:name=xxx:keys=xxx ... [ if filter] > event/trigger

Named histograms must use a 'compatible' set of keys and values, which
means each event added to a set of named triggers must have the same
names and types.

Reading the 'hist' file of any of the participating events will
produce the same output as any other participating event, which is to
be expected since they share the same data.

Link: http://lkml.kernel.org/r/1dbc84ee3322a75daaf5b3ef1d0cc0a2fb682fc7.1457029949.git.tom.zanussi@linux.intel.com

Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Tested-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-04-19 18:56:01 -04:00
Tom Zanussi
db1388b4ff tracing: Add support for named triggers
Named triggers are sets of triggers that share a common set of trigger
data.  An example of functionality that could benefit from this type
of capability would be a set of inlined probes that would each
contribute event counts, for example, to a shared counter data
structure.

The first named trigger registered with a given name owns the common
trigger data that the others subsequently registered with the same
name will reference.  The functions defined here allow users to add,
delete, and find named triggers.

It also adds functions to pause and unpause named triggers; since
named triggers act upon common data, they should also be paused and
unpaused as a group.

Link: http://lkml.kernel.org/r/c09ff648360f65b10a3e321eddafe18060b4a04f.1457029949.git.tom.zanussi@linux.intel.com

Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Tested-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-04-19 18:56:00 -04:00
Tom Zanussi
52a7f16ded tracing: Add support for multiple hist triggers per event
Allow users to define any number of hist triggers per trace event.
Any number of hist triggers may be added for a given event, which may
differ by key, value, or filter.

Reading the event's 'hist' file will display the output of all the
hist triggers defined on an event concatenated in the order they were
defined.

Link: http://lkml.kernel.org/r/48a0c8dd34c344571de880fb35e211c6d9a28961.1457029949.git.tom.zanussi@linux.intel.com

Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Tested-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-04-19 18:55:59 -04:00
Tom Zanussi
d0bad49bb0 tracing: Add enable_hist/disable_hist triggers
Similar to enable_event/disable_event triggers, these triggers enable
and disable the aggregation of events into maps rather than enabling
and disabling their writing into the trace buffer.

They can be used to automatically start and stop hist triggers based
on a matching filter condition.

If there's a paused hist trigger on system:event, the following would
start it when the filter condition was hit:

  # echo enable_hist:system:event [ if filter] > event/trigger

And the following would disable a running system:event hist trigger:

  # echo disable_hist:system:event [ if filter] > event/trigger

See Documentation/trace/events.txt for real examples.

Link: http://lkml.kernel.org/r/f812f086e52c8b7c8ad5443487375e03c96a601f.1457029949.git.tom.zanussi@linux.intel.com

Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Tested-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-04-19 18:55:57 -04:00
Tom Zanussi
6a475cb17f tracing: Remove restriction on string position in hist trigger keys
If we assume the maximum size for a string field, we don't have to
worry about its position.  Since we only allow two keys in a compound
key and having more than one string key in a given compound key
doesn't make much sense anyway, trading a bit of extra space instead
of introducing an arbitrary restriction makes more sense.

We also need to use the event field size for static strings when
copying the contents, otherwise we get random garbage in the key.

Also, cast string return values to avoid warnings on 32-bit compiles.

Finally, rearrange the code without changing any functionality by
moving the compound key updating code into a separate function.

Link: http://lkml.kernel.org/r/8976e1ab04b66bc2700ad1ed0768a2de85ac1983.1457029949.git.tom.zanussi@linux.intel.com

Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Tested-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-04-19 18:55:56 -04:00
Namhyung Kim
79e577cbce tracing: Support string type key properly
The string in a trace event is usually recorded as dynamic array which
is variable length.  But current hist code only support fixed length
array so it cannot support most strings.

