Impact: limit ftrace dump output
Currently ftrace_dump only calls ftrace_kill that is a fast way
to prevent the function tracer functions from being called (just sets
a flag and clears the function to call, nothing else). It is better
to also turn off any recording to the ring buffers as well.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: reset struct buffer_page.write when interrupt storm
if struct buffer_page.write is not reset, any succedent committing
will corrupted ring_buffer:
static inline void
rb_set_commit_to_write(struct ring_buffer_per_cpu *cpu_buffer)
{
......
cpu_buffer->commit_page->commit =
cpu_buffer->commit_page->write;
......
}
when "if (RB_WARN_ON(cpu_buffer, next_page == reader_page))", ring_buffer
is disabled, but some reserved buffers may haven't been committed.
we need reset struct buffer_page.write.
when "if (unlikely(next_page == cpu_buffer->commit_page))", ring_buffer
is still available, we should not corrupt it.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: fix to print out ftrace_dump when expected
I was debugging a hard race condition to only find out that
after I hit the race, my log level was not at level to show
KERN_INFO. The time it took to trigger the race was wasted because
I did not capture the trace.
Since ftrace_dump is only called from kernel oops (and only when
it is set in the kernel command line to do so), or when a
developer adds it to their own local tree, the log level of
the print should be at KERN_EMERG to make sure the print appears.
ftrace_dump is not called by a normal user setup, and will not
add extra unwanted print out to the console. There is no reason
it should be at KERN_INFO.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: new tracer
The workqueue tracer provides some statistical informations
about each cpu workqueue thread such as the number of the
works inserted and executed since their creation. It can help
to evaluate the amount of work each of them have to perform.
For example it can help a developer to decide whether he should
choose a per cpu workqueue instead of a singlethreaded one.
It only traces statistical informations for now but it will probably later
provide event tracing too.
Such a tracer could help too, and be improved, to help rt priority sorted
workqueue development.
To have a snapshot of the workqueues state at any time, just do
cat /debugfs/tracing/trace_stat/workqueues
Ie:
1 125 125 reiserfs/1
1 0 0 scsi_tgtd/1
1 0 0 aio/1
1 0 0 ata/1
1 114 114 kblockd/1
1 0 0 kintegrityd/1
1 2147 2147 events/1
0 0 0 kpsmoused
0 105 105 reiserfs/0
0 0 0 scsi_tgtd/0
0 0 0 aio/0
0 0 0 ata_aux
0 0 0 ata/0
0 0 0 cqueue
0 0 0 kacpi_notify
0 0 0 kacpid
0 149 149 kblockd/0
0 0 0 kintegrityd/0
0 1000 1000 khelper
0 2270 2270 events/0
Changes in V2:
_ Drop the static array based on NR_CPU and dynamically allocate the stat array
with num_possible_cpus() and other cpu mask facilities....
_ Trace workqueue insertion at a bit lower level (insert_work instead of queue_work) to handle
even the workqueue barriers.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: tracing's Api change
Currently, the stat tracing depends on the events tracing.
When you switch to a new tracer, the stats files of the previous tracer
will disappear. But it's more scalable to separate those two engines.
This way, we can keep the stat files of one or several tracers when we
want, without bothering of multiple tracer stat files or tracer switching.
To build/destroys its stats files, a tracer just have to call
register_stat_tracer/unregister_stat_tracer everytimes it wants to.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Define FTRACE_ADDR. In IA64, a function pointer isn't a 'unsigned long' but a
'struct {unsigned long ip, unsigned long gp}'.
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
In IA64, a function pointer isn't a 'unsigned long' but a
'struct {unsigned long ip, unsigned long gp}'. MCOUNT_ADDR is determined
at link time not compile time, so explictly ignore kernel/trace/ftrace.o
in recordmcount.pl.
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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>
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>
Impact: new API for tracers
Make the stat tracing API reentrant. And also provide the new directory
/debugfs/tracing/trace_stat which will contain all the stat files for the
current active tracer.
Now a tracer will, if desired, want to provide a zero terminated array of
tracer_stat structures.
Each one contains the callbacks necessary for one stat file.
It have to provide at least a name for its stat file, an iterator with
stat_start/start_next callback and an output callback for one stat entry.
Also adapt the branch tracer to this new API.
We create two files "all" and "annotated" inside the /debugfs/tracing/trace_stat
directory, making the both stats simultaneously available instead of needing
to change an option to switch from one stat file to another.
The output of these stats haven't changed.
