Commit graph

6232 commits

Author SHA1 Message Date
Ingo Molnar
ac07bcaa82 Merge branch 'tip/tracing/ftrace' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into tracing/ftrace 2009-02-18 01:09:07 +01:00
Ingo Molnar
37bd824a35 Merge branches 'tracing/ftrace' and 'tracing/urgent' into tracing/core 2009-02-18 01:08:13 +01:00
Linus Torvalds
e78ac4b9de Merge branch 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  sched: cpu hotplug fix
2009-02-17 14:30:06 -08:00
Linus Torvalds
29a0c5ce5d Merge branch 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  timers: more consistently use clock vs timer
2009-02-17 14:29:42 -08:00
Linus Torvalds
f8effd1a4a Merge branch 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  doc: mmiotrace.txt, buffer size control change
  trace: mmiotrace to the tracer menu in Kconfig
  mmiotrace: count events lost due to not recording
2009-02-17 14:29:15 -08:00
Linus Torvalds
8ce9a75a30 Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  iommu: fix Intel IOMMU write-buffer flushing
  futex: fix reference leak

Trivial conflicts fixed manually in drivers/pci/intel-iommu.c
2009-02-17 14:26:35 -08:00
Frederic Weisbecker
5b058bcde9 tracing/function-graph-tracer: trace the idle tasks
When the function graph tracer is activated, it iterates over the task_list
to allocate a stack to store the return addresses.

But the per cpu idle tasks are not iterated by using
do_each_thread / while_each_thread.

So we have to iterate on them manually.

This fixes somes weirdness in the traces and many losses of traces.
Examples on two cpus:

 0)   Xorg-4287    |   2.906 us    |              }
 0)   Xorg-4287    |   3.965 us    |            }
 0)   Xorg-4287    |   5.302 us    |          }
 ------------------------------------------
 0)   Xorg-4287    =>    <idle>-0
 ------------------------------------------

 0)    <idle>-0    |   2.861 us    |                        }
 0)    <idle>-0    |   0.526 us    |                        set_normalized_timespec();
 0)    <idle>-0    |   7.201 us    |                      }
 0)    <idle>-0    |   8.214 us    |                    }
 0)    <idle>-0    |               |                    clockevents_program_event() {
 0)    <idle>-0    |               |                      lapic_next_event() {
 0)    <idle>-0    |   0.510 us    |                        native_apic_mem_write();
 0)    <idle>-0    |   1.546 us    |                      }
 0)    <idle>-0    |   2.583 us    |                    }
 0)    <idle>-0    | + 12.435 us   |                  }
 0)    <idle>-0    | + 13.470 us   |                }
 0)    <idle>-0    |   0.608 us    |                _spin_unlock_irqrestore();
 0)    <idle>-0    | + 23.270 us   |              }
 0)    <idle>-0    | + 24.336 us   |            }
 0)    <idle>-0    | + 25.417 us   |          }
 0)    <idle>-0    |   0.593 us    |          _spin_unlock();
 0)    <idle>-0    | + 41.869 us   |        }
 0)    <idle>-0    | + 42.906 us   |      }
 0)    <idle>-0    | + 95.035 us   |    }
 0)    <idle>-0    |   0.540 us    |    menu_reflect();
 0)    <idle>-0    | ! 100.404 us  |  }
 0)    <idle>-0    |   0.564 us    |  mce_idle_callback();
 0)    <idle>-0    |               |  enter_idle() {
 0)    <idle>-0    |   0.526 us    |    mce_idle_callback();
 0)    <idle>-0    |   1.757 us    |  }
 0)    <idle>-0    |               |  cpuidle_idle_call() {
 0)    <idle>-0    |               |    menu_select() {
 0)    <idle>-0    |   0.525 us    |      pm_qos_requirement();
 0)    <idle>-0    |   0.518 us    |      tick_nohz_get_sleep_length();
 0)    <idle>-0    |   2.621 us    |    }
[...]
 1)    <idle>-0    |   0.518 us    |              touch_softlockup_watchdog();
 1)    <idle>-0    | + 14.355 us   |            }
 1)    <idle>-0    | + 22.840 us   |          }
 1)    <idle>-0    | + 25.949 us   |        }
 1)    <idle>-0    |               |        handle_irq() {
 1)    <idle>-0    |   0.511 us    |          irq_to_desc();
 1)    <idle>-0    |               |          handle_edge_irq() {
 1)    <idle>-0    |   0.638 us    |            _spin_lock();
 1)    <idle>-0    |               |            ack_apic_edge() {
 1)    <idle>-0    |   0.510 us    |              irq_to_desc();
 1)    <idle>-0    |               |              move_native_irq() {
 1)    <idle>-0    |   0.510 us    |                irq_to_desc();
 1)    <idle>-0    |   1.532 us    |              }
 1)    <idle>-0    |   0.511 us    |              native_apic_mem_write();
 ------------------------------------------
 1)    <idle>-0    =>    cat-5073
 ------------------------------------------

 1)    cat-5073    |   3.731 us    |                    }
 1)    cat-5073    |               |                    run_local_timers() {
 1)    cat-5073    |   0.533 us    |                      hrtimer_run_queues();
 1)    cat-5073    |               |                      raise_softirq() {
 1)    cat-5073    |               |                        __raise_softirq_irqoff() {
 1)    cat-5073    |               |                          /* nr: 1 */
 1)    cat-5073    |   2.718 us    |                        }
 1)    cat-5073    |   3.814 us    |                      }

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-17 19:20:17 +01:00
Steven Rostedt
35ebf1caa4 ftrace: show unlimited when traceon or traceoff has no counter
Impact: clean up

The traceon and traceoff function probes are confusing to developers
to what happens when a counter is not specified. This should help
clear things up.

 # echo "*:traceoff" > set_ftrace_filter
 # cat /debug/tracing/set_ftrace_filter

  #### all functions enabled ####
  do_fork:traceoff:unlimited

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
2009-02-17 13:12:12 -05:00
Wenji Huang
73d8b8bc4f tracing: fix typing mistake in hint message and comments
Impact: cleanup

Fix incorrect hint message in code and typos in comments.

Signed-off-by: Wenji Huang <wenji.huang@oracle.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
2009-02-17 12:38:24 -05:00
Wenji Huang
d2ef7c2f0f tracing: fix the return value of trace selftest
This patch is to fix the return value of trace_selftest_startup_sysprof
and trace_selftest_startup_branch on failure.

Signed-off-by: Wenji Huang <wenji.huang@oracle.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
2009-02-17 12:38:24 -05:00
Wenji Huang
af51309845 tracing: use the more proper parameter
Pass tsk to tracing_record_cmdline instead of current.

Signed-off-by: Wenji Huang <wenji.huang@oracle.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
2009-02-17 12:38:23 -05:00
Steven Rostedt
b6887d7916 ftrace: rename _hook to _probe
Impact: clean up

Ingo Molnar did not like the _hook naming convention used by the
select function tracer. Luis Claudio R. Goncalves suggested using
the "_probe" extension. This patch implements the change of
calling the functions and variables "_hook" and replacing them
with "_probe".

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
2009-02-17 12:32:04 -05:00
Steven Rostedt
6a24a244cd ftrace: clean up coding style
Ingo Molnar pointed out some coding style issues with the recent ftrace
updates. This patch cleans them up.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
2009-02-17 11:20:26 -05:00
Ingo Molnar
73d3fd96e7 ftrace: fix !CONFIG_DYNAMIC_FTRACE ftrace_swapper_pid definition
Impact: build fix

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-17 11:50:42 +01:00
Ingo Molnar
f492d3f838 Merge branch 'tip/tracing/ftrace' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into tracing/ftrace 2009-02-17 11:31:01 +01:00
Ingo Molnar
c4e2b432d5 Merge branches 'tracing/hw-branch-tracing' and 'tracing/power-tracer' into tracing/core 2009-02-17 11:29:53 +01:00
Steven Rostedt
e110e3d1ea ftrace: add pretty print function for traceon and traceoff hooks
This patch adds a pretty print version of traceon and traceoff
output for set_ftrace_filter.

  # echo 'sys_open:traceon:4' > set_ftrace_filter
  # cat set_ftrace_filter

 #### all functions enabled ####
 sys_open:traceon:count=4

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
2009-02-16 23:38:13 -05:00
Steven Rostedt
809dcf29ce ftrace: add pretty print to selected fuction traces
This patch adds a call back for the tracers that have hooks to
selected functions. This allows the tracer to show better output
in the set_ftrace_filter file.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
2009-02-16 23:06:01 -05:00
Steven Rostedt
8fc0c701c5 ftrace: show selected functions in set_ftrace_filter
This patch adds output to show what functions have tracer hooks
attached to them.

  # echo 'sys_open:traceon:4' > /debug/tracing/set_ftrace_filter
  # cat set_ftrace_filter

 #### all functions enabled ####
 sys_open:ftrace_traceon:0000000000000004

  # echo 'do_fork:traceoff:' > set_ftrace_filter
  # cat set_ftrace_filter

 #### all functions enabled ####
 sys_open:ftrace_traceon:0000000000000002
 do_fork:ftrace_traceoff:ffffffffffffffff

Note the 4 changed to a 2. This is because The code was executed twice
since the traceoff was added. If a cat is done again:

 #### all functions enabled ####
 sys_open:ftrace_traceon
 do_fork:ftrace_traceoff:ffffffffffffffff

The number disappears. That is because it will not print a NULL.