This patch fixes it by checking filter_type of the field and get
proper pointer with it.  With this, it can get a histogram of exec()
based on filenames like below:

  # cd /sys/kernel/tracing/events/sched/sched_process_exec
  # cat 'hist:key=filename' > trigger
  # ps
   PID TTY       TIME CMD
     1 ?     00:00:00 init
    29 ?     00:00:00 sh
    38 ?     00:00:00 ps
  # ls
  enable  filter  format  hist  id  trigger
  # cat hist
  # trigger info: hist:keys=filename:vals=hitcount:sort=hitcount:size=2048 [active]

  { filename: /usr/bin/ps                         } hitcount:          1
  { filename: /usr/bin/ls                         } hitcount:          1
  { filename: /usr/bin/cat                        } hitcount:          1

  Totals:
      Hits: 3
      Entries: 3
      Dropped: 0

Link: http://lkml.kernel.org/r/610180d6df0cfdf11ee205452f3b241dea657233.1457029949.git.tom.zanussi@linux.intel.com

Cc: Tom Zanussi <tom.zanussi@linux.intel.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
[ Added (unsigned long) typecast to fix compile warning ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-04-19 18:55:00 -04:00
Tom Zanussi
69a0200c2e tracing: Add hist trigger support for stacktraces as keys
It's often useful to be able to use a stacktrace as a hash key, for
keeping a count of the number of times a particular call path resulted
in a trace event, for instance.  Add a special key named 'stacktrace'
which can be used as key in a 'keys=' param for this purpose:

    # echo hist:keys=stacktrace ... \
               [ if filter] > event/trigger

Link: http://lkml.kernel.org/r/87515e90b3785232a874a12156174635a348edb1.1457029949.git.tom.zanussi@linux.intel.com

Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Tested-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-04-19 12:19:01 -04:00
Tom Zanussi
316961988b tracing: Add hist trigger 'syscall' modifier
Allow users to have syscall id fields displayed as syscall names in
the output by appending '.syscall' to field names:

   # echo hist:keys=aaa.syscall ... \
              [ if filter] > event/trigger

Link: http://lkml.kernel.org/r/2bab1e59933d76a14b545bd2e02f80b8b08ac4d3.1457029949.git.tom.zanussi@linux.intel.com

Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Tested-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-04-19 12:18:04 -04:00
Tom Zanussi
6b4827ad02 tracing: Add hist trigger 'execname' modifier
Allow users to have common_pid field values displayed as program names
in the output by appending '.execname' to a common_pid field name:

   # echo hist:keys=common_pid.execname ... \
              [ if filter] > event/trigger

Link: http://lkml.kernel.org/r/e172e81f10f5b8d1f08450e3763c850f39fbf698.1457029949.git.tom.zanussi@linux.intel.com

Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Tested-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-04-19 12:17:56 -04:00
Tom Zanussi
c6afad49d1 tracing: Add hist trigger 'sym' and 'sym-offset' modifiers
Allow users to have address fields displayed as symbols in the output
by appending '.sym' or 'sym-offset' to field names:

   # echo hist:keys=aaa.sym,bbb.sym-offset ... \
              [ if filter] > event/trigger

Link: http://lkml.kernel.org/r/87d4935821491c0275513f0fbfb9bab8d3d3f079.1457029949.git.tom.zanussi@linux.intel.com

Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Tested-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-04-19 12:17:51 -04:00
Tom Zanussi
0c4a6b4666 tracing: Add hist trigger 'hex' modifier for displaying numeric fields
Allow users to have numeric fields displayed as hex values in the
output by appending '.hex' to field names:

   # echo hist:keys=aaa,bbb.hex:vals=ccc.hex ... \
              [ if filter] > event/trigger

Link: http://lkml.kernel.org/r/67bd431edda2af5798d7694818f7e8d71b6b3463.1457029949.git.tom.zanussi@linux.intel.com

Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Tested-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-04-19 12:17:43 -04:00
Tom Zanussi
e86ae9baac tracing: Add hist trigger support for clearing a trace
Allow users to append 'clear' to an existing trigger in order to have
the hash table cleared.

This expands the hist trigger syntax from this:
    # echo hist:keys=xxx:vals=yyy:sort=zzz.descending:pause/cont \
           [ if filter] >> event/trigger

to this:

    # echo hist:keys=xxx:vals=yyy:sort=zzz.descending:pause/cont/clear \
          [ if filter] >> event/trigger

Link: http://lkml.kernel.org/r/ae15dd0d9b2f7af07a37c1ff682063e2dbcdf160.1457029949.git.tom.zanussi@linux.intel.com

Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Tested-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-04-19 12:17:35 -04:00
Tom Zanussi
83e99914c9 tracing: Add hist trigger support for pausing and continuing a trace
Allow users to append 'pause' or 'continue' to an existing trigger in
order to have it paused or to have a paused trace continue.