Changes in v2:
_ Apply the previous memory leak fix (rebase against tip/master)
Changes in v3:
_ Merge the patch that adapted the branch tracer to this Api in this patch to
not break the kernel build.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rric/oprofile: (31 commits)
powerpc/oprofile: fix whitespaces in op_model_cell.c
powerpc/oprofile: IBM CELL: add SPU event profiling support
powerpc/oprofile: fix cell/pr_util.h
powerpc/oprofile: IBM CELL: cleanup and restructuring
oprofile: make new cpu buffer functions part of the api
oprofile: remove #ifdef CONFIG_OPROFILE_IBS in non-ibs code
ring_buffer: fix ring_buffer_event_length()
oprofile: use new data sample format for ibs
oprofile: add op_cpu_buffer_get_data()
oprofile: add op_cpu_buffer_add_data()
oprofile: rework implementation of cpu buffer events
oprofile: modify op_cpu_buffer_read_entry()
oprofile: add op_cpu_buffer_write_reserve()
oprofile: rename variables in add_ibs_begin()
oprofile: rename add_sample() in cpu_buffer.c
oprofile: rename variable ibs_allowed to has_ibs in op_model_amd.c
oprofile: making add_sample_entry() inline
oprofile: remove backtrace code for ibs
oprofile: remove unused ibs macro
oprofile: remove unused components in struct oprofile_cpu_buffer
...
Function ring_buffer_event_length() provides an interface to detect
the length of data stored in an entry. However, the length contains
offsets depending on the internal usage. This makes it unusable. This
patch fixes this and now ring_buffer_event_length() returns the
alligned length that has been used in ring_buffer_lock_reserve().
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Robert Richter <robert.richter@amd.com>
Impact: clean up
Andrew Morton pointed out that the entry assignment in stat_seq_show
did not need to be done in the declaration, causing funny line breaks.
This patch makes it a bit more pleasing on the eyes.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: fix memory leak
This patch fixes a memory leak inside reset_stat_list(). The freeing
loop iterated only once.
Also turn the stat_list into a simple struct list_head, which
simplify the code and avoid an unused static pointer.
Reported-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: fix to unsigned compared to less than zero
Roel Kluin pointed out that there is a compare of an unsigned number
to less than zero. A previous clean up had the unsigned index set
to -1 for certain cases, but never converted it to signed.
Frederic Weisbecker noticed that another index is used to compare
the above index to and it also needs to be converted to signed.
[
Converted ftrace_page->index to int from unsigned long as
Andrew Morton pointed out that there's no need for it to
stay a long.
]
Reported-by: Roel Kluin <roel.kluin@gmail.com>
Reported-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: build fix
leftover from the relayfs version - but we want to keep it because
this call is the earliest opportunity when we can start kmemtrace
tracing. (after kmem_cache_init()).
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup
kmemtrace now uses ftrace. This patch removes the relay version.
Signed-off-by: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: Reduce future memory usage, use new cpumask API.
Since the last patch was created and acked, more old cpumask users
slipped into kernel/trace.
Mostly trivial conversions, except struct trace_iterator's "started"
member becomes a cpumask_var_t.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Impact: Reduce future memory usage, use new cpumask API.
(Eventually, cpumask_var_t will be allocated based on nr_cpu_ids, not NR_CPUS).
Convert kernel trace functions to use struct cpumask API:
1) Use cpumask_copy/cpumask_test_cpu/for_each_cpu.
2) Use cpumask_var_t and alloc_cpumask_var/free_cpumask_var everywhere.
3) Use on_each_cpu instead of playing with current->cpus_allowed.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Mike Travis <travis@sgi.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
* 'oprofile-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
oprofile: select RING_BUFFER
ring_buffer: adding EXPORT_SYMBOLs
oprofile: fix lost sample counter
oprofile: remove nr_available_slots()
oprofile: port to the new ring_buffer
ring_buffer: add remaining cpu functions to ring_buffer.h
oprofile: moving cpu_buffer_reset() to cpu_buffer.h
oprofile: adding cpu_buffer_entries()
oprofile: adding cpu_buffer_write_commit()
oprofile: adding cpu buffer r/w access functions
ftrace: remove unused function arg in trace_iterator_increment()
ring_buffer: update description for ring_buffer_alloc()
oprofile: set values to default when creating oprofilefs
oprofile: implement switch/case in buffer_sync.c
x86/oprofile: cleanup IBS init/exit functions in op_model_amd.c
x86/oprofile: reordering IBS code in op_model_amd.c
oprofile: fix typo
oprofile: whitspace changes only
oprofile: update comment for oprofile_add_sample()
oprofile: comment cleanup
* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
hrtimers: fix warning in kernel/hrtimer.c
x86: make sure we really have an hpet mapping before using it
x86: enable HPET on Fujitsu u9200
linux/timex.h: cleanup for userspace
posix-timers: simplify de_thread()->exit_itimers() path
posix-timers: check ->it_signal instead of ->it_pid to validate the timer
posix-timers: use "struct pid*" instead of "struct task_struct*"
nohz: suppress needless timer reprogramming
clocksource, acpi_pm.c: put acpi_pm_read_slow() under CONFIG_PCI
nohz: no softirq pending warnings for offline cpus
hrtimer: removing all ur callback modes, fix
hrtimer: removing all ur callback modes, fix hotplug
hrtimer: removing all ur callback modes
x86: correct link to HPET timer specification
rtc-cmos: export second NVRAM bank
Fixed up conflicts in sound/drivers/pcsp/pcsp.c and sound/core/hrtimer.c
manually.