Callbacks to allow the tracer to pretty print will be implemented soon.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
2009-02-16 22:50:06 -05:00
Steven Rostedt
23b4ff3aa4 ftrace: add traceon traceoff commands to enable/disable the buffers
This patch adds the new function selection commands traceon and
traceoff. traceon sets the function to enable the ring buffers
while traceoff disables the ring buffers.  You can pass in the
number of times you want the command to be executed when the function
is hit. It will only execute if the state of the buffers are not
already in that state.

Example:

 # echo do_fork:traceon:4

Will enable the ring buffers if they are disabled every time it
hits do_fork, up to 4 times.

 # echo sys_close:traceoff

This will disable the ring buffers every time (unlimited) when
sys_close is called.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
2009-02-16 22:50:04 -05:00
Steven Rostedt
988ae9d6b2 ring-buffer: add tracing_is_on to test if ring buffer is enabled
This patch adds the tracing_is_on() interface to tell if the ring
buffer is turned on or not.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
2009-02-16 22:50:01 -05:00
Steven Rostedt
59df055f19 ftrace: trace different functions with a different tracer
Impact: new feature

Currently, the function tracer only gives you an ability to hook
a tracer to all functions being traced. The dynamic function trace
allows you to pick and choose which of those functions will be
traced, but all functions being traced will call all tracers that
registered with the function tracer.

This patch adds a new feature that allows a tracer to hook to specific
functions, even when all functions are being traced. It allows for
different functions to call different tracer hooks.

The way this is accomplished is by a special function that will hook
to the function tracer and will set up a hash table knowing which
tracer hook to call with which function. This is the most general
and easiest method to accomplish this. Later, an arch may choose
to supply their own method in changing the mcount call of a function
to call a different tracer. But that will be an exercise for the
future.

To register a function:

 struct ftrace_hook_ops {
	void			(*func)(unsigned long ip,
					unsigned long parent_ip,
					void **data);
	int			(*callback)(unsigned long ip, void **data);
	void			(*free)(void **data);
 };

 int register_ftrace_function_hook(char *glob, struct ftrace_hook_ops *ops,
				  void *data);

glob is a simple glob to search for the functions to hook.
ops is a pointer to the operations (listed below)
data is the default data to be passed to the hook functions when traced

ops:
 func is the hook function to call when the functions are traced
 callback is a callback function that is called when setting up the hash.
   That is, if the tracer needs to do something special for each
   function, that is being traced, and wants to give each function
   its own data. The address of the entry data is passed to this
   callback, so that the callback may wish to update the entry to
   whatever it would like.
 free is a callback for when the entry is freed. In case the tracer
   allocated any data, it is give the chance to free it.

To unregister we have three functions:

  void
  unregister_ftrace_function_hook(char *glob, struct ftrace_hook_ops *ops,
				void *data)

This will unregister all hooks that match glob, point to ops, and
have its data matching data. (note, if glob is NULL, blank or '*',
all functions will be tested).

  void
  unregister_ftrace_function_hook_func(char *glob,
				 struct ftrace_hook_ops *ops)

This will unregister all functions matching glob that has an entry
pointing to ops.

  void unregister_ftrace_function_hook_all(char *glob)

This simply unregisters all funcs.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
2009-02-16 22:44:09 -05:00
Steven Rostedt
e6ea44e9b4 ftrace: consolidate mutexes
Impact: clean up

Now that ftrace_lock is a mutex, there is no reason to have three
different mutexes protecting similar data. All the mutex paths
are not in hot paths, so having a mutex to cover more data is
not a problem.

This patch removes the ftrace_sysctl_lock and ftrace_start_lock
and uses the ftrace_lock to protect the locations that were protected
by these locks. By doing so, this change also removes some of
the lock nesting that was taking place.

There are still more mutexes in ftrace.c that can probably be
consolidated, but they can be dealt with later. We need to be careful
about the way the locks are nested, and by consolidating, we can cause
a recursive deadlock.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
2009-02-16 18:15:31 -05:00
Steven Rostedt
52baf11922 ftrace: convert ftrace_lock from a spinlock to mutex
Impact: clean up

The older versions of ftrace required doing the ftrace list
search under atomic context. Now all the calls are in non-atomic
context. There is no reason to keep the ftrace_lock as a spinlock.

This patch converts it to a mutex.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
2009-02-16 17:33:14 -05:00
Steven Rostedt
f6180773d9 ftrace: add command interface for function selection
Allow for other tracers to add their own commands for function
selection. This interface gives a trace the ability to name a
command for function selection. Right now it is pretty limited
in what it offers, but this is a building step for more features.

The :mod: command is converted to this interface and also serves
as a template for other implementations.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
2009-02-16 17:06:02 -05:00
Steven Rostedt
e68746a271 ftrace: enable filtering only when a function is filtered on
Impact: fix to prevent empty set_ftrace_filter and no ftrace output

The function filter is used to only trace a given set of functions.
The filter is enabled when a function name is echoed into the
set_ftrace_filter file. But if the name has a typo and the function
is not found, the filter is enabled, but no function is listed.

This makes a confusing situation where set_ftrace_filter is empty
but no functions ever get enabled for tracing.

For example:

 # cat /debug/tracing/set_ftrace_filter

  #### all functions enabled ####

 # echo bad_name > set_ftrace_filter
 # cat /debug/tracing/set_ftrace_filter

 # echo function > current_tracer
 # cat trace

  # tracer: nop
  #
  #           TASK-PID    CPU#    TIMESTAMP  FUNCTION
  #              | |       |          |         |

This patch changes that to only enable filtering if a function
is set to be filtered on. Now, the filter is not enabled if
a bad name is echoed into set_ftrace_filter.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
2009-02-16 17:03:49 -05:00
Steven Rostedt
64e7c44061 ftrace: add module command function filter selection
This patch adds a "command" syntax to the function filtering files:

  /debugfs/tracing/set_ftrace_filter
  /debugfs/tracing/set_ftrace_notrace

Of the format:  <function>:<command>:<parameter>

The command is optional, and dependent on the command, so are
the parameters.

 echo do_fork > set_ftrace_filter

Will only trace 'do_fork'.

 echo 'sched_*' > set_ftrace_filter

Will only trace functions starting with the letters 'sched_'.

 echo '*:mod:ext3' > set_ftrace_filter

Will trace only the ext3 module functions.

 echo '*write*:mod:ext3' > set_ftrace_notrace

Will prevent the ext3 functions with the letters 'write' in
the name from being traced.

 echo '!*_allocate:mod:ext3' > set_ftrace_filter

Will remove the functions in ext3 that end with the letters
'_allocate' from the ftrace filter.

Although this patch implements the 'command' format, only the
'mod' command is supported. More commands to follow.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
2009-02-16 16:55:50 -05:00
Steven Rostedt
9f4801e30a ftrace: break up ftrace_match_records into smaller components
Impact: clean up

ftrace_match_records does a lot of things that other features
can use. This patch breaks up ftrace_match_records and pulls
out ftrace_setup_glob and ftrace_match_record.

ftrace_setup_glob prepares a simple glob expression for use with
ftrace_match_record. ftrace_match_record compares a single record
with a glob type.

Breaking this up will allow for more features to run on individual
records.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
2009-02-16 16:49:57 -05:00
Steven Rostedt
7f24b31b01 ftrace: rename ftrace_match to ftrace_match_records
Impact: clean up

ftrace_match is too generic of a name. What it really does is
search all records and matches the records with the given string,
and either sets or unsets the functions to be traced depending
on if the parameter 'enable' is set or not.

This allows us to make another function called ftrace_match that
can be used to test a single record.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
2009-02-16 16:33:15 -05:00
Steven Rostedt
265c831cb0 ftrace: add do_for_each_ftrace_rec and while_for_each_ftrace_rec
Impact: clean up

To iterate over all the functions that dynamic trace knows about
it requires two for loops. One to iterate over the pages and the
other to iterate over the records within the page.

There are several duplications of these loops in ftrace.c. This
patch creates the macros do_for_each_ftrace_rec and
while_for_each_ftrace_rec to handle this logic, and removes the
duplicate code.

While making this change, I also discovered and fixed a small
bug that one of the iterations should exit the loop after it found the
record it was searching for. This used a break when it should have
used a goto, since there were two loops it needed to break out
from.  No real harm was done by this bug since it would only continue
to search the other records, and the code was in a slow path anyway.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
2009-02-16 16:25:12 -05:00
Steven Rostedt
0c75a3ed63 ftrace: state that all functions are enabled in set_ftrace_filter
Impact: clean up, make set_ftrace_filter less confusing

The set_ftrace_filter shows only the functions that will be traced.
But when it is empty, it will trace all functions. This can be a bit
confusing.

This patch makes set_ftrace_filter show:

  #### all functions enabled ####

When all functions will be traced, and we do not filter only a select
few.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
2009-02-16 16:21:35 -05:00
Ingo Molnar
72b623c736 Merge branch 'tip/tracing/ftrace' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into tracing/power-tracer 2009-02-15 20:43:03 +01:00
Rakib Mullick
a234aa9ecd tracing: fix section mismatch in trace_hw_branches.c
The function bts_trace_init() references a variable
bts_hotcpu_notifier which is marked
as __cpuinitdata. Thus causes section mismatch. This patch fixes it.