This expands the hist trigger syntax from this:
    # echo hist:keys=xxx:vals=yyy:sort=zzz.descending \
          [ if filter] >> event/trigger

to this:

    # echo hist:keys=xxx:vals=yyy:sort=zzz.descending:pause or cont \
          [ if filter] >> event/trigger

Link: http://lkml.kernel.org/r/b672a92c14702cb924cdf6fc27ea1809bed04907.1457029949.git.tom.zanussi@linux.intel.com

Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Tested-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-04-19 12:17:29 -04:00
Tom Zanussi
e62347d245 tracing: Add hist trigger support for user-defined sorting ('sort=' param)
Allow users to specify keys and/or values to sort on.  With this
addition, keys and values specified using the 'keys=' and 'vals='
keywords can be used to sort the hist trigger output via a new 'sort='
keyword.  If multiple sort keys are specified, the output will be
sorted using the second key as a secondary sort key, etc.  The default
sort order is ascending; if the user wants a different sort order,
'.descending' can be appended to the specific sort key.  Before this
addition, output was always sorted by 'hitcount' in ascending order.

This expands the hist trigger syntax from this:

    # echo hist:keys=xxx:vals=yyy \
          [ if filter] > event/trigger

to this:

    # echo hist:keys=xxx:vals=yyy:sort=zzz.descending \
          [ if filter] > event/trigger

Link: http://lkml.kernel.org/r/b30a41db66ba486979c4f987aff5fab500ea53b3.1457029949.git.tom.zanussi@linux.intel.com

Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Tested-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-04-19 12:17:19 -04:00
Tom Zanussi
76a3b0c8ac tracing: Add hist trigger support for compound keys
Allow users to specify multiple trace event fields to use in keys by
allowing multiple fields in the 'keys=' keyword.  With this addition,
any unique combination of any of the fields named in the 'keys'
keyword will result in a new entry being added to the hash table.

Link: http://lkml.kernel.org/r/0cfa24e6ac3b0dcece7737d94aa1f322ae3afc4b.1457029949.git.tom.zanussi@linux.intel.com

Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Tested-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-04-19 12:16:33 -04:00
Tom Zanussi
f2606835d7 tracing: Add hist trigger support for multiple values ('vals=' param)
Allow users to specify trace event fields to use in aggregated sums
via a new 'vals=' keyword.  Before this addition, the only aggregated
sum supported was the implied value 'hitcount'.  With this addition,
'hitcount' is also supported as an explicit value field, as is any
numeric trace event field.

This expands the hist trigger syntax from this:

  # echo hist:keys=xxx [ if filter] > event/trigger

to this:

  # echo hist:keys=xxx:vals=yyy [ if filter] > event/trigger

Link: http://lkml.kernel.org/r/2a5d1adb5ba6c65d7bb2148e379f2fed47f29a68.1457029949.git.tom.zanussi@linux.intel.com

Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Tested-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-04-19 12:16:23 -04:00
Tom Zanussi
7ef224d1d0 tracing: Add 'hist' event trigger command
'hist' triggers allow users to continually aggregate trace events,
which can then be viewed afterwards by simply reading a 'hist' file
containing the aggregation in a human-readable format.

The basic idea is very simple and boils down to a mechanism whereby
trace events, rather than being exhaustively dumped in raw form and
viewed directly, are automatically 'compressed' into meaningful tables
completely defined by the user.

This is done strictly via single-line command-line commands and
without the aid of any kind of programming language or interpreter.

A surprising number of typical use cases can be accomplished by users
via this simple mechanism.  In fact, a large number of the tasks that
users typically do using the more complicated script-based tracing
tools, at least during the initial stages of an investigation, can be
accomplished by simply specifying a set of keys and values to be used
in the creation of a hash table.