Impact: new tracer plugin
This patch adapts kmemtrace raw events tracing to the unified tracing API.
To enable and use this tracer, just do the following:
echo kmemtrace > /debugfs/tracing/current_tracer
cat /debugfs/tracing/trace
You will have the following output:
# tracer: kmemtrace
#
#
# ALLOC TYPE REQ GIVEN FLAGS POINTER NODE CALLER
# FREE | | | | | | | |
# |
type_id 1 call_site 18446744071565527833 ptr 18446612134395152256
type_id 0 call_site 18446744071565585597 ptr 18446612134405955584 bytes_req 4096 bytes_alloc 4096 gfp_flags 208 node -1
type_id 1 call_site 18446744071565585534 ptr 18446612134405955584
type_id 0 call_site 18446744071565585597 ptr 18446612134405955584 bytes_req 4096 bytes_alloc 4096 gfp_flags 208 node -1
type_id 0 call_site 18446744071565636711 ptr 18446612134345164672 bytes_req 240 bytes_alloc 240 gfp_flags 208 node -1
type_id 1 call_site 18446744071565585534 ptr 18446612134405955584
type_id 0 call_site 18446744071565585597 ptr 18446612134405955584 bytes_req 4096 bytes_alloc 4096 gfp_flags 208 node -1
type_id 0 call_site 18446744071565636711 ptr 18446612134345164912 bytes_req 240 bytes_alloc 240 gfp_flags 208 node -1
type_id 1 call_site 18446744071565585534 ptr 18446612134405955584
type_id 0 call_site 18446744071565585597 ptr 18446612134405955584 bytes_req 4096 bytes_alloc 4096 gfp_flags 208 node -1
type_id 0 call_site 18446744071565636711 ptr 18446612134345165152 bytes_req 240 bytes_alloc 240 gfp_flags 208 node -1
type_id 0 call_site 18446744071566144042 ptr 18446612134346191680 bytes_req 1304 bytes_alloc 1312 gfp_flags 208 node -1
type_id 1 call_site 18446744071565585534 ptr 18446612134405955584
type_id 0 call_site 18446744071565585597 ptr 18446612134405955584 bytes_req 4096 bytes_alloc 4096 gfp_flags 208 node -1
type_id 1 call_site 18446744071565585534 ptr 18446612134405955584
That was to stay backward compatible with the format output produced in
inux/tracepoint.h.
This is the default ouput, but note that I tried something else.
If you change an option:
echo kmem_minimalistic > /debugfs/trace_options
and then cat /debugfs/trace, you will have the following output:
# tracer: kmemtrace
#
#
# ALLOC TYPE REQ GIVEN FLAGS POINTER NODE CALLER
# FREE | | | | | | | |
# |
- C 0xffff88007c088780 file_free_rcu
+ K 4096 4096 000000d0 0xffff88007cad6000 -1 getname
- C 0xffff88007cad6000 putname
+ K 4096 4096 000000d0 0xffff88007cad6000 -1 getname
+ K 240 240 000000d0 0xffff8800790dc780 -1 d_alloc
- C 0xffff88007cad6000 putname
+ K 4096 4096 000000d0 0xffff88007cad6000 -1 getname
+ K 240 240 000000d0 0xffff8800790dc870 -1 d_alloc
- C 0xffff88007cad6000 putname
+ K 4096 4096 000000d0 0xffff88007cad6000 -1 getname
+ K 240 240 000000d0 0xffff8800790dc960 -1 d_alloc
+ K 1304 1312 000000d0 0xffff8800791d7340 -1 reiserfs_alloc_inode
- C 0xffff88007cad6000 putname
+ K 4096 4096 000000d0 0xffff88007cad6000 -1 getname
- C 0xffff88007cad6000 putname
+ K 992 1000 000000d0 0xffff880079045b58 -1 alloc_inode
+ K 768 1024 000080d0 0xffff88007c096400 -1 alloc_pipe_info
+ K 240 240 000000d0 0xffff8800790dca50 -1 d_alloc
+ K 272 320 000080d0 0xffff88007c088780 -1 get_empty_filp
+ K 272 320 000080d0 0xffff88007c088000 -1 get_empty_filp
Yeah I shall confess kmem_minimalistic should be: kmem_alternative.