   LD      kernel/trace/built-in.o
 WARNING: kernel/trace/built-in.o(.text+0xc90c): Section mismatch in
 reference from the function bts_trace_init() to the variable
 .cpuinit.data:bts_hotcpu_notifier
 The function bts_trace_init() references
 the variable __cpuinitdata bts_hotcpu_notifier.
 This is often because bts_trace_init lacks a __cpuinitdata
 annotation or the annotation of bts_hotcpu_notifier is wrong.

 WARNING: kernel/trace/built-in.o(.text+0xc92a): Section mismatch in
 reference from the function bts_trace_reset() to the variable
 .cpuinit.data:bts_hotcpu_notifier
 The function bts_trace_reset() references
 the variable __cpuinitdata bts_hotcpu_notifier.
 This is often because bts_trace_reset lacks a __cpuinitdata
 annotation or the annotation of bts_hotcpu_notifier is wrong.

Signed-off-by: Rakib Mullick <rakib.mullick@gmail.com>
Cc: markus.t.metzger@gmail.com
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-15 20:41:08 +01:00
Ingo Molnar
9abd603048 Merge branches 'tracing/ftrace' and 'tracing/urgent' into tracing/core
Conflicts:
	kernel/trace/trace_mmiotrace.c
2009-02-15 20:08:55 +01:00
Pekka Paalanen
6bc5c366b1 trace: mmiotrace to the tracer menu in Kconfig
Impact: cosmetic change in Kconfig menu layout

This patch was originally suggested by Peter Zijlstra, but seems it
was forgotten.

CONFIG_MMIOTRACE and CONFIG_MMIOTRACE_TEST were selectable
directly under the Kernel hacking / debugging menu in the kernel
configuration system. They were present only for x86 and x86_64.

Other tracers that use the ftrace tracing framework are in their own
sub-menu. This patch moves the mmiotrace configuration options there.
Since the Kconfig file, where the tracer menu is, is not architecture
specific, HAVE_MMIOTRACE_SUPPORT is introduced and provided only by
x86/x86_64. CONFIG_MMIOTRACE now depends on it.

Signed-off-by: Pekka Paalanen <pq@iki.fi>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-15 20:03:28 +01:00
Pekka Paalanen
391b170f10 mmiotrace: count events lost due to not recording
Impact: enhances lost events counting in mmiotrace

The tracing framework, or the ring buffer facility it uses, has a switch
to stop recording data. When recording is off, the trace events will be
lost. The framework does not count these, so mmiotrace has to count them
itself.

Signed-off-by: Pekka Paalanen <pq@iki.fi>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-15 20:02:42 +01:00
Peter Zijlstra
868a23a804 lockdep: build fix for !PROVE_LOCKING
The __GFP_FS annotations fail to build with CONFIG_LOCKDEP=y,
CONFIG_PROVE_LOCKING=n, ammend that.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-15 00:30:26 +01:00
Peter Zijlstra
9833f8cb95 lockstat: warn about disabled lock debugging
Avoid confusion and clearly state lock debugging got disabled.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-14 23:28:28 +01:00
Peter Zijlstra
b4b136f44b lockdep: use stringify.h
Arnd pointed out we have the stringify macro magic already in-kernel.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
CC: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-14 23:28:26 +01:00
Peter Zijlstra
4f367d8adc lockdep: simplify check_prev_add_irq()
Remove the manual state iteration thingy.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-14 23:28:24 +01:00
Peter Zijlstra
f510b233cf lockdep: get_user_chars() redo
Generic, states independent, get_user_chars().

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-14 23:28:22 +01:00
Peter Zijlstra
3ff176ca47 lockdep: simplify get_user_chars()
there's too much repetition of code..

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-14 23:28:21 +01:00
Peter Zijlstra
38aa271438 lockdep: add comments to mark_lock_irq()
re-add some of the comments that got lost in the refactoring.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-14 23:28:19 +01:00
Peter Zijlstra
cf2ad4d13c lockdep: remove macro usage from mark_held_locks()
Now that we have nice numerical relations for the states, remove the macro
magics.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-14 23:28:17 +01:00
Peter Zijlstra
9d3651a23d lockdep: fully reduce mark_lock_irq()
Now what its only two functions, they again look rather similar.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-14 23:28:15 +01:00
Peter Zijlstra
42c50d544e lockdep: merge the !_READ mark_lock_irq() helpers
These two are also remakably similar

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-14 23:28:13 +01:00
Peter Zijlstra
780e820b2d lockdep: merge the _READ mark_lock_irq() helpers
The _READ helpers show remarkable similarity, merge them.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-14 23:28:12 +01:00
Peter Zijlstra
cd95302d25 lockdep: simplify mark_lock_irq() helpers #3
Kill another argument

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-14 23:28:10 +01:00
Peter Zijlstra
f989209e2f lockdep: further simplify mark_lock_irq() helpers
take away another parameter

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-14 23:28:08 +01:00
Peter Zijlstra
604de3b5b6 lockdep: simplify the mark_lock_irq() helpers
In order to unify them, take some arguments away

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-14 23:28:06 +01:00
Peter Zijlstra
6a6904d347 lockdep: split up mark_lock_irq()
split mark_lock_irq() into 4 simple helper functions

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-14 23:28:04 +01:00
Peter Zijlstra
fabe9c42c6 lockdep: generate usage strings
generate the usage strings

XXX capital invasion :-(

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-14 23:28:02 +01:00
Peter Zijlstra
d7b1b02134 lockdep: generate the state bit definitions
Generate the state bit definitions from the lockdep_states.h file.

Also, move LOCK_USED to last, so that the

 USED_IN
 USED_IN_READ
 ENABLED
 ENABLED_READ

states are nicely bit aligned -- we're going to use that property

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-14 23:28:01 +01:00
Peter Zijlstra
9851673bc3 lockdep: move state bit definitions around
For convenience later.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-14 23:27:59 +01:00
Peter Zijlstra
5346417e17 lockdep: simplify mark_lock()
remove the state iteration

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-14 23:27:57 +01:00
Peter Zijlstra
36bfb9bb03 lockdep: simplify mark_held_locks
remove the explicit state iteration

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-14 23:27:56 +01:00
Peter Zijlstra
9fe51abf7a lockdep: lockdep_states.h
Introduce a header file to generate all the states from.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-14 23:27:54 +01:00
Peter Zijlstra
a652d7081b lockdep: sanitize reclaim bit names
s/HELD_OVER/ENABLED/g

so that its similar to the hard and soft-irq names.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-14 23:27:52 +01:00
Peter Zijlstra
4fc95e867f lockdep: sanitize bit names
s/\(LOCKF\?_ENABLED_[^ ]*\)S\(_READ\)\?\>/\1\2/g

So that the USED_IN and ENABLED have the same names.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-14 23:27:51 +01:00
Nick Piggin
cf40bd16fd lockdep: annotate reclaim context (__GFP_NOFS)
Here is another version, with the incremental patch rolled up, and
added reclaim context annotation to kswapd, and allocation tracing
to slab allocators (which may only ever reach the page allocator
in rare cases, so it is good to put annotations here too).

Haven't tested this version as such, but it should be getting closer
to merge worthy ;)

--
After noticing some code in mm/filemap.c accidentally perform a __GFP_FS
allocation when it should not have been, I thought it might be a good idea to
try to catch this kind of thing with lockdep.

I coded up a little idea that seems to work. Unfortunately the system has to
actually be in __GFP_FS page reclaim, then take the lock, before it will mark
it. But at least that might still be some orders of magnitude more common
(and more debuggable) than an actual deadlock condition, so we have some
improvement I hope (the concept is no less complete than discovery of a lock's
interrupt contexts).

I guess we could even do the same thing with __GFP_IO (normal reclaim), and
even GFP_NOIO locks too... but filesystems will have the most locks and fiddly
code paths, so let's start there and see how it goes.

It *seems* to work. I did a quick test.

=================================
[ INFO: inconsistent lock state ]
2.6.28-rc6-00007-ged31348-dirty #26
---------------------------------
inconsistent {in-reclaim-W} -> {ov-reclaim-W} usage.
modprobe/8526 [HC0[0]:SC0[0]:HE1:SE1] takes:
 (testlock){--..}, at: [<ffffffffa0020055>] brd_init+0x55/0x216 [brd]
{in-reclaim-W} state was registered at:
  [<ffffffff80267bdb>] __lock_acquire+0x75b/0x1a60
  [<ffffffff80268f71>] lock_acquire+0x91/0xc0
  [<ffffffff8070f0e1>] mutex_lock_nested+0xb1/0x310
  [<ffffffffa002002b>] brd_init+0x2b/0x216 [brd]
  [<ffffffff8020903b>] _stext+0x3b/0x170
  [<ffffffff80272ebf>] sys_init_module+0xaf/0x1e0
  [<ffffffff8020c3fb>] system_call_fastpath+0x16/0x1b
  [<ffffffffffffffff>] 0xffffffffffffffff
irq event stamp: 3929
hardirqs last  enabled at (3929): [<ffffffff8070f2b5>] mutex_lock_nested+0x285/0x310
hardirqs last disabled at (3928): [<ffffffff8070f089>] mutex_lock_nested+0x59/0x310
softirqs last  enabled at (3732): [<ffffffff8061f623>] sk_filter+0x83/0xe0
softirqs last disabled at (3730): [<ffffffff8061f5b6>] sk_filter+0x16/0xe0

other info that might help us debug this:
1 lock held by modprobe/8526:
 #0:  (testlock){--..}, at: [<ffffffffa0020055>] brd_init+0x55/0x216 [brd]

