I originally wrote commit 35bb4399bd to shrink the size of the overhead of
tracepoints by several kilobytes. Later, I received a patch from Vaibhav
Nagarnaik that fixed a bug in the same code that this commit touches. Not
only did it fix a bug, it also removed code and shrunk the size of the
overhead of trace events even more than this commit did.
Since this commit is scheduled for 3.15 and Vaibhav's patch is already in
mainline, I need to revert this patch in order to keep it from conflicting
with Vaibhav's patch. Not to mention, Vaibhav's patch makes this patch
obsolete.
Link: http://lkml.kernel.org/r/20140320225637.0226041b@gandalf.local.home
Cc: Vaibhav Nagarnaik <vnagarnaik@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
With CONFIG_DYNAMIC_FTRACE=n, I see a warning:
kernel/trace/ftrace.c:240:13: warning: 'control_ops_free' defined but not used
static void control_ops_free(struct ftrace_ops *ops)
^
Move that function around to an already existing #ifdef
CONFIG_DYNAMIC_FTRACE block as the function is used solely from the
dynamic function tracing functions.
Link: http://lkml.kernel.org/r/1394484131-5107-1-git-send-email-jslaby@suse.cz
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
We should print some warning and kill ftrace functionality when the ftrace
function is not set correctly. Otherwise, ftrace might do crazy things without
an explanation. The error value has been ignored so far.
Note that an error that happens during updating all the traced calls is handled
in ftrace_replace_code(). We print more details about the particular
failing address via ftrace_bug() there.
Link: http://lkml.kernel.org/r/1393258342-29978-3-git-send-email-pmladek@suse.cz
Signed-off-by: Petr Mladek <pmladek@suse.cz>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
As the data parameter is not really used by any ftrace_dyn_arch_init,
remove that from ftrace_dyn_arch_init. This also removes the addr
local variable from ftrace_init which is now unused.
Note the documentation was imprecise as it did not suggest to set
(*data) to 0.
Link: http://lkml.kernel.org/r/1393268401-24379-4-git-send-email-jslaby@suse.cz
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: linux-arch@vger.kernel.org
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
No architecture uses the "data" parameter in ftrace_dyn_arch_init() in any
way, it just sets the value to 0. And this is used as a return value
in the caller -- ftrace_init, which just checks the retval against
zero.
Note there is also "return 0" in every ftrace_dyn_arch_init. So it is
enough to check the retval and remove all the indirect sets of data on
all archs.
Link: http://lkml.kernel.org/r/1393268401-24379-3-git-send-email-jslaby@suse.cz
Cc: linux-arch@vger.kernel.org
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The function used to do allocations some time ago. This no longer
happens and it only checks the count and prints some info. This patch
inlines the body to the only caller. There are two reasons:
* the name of the function was misleading
* it's clear what is going on in ftrace_init now
Link: http://lkml.kernel.org/r/1393268401-24379-2-git-send-email-jslaby@suse.cz
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Some of them can be local to functions, so make them local and pass
them as parameters where needed:
* __start_mcount_loc+__stop_mcount_loc are local to ftrace_init
* ftrace_new_pgs -> new_pgs/start_pg
* ftrace_update_cnt -> local update_cnt in ftrace_update_code
Link: http://lkml.kernel.org/r/1393268401-24379-1-git-send-email-jslaby@suse.cz
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The functions that assign the contents for the ftrace events are
defined by the TRACE_EVENT() macros. Each event has its own unique
way to assign data to its buffer. When you have over 500 events,
that means there's 500 functions assigning data uniquely for each
event (not really that many, as DECLARE_EVENT_CLASS() and multiple
DEFINE_EVENT()s will only need a single function).
By making helper functions in the core kernel to do some of the work
instead, we can shrink the size of the kernel down a bit.
With a kernel configured with 502 events, the change in size was:
text data bss dec hex filename
12987390 1913504 9785344 24686238 178ae9e /tmp/vmlinux
12959102 1913504 9785344 24657950 178401e /tmp/vmlinux.patched
That's a total of 28288 bytes, which comes down to 56 bytes per event.
Link: http://lkml.kernel.org/r/20120810034708.370808175@goodmis.org
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The code that shows array fields for events is defined for all events.
This can add up quite a bit when you have over 500 events.