Whatever, I find it more readable but this a personal opinion of course.
We can drop it if you want.
On the ALLOC/FREE column, + means an allocation and - a free.
On the type column, you have K = kmalloc, C = cache, P = page
I would like the flags to be GFP_* strings but that would not be easy to not
break the column with strings....
About the node...it seems to always be -1. I don't know why but that shouldn't
be difficult to find.
I moved linux/tracepoint.h to trace/tracepoint.h as well. I think that would
be more easy to find the tracer headers if they are all in their common
directory.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: build fix
On !CONFIG_CONTEXT_SWITCH_TRACER trace_find_cmdline() is not defined:
kernel/trace/trace_output.c: In function 'trace_ctxwake_print':
kernel/trace/trace_output.c:499: error: implicit declaration of function 'trace_find_cmdline'
kernel/trace/trace_output.c:499: warning: assignment makes pointer from integer without a cast
Move it to the generic section in trace.h.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: extend the tracing API
The goal of this patch is to normalize and make more easy the
implementation of statistical (histogram) tracing.
It implements a trace_stat file into the /debugfs/tracing directory where
one can print a one-shot output of statistics/histogram entries.
A tracer has to provide two basic iterator callbacks:
stat_start() => the first entry
stat_next(prev, idx) => the next one.
Note that it is adapted for arrays or hash tables or lists.... since it
provides a pointer to the previous entry and the current index of the
iterator.
These two callbacks are called to get a snapshot of the statistics at each
opening of the trace_stat file because. The values are so updated between
two "cat trace_stat". And the tracer is free to lock its datas during the
iteration to keep consistent values.
Since it is almost always interesting to sort statisticals values to
address the problems by priority, this infrastructure provides a "sorting"
of the stat entries too if desired. A tracer has just to provide a
stat_cmp callback to compare two entries and the stat tracing
infrastructure will build a sorted list of the given entries.
A last callback, called stat_headers, can be implemented by a tracer to
output headers on its trace.
If one of these callbacks is changed on runtime, it just have to signal it
to the stat tracing API by calling the init_tracer_stat() helper.
Changes in V2:
- Fix a memory leak if the user opens multiple times the trace_stat file
without closing it. Now we always free our list before rebuilding it.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: rework trace.c to use new event register API
Almost every ftrace event has to implement its output display in
trace.c through a different function. Some events did not handle
all the formats (trace, latency-trace, raw, hex, binary), and
this method does not scale well.
This patch converts the format functions to use the event API to
find the event and and print its format. Currently, we have
a print function for trace, latency_trace, raw, hex and binary.
A trace_nop_print is available if the event wants to avoid output
on a particular format.
Perhaps other tracers could use this in the future (like mmiotrace and
function_graph).
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: simplify/generalize/refactor trace.c
The trace.c file is becoming more difficult to maintain due to the
growing number of events. There is several formats that an event may
be printed. This patch sets up the infrastructure of an event hash to
allow for events to register how they should be printed.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup, remove obsolete code
Now that the ring buffer used by ftrace allows for variable length
entries, we do not need the 'cont' feature of the buffer. This code
makes other parts of ftrace more complex and by removing this it
simplifies the ftrace code.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* 'tracing-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (241 commits)
sched, trace: update trace_sched_wakeup()
tracing/ftrace: don't trace on early stage of a secondary cpu boot, v3
Revert "x86: disable X86_PTRACE_BTS"
ring-buffer: prevent false positive warning
ring-buffer: fix dangling commit race
ftrace: enable format arguments checking
x86, bts: memory accounting
x86, bts: add fork and exit handling
ftrace: introduce tracing_reset_online_cpus() helper
tracing: fix warnings in kernel/trace/trace_sched_switch.c
tracing: fix warning in kernel/trace/trace.c
tracing/ring-buffer: remove unused ring_buffer size
trace: fix task state printout
ftrace: add not to regex on filtering functions
trace: better use of stack_trace_enabled for boot up code
trace: add a way to enable or disable the stack tracer
x86: entry_64 - introduce FTRACE_ frame macro v2
tracing/ftrace: add the printk-msg-only option
tracing/ftrace: use preempt_enable_no_resched_notrace in ring_buffer_time_stamp()
x86, bts: correctly report invalid bts records
...
Fixed up trivial conflict in scripts/recordmcount.pl due to SH bits
being already partly merged by the SH merge.
Impact: tracer output improvement
Ending newlines are appended automatically on comments by the function
graph tracer because the newline needs to be placed after the "*/"
comment characters.
So if the user puts an ending newline, we want to strip it.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: extend the wakeup tracepoint with the info whether the wakeup was real
Add the information needed to distinguish 'real' wakeups from 'false'
wakeups.
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: eliminate false WARN_ON message
If an interrupt goes off after the setting of the local variable
tail_page and before incrementing the write index of that page,
the interrupt could push the commit forward to the next page.