stack backtrace:
Pid: 8526, comm: modprobe Not tainted 2.6.28-rc6-00007-ged31348-dirty #26
Call Trace:
 [<ffffffff80265483>] print_usage_bug+0x193/0x1d0
 [<ffffffff80266530>] mark_lock+0xaf0/0xca0
 [<ffffffff80266735>] mark_held_locks+0x55/0xc0
 [<ffffffffa0020000>] ? brd_init+0x0/0x216 [brd]
 [<ffffffff802667ca>] trace_reclaim_fs+0x2a/0x60
 [<ffffffff80285005>] __alloc_pages_internal+0x475/0x580
 [<ffffffff8070f29e>] ? mutex_lock_nested+0x26e/0x310
 [<ffffffffa0020000>] ? brd_init+0x0/0x216 [brd]
 [<ffffffffa002006a>] brd_init+0x6a/0x216 [brd]
 [<ffffffffa0020000>] ? brd_init+0x0/0x216 [brd]
 [<ffffffff8020903b>] _stext+0x3b/0x170
 [<ffffffff8070f8b9>] ? mutex_unlock+0x9/0x10
 [<ffffffff8070f83d>] ? __mutex_unlock_slowpath+0x10d/0x180
 [<ffffffff802669ec>] ? trace_hardirqs_on_caller+0x12c/0x190
 [<ffffffff80272ebf>] sys_init_module+0xaf/0x1e0
 [<ffffffff8020c3fb>] system_call_fastpath+0x16/0x1b

Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-14 23:27:49 +01:00
Johannes Berg
6f2b9b9a9d timer: implement lockdep deadlock detection
This modifies the timer code in a way to allow lockdep to detect
deadlocks resulting from a lock being taken in the timer function
as well as around the del_timer_sync() call.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
2009-02-14 23:25:52 +01:00
Serge E. Hallyn
fb5ae64fdd User namespaces: Only put the userns when we unhash the uid
uids in namespaces other than init don't get a sysfs entry.

For those in the init namespace, while we're waiting to remove
the sysfs entry for the uid the uid is still hashed, and
alloc_uid() may re-grab that uid without getting a new
reference to the user_ns, which we've already put in free_user
before scheduling remove_user_sysfs_dir().

Reported-and-tested-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Acked-by: David Howells <dhowells@redhat.com>
Tested-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-02-13 08:07:40 -08:00
Jason Baron
b5f9fd0f8a tracing: convert c/p state power tracer to use tracepoints
Convert the c/p state "power" tracer to use tracepoints. Avoids a
function call when the tracer is disabled.

Signed-off-by: Jason Baron <jbaron@redhat.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
2009-02-13 09:06:18 -05:00
Peter Zijlstra
3997ad317f timers: more consistently use clock vs timer
While reviewing the manpages, I noticed I'd missed some clock vs timer sites.

Make sure that all timer functions call cpu_timer_sample_group() and not
cpu_clock_sample_group(). This ensures that we enable the process wide timer
in time, and therefore pay the O(n) thread group cost from the syscall.

Not doing it here, will result in the first jiffy tick after setting the timer
doing this, resulting in a very expensive tick (but only once) and a delay in
actually starting the timer.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-13 13:04:05 +01:00
Ingo Molnar
d351c8db95 Merge branch 'tip/tracing/ftrace' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into tracing/ftrace 2009-02-13 10:26:45 +01:00
Ingo Molnar
1c511f740f Merge branches 'tracing/ftrace', 'tracing/ring-buffer', 'tracing/sysprof', 'tracing/urgent' and 'linus' into tracing/core 2009-02-13 10:25:18 +01:00
Steven Rostedt
45141d4667 ring-buffer: rename label out_unlock to out_reset
Impact: clean up

While reviewing the ring buffer code, I thougth I saw a bug with

	if (!__raw_spin_trylock(&cpu_buffer->lock))
		goto out_unlock;

But I forgot that we use a variable "lock_taken" that is set if
the spinlock is taken, and only unlock it if that variable is set.

To avoid further confusion from other reviewers, this patch
renames the label out_unlock with out_reset, which is the more
appropriate name.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
2009-02-12 13:39:46 -05:00
Ingo Molnar
a0490fa35d sched: cpu hotplug fix
rq_attach_root() does a kfree() with the runqueue lock held.

That's not a very wise move, fix it.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-12 11:57:36 +01:00
Li Zefan
cfebe563bd cgroups: fix lockdep subclasses overflow
I enabled all cgroup subsystems when compiling kernel, and then:
 # mount -t cgroup -o net_cls xxx /mnt
 # mkdir /mnt/0

This showed up immediately:
 BUG: MAX_LOCKDEP_SUBCLASSES too low!
 turning off the locking correctness validator.

It's caused by the cgroup hierarchy lock:
	for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) {
		struct cgroup_subsys *ss = subsys[i];
		if (ss->root == root)
			mutex_lock_nested(&ss->hierarchy_mutex, i);
	}

Now we have 9 cgroup subsystems, and the above 'i' for net_cls is 8, but
MAX_LOCKDEP_SUBCLASSES is 8.

This patch uses different lockdep keys for different subsystems.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-02-11 14:25:36 -08:00
Sven Wegener
fc3501d411 mm: fix dirty_bytes/dirty_background_bytes sysctls on 64bit arches
We need to pass an unsigned long as the minimum, because it gets casted
to an unsigned long in the sysctl handler. If we pass an int, we'll
access four more bytes on 64bit arches, resulting in a random minimum
value.

[rientjes@google.com: fix type of `old_bytes']
Signed-off-by: Sven Wegener <sven.wegener@stealer.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-02-11 14:25:35 -08:00
Peter Zijlstra
2fff78c784 futex: fix reference leak
Catalin noticed that (38d47c1b70: futex: rely on get_user_pages() for
shared futexes) caused an mm_struct leak.

Some tracing with the function graph tracer quickly pointed out that
futex_wait() has exit paths with unbalanced reference counts.

This regression was discovered by kmemleak.

Reported-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Tested-by: "Pallipadi, Venkatesh" <venkatesh.pallipadi@intel.com>
Tested-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-11 18:24:08 +01:00
Linus Torvalds
6c6f1f0f4d Merge branch 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  sched: revert recent sync wakeup changes
2009-02-11 08:25:06 -08:00
Linus Torvalds
94dba89533 Merge branch 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  timers: fix TIMER_ABSTIME for process wide cpu timers
  timers: split process wide cpu clocks/timers, fix
  x86: clean up hpet timer reinit
  timers: split process wide cpu clocks/timers, remove spurious warning
  timers: split process wide cpu clocks/timers
  signal: re-add dead task accumulation stats.
  x86: fix hpet timer reinit for x86_64
  sched: fix nohz load balancer on cpu offline
2009-02-11 08:24:32 -08:00
Linus Torvalds
9ce04f9238 Merge branch 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  ptrace, x86: fix the usage of ptrace_fork()
  i8327: fix outb() parameter order
  x86: fix math_emu register frame access
  x86: math_emu info cleanup
  x86: include correct %gs in a.out core dump
  x86, vmi: put a missing paravirt_release_pmd in pgd_dtor
  x86: find nr_irqs_gsi with mp_ioapic_routing
  x86: add clflush before monitor for Intel 7400 series
  x86: disable intel_iommu support by default
  x86: don't apply __supported_pte_mask to non-present ptes
  x86: fix grammar in user-visible BIOS warning
  x86/Kconfig.cpu: make Kconfig help readable in the console
  x86, 64-bit: print DMI info in the oops trace
2009-02-11 08:23:22 -08:00
Peter Zijlstra
fc631c82e1 sched: revert recent sync wakeup changes
Intel reported a 10% regression (mysql+sysbench) on a 16-way machine
with these patches:

  1596e29: sched: symmetric sync vs avg_overlap
  d942fb6: sched: fix sync wakeups

Revert them.

Reported-by: "Zhang, Yanmin" <yanmin_zhang@linux.intel.com>
Bisected-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-11 14:43:35 +01:00
Peter Zijlstra
4da94d49b2 timers: fix TIMER_ABSTIME for process wide cpu timers
The POSIX timer interface allows for absolute time expiry values through the
TIMER_ABSTIME flag, therefore we have to synchronize the timer to the clock
every time we start it.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-11 14:04:21 +01:00
Peter Zijlstra
3fccfd67df timers: split process wide cpu clocks/timers, fix
To decrease the chance of a missed enable, always enable the timer when we
sample it, we'll always disable it when we find that there are no active timers
in the jiffy tick.

This fixes a flood of warnings reported by Mike Galbraith.

Reported-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-11 14:04:19 +01:00
Arnaldo Carvalho de Melo
00f62f614b ring_buffer: pahole struct ring_buffer
While fixing some bugs in pahole (built-in.o files were not being
processed due to relocation problems) I found out about these packable
structures:

$ pahole --packable kernel/trace/ring_buffer.o  | grep ring
ring_buffer	72	64	8
ring_buffer_per_cpu	112	104	8

If we take a look at the current layout of struct ring_buffer we can see
that we have two 4 bytes holes.