The Linux kernel trace event subsystem happens to provide an extensive
list of keys and values ready-made for such a purpose in the form of
the event format files associated with each trace event.  By simply
consulting the format file for field names of interest and by plugging
them into the hist trigger command, users can create an endless number
of useful aggregations to help with investigating various properties
of the system.  See Documentation/trace/events.txt for examples.

hist triggers are implemented on top of the existing event trigger
infrastructure, and as such are consistent with the existing triggers
from a user's perspective as well.

The basic syntax follows the existing trigger syntax.  Users start an
aggregation by writing a 'hist' trigger to the event of interest's
trigger file:

  # echo hist:keys=xxx [ if filter] > event/trigger

Once a hist trigger has been set up, by default it continually
aggregates every matching event into a hash table using the event key
and a value field named 'hitcount'.

To view the aggregation at any point in time, simply read the 'hist'
file in the same directory as the 'trigger' file:

  # cat event/hist

The detailed syntax provides additional options for user control, and
is described exhaustively in Documentation/trace/events.txt and in the
virtual tracing/README file in the tracing subsystem.

Link: http://lkml.kernel.org/r/72d263b5e1853fe9c314953b65833c3aa75479f2.1457029949.git.tom.zanussi@linux.intel.com

Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Tested-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-04-19 12:16:14 -04:00
Tom Zanussi
3b772b96b8 tracing: Update some tracing_map constants and comments
Make it clear exactly how many keys and values are supported through
better defines, and add 1 to the vals count, since normally clients
want support for at least a hitcount and two other values.

Also, note the error return value for tracing_map_add_key/val_field()
in the comments.

Link: http://lkml.kernel.org/r/6696fa02ebc716aa344c27a571a2afaa25e5b4d4.1457029949.git.tom.zanussi@linux.intel.com

Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-04-19 12:16:06 -04:00
Steven Rostedt (Red Hat)
8d44f2f34f tracing: Fix TRACING_MAP Kconfig
The config option for TRACING_MAP has "default n", which is not needed
because the default of configs is 'n'.

Also, since the TRACING_MAP has no config prompt, there's no reason to
include "If in doubt, say N" in the help text.

Fixed a typo in the comments of tracing_map.h.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-04-19 12:15:54 -04:00
Tom Zanussi
08d43a5fa0 tracing: Add lock-free tracing_map
Add tracing_map, a special-purpose lock-free map for tracing.

tracing_map is designed to aggregate or 'sum' one or more values
associated with a specific object of type tracing_map_elt, which
is associated by the map to a given key.

It provides various hooks allowing per-tracer customization and is
separated out into a separate file in order to allow it to be shared
between multiple tracers, but isn't meant to be generally used outside
of that context.

The tracing_map implementation was inspired by lock-free map
algorithms originated by Dr. Cliff Click:

 http://www.azulsystems.com/blog/cliff/2007-03-26-non-blocking-hashtable
 http://www.azulsystems.com/events/javaone_2007/2007_LockFreeHash.pdf

Link: http://lkml.kernel.org/r/b43d68d1add33582a396f553c8ef705a33a6a748.1449767187.git.tom.zanussi@linux.intel.com

Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Tested-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-04-19 12:04:59 -04:00
Steven Rostedt
c37775d578 tracing: Add infrastructure to allow set_event_pid to follow children
Add the infrastructure needed to have the PIDs in set_event_pid to
automatically add PIDs of the children of the tasks that have their PIDs in
set_event_pid. This will also remove PIDs from set_event_pid when a task
exits

This is implemented by adding hooks into the fork and exit tracepoints. On
fork, the PIDs are added to the list, and on exit, they are removed.

Add a new option called event_fork that when set, PIDs in set_event_pid will
automatically get their children PIDs added when they fork, as well as any
task that exits will have its PID removed from set_event_pid.

This works for instances as well.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-04-19 10:28:28 -04:00
Steven Rostedt
f4d34a87e9 tracing: Use pid bitmap instead of a pid array for set_event_pid
In order to add the ability to let tasks that are filtered by the events
have their children also be traced on fork (and then not traced on exit),
convert the array into a pid bitmask. Most of the time the number of pids is
only 32768 pids or a 4k bitmask, which is the same size as the default list
currently is, and that list could grow if more pids are listed.

This also greatly simplifies the code.