Later a check is made to see if interrupts pushed the buffer around
the entire ring buffer by comparing the next page to the last commited
page. This can produce a false positive if the interrupt had pushed
the commit page forward as stated above.
Thanks to Jiaying Zhang for finding this race.
Reported-by: Jiaying Zhang <jiayingz@google.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Cc: <stable@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: fix stuck trace-buffers
If an interrupt comes in during the rb_set_commit_to_write and
pushes the tail page forward just at the right time, the commit
updates will miss the adding of the interrupt data. This will
cause the commit pointer to cease from moving forward.
Thanks to Jiaying Zhang for finding this race.
Reported-by: Jiaying Zhang <jiayingz@google.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Cc: <stable@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup
This patch factors out common code from multiple tracers into a
tracing_reset_online_cpus() function and converts the tracers to use it.
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
these warnings:
kernel/trace/trace_sched_switch.c: In function ‘tracing_sched_register’:
kernel/trace/trace_sched_switch.c:96: warning: passing argument 1 of ‘register_trace_sched_wakeup_new’ from incompatible pointer type
kernel/trace/trace_sched_switch.c:112: warning: passing argument 1 of ‘unregister_trace_sched_wakeup_new’ from incompatible pointer type
kernel/trace/trace_sched_switch.c: In function ‘tracing_sched_unregister’:
kernel/trace/trace_sched_switch.c:121: warning: passing argument 1 of ‘unregister_trace_sched_wakeup_new’ from incompatible pointer type
Trigger because sched_wakeup_new tracepoints need the same trace
signature as sched_wakeup - which was changed recently.
Fix it.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
this warning:
kernel/trace/trace.c: In function ‘print_lat_fmt’:
kernel/trace/trace.c:1826: warning: unused variable ‘state’
Triggers because 'state' has become unused - remove it.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: remove dead code
struct ring_buffer.size is not set after ring_buffer is initialized
or resized. it is always 0.
we can use "buffer->pages * PAGE_SIZE" to get ring_buffer's size
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: fix occasionally incorrect trace output
The tracing code has interesting varieties of printing out task state.
Unfortunalely only one of the instances is correct as it copies the
code from sched.c:sched_show_task(). The others are plain wrong as
they treatthe bitfield as an integer offset into the character
array. Also the size check of the character array is wrong as it
includes the trailing \0.
Use a common state decoder inline which does the Right Thing.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: enhancement
Ingo Molnar has asked about a way to remove items from the filter
lists. Currently, you can only add or replace items. The way
items are added to the list is through opening one of the list
files (set_ftrace_filter or set_ftrace_notrace) via append.
If the file is opened for truncate, the list is cleared.
echo spin_lock > /debug/tracing/set_ftrace_filter
The above will replace the list with only spin_lock
echo spin_lock >> /debug/tracing/set_ftrace_filter
The above will add spin_lock to the list.
Now this patch adds:
echo '!spin_lock' >> /debug/tracing/set_ftrace_filter
This will remove spin_lock from the list.
The limited glob features of these lists also can be notted.
echo '!spin_*' >> /debug/tracing/set_ftrace_filter
This will remove all functions that start with 'spin_'
Note:
echo '!spin_*' > /debug/tracing/set_ftrace_filter
will simply clear out the list (notice the '>' instead of '>>')
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: clean up
Andrew Morton suggested to use the stack_tracer_enabled variable
to decide whether or not to start stack tracing on bootup.
This lets us remove the start_stack_trace variable.
Reported-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: enhancement to stack tracer
The stack tracer currently is either on when configured in or
off when it is not. It can not be disabled when it is configured on.
(besides disabling the function tracer that it uses)
This patch adds a way to enable or disable the stack tracer at
run time. It defaults off on bootup, but a kernel parameter 'stacktrace'
has been added to enable it on bootup.
A new sysctl has been added "kernel.stack_tracer_enabled" to let
the user enable or disable the stack tracer at run time.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: display ftrace_printk messages "as is"
By default, ftrace_printk() messages find their output with some other
informations like pid, caller, ...
Sometimes a developer just want to have the ftrace_printk left "as is", without
other information.
This is done by providing a default-off option called printk-msg-only.
To enable it, just do `echo printk-msg-only > /debugfs/tracing/trace_options`
Before the patch:
<...>-2739 [000] 145.692153: __might_sleep: I'm an ftrace_printk msg in __might_sleep
<...>-2739 [000] 145.692155: __might_sleep: I'm another ftrace_printk msg in __might_sleep
After the patch and the printk-msg-only option enabled:
I'm an ftrace_printk msg in __might_sleep
I'm another ftrace_printk msg in __might_sleep
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: prevent a trace recursion
After some tests with function graph tracer under x86-32, I saw some recursions
caused by ring_buffer_time_stamp() that calls preempt_enable_no_notrace() which
calls preempt_schedule() which is traced itself.