$ pahole -C ring_buffer kernel/trace/ring_buffer.o
struct ring_buffer {
	unsigned int               pages;           /*     0     4 */
	unsigned int               flags;           /*     4     4 */
	int                        cpus;            /*     8     4 */

	/* XXX 4 bytes hole, try to pack */

	cpumask_var_t              cpumask;         /*    16     8 */
	atomic_t                   record_disabled; /*    24     4 */

	/* XXX 4 bytes hole, try to pack */

	struct mutex               mutex;           /*    32    32 */
	/* --- cacheline 1 boundary (64 bytes) --- */
	struct ring_buffer_per_cpu * * buffers;     /*    64     8 */

	/* size: 72, cachelines: 2, members: 7 */
	/* sum members: 64, holes: 2, sum holes: 8 */
	/* last cacheline: 8 bytes */
};

So, if I ask pahole to reorganize it:

$ pahole -C ring_buffer --reorganize kernel/trace/ring_buffer.o

struct ring_buffer {
	unsigned int               pages;           /*     0     4 */
	unsigned int               flags;           /*     4     4 */
	int                        cpus;            /*     8     4 */
	atomic_t                   record_disabled; /*    12     4 */
	cpumask_var_t              cpumask;         /*    16     8 */
	struct mutex               mutex;           /*    24    32 */
	struct ring_buffer_per_cpu * * buffers;     /*    56     8 */
	/* --- cacheline 1 boundary (64 bytes) --- */

	/* size: 64, cachelines: 1, members: 7 */
};   /* saved 8 bytes and 1 cacheline! */

We get it using just one 64 bytes cacheline.

To see what it did:

$ pahole -C ring_buffer --reorganize --show_reorg_steps \
	kernel/trace/ring_buffer.o | grep \/
/* Moving 'record_disabled' from after 'cpumask' to after 'cpus' */

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-11 13:21:40 +01:00
Frederic Weisbecker
b22f485812 tracing/sysprof: add missing tracing_{start,stop}_record_cmdline()
Add the missing pair tracing_{start,stop}_record_cmdline() to record well
the cmdline associated with pid.

Changes in v2:

- fix a build error, the sched_switch tracer is needed to record the
  cmdline.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-11 12:55:19 +01:00
Oleg Nesterov
06eb23b1ba ptrace, x86: fix the usage of ptrace_fork()
I noticed by pure accident we have ptrace_fork() and friends. This was
added by "x86, bts: add fork and exit handling", commit
bf53de907d.

I can't test this, ds_request_bts() returns -EOPNOTSUPP, but I strongly
believe this needs the fix. I think something like this program

	int main(void)
	{
		int pid = fork();

		if (!pid) {
			ptrace(PTRACE_TRACEME, 0, NULL, NULL);
			kill(getpid(), SIGSTOP);
			fork();
		} else {
			struct ptrace_bts_config bts = {
				.flags = PTRACE_BTS_O_ALLOC,
				.size  = 4 * 4096,
			};

			wait(NULL);

			ptrace(PTRACE_SETOPTIONS, pid, NULL, PTRACE_O_TRACEFORK);
			ptrace(PTRACE_BTS_CONFIG, pid, &bts, sizeof(bts));
			ptrace(PTRACE_CONT, pid, NULL, NULL);

			sleep(1);
		}

		return 0;
	}

should crash the kernel.

If the task is traced by its natural parent ptrace_reparented() returns 0
but we should clear ->btsxxx anyway.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Markus Metzger <markus.t.metzger@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-11 10:32:46 +01:00
Hannes Eder
e7669b8e32 tracing: fix sparse warning: attribute function with __acquires/__releases
Fix this sparse warning:

  kernel/trace/trace.c:458:9: warning: context imbalance in 'register_tracer' - unexpected unlock

Signed-off-by: Hannes Eder <hannes@hanneseder.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-11 10:15:42 +01:00
Hannes Eder
5e39841c45 tracing: fix sparse warnings: fix (un-)signedness
Fix these sparse warnings:

  kernel/trace/ring_buffer.c:70:37: warning: incorrect type in argument 2 (different signedness)
  kernel/trace/ring_buffer.c:84:39: warning: incorrect type in argument 2 (different signedness)
  kernel/trace/ring_buffer.c:96:43: warning: incorrect type in argument 2 (different signedness)
  kernel/trace/ring_buffer.c:2475:13: warning: incorrect type in argument 2 (different signedness)
  kernel/trace/ring_buffer.c:2475:13: warning: incorrect type in argument 2 (different signedness)
  kernel/trace/ring_buffer.c:2478:42: warning: incorrect type in argument 2 (different signedness)
  kernel/trace/ring_buffer.c:2478:42: warning: incorrect type in argument 2 (different signedness)
  kernel/trace/ring_buffer.c:2500:40: warning: incorrect type in argument 3 (different signedness)
  kernel/trace/ring_buffer.c:2505:44: warning: incorrect type in argument 2 (different signedness)
  kernel/trace/ring_buffer.c:2507:46: warning: incorrect type in argument 2 (different signedness)
  kernel/trace/trace.c:2130:40: warning: incorrect type in argument 3 (different signedness)
  kernel/trace/trace.c:2280:40: warning: incorrect type in argument 3 (different signedness)

Signed-off-by: Hannes Eder <hannes@hanneseder.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-11 10:15:42 +01:00
Hannes Eder
4fd2735881 tracing: fix sparse warnings: make symbols static
Impact: make global variables and a global function static

The function '__trace_userstack' does not seem to have a caller, so it
is commented out.

Fix this sparse warnings:
  kernel/trace/trace.c:82:5: warning: symbol 'tracing_disabled' was not declared. Should it be static?
  kernel/trace/trace.c:600:10: warning: symbol 'trace_record_cmdline_disabled' was not declared. Should it be static?
  kernel/trace/trace.c:957:6: warning: symbol '__trace_userstack' was not declared. Should it be static?
  kernel/trace/trace.c:1694:5: warning: symbol 'tracing_release' was not declared. Should it be static?

Signed-off-by: Hannes Eder <hannes@hanneseder.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-11 10:15:41 +01:00
Ingo Molnar
4040068dce Merge branch 'tip/tracing/ftrace' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into tracing/ftrace 2009-02-11 10:03:53 +01:00
Wenji Huang
c3706f005c tracing: fix typos in comments
Impact: clean up.

Fix typos in the comments.

Signed-off-by: Wenji Huang <wenji.huang@oracle.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
2009-02-10 12:32:35 -05:00
Wenji Huang
810dc73265 tracing: provide correct return value after outputting the event
This patch is to make the function return early on failure, and give
correct return value on success.

Signed-off-by: Wenji Huang <wenji.huang@oracle.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
2009-02-10 12:32:33 -05:00
Wenji Huang
f54fc98aa6 tracing: remove unneeded variable
Impact: clean up.

Remove the unnecessary variable ret.

Signed-off-by: Wenji Huang <wenji.huang@oracle.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
2009-02-10 12:32:18 -05:00
Tobias Klauser
4543ae7ce1 tracing: storage class should be before const qualifier
The C99 specification states in section 6.11.5:

The placement of a storage-class specifier other than at the beginning
of the declaration specifiers in a declaration is an obsolescent
feature.

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
2009-02-10 11:58:45 -05:00
Lai Jiangshan
667d241258 ring_buffer: fix ring_buffer_read_page()
Impact: change API and init bpage when copy

ring_buffer_read_page()/rb_remove_entries() may be called for
a partially consumed page.

Add a parameter for rb_remove_entries() and make it update
cpu_buffer->entries correctly for partially consumed pages.

ring_buffer_read_page() now returns the offset to the next event.

Init the bpage's time_stamp when return value is 0.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
2009-02-10 09:17:37 -05:00
Lai Jiangshan
b85fa01ed9 ring_buffer: fix typing mistake
Impact: Fix bug

I found several very very curious line.
It's so curious that it may be brought by typing mistake.

When (cpu_buffer->reader_page == cpu_buffer->commit_page):

1) We haven't copied it for bpage is changed:
   bpage = cpu_buffer->reader_page->page;
   memcpy(bpage->data, cpu_buffer->reader_page->page->data + read ... )
2) We need update cpu_buffer->reader_page->read, but
   "cpu_buffer->reader_page += read;" is not right.

[
  This bug was a typo. The commit->reader_page is a page pointer
  and not an index into the page. The line should have been
  commit->reader_page->read += read.  The other changes
  by Lai are nice clean ups to the code.  - SDR
]

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
2009-02-10 09:17:19 -05:00
Ingo Molnar
ae216dd239 Merge branch 'tip/tracing/ftrace' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into tracing/ftrace 2009-02-10 13:58:28 +01:00
Ingo Molnar
f9915bfef3 Merge branches 'tracing/ftrace' and 'tracing/urgent' into tracing/core 2009-02-10 13:25:42 +01:00
Hugh Dickins
acd895795d profiling: fix broken profiling regression
Impact: fix broken /proc/profile on UP machines

Commit c309b917ca "cpumask: convert
kernel/profile.c" broke profiling.  prof_cpu_mask was previously
initialized to CPU_MASK_ALL, but left uninitialized in that commit.
We need to copy cpu_possible_mask (cpu_online_mask is not enough).

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-10 00:50:37 +01:00
Steven Rostedt
34cd4998d3 tracing: clean up splice code
Ingo Molnar suggested a series of clean ups for the splice code.
This patch implements those suggestions.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
2009-02-09 12:24:58 -05:00
Eduard - Gabriel Munteanu
ff98781bab tracing: Move pipe waiting code out of tracing_read_pipe().
This moves the pipe waiting code from tracing_read_pipe() into
tracing_wait_pipe(), which is useful to implement other fops, like
splice_read.