By making helper functions in the core kernel to do the work
instead, we can shrink the size of the kernel down a bit.
With a kernel configured with 502 events, the change in size was:
text data bss dec hex filename
12990946 1913568 9785344 24689858 178bcc2 /tmp/vmlinux
12987390 1913504 9785344 24686238 178ae9e /tmp/vmlinux.patched
That's a total of 3556 bytes, which comes down to 7 bytes per event.
Although it's not much, this code is just called at initialization of
the events.
Link: http://lkml.kernel.org/r/20120810034708.084036335@goodmis.org
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The code for trace events to format the raw recorded event data
into human readable format in the 'trace' file is repeated for every
event in the system. When you have over 500 events, this can add up
quite a bit.
By making helper functions in the core kernel to do the work
instead, we can shrink the size of the kernel down a bit.
With a kernel configured with 502 events, the change in size was:
text data bss dec hex filename
12991007 1913568 9785344 24689919 178bcff /tmp/vmlinux.orig
12990946 1913568 9785344 24689858 178bcc2 /tmp/vmlinux.patched
Note, this version does not save as much as the version of this patch
I had a few years ago. That is because in the mean time, commit
f71130de5c ("tracing: Add a helper function for event print functions")
did a lot of the work my original patch did. But this change helps
slightly, and is part of a larger clean up to reduce the size much further.
Link: http://lkml.kernel.org/r/20120810034707.378538034@goodmis.org
Cc: Li Zefan <lizefan@huawei.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The ENABLED flag needs to be cleared when a ftrace_ops is unregistered
otherwise it wont be able to be registered again.
This is only for static tracing and does not affect DYNAMIC_FTRACE at
all.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Being able to change the trace clock at boot can be advantageous if
you need a better source of when things happen across CPUs. The default
trace clock is the fastest, but it uses local clocks which may not be
synced across CPUs and it does not let you know when events took place
with respect to events on other CPUs.
The global trace clock can help in this case, and if you do not care
about timings, the counter "clock" is the best, as that is just a simple
atomic counter that is incremented for every event.
Usage is to add "trace_clock=counter" on the kernel command line. You
can replace counter with "global" or any of the clocks listed in
/sys/kernel/debug/tracing/trace_clock
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Appreciated-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
It seems there's no reason to prevent mixed used of ftrace and perf
for a single uprobe event. At least the kprobes already support it.
Link: http://lkml.kernel.org/r/1389946120-19610-6-git-send-email-namhyung@kernel.org
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Add support for event triggering to uprobes. This is same as kprobes
support added by Tom (plus cleanup by Steven).
Link: http://lkml.kernel.org/r/1389946120-19610-5-git-send-email-namhyung@kernel.org
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Cc: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Support multi-buffer on uprobe-based dynamic events by
using ftrace_event_file.
This patch is based kprobe-based dynamic events multibuffer
support work initially, commited by Masami(commit 41a7dd420c),
but revised as below:
Oleg changed the kprobe-based multibuffer design from
array-pointers of ftrace_event_file into simple list,
so this patch also change to the list design.
rcu_read_lock/unlock added into uprobe_trace_func/uretprobe_trace_func,
to synchronize with ftrace_event_file list add and delete.
Even though we allow multi-uprobes instances now,
but TP_FLAG_PROFILE/TP_FLAG_TRACE are still mutually exclusive
in probe_event_enable currently, this means we cannot allow
one user is using uprobe-tracer, and another user is using
perf-probe on same uprobe concurrently.
(Perhaps this will be fix in future, kprobe don't have this
limitation now)
Link: http://lkml.kernel.org/r/1389946120-19610-4-git-send-email-namhyung@kernel.org
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
A single uprobe event might serve different users like ftrace and
perf. And this is especially important for upcoming multi buffer
support. But in this case it'll fetch (same) data from userspace
multiple times. So move it to the beginning of the dispatcher
function and reuse it for each users.
Link: http://lkml.kernel.org/r/1389946120-19610-3-git-send-email-namhyung@kernel.org
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The uprobe_{trace,perf}_print functions are misnomers since what they
do is not printing. There's also a real print function named
print_uprobe_event() so they'll only increase confusion IMHO.
Rename them with double underscores to follow convention of kprobe.