This patch re-enables preemption without rescheduling.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: change calling convention of existing cpumask APIs
Most cpumask functions started with cpus_: these have been replaced by
cpumask_ ones which take struct cpumask pointers as expected.
These four functions don't have good replacement names; fortunately
they're rarely used, so we just change them over.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Mike Travis <travis@sgi.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: paulus@samba.org
Cc: mingo@redhat.com
Cc: tony.luck@intel.com
Cc: ralf@linux-mips.org
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: cl@linux-foundation.org
Cc: srostedt@redhat.com
Impact: restructure code, cleanup
Remove BTS bits from the hw-branch-tracer (renamed from bts-tracer) and
use the ds interface.
Signed-off-by: Markus Metzger <markut.t.metzger@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
I added EXPORT_SYMBOL_GPLs for all functions part of the API
(ring_buffer.h). This is required since oprofile is using the ring
buffer and the compilation as modules would fail otherwise.
Signed-off-by: Robert Richter <robert.richter@amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
this warning:
kernel/trace/trace.c: In function ‘trace_vprintk’:
kernel/trace/trace.c:3626: warning: ‘flags’ may be used uninitialized in this function
shows some confusion about irq_flags / flags use here. We already have
irq_flags so remove the extra flags variable.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: Provide a way to pause the function graph tracer
As suggested by Steven Rostedt, the previous patch that prevented from
spinlock function tracing shouldn't use the raw_spinlock to fix it.
It's much better to follow lockdep with normal spinlock, so this patch
adds a new flag for each task to make the function graph tracer able
to be paused. We also can send an ftrace_printk whithout worrying of
the irrelevant traced spinlock during insertion.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup
Apply some suggestions of Steven Rostedt:
_turn tracing_selftest_running into a simple int (no need of an atomic_t)
_set it __read_mostly
_fix a comment style
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: provide trace headers to explain a bit the output
This patch implements the print_headers callback for the function graph
tracer. These headers are output according to the current trace options.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: clean up
Using (struct pid *)-1 as the pointer for ftrace_swapper_pid is
a little confusing for others. This patch uses the address of the
actual init pid structure instead. This change is only for
clarity. It does not affect the code itself. Hopefully soon the
swapper tasks will all have their own pid structure and then
we can clean up the code a bit more.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup
As suggested by Steven Rostedt, this patch provide a new macro
task_curr_ret_stack() to move the cpp conditionnal CONFIG into
the linux/ftrace.h headers.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: fix default empty traces on function-graph-tracer
The actual ftrace_trace_task() checks if ftrace_pid_trace is allocated
and return 1 if it is true.
If it is NULL, it will check the bit of pid tracing flag for the current
task (which are not set by default).
So by default, a task is not traced.
Actually all tasks should be traced by default and filter_by_pid when
ftrace_pid_trace is allocated.
The appropriate condition should be to return 1 if filter_by_pid is
set.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acke-dby: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: fix tracer selfstests false results
After setting a ftrace_printk somewhere in th kernel, I saw the
Function tracer selftest failing.
When a selftest occurs, the ring buffer is lurked to see if
some entries were inserted. But concurrent insertion such as
ftrace_printk could occured at the same time and could give
false positive or negative results.
This patch prevent prevent from TRACE_PRINT entries insertion
during selftests.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Handle the TRACE_PRINT entries from the function grapg tracer
and output them as a C comment just below the function that called
it, as if it was a comment inside this function.
Example with an ftrace_printk inside might_sleep() function:
void __might_sleep(char *file, int line)
{
static unsigned long prev_jiffy; /* ratelimiting */
ftrace_printk("Hi I'm a comment in might_sleep() :-)");
A chunk of a resulting trace:
0) | _reiserfs_free_block() {
0) | reiserfs_read_bitmap_block() {
0) | __bread() {
0) | __getblk() {
0) | __find_get_block() {
0) 0.698 us | mark_page_accessed();
0) 2.267 us | }
0) | __might_sleep() {
0) | /* Hi I'm a comment in might_sleep() :-) */
0) 1.321 us | }
0) 5.872 us | }
0) 7.313 us | }
0) 8.718 us | }
And this patch brings two minor fixes:
- The newline after a switch-out task has disappeared
- The "|" sign just before the cpu number on task-switch has been deleted.