Signed-off-by: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
2009-02-09 12:24:51 -05:00
Eduard - Gabriel Munteanu
3c56819b14 tracing: splice support for tracing_pipe
Added and implemented tracing_pipe_fops->splice_read(). This allows
userspace programs to get tracing data more efficiently.

Signed-off-by: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
2009-02-09 12:24:34 -05:00
Frederic Weisbecker
b91facc367 tracing/function-graph-tracer: handle the leaf functions from trace_pipe
When one cats the trace file, the leaf functions are printed without brackets:

 function();

whereas in the trace_pipe file we'll see the following:

 function() {
 }

This is because the ring_buffer handling is not the same between those two files.
On the trace file, when an entry is printed, the iterator advanced and then we can
check the next entry.

There is no iterator with trace_pipe, the current entry to print has been peeked
and not consumed. So checking the next entry will still return the current one while
we don't consume it.

This patch introduces a new value for the output callbacks to ask the tracing
core to not consume the current entry after printing it.

We need it because we will have to consume the current entry ourself to check
the next one.

Now the trace_pipe is able to handle well the leaf functions.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-09 12:37:27 +01:00
Ingo Molnar
1dfba05d0f tracing/blktrace: move the tracing file to kernel/trace, fix
Impact: build fix

The BLK_DEV_IO_TRACE entry used to be in block/Kconfig - which
file itself was dependent on CONFIG_BLOCK. But now the entry is
in kernel/trace/Kconfig - which is present even on !CONFIG_BLOCK.

So add a 'depends on BLOCK' to BLK_DEV_IO_TRACE.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-09 12:07:28 +01:00
Arnaldo Carvalho de Melo
b5db03c435 tracing: handle unregistering the current tracer
Impact: simplification

Instead of requiring that plugins have the sequence:

  my_tracer_stop(my_trace_array);
  unregister_tracer(my_tracer);

it should be possible just do a:

  unregister_tracer(my_tracer);

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-09 10:56:53 +01:00
Frederic Weisbecker
3861a17bcc tracing/function-graph-tracer: drop the kernel_text_address check
When the function graph tracer picks a return address, it ensures this address
is really a kernel text one by calling __kernel_text_address()

Actually this path has never been taken.Its role was more likely to debug the tracer
on the beginning of its development but this function is wasteful since it is called
for every traced function.

The fault check is already sufficient.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-09 10:51:38 +01:00
Frederic Weisbecker
1292211058 tracing/power: move the power trace headers to a dedicated file
Impact: cleanup

Move the power tracer headers to trace/power.h to keep ftrace.h and power bits
more easy to maintain as separated topics.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-09 10:51:38 +01:00
Frederic Weisbecker
7447dce96f tracing/function-graph-tracer: provide a selftest for the function graph tracer
Making it more easy to do a basic regression test for this tracer.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-09 10:51:37 +01:00
Frederic Weisbecker
2db270a80b tracing/blktrace: move the tracing file to kernel/trace
Impact: cleanup

Move blktrace.c to kernel/trace, also move its config entry.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-09 10:51:02 +01:00
Ingo Molnar
44b0635481 Merge branch 'tip/tracing/core/devel' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into tracing/ftrace
Conflicts:
	kernel/trace/trace_hw_branches.c
2009-02-09 10:35:12 +01:00
Ingo Molnar
4ad476e11f Merge commit 'v2.6.29-rc4' into tracing/core 2009-02-09 10:32:48 +01:00
Stefan Richter
f7de7621f0 async: use list_move_tail
list.h provides a dedicated primitive for
"list_del followed by list_add_tail"... list_move_tail.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
2009-02-08 10:00:26 -08:00
Cornelia Huck
766ccb9ed4 async: Rename _special -> _domain for clarity.
Rename the async_*_special() functions to async_*_domain(), which
describes the purpose of these functions much better.
[Broke up long lines to silence checkpatch]

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
2009-02-08 09:56:11 -08:00
Cornelia Huck
f30d5b307c async: Add some documentation.
Add some kerneldoc to the async interface.

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
2009-02-08 09:56:11 -08:00
Cornelia Huck
86532d8b16 async: Handle kthread_run() return codes.
If we fail to create the manager thread, fall back to non-fastboot.
If we fail to create an async thread, try again after waiting for
a bit.

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
2009-02-08 09:56:10 -08:00
Cornelia Huck
7a89bbc749 async: Fix running list handling.
async_schedule() should pass in async_running as the running
list, and run_one_entry() should put the entry to be run on
the provided running list instead of always on the generic one.

Reported-by: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
2009-02-08 09:56:10 -08:00
Wenji Huang
57794a9d48 trace: trivial fixes in comment typos.
Impact: clean up

Fixed several typos in the comments.

Signed-off-by: Wenji Huang <wenji.huang@oracle.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
2009-02-07 20:03:36 -05:00
Steven Rostedt
a81bd80a0b ring-buffer: use generic version of in_nmi
Impact: clean up

Now that a generic in_nmi is available, this patch removes the
special code in the ring_buffer and implements the in_nmi generic
version instead.

With this change, I was also able to rename the "arch_ftrace_nmi_enter"
back to "ftrace_nmi_enter" and remove the code from the ring buffer.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
2009-02-07 20:03:33 -05:00
Steven Rostedt
78d904b46a ring-buffer: add NMI protection for spinlocks
Impact: prevent deadlock in NMI

The ring buffers are not yet totally lockless with writing to
the buffer. When a writer crosses a page, it grabs a per cpu spinlock
to protect against a reader. The spinlocks taken by a writer are not
to protect against other writers, since a writer can only write to
its own per cpu buffer. The spinlocks protect against readers that
can touch any cpu buffer. The writers are made to be reentrant
with the spinlocks disabling interrupts.

The problem arises when an NMI writes to the buffer, and that write
crosses a page boundary. If it grabs a spinlock, it can be racing
with another writer (since disabling interrupts does not protect
against NMIs) or with a reader on the same CPU. Luckily, most of the
users are not reentrant and protects against this issue. But if a
user of the ring buffer becomes reentrant (which is what the ring
buffers do allow), if the NMI also writes to the ring buffer then
we risk the chance of a deadlock.

This patch moves the ftrace_nmi_enter called by nmi_enter() to the
ring buffer code. It replaces the current ftrace_nmi_enter that is
used by arch specific code to arch_ftrace_nmi_enter and updates
the Kconfig to handle it.

When an NMI is called, it will set a per cpu variable in the ring buffer
code and will clear it when the NMI exits. If a write to the ring buffer
crosses page boundaries inside an NMI, a trylock is used on the spin
lock instead. If the spinlock fails to be acquired, then the entry
is discarded.

This bug appeared in the ftrace work in the RT tree, where event tracing
is reentrant. This workaround solved the deadlocks that appeared there.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
2009-02-07 20:00:17 -05:00
Steven Rostedt
1830b52d0d trace: remove deprecated entry->cpu
Impact: fix to prevent developers from using entry->cpu

With the new ring buffer infrastructure, the cpu for the entry is
implicit with which CPU buffer it is on.

The original code use to record the current cpu into the generic
entry header, which can be retrieved by entry->cpu. When the
ring buffer was introduced, the users were convert to use the
the cpu number of which cpu ring buffer was in use (this was passed
to the tracers by the iterator: iter->cpu).

Unfortunately, the cpu item in the entry structure was never removed.
This allowed for developers to use it instead of the proper iter->cpu,
unknowingly, using an uninitialized variable. This was not the fault
of the developers, since it would seem like the logical place to
retrieve the cpu identifier.

This patch removes the cpu item from the entry structure and fixes
all the users that should have been using iter->cpu.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
2009-02-07 19:38:43 -05:00
Ingo Molnar
673f820591 Merge branch 'linus' into core/locking
Conflicts:
	fs/btrfs/locking.c
2009-02-07 18:31:54 +01:00
Len Brown
2d29c6a075 Merge branches 'release', 'asus', 'bugzilla-12450', 'cpuidle', 'debug', 'ec', 'misc', 'printk' and 'processor' into release 2009-02-07 01:34:56 -05:00
Li Zefan
04ec93fe9b fork.c: fix NULL pointer dereference when nr_threads == threads-max
I happened to forked lots of processes, and hit NULL pointer dereference.
It is because in copy_process() after checking max_threads, 0 is returned
but not -EAGAIN.

The bug is introduced by "CRED: Detach the credentials from task_struct"
(commit f1752eec61).

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-02-06 08:43:11 -08:00
Arnaldo Carvalho de Melo
b6f11df26f trace: Call tracing_reset_online_cpus before tracer->init()
Impact: cleanup

To make it easy for ftrace plugin writers, as this was open coded in
the existing plugins

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Frédéric Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-06 01:01:41 +01:00
Arnaldo Carvalho de Melo
51a763dd84 tracing: Introduce trace_buffer_{lock_reserve,unlock_commit}
Impact: new API

These new functions do what previously was being open coded, reducing
the number of details ftrace plugin writers have to worry about.

It also standardizes the handling of stacktrace, userstacktrace and
other trace options we may introduce in the future.

With this patch, for instance, the blk tracer (and some others already
in the tree) can use the "userstacktrace" /d/tracing/trace_options
facility.