Suggested-by: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-04-19 10:28:27 -04:00
Steven Rostedt
9ebc57cfaa tracing: Rename check_ignore_pid() to ignore_this_task()
The name "check_ignore_pid" is confusing in trying to figure out if the pid
should be ignored or not. Rename it to "ignore_this_task" which is pretty
straight forward, as a task (not a pid) is passed in, and should if true
should be ignored.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2016-04-19 10:28:26 -04:00
Linus Torvalds
ac82a57aff Merge branch 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking fixlet from Ingo Molnar:
 "Fixes a build warning on certain Kconfig combinations"

* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  locking/lockdep: Fix print_collision() unused warning
2016-04-16 15:43:19 -07:00
Linus Torvalds
51d7b12041 /proc/iomem: only expose physical resource addresses to privileged users
In commit c4004b02f8 ("x86: remove the kernel code/data/bss resources
from /proc/iomem") I was hoping to remove the phyiscal kernel address
data from /proc/iomem entirely, but that had to be reverted because some
system programs actually use it.

This limits all the detailed resource information to properly
credentialed users instead.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-14 12:56:09 -07:00
Linus Torvalds
4a2d057e4f Merge branch 'PAGE_CACHE_SIZE-removal'
Merge PAGE_CACHE_SIZE removal patches from Kirill Shutemov:
 "PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time
  ago with promise that one day it will be possible to implement page
  cache with bigger chunks than PAGE_SIZE.

  This promise never materialized.  And unlikely will.

  Let's stop pretending that pages in page cache are special.  They are
  not.

  The first patch with most changes has been done with coccinelle.  The
  second is manual fixups on top.

  The third patch removes macros definition"

[ I was planning to apply this just before rc2, but then I spaced out,
  so here it is right _after_ rc2 instead.

  As Kirill suggested as a possibility, I could have decided to only
  merge the first two patches, and leave the old interfaces for
  compatibility, but I'd rather get it all done and any out-of-tree
  modules and patches can trivially do the converstion while still also
  working with older kernels, so there is little reason to try to
  maintain the redundant legacy model.    - Linus ]

* PAGE_CACHE_SIZE-removal:
  mm: drop PAGE_CACHE_* and page_cache_{get,release} definition
  mm, fs: remove remaining PAGE_CACHE_* and page_cache_{get,release} usage
  mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros
2016-04-04 10:50:24 -07:00
Kirill A. Shutemov
09cbfeaf1a mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros
PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time
ago with promise that one day it will be possible to implement page
cache with bigger chunks than PAGE_SIZE.

This promise never materialized.  And unlikely will.

We have many places where PAGE_CACHE_SIZE assumed to be equal to
PAGE_SIZE.  And it's constant source of confusion on whether
PAGE_CACHE_* or PAGE_* constant should be used in a particular case,
especially on the border between fs and mm.

Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much
breakage to be doable.

Let's stop pretending that pages in page cache are special.  They are
not.

The changes are pretty straight-forward:

 - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>;

 - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>;

 - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN};

 - page_cache_get() -> get_page();

 - page_cache_release() -> put_page();

This patch contains automated changes generated with coccinelle using
script below.  For some reason, coccinelle doesn't patch header files.
I've called spatch for them manually.

The only adjustment after coccinelle is revert of changes to
PAGE_CAHCE_ALIGN definition: we are going to drop it later.

There are few places in the code where coccinelle didn't reach.  I'll
fix them manually in a separate patch.  Comments and documentation also
will be addressed with the separate patch.

virtual patch

@@
expression E;
@@
- E << (PAGE_CACHE_SHIFT - PAGE_SHIFT)
+ E

@@
expression E;
@@
- E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT)
+ E

@@
@@
- PAGE_CACHE_SHIFT
+ PAGE_SHIFT

@@
@@
- PAGE_CACHE_SIZE
+ PAGE_SIZE

@@
@@
- PAGE_CACHE_MASK
+ PAGE_MASK

@@
expression E;
@@
- PAGE_CACHE_ALIGN(E)
+ PAGE_ALIGN(E)

@@
expression E;
@@
- page_cache_get(E)
+ get_page(E)

@@
expression E;
@@
- page_cache_release(E)
+ put_page(E)