0) 0.616 us | pick_next_task_rt();
0) 1.457 us | _spin_trylock();
0) 0.653 us | _spin_unlock();
0) 0.728 us | _spin_trylock();
0) 0.631 us | _spin_unlock();
0) 0.729 us | native_load_sp0();
0) 0.593 us | native_load_tls();
------------------------------------------
0) cat-2834 => migrati-3
------------------------------------------
0) | finish_task_switch() {
0) 0.841 us | _spin_unlock_irq();
0) 0.616 us | post_schedule_rt();
0) 3.882 us | }
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: fix a bug in function filter setting
when writing function to set_graph_function, we should check whether it
has existed in set_graph_function to avoid duplicating.
Signed-off-by: Liming Wang <liming.wang@windriver.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: new feature
This patch lets the swapper tasks of all CPUS be filtered by the
set_ftrace_pid file.
If '0' is echoed into this file, then all the idle tasks (aka swapper)
is flagged to be traced. This affects all CPU idle tasks.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: clean up, extend PID filtering to PID namespaces
Eric Biederman suggested using the struct pid for filtering on
pids in the kernel. This patch is based off of a demonstration
of an implementation that Eric sent me in an email.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: New feature
This patch makes the changes to set_ftrace_pid apply to the function
graph tracer.
# echo $$ > /debugfs/tracing/set_ftrace_pid
# echo function_graph > /debugfs/tracing/current_tracer
Will cause only the current task to be traced. Note, the trace flags are
also inherited by child processes, so the children of the shell
will also be traced.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: clean up
Use the new task struct trace flags to determine if a process should be
traced or not.
Note: this moves the searching of the pid to the slow path of setting
the pid field. This needs to be converted to the pid name space.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This patch adds the file:
/debugfs/tracing/set_graph_function
which can be used along with the function graph tracer.
When this file is empty, the function graph tracer will act as
usual. When the file has a function in it, the function graph
tracer will only trace that function.
For example:
# echo blk_unplug > /debugfs/tracing/set_graph_function
# cat /debugfs/tracing/trace
[...]
------------------------------------------
| 2) make-19003 => kjournald-2219
------------------------------------------
2) | blk_unplug() {
2) | dm_unplug_all() {
2) | dm_get_table() {
2) 1.381 us | _read_lock();
2) 0.911 us | dm_table_get();
2) 1. 76 us | _read_unlock();
2) + 12.912 us | }
2) | dm_table_unplug_all() {
2) | blk_unplug() {
2) 0.778 us | generic_unplug_device();
2) 2.409 us | }
2) 5.992 us | }
2) 0.813 us | dm_table_put();
2) + 29. 90 us | }
2) + 34.532 us | }
You can add up to 32 functions into this file. Currently we limit it
to 32, but this may change with later improvements.
To add another function, use the append '>>':
# echo sys_read >> /debugfs/tracing/set_graph_function
# cat /debugfs/tracing/set_graph_function
blk_unplug
sys_read
Using the '>' will clear out the function and write anew:
# echo sys_write > /debug/tracing/set_graph_function
# cat /debug/tracing/set_graph_function
sys_write
Note, if you have function graph running while doing this, the small
time between clearing it and updating it will cause the graph to
record all functions. This should not be an issue because after
it sets the filter, only those functions will be recorded from then on.
If you need to only record a particular function then set this
file first before starting the function graph tracer. In the future
this side effect may be corrected.
The set_graph_function file is similar to the set_ftrace_filter but
it does not take wild cards nor does it allow for more than one
function to be set with a single write. There is no technical reason why
this is the case, I just do not have the time yet to implement that.
Note, dynamic ftrace must be enabled for this to appear because it
uses the dynamic ftrace records to match the name to the mcount
call sites.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Conflicts:
fs/nfsd/nfs4recover.c
Manually fixed above to use new creds API functions, e.g.
nfs4_save_creds().
Signed-off-by: James Morris <jmorris@namei.org>
Impact: fix to output of stack trace
If a function is not found in the stack of the stack tracer, the
number printed is quite strange. This fixes the algorithm to handle
missing functions better.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
CONFIG_FUNCTION_GRAPH_TRACER depends on FUNCTION_TRACER already,
(turning it non-default) so it so making it default-n is pointless.
So enable it by default - it's a nice extension of the function tracer.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: better trace output of duration for long calls
The old duration output didn't exceeded 9999.999 us to fit the column
and the nanosecs were always 3 numbers. As Ingo suggested, it's better
to have the whole microseconds elapsed time and shift the nanosecs precision
if needed to fit the maximum 7 numbers. And usec need more number, the case
should be rare and important enough to break a bit the column alignment to
show it.
So, depending of the duration value, we now have these patterns:
u.nnn us
uu.nnn us
uuu.nnn us
uuuu.nnn us
uuuuu.nn us
uuuuuu.n us
uuuuuuuu..... us
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: extend function-graph output: let one know which thread called a function
This patch implements a helper function to print the couple cmdline/pid.
Its output is provided during task switching and on each row if the new
"funcgraph-proc" defualt-off option is set through trace_options file.