$ codiff /tmp/vmlinux.before /tmp/vmlinux.after
linux-2.6-tip/kernel/trace/trace.c:
  trace_vprintk              |   -5
  trace_graph_return         |  -22
  trace_graph_entry          |  -26
  trace_function             |  -45
  __ftrace_trace_stack       |  -27
  ftrace_trace_userstack     |  -29
  tracing_sched_switch_trace |  -66
  tracing_stop               |   +1
  trace_seq_to_user          |   -1
  ftrace_trace_special       |  -63
  ftrace_special             |   +1
  tracing_sched_wakeup_trace |  -70
  tracing_reset_online_cpus  |   -1
 13 functions changed, 2 bytes added, 355 bytes removed, diff: -353

linux-2.6-tip/block/blktrace.c:
  __blk_add_trace |  -58
 1 function changed, 58 bytes removed, diff: -58

linux-2.6-tip/kernel/trace/trace.c:
  trace_buffer_lock_reserve  |  +88
  trace_buffer_unlock_commit |  +86
 2 functions changed, 174 bytes added, diff: +174

/tmp/vmlinux.after:
 16 functions changed, 176 bytes added, 413 bytes removed, diff: -237

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Frédéric Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-06 01:01:41 +01:00
Arnaldo Carvalho de Melo
0a9877514c ring_buffer: remove unused flags parameter
Impact: API change, cleanup

>From ring_buffer_{lock_reserve,unlock_commit}.

$ codiff /tmp/vmlinux.before /tmp/vmlinux.after
linux-2.6-tip/kernel/trace/trace.c:
  trace_vprintk              |  -14
  trace_graph_return         |  -14
  trace_graph_entry          |  -10
  trace_function             |   -8
  __ftrace_trace_stack       |   -8
  ftrace_trace_userstack     |   -8
  tracing_sched_switch_trace |   -8
  ftrace_trace_special       |  -12
  tracing_sched_wakeup_trace |   -8
 9 functions changed, 90 bytes removed, diff: -90

linux-2.6-tip/block/blktrace.c:
  __blk_add_trace |   -1
 1 function changed, 1 bytes removed, diff: -1

/tmp/vmlinux.after:
 10 functions changed, 91 bytes removed, diff: -91

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Frédéric Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-06 01:01:40 +01:00
Johannes Weiner
777c6c5f1f wait: prevent exclusive waiter starvation
With exclusive waiters, every process woken up through the wait queue must
ensure that the next waiter down the line is woken when it has finished.

Interruptible waiters don't do that when aborting due to a signal.  And if
an aborting waiter is concurrently woken up through the waitqueue, noone
will ever wake up the next waiter.

This has been observed with __wait_on_bit_lock() used by
lock_page_killable(): the first contender on the queue was aborting when
the actual lock holder woke it up concurrently.  The aborted contender
didn't acquire the lock and therefor never did an unlock followed by
waking up the next waiter.

Add abort_exclusive_wait() which removes the process' wait descriptor from
the waitqueue, iff still queued, or wakes up the next waiter otherwise.
It does so under the waitqueue lock.  Racing with a wake up means the
aborting process is either already woken (removed from the queue) and will
wake up the next waiter, or it will remove itself from the queue and the
concurrent wake up will apply to the next waiter after it.

Use abort_exclusive_wait() in __wait_event_interruptible_exclusive() and
__wait_on_bit_lock() when they were interrupted by other means than a wake
up through the queue.

[akpm@linux-foundation.org: coding-style fixes]
Reported-by: Chris Mason <chris.mason@oracle.com>
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Mentored-by: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Matthew Wilcox <matthew@wil.cx>
Cc: Chuck Lever <cel@citi.umich.edu>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: <stable@kernel.org>		["after some testing"]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-02-05 12:56:48 -08:00
Andrew Morton
60fd760fb9 revert "rlimit: permit setting RLIMIT_NOFILE to RLIM_INFINITY"
Revert commit 0c2d64fb6c because it causes
(arguably poorly designed) existing userspace to spend interminable
periods closing billions of not-open file descriptors.

We could bring this back, with some sort of opt-in tunable in /proc, which
defaults to "off".

Peter's alanysis follows:

: I spent several hours trying to get to the bottom of a serious
: performance issue that appeared on one of our servers after upgrading to
: 2.6.28.  In the end it's what could be considered a userspace bug that
: was triggered by a change in 2.6.28.  Since this might also affect other
: people I figured I'd at least document what I found here, and maybe we
: can even do something about it:
:
:
: So, I upgraded some of debian.org's machines to 2.6.28.1 and immediately
: the team maintaining our ftp archive complained that one of their
: scripts that previously ran in a few minutes still hadn't even come
: close to being done after an hour or so.  Downgrading to 2.6.27 fixed
: that.
:
: Turns out that script is forking a lot and something in it or python or
: whereever closes all the file descriptors it doesn't want to pass on.
: That is, it starts at zero and goes up to ulimit -n/RLIMIT_NOFILE and
: closes them all with a few exceptions.
:
: Turns out that takes a long time when your limit -n is now 2^20 (1048576).
:
: With 2.6.27.* the ulimit -n was the standard 1024, but with 2.6.28 it is
: now a thousand times that.
:
: 2.6.28 included a patch titled "rlimit: permit setting RLIMIT_NOFILE to
: RLIM_INFINITY" (0c2d64fb6c)[1] that
: allows, as the title implies, to set the limit for number of files to
: infinity.
:
: Closer investigation showed that the broken default ulimit did not apply
: to "system" processes (like stuff started from init).  In the end I
: could establish that all processes that passed through pam_limit at one
: point had the bad resource limit.
:
: Apparently the pam library in Debian etch (4.0) initializes the limits
: to some default values when it doesn't have any settings in limit.conf
: to override them.  Turns out that for nofiles this is RLIM_INFINITY.
: Commenting out "case RLIMIT_NOFILE" in pam_limit.c:267 of our pam
: package version 0.79-5 fixes that - tho I'm not sure what side effects
: that has.
:
: Debian lenny (the upcoming 5.0 version) doesn't have this issue as it
: uses a different pam (version).

Reported-by: Peter Palfrader <weasel@debian.org>
Cc: Adam Tkac <vonsch@gmail.com>
Cc: Michael Kerrisk <mtk.manpages@googlemail.com>
Cc: <stable@kernel.org>		[2.6.28.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-02-05 12:56:47 -08:00
Andrew Morton
58763a2974 kernel/async.c: fix printk warnings
alpha:

kernel/async.c: In function 'run_one_entry':
kernel/async.c:141: warning: format '%lli' expects type 'long long int', but argument 2 has type 'async_cookie_t'
kernel/async.c:149: warning: format '%lli' expects type 'long long int', but argument 2 has type 'async_cookie_t'
kernel/async.c:149: warning: format '%lld' expects type 'long long int', but argument 4 has type 's64'
kernel/async.c: In function 'async_synchronize_cookie_special':
kernel/async.c:250: warning: format '%lli' expects type 'long long int', but argument 3 has type 's64'

Cc: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-02-05 12:56:46 -08:00
Steven Rostedt
dac7494028 trace: code style clean up
Ingo Molnar suggested using goto logic to keep the indentation
down and to be able to remove the nasty line breaks. This actually
makes the code a bit more readable.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-05 14:35:47 +01:00
Arnaldo Carvalho de Melo
7be421510b trace: Remove unused trace_array_cpu parameter
Impact: cleanup

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-05 14:35:47 +01:00
Arnaldo Carvalho de Melo
97e5b191ae trace_branch: Remove unused function
Impact: cleanup

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-05 14:35:46 +01:00
Arnaldo Carvalho de Melo
268ccda0cb trace: assign defaults at register_ftrace_event
Impact: simplification of tracers

As all tracers are doing this we might as well do it in
register_ftrace_event and save one branch each time we call these
callbacks.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-05 14:35:46 +01:00
Peter Zijlstra
4cd4c1b40d timers: split process wide cpu clocks/timers
Change the process wide cpu timers/clocks so that we:

 1) don't mess up the kernel with too many threads,
 2) don't have a per-cpu allocation for each process,
 3) have no impact when not used.

In order to accomplish this we're going to split it into two parts:

 - clocks; which can take all the time they want since they run
           from user context -- ie. sys_clock_gettime(CLOCK_PROCESS_CPUTIME_ID)

 - timers; which need constant time sampling but since they're
           explicity used, the user can pay the overhead.

The clock readout will go back to a full sum of the thread group, while the
timers will run of a global 'clock' that only runs when needed, so only
programs that make use of the facility pay the price.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-05 13:04:33 +01:00
Peter Zijlstra
32bd671d6c signal: re-add dead task accumulation stats.
We're going to split the process wide cpu accounting into two parts:

 - clocks; which can take all the time they want since they run
           from user context.

 - timers; which need constant time tracing but can affort the overhead
           because they're default off -- and rare.

The clock readout will go back to a full sum of the thread group, for this
we need to re-add the exit stats that were removed in the initial itimer
rework (f06febc9: timers: fix itimer/many thread hang).

Furthermore, since that full sum can be rather slow for large thread groups
and we have the complete dead task stats, revert the do_notify_parent time
computation.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-05 13:04:33 +01:00
Linus Torvalds
647802d6db Merge branch 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86: APIC: enable workaround on AMD Fam10h CPUs
  xen: disable interrupts before saving in percpu
  x86: add x86@kernel.org to MAINTAINERS
  x86: push old stack address on irqstack for unwinder
  irq, x86: fix lock status with numa_migrate_irq_desc
  x86: add cache descriptors for Intel Core i7
  x86/Voyager: make it build and boot
2009-02-04 13:58:50 -08:00
Suresh Siddha
483b4ee60e sched: fix nohz load balancer on cpu offline
Christian Borntraeger reports:

> After a logical cpu offline, even on a complete idle system, there
> is one cpu with full ticks. It turns out that nohz.cpu_mask has the
> the offlined cpu still set.
>
> In select_nohz_load_balancer() we check if the system is completely
> idle to turn of load balancing. We compare cpu_online_map with
> nohz.cpu_mask.  Since cpu_online_map is updated on cpu unplug,
> but nohz.cpu_mask is not, the check fails and the scheduler believes
> that we need an "idle load balancer" even on a fully idle system.
> Since the ilb cpu does not deactivate the timer tick this breaks NOHZ.