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-04 10:41:08 -07:00
Borislav Petkov
5c8a010c24 locking/lockdep: Fix print_collision() unused warning
Fix this:

  kernel/locking/lockdep.c:2051:13: warning: ‘print_collision’ defined but not used [-Wunused-function]
  static void print_collision(struct task_struct *curr,
              ^

Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1459759327-2880-1-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-04-04 11:41:34 +02:00
Linus Torvalds
4c3b73c6a2 Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf fixes from Ingo Molnar:
 "Misc kernel side fixes:

   - fix event leak
   - fix AMD PMU driver bug
   - fix core event handling bug
   - fix build bug on certain randconfigs

  Plus misc tooling fixes"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/x86/amd/ibs: Fix pmu::stop() nesting
  perf/core: Don't leak event in the syscall error path
  perf/core: Fix time tracking bug with multiplexing
  perf jit: genelf makes assumptions about endian
  perf hists: Fix determination of a callchain node's childlessness
  perf tools: Add missing initialization of perf_sample.cpumode in synthesized samples
  perf tools: Fix build break on powerpc
  perf/x86: Move events_sysfs_show() outside CPU_SUP_INTEL
  perf bench: Fix detached tarball building due to missing 'perf bench memcpy' headers
  perf tests: Fix tarpkg build test error output redirection
2016-04-03 07:22:12 -05:00
Linus Torvalds
7b367f5dba Merge branch 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull core kernel fixes from Ingo Molnar:
 "This contains the nohz/atomic cleanup/fix for the fetch_or() ugliness
  you noted during the original nohz pull request, plus there's also
  misc fixes:

   - fix liblockdep build bug
   - fix uapi header build bug
   - print more lockdep hash collision info to help debug recent reports
     of hash collisions
   - update MAINTAINERS email address"

* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  MAINTAINERS: Update my email address
  locking/lockdep: Print chain_key collision information
  uapi/linux/stddef.h: Provide __always_inline to userspace headers
  tools/lib/lockdep: Fix unsupported 'basename -s' in run_tests.sh
  locking/atomic, sched: Unexport fetch_or()
  timers/nohz: Convert tick dependency mask to atomic_t
  locking/atomic: Introduce atomic_fetch_or()
2016-04-03 07:06:53 -05:00
Linus Torvalds
05cf8077e5 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Pull networking fixes from David Miller:

 1) Missing device reference in IPSEC input path results in crashes
    during device unregistration.  From Subash Abhinov Kasiviswanathan.

 2) Per-queue ISR register writes not being done properly in macb
    driver, from Cyrille Pitchen.

 3) Stats accounting bugs in bcmgenet, from Patri Gynther.

 4) Lightweight tunnel's TTL and TOS were swapped in netlink dumps, from
    Quentin Armitage.

 5) SXGBE driver has off-by-one in probe error paths, from Rasmus
    Villemoes.

 6) Fix race in save/swap/delete options in netfilter ipset, from
    Vishwanath Pai.

 7) Ageing time of bridge not set properly when not operating over a
    switchdev device.  Fix from Haishuang Yan.

 8) Fix GRO regression wrt nested FOU/GUE based tunnels, from Alexander
    Duyck.

 9) IPV6 UDP code bumps wrong stats, from Eric Dumazet.

10) FEC driver should only access registers that actually exist on the
    given chipset, fix from Fabio Estevam.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (73 commits)
  net: mvneta: fix changing MTU when using per-cpu processing
  stmmac: fix MDIO settings
  Revert "stmmac: Fix 'eth0: No PHY found' regression"
  stmmac: fix TX normal DESC
  net: mvneta: use cache_line_size() to get cacheline size
  net: mvpp2: use cache_line_size() to get cacheline size
  net: mvpp2: fix maybe-uninitialized warning
  tun, bpf: fix suspicious RCU usage in tun_{attach, detach}_filter
  net: usb: cdc_ncm: adding Telit LE910 V2 mobile broadband card
  rtnl: fix msg size calculation in if_nlmsg_size()
  fec: Do not access unexisting register in Coldfire
  net: mvneta: replace MVNETA_CPU_D_CACHE_LINE_SIZE with L1_CACHE_BYTES
  net: mvpp2: replace MVPP2_CPU_D_CACHE_LINE_SIZE with L1_CACHE_BYTES
  net: dsa: mv88e6xxx: Clear the PDOWN bit on setup
  net: dsa: mv88e6xxx: Introduce _mv88e6xxx_phy_page_{read, write}
  bpf: make padding in bpf_tunnel_key explicit
  ipv6: udp: fix UDP_MIB_IGNOREDMULTI updates
  bnxt_en: Fix ethtool -a reporting.
  bnxt_en: Fix typo in bnxt_hwrm_set_pause_common().
  bnxt_en: Implement proper firmware message padding.
  ...
2016-04-01 20:03:33 -05:00
Alfredo Alvarez Fernandez
39e2e173fb locking/lockdep: Print chain_key collision information
A sequence of pairs [class_idx -> corresponding chain_key iteration]
is printed for both the current held_lock chain and the cached chain.