The output is center aligned and never exceeds 14 characters. The cmdline
is truncated over 7 chars.
But note that if the pid exceeds 6 characters, the column will overflow (but
the situation is abnormal).
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: feature, let entry function decide to trace or not
This patch lets the graph tracer entry function decide if the tracing
should be done at the end as well. This requires all function graph
entry functions return 1 if it should trace, or 0 if the return should
not be traced.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: clean up
Andrew Morton pointed out that the kernel convention of a variable
named page should be of type page struct. The ring buffer uses
a variable named "page" for a pointer to something else.
This patch converts those to be called "bpage" (as in "buffer page").
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: new ftrace_graph_stop function
While developing more features of function graph, I hit a bug that
caused the WARN_ON to trigger in the prepare_ftrace_return function.
Well, it was hard for me to find out that was happening because the
bug would not print, it would just cause a hard lockup or reboot.
The reason is that it is not safe to call printk from this function.
Looking further, I also found that it calls unregister_ftrace_graph,
which grabs a mutex and calls kstop machine. This would definitely
lock the box up if it were to trigger.
This patch adds a fast and safe ftrace_graph_stop() which will
stop the function tracer. Then it is safe to call the WARN ON.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: new API to ring buffer
This patch adds a new interface into the ring buffer that allows a
page to be read from the ring buffer on a given CPU. For every page
read, one must also be given to allow for a "swap" of the pages.
rpage = ring_buffer_alloc_read_page(buffer);
if (!rpage)
goto err;
ret = ring_buffer_read_page(buffer, &rpage, cpu, full);
if (!ret)
goto empty;
process_page(rpage);
ring_buffer_free_read_page(rpage);
The caller of these functions must handle any waits that are
needed to wait for new data. The ring_buffer_read_page will simply
return 0 if there is no data, or if "full" is set and the writer
is still on the current page.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: get ready for splice changes
This patch moves the commit and timestamp into the beginning of each
data page of the buffer. This change will allow the page to be moved
to another location (disk, network, etc) and still have information
in the page to be able to read it.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: fix for lockdep and ftrace
The raw_local_irq_save/restore confuses lockdep. This patch
converts them to the local_irq_save/restore variants.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: extend and enable the function graph tracer to 64-bit x86
This patch implements the support for function graph tracer under x86-64.
Both static and dynamic tracing are supported.
This causes some small CPP conditional asm on arch/x86/kernel/ftrace.c I
wanted to use probe_kernel_read/write to make the return address
saving/patching code more generic but it causes tracing recursion.
That would be perhaps useful to implement a notrace version of these
function for other archs ports.
Note that arch/x86/process_64.c is not traced, as in X86-32. I first
thought __switch_to() was responsible of crashes during tracing because I
believed current task were changed inside but that's actually not the
case (actually yes, but not the "current" pointer).
So I will have to investigate to find the functions that harm here, to
enable tracing of the other functions inside (but there is no issue at
this time, while process_64.c stays out of -pg flags).
A little possible race condition is fixed inside this patch too. When the
tracer allocate a return stack dynamically, the current depth is not
initialized before but after. An interrupt could occur at this time and,
after seeing that the return stack is allocated, the tracer could try to
trace it with a random uninitialized depth. It's a prevention, even if I
hadn't problems with it.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tim Bird <tim.bird@am.sony.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: fix "no output from tracer" bug caused by ftrace_update_pid_func()
When disabling single thread function trace using
"echo -1 > set_ftrace_pid", the normal function trace
has to restore to original function, otherwise the normal
function trace will not work well.
Without this commit, something like below:
$ ps |grep 850
850 root 2556 S -/bin/sh
$ echo 850 > /debug/tracing/set_ftrace_pid
$ echo function > /debug/tracing/current_tracer
$ echo 1 > /debug/tracing/tracing_enabled
$ sleep 1
$ echo 0 > /debug/tracing/tracing_enabled
$ cat /debug/tracing/trace_pipe |wc -l
59704
$ echo -1 > /debug/tracing/set_ftrace_pid
$ echo 1 > /debug/tracing/tracing_enabled
$ sleep 1
$ echo 0 > /debug/tracing/tracing_enabled
$ more /debug/tracing/trace_pipe
<====== nothing output now!
it should output trace record.
Signed-off-by: Liming Wang <liming.wang@windriver.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Steven Rostedt
Lai Jiangshan
Uwe Kleine-Koenig
Frederic Weisbecker
Shaohua Li
Pekka Paalanen
Andrew Morton
Ingo Molnar
Linus Torvalds
Robert Richter
Eduard - Gabriel Munteanu
Rusty Russell
Huang Weiyi
Peter Zijlstra
Pekka J Enberg
Thomas Gleixner
Markus Metzger
Liming Wang
James Morris