Fix the select_nohz_load_balancer() to not set the nohz.cpu_mask
while a cpu is going offline.

Reported-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Tested-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-04 22:31:19 +01:00
Arnaldo Carvalho de Melo
ae7462b4f1 trace: make the trace_event callbacks return enum print_line_t
As they actually all return these enumerators.

Reported-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-04 20:48:39 +01:00
Arnaldo Carvalho de Melo
d9793bd801 trace: judicious error checking of trace_seq results
Impact: bugfix and cleanup

Some callsites were returning either TRACE_ITER_PARTIAL_LINE if the
trace_seq routines (trace_seq_printf, etc) returned 0 meaning its buffer
was full, or zero otherwise.

But...

/* Return values for print_line callback */
enum print_line_t {
        TRACE_TYPE_PARTIAL_LINE = 0,    /* Retry after flushing the seq */
        TRACE_TYPE_HANDLED      = 1,
        TRACE_TYPE_UNHANDLED    = 2     /* Relay to other output functions */
};

In other cases the return value was not being relayed at all.

Most of the time it didn't hurt because the page wasn't get filled, but
for correctness sake, handle the return values everywhere.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-04 20:48:30 +01:00
Ingo Molnar
ce70a0b472 Merge branches 'tracing/blktrace', 'tracing/ftrace', 'tracing/urgent' and 'linus' into tracing/core 2009-02-04 20:45:41 +01:00
Ingo Molnar
bb960a1e42 Merge branch 'core/xen' into x86/urgent 2009-02-04 14:54:56 +01:00
Oleg Nesterov
229c4ef8ae ftrace: do_each_pid_task() needs rcu lock
"ftrace: use struct pid" commit 978f3a45d9
converted ftrace_pid_trace to "struct pid*".

But we can't use do_each_pid_task() without rcu_read_lock() even if
we know the pid itself can't go away (it was pinned in ftrace_pid_write).
The exiting task can detach itself from this pid at any moment.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-03 22:50:58 +01:00
Arnaldo Carvalho de Melo
2c9b238eb3 trace: Change struct trace_event callbacks parameter list
Impact: API change

The trace_seq and trace_entry are in trace_iterator, where there are
more fields that may be needed by tracers, so just pass the
tracer_iterator as is already the case for struct tracer->print_line.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-03 14:03:52 +01:00
Frederic Weisbecker
c4a8e8be2d trace: better manage the context info for events
Impact: make trace_event more convenient for tracers

All tracers (for the moment) that use the struct trace_event want to
have the context info printed before their own output: the pid/cmdline,
cpu, and timestamp.

But some other tracers that want to implement their trace_event
callbacks will not necessary need these information or they may want to
format them as they want.

This patch adds a new default-enabled trace option:
TRACE_ITER_CONTEXT_INFO When disabled through:

echo nocontext-info > /debugfs/tracing/trace_options

The pid, cpu and timestamps headers will not be printed.

IE with the sched_switch tracer with context-info (default):

     bash-2935 [001] 100.356561: 2935:120:S ==> [001]  0:140:R <idle>
   <idle>-0    [000] 100.412804:    0:140:R   + [000] 11:115:S events/0
   <idle>-0    [000] 100.412816:    0:140:R ==> [000] 11:115:R events/0
 events/0-11   [000] 100.412829:   11:115:S ==> [000]  0:140:R <idle>

Without context-info:

 2935:120:S ==> [001]  0:140:R <idle>
    0:140:R   + [000] 11:115:S events/0
    0:140:R ==> [000] 11:115:R events/0
   11:115:S ==> [000]  0:140:R <idle>

A tracer can disable it at runtime by clearing the bit
TRACE_ITER_CONTEXT_INFO in trace_flags.

The print routines were renamed to trace_print_context and
trace_print_lat_context, so that they can be used by tracers if they
want to use them for one of the trace_event callbacks.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-03 14:03:52 +01:00
Steven Rostedt
79fb0768fb trace: let boot trace be chosen by command line
Now that we have a working ftrace=<tracer> function, make the boot
tracer get activated by it. This way we can turn it on or off without
recompiling the kernel, as well as keeping the selftests on. The
selftests are disabled whenever a default tracer starts running.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-03 06:26:12 +01:00
Steven Rostedt
b2821ae68b trace: fix default boot up tracer
Peter Zijlstra started the functionality to start up a default
tracing at bootup. This patch finishes the work.

Now if you add 'ftrace=<tracer>' to the command line, when that tracer
is registered on bootup, that tracer is selected and starts tracing.

Note, all selftests for tracers that are registered after this tracer
is disabled. This prevents the selftests from disturbing the running
tracer, or the running tracer from disturbing the selftest.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-03 06:26:12 +01:00
Ingo Molnar
dc573f9b20 Merge branches 'tracing/ftrace', 'tracing/kmemtrace' and 'linus' into tracing/core 2009-02-03 06:25:38 +01:00
Linus Torvalds
31c952dcf8 Merge branch 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  sched_rt: don't use first_cpu on cpumask created with cpumask_and
  sched: fix buddie group latency
  sched: clear buddies more aggressively
  sched: symmetric sync vs avg_overlap
  sched: fix sync wakeups
  cpuset: fix possible deadlock in async_rebuild_sched_domains
2009-02-02 19:26:29 -08:00
Eric Dumazet
720eba31f4 modules: Use a better scheme for refcounting
Current refcounting for modules (done if CONFIG_MODULE_UNLOAD=y) is
using a lot of memory.

Each 'struct module' contains an [NR_CPUS] array of full cache lines.

This patch uses existing infrastructure (percpu_modalloc() &
percpu_modfree()) to allocate percpu space for the refcount storage.

Instead of wasting NR_CPUS*128 bytes (on i386), we now use
nr_cpu_ids*sizeof(local_t) bytes.

On a typical distro, where NR_CPUS=8, shiping 2000 modules, we reduce
size of module files by about 2 Mbytes. (1Kb per module)

Instead of having all refcounters in the same memory node - with TLB misses
because of vmalloc() - this new implementation permits to have better
NUMA properties, since each  CPU will use storage on its preferred node,
thanks to percpu storage.

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-02-02 19:17:55 -08:00
Yinghai Lu
10b888d6ce irq, x86: fix lock status with numa_migrate_irq_desc
Eric Paris reported:

> I have an hp dl785g5 which is unable to successfully run
> 2.6.29-0.66.rc3.fc11.x86_64 or 2.6.29-rc2-next-20090126.  During bootup
> (early in userspace daemons starting) I get the below BUG, which quickly
> renders the machine dead.  I assume it is because sparse_irq_lock never
> gets released when the BUG kills that task.

Adjust lock sequence when migrating a descriptor with
CONFIG_NUMA_MIGRATE_IRQ_DESC enabled.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-01 11:36:31 +01:00
Rusty Russell
3d398703ef sched_rt: don't use first_cpu on cpumask created with cpumask_and
cpumask_and() only initializes nr_cpu_ids bits, so the (deprecated)
first_cpu() might find one of those uninitialized bits if nr_cpu_ids
is less than NR_CPUS (as it can be for CONFIG_CPUMASK_OFFSTACK).

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-01 10:49:52 +01:00
Peter Zijlstra
a571bbeafb sched: fix buddie group latency
Similar to the previous patch, by not clearing buddies we can select entities
past their run quota, which can increase latency. This means we have to clear
group buddies as well.

Do not use the group clear for pick_next_task(), otherwise that'll get O(n^2).

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-01 10:49:51 +01:00
Mike Galbraith
a9f3e2b549 sched: clear buddies more aggressively
It was noticed that a task could get re-elected past its run quota due to buddy
affinities. This could increase latency a little. Cure it by more aggresively
clearing buddy state.

We do so in two situations:
 - when we force preempt
 - when we select a buddy to run

Signed-off-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-01 10:49:50 +01:00
Peter Zijlstra
1596e29773 sched: symmetric sync vs avg_overlap
Reinstate the weakening of the sync hint if set. This yields a more
symmetric usage of avg_overlap.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-01 10:49:49 +01:00
Peter Zijlstra
d942fb6c7d sched: fix sync wakeups
Pawel Dziekonski reported that the openssl benchmark and his
quantum chemistry application both show slowdowns due to the
scheduler under-parallelizing execution.

The reason are pipe wakeups still doing 'sync' wakeups which
overrides the normal buddy wakeup logic - even if waker and
wakee are loosely coupled.

Fix an inversion of logic in the buddy wakeup code.

Reported-by: Pawel Dziekonski <dzieko@gmail.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-01 10:49:06 +01:00
Linus Torvalds
1347e965f5 Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  generic-ipi: use per cpu data for single cpu ipi calls
  cpumask: convert lib/smp_processor_id to new cpumask ops
  signals, debug: fix BUG: using smp_processor_id() in preemptible code in print_fatal_signal()
2009-01-31 15:55:05 -08:00