That exposes the two different class_idx sequences that led to that
particular hash value.

This helps with debugging hash chain collision reports.

Signed-off-by: Alfredo Alvarez Fernandez <alfredoalvarezfernandez@gmail.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-fsdevel@vger.kernel.org
Cc: sedat.dilek@gmail.com
Cc: tytso@mit.edu
Link: http://lkml.kernel.org/r/1459357416-19190-1-git-send-email-alfredoalvarezernandez@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-03-31 15:03:58 +02:00
Alexander Shishkin
201c2f85bd perf/core: Don't leak event in the syscall error path
In the error path, event_file not being NULL is used to determine
whether the event itself still needs to be free'd, so fix it up to
avoid leaking.

Reported-by: Leon Yu <chianglungyu@gmail.com>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Fixes: 130056275a ("perf: Do not double free")
Link: http://lkml.kernel.org/r/87twk06yxp.fsf@ashishki-desk.ger.corp.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-03-31 09:54:07 +02:00
Peter Zijlstra
8fdc65391c perf/core: Fix time tracking bug with multiplexing
Stephane reported that commit:

  3cbaa59069 ("perf: Fix ctx time tracking by introducing EVENT_TIME")

introduced a regression wrt. time tracking, as easily observed by:

> This patch introduce a bug in the time tracking of events when
> multiplexing is used.
>
> The issue is easily reproducible with the following perf run:
>
>  $ perf stat -a -C 0 -e branches,branches,branches,branches,branches,branches -I 1000
>      1.000730239            652,394      branches   (66.41%)
>      1.000730239            597,809      branches   (66.41%)
>      1.000730239            593,870      branches   (66.63%)
>      1.000730239            651,440      branches   (67.03%)
>      1.000730239            656,725      branches   (66.96%)
>      1.000730239      <not counted>      branches
>
> One branches event is shown as not having run. Yet, with
> multiplexing, all events should run especially with a 1s (-I 1000)
> interval. The delta for time_running comes out to 0. Yet, the event
> has run because the kernel is actually multiplexing the events. The
> problem is that the time tracking is the kernel and especially in
> ctx_sched_out() is wrong now.
>
> The problem is that in case that the kernel enters ctx_sched_out() with the
> following state:
>    ctx->is_active=0x7 event_type=0x1
>    Call Trace:
>     [<ffffffff813ddd41>] dump_stack+0x63/0x82
>     [<ffffffff81182bdc>] ctx_sched_out+0x2bc/0x2d0
>     [<ffffffff81183896>] perf_mux_hrtimer_handler+0xf6/0x2c0
>     [<ffffffff811837a0>] ? __perf_install_in_context+0x130/0x130
>     [<ffffffff810f5818>] __hrtimer_run_queues+0xf8/0x2f0
>     [<ffffffff810f6097>] hrtimer_interrupt+0xb7/0x1d0
>     [<ffffffff810509a8>] local_apic_timer_interrupt+0x38/0x60
>     [<ffffffff8175ca9d>] smp_apic_timer_interrupt+0x3d/0x50
>     [<ffffffff8175ac7c>] apic_timer_interrupt+0x8c/0xa0
>
> In that case, the test:
>       if (is_active & EVENT_TIME)
>
> will be false and the time will not be updated. Time must always be updated on
> sched out.