Link: http://lkml.kernel.org/r/1389946120-19610-2-git-send-email-namhyung@kernel.org
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Create a "set_ftrace_filter" and "set_ftrace_notrace" files in the instance
directories to let users filter of functions to trace for the given instance.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
In preparation for having the function tracing instances be able to
filter on functions, the generic filter functions must first be
converted to take in the global_ops as a parameter.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Allow instances (sub-buffers) to enable function tracing.
Each instance will have its own function tracing capability.
For now, instances will not have function stack tracing, or will
they be able to pick and choose what functions they can trace.
Picking and choosing their own functions will come later.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
As tracers will soon be used by instances, the tracer enabled field
needs to be converted to a counter instead of a boolean.
This counter is protected by the trace_types_lock mutex.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
When an instance is about to be deleted, make sure the tracer
is set to nop. If it isn't reset the tracer and set it to the nop
tracer, otherwise memory leaks and bad pointers may result.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
If global_ops function is being called directly, instead of the global_ops
list function, set the global_ops private to be the same as the ops private
that's being called directly.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Currently the tracers (function, function_graph, irqsoff, etc) can only
be used by the top level tracing directory (not for instances).
This sets up the infrastructure to allow instances to be able to
run a separate tracer apart from the what the top level tracing is
doing.
As tracers need to adapt for being used by instances, the tracers
must flag if they can be used by instances or not. Currently only the
'nop' tracer can be used by all instances.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
As options (flags) may affect instances instead of being global
the flag_changed() callbacks need to receive the trace_array descriptor
of the instance they will be modifying.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
As options (flags) may affect instances instead of being global
the set_flag() callbacks need to receive the trace_array descriptor
of the instance they will be modifying.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Each sub-buffer (buffer page) has a full 64 bit timestamp. The events on
that page use a 27 bit delta against that timestamp in order to save on
bits written to the ring buffer. If the time between events is larger than
what the 27 bits can hold, a "time extend" event is added to hold the
entire 64 bit timestamp again and the events after that hold a delta from
that timestamp.
As a "time extend" is always paired with an event, it is logical to just
allocate the event with the time extend, to make things a bit more efficient.
Unfortunately, when the pairing code was written, it removed the "delta = 0"
from the first commit on a page, causing the events on the page to be
slightly skewed.
Fixes: 69d1b839f7 "ring-buffer: Bind time extend and data events together"
Cc: stable@vger.kernel.org # 2.6.37+
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Pull core block IO changes from Jens Axboe:
"The major piece in here is the immutable bio_ve series from Kent, the
rest is fairly minor. It was supposed to go in last round, but
various issues pushed it to this release instead. The pull request
contains:
- Various smaller blk-mq fixes from different folks. Nothing major
here, just minor fixes and cleanups.
- Fix for a memory leak in the error path in the block ioctl code
from Christian Engelmayer.
- Header export fix from CaiZhiyong.
- Finally the immutable biovec changes from Kent Overstreet. This
enables some nice future work on making arbitrarily sized bios
possible, and splitting more efficient. Related fixes to immutable
bio_vecs:
- dm-cache immutable fixup from Mike Snitzer.
- btrfs immutable fixup from Muthu Kumar.
- bio-integrity fix from Nic Bellinger, which is also going to stable"
* 'for-3.14/core' of git://git.kernel.dk/linux-block: (44 commits)
xtensa: fixup simdisk driver to work with immutable bio_vecs
block/blk-mq-cpu.c: use hotcpu_notifier()
blk-mq: for_each_* macro correctness
block: Fix memory leak in rw_copy_check_uvector() handling
bio-integrity: Fix bio_integrity_verify segment start bug
block: remove unrelated header files and export symbol
blk-mq: uses page->list incorrectly
blk-mq: use __smp_call_function_single directly
btrfs: fix missing increment of bi_remaining
Revert "block: Warn and free bio if bi_end_io is not set"
block: Warn and free bio if bi_end_io is not set
blk-mq: fix initializing request's start time
block: blk-mq: don't export blk_mq_free_queue()
block: blk-mq: make blk_sync_queue support mq
block: blk-mq: support draining mq queue
dm cache: increment bi_remaining when bi_end_io is restored
block: fixup for generic bio chaining
block: Really silence spurious compiler warnings
block: Silence spurious compiler warnings
block: Kill bio_pair_split()
...
the new features added to 3.14.