Fix this by always updating time if EVENT_TIME was set, as opposed to
only updating time when EVENT_TIME changed.

Reported-by: Stephane Eranian <eranian@google.com>
Tested-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: kan.liang@intel.com
Cc: namhyung@kernel.org
Fixes: 3cbaa59069 ("perf: Fix ctx time tracking by introducing EVENT_TIME")
Link: http://lkml.kernel.org/r/20160329072644.GB3408@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-03-31 09:54:06 +02:00
Frederic Weisbecker
5529578a27 locking/atomic, sched: Unexport fetch_or()
This patch functionally reverts:

  5fd7a09cfb ("atomic: Export fetch_or()")

During the merge Linus observed that the generic version of fetch_or()
was messy:

  " This makes the ugly "fetch_or()" macro that the scheduler used
    internally a new generic helper, and does a bad job at it. "

  e23604edac Merge branch 'timers-nohz-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Now that we have introduced atomic_fetch_or(), fetch_or() is only used
by the scheduler in order to deal with thread_info flags which type
can vary across architectures.

Lets confine fetch_or() back to the scheduler so that we encourage
future users to use the more robust and well typed atomic_t version
instead.

While at it, fetch_or() gets robustified, pasting improvements from a
previous patch by Ingo Molnar that avoids needless expression
re-evaluations in the loop.

Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1458830281-4255-4-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-03-29 11:52:11 +02:00
Frederic Weisbecker
f009a7a767 timers/nohz: Convert tick dependency mask to atomic_t
The tick dependency mask was intially unsigned long because this is the
type on which clear_bit() operates on and fetch_or() accepts it.

But now that we have atomic_fetch_or(), we can instead use
atomic_andnot() to clear the bit. This consolidates the type of our
tick dependency mask, reduce its size on structures and benefit from
possible architecture optimizations on atomic_t operations.

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1458830281-4255-3-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-03-29 11:52:11 +02:00
Alexander Potapenko
be7635e728 arch, ftrace: for KASAN put hard/soft IRQ entries into separate sections
KASAN needs to know whether the allocation happens in an IRQ handler.
This lets us strip everything below the IRQ entry point to reduce the
number of unique stack traces needed to be stored.

Move the definition of __irq_entry to <linux/interrupt.h> so that the
users don't need to pull in <linux/ftrace.h>.  Also introduce the
__softirq_entry macro which is similar to __irq_entry, but puts the
corresponding functions to the .softirqentry.text section.

Signed-off-by: Alexander Potapenko <glider@google.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Andrey Konovalov <adech.fo@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Konstantin Serebryany <kcc@google.com>
Cc: Dmitry Chernenkov <dmitryc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-25 16:37:42 -07:00
Michal Hocko
36324a990c oom: clear TIF_MEMDIE after oom_reaper managed to unmap the address space
When oom_reaper manages to unmap all the eligible vmas there shouldn't
be much of the freable memory held by the oom victim left anymore so it
makes sense to clear the TIF_MEMDIE flag for the victim and allow the
OOM killer to select another task.

The lack of TIF_MEMDIE also means that the victim cannot access memory
reserves anymore but that shouldn't be a problem because it would get
the access again if it needs to allocate and hits the OOM killer again
due to the fatal_signal_pending resp.  PF_EXITING check.  We can safely
hide the task from the OOM killer because it is clearly not a good
candidate anymore as everyhing reclaimable has been torn down already.

This patch will allow to cap the time an OOM victim can keep TIF_MEMDIE
and thus hold off further global OOM killer actions granted the oom
reaper is able to take mmap_sem for the associated mm struct.  This is
not guaranteed now but further steps should make sure that mmap_sem for
write should be blocked killable which will help to reduce such a lock
contention.  This is not done by this patch.

Note that exit_oom_victim might be called on a remote task from
__oom_reap_task now so we have to check and clear the flag atomically
otherwise we might race and underflow oom_victims or wake up waiters too
early.

Signed-off-by: Michal Hocko <mhocko@suse.com>
Suggested-by: Johannes Weiner <hannes@cmpxchg.org>
Suggested-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Andrea Argangeli <andrea@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-25 16:37:42 -07:00