The third patch is a minor bugfix to the trace_puts() functions that
will crash the system if a developer adds one before the tracing system
is setup. It also affects trace_printk() if it has no arguments, as
the code will convert it to a trace_puts() as well. Note, this bug
will not affect unmodified kernels, as trace_printk() and trace_puts()
should only be used by developers for testing.
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Merge tag 'trace-fixes-3.14' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing fixes from Steven Rostedt:
"The first two patches fix the debugfs README file to reflect better
the new features added to 3.14.
The third patch is a minor bugfix to the trace_puts() functions that
will crash the system if a developer adds one before the tracing
system is setup. It also affects trace_printk() if it has no
arguments, as the code will convert it to a trace_puts() as well.
Note, this bug will not affect unmodified kernels, as trace_printk()
and trace_puts() should only be used by developers for testing"
* tag 'trace-fixes-3.14' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
tracing: Check if tracing is enabled in trace_puts()
tracing: Fix formatting of trace README file
tracing/README: Add event file usage to tracing mini-HOWTO
If trace_puts() is used very early in boot up, it can crash the machine
if it is called before the ring buffer is allocated. If a trace_printk()
is used with no arguments, then it will be converted into a trace_puts()
and suffer the same fate.
Cc: stable@vger.kernel.org # 3.10+
Fixes: 09ae72348e "tracing: Add trace_puts() for even faster trace_printk() tracing"
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Fix the formatting of the README file in the trace debugfs to fit in
an 80 character window.
Also add a comment about the event trigger counter with regards to
traceon and traceoff.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
It would be useful to have a cheat-sheet for everything under
tracing/events/ alongside the existing text describing the other files
in the tracing/ dir.
Add short descriptions of the directories and files under events/
along with examples, similar to the existing text for the other files
in tracing/.
Also clean up a few minor alignment problems noticed when adding the
new text.
Link: http://lkml.kernel.org/r/1389993104.3040.445.camel@empanada
Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
triggers by Tom Zanussi. A trigger is a way to enable an action when an
event is hit. The actions are:
o trace on/off - enable or disable tracing
o snapshot - save the current trace buffer in the snapshot
o stacktrace - dump the current stack trace to the ringbuffer
o enable/disable events - enable or disable another event
Namhyung Kim added updates to the tracing uprobes code. Having the
uprobes add support for fetch methods.
The rest are various bug fixes with the new code, and minor ones for
the old code.
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Merge tag 'trace-3.14' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing updates from Steven Rostedt:
"This pull request has a new feature to ftrace, namely the trace event
triggers by Tom Zanussi. A trigger is a way to enable an action when
an event is hit. The actions are:
o trace on/off - enable or disable tracing
o snapshot - save the current trace buffer in the snapshot
o stacktrace - dump the current stack trace to the ringbuffer
o enable/disable events - enable or disable another event
Namhyung Kim added updates to the tracing uprobes code. Having the
uprobes add support for fetch methods.
The rest are various bug fixes with the new code, and minor ones for
the old code"
* tag 'trace-3.14' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (38 commits)
tracing: Fix buggered tee(2) on tracing_pipe
tracing: Have trace buffer point back to trace_array
ftrace: Fix synchronization location disabling and freeing ftrace_ops
ftrace: Have function graph only trace based on global_ops filters
ftrace: Synchronize setting function_trace_op with ftrace_trace_function
tracing: Show available event triggers when no trigger is set
tracing: Consolidate event trigger code
tracing: Fix counter for traceon/off event triggers
tracing: Remove double-underscore naming in syscall trigger invocations
tracing/kprobes: Add trace event trigger invocations
tracing/probes: Fix build break on !CONFIG_KPROBE_EVENT
tracing/uprobes: Add @+file_offset fetch method
uprobes: Allocate ->utask before handler_chain() for tracing handlers
tracing/uprobes: Add support for full argument access methods
tracing/uprobes: Fetch args before reserving a ring buffer
tracing/uprobes: Pass 'is_return' to traceprobe_parse_probe_arg()
tracing/probes: Implement 'memory' fetch method for uprobes
tracing/probes: Add fetch{,_size} member into deref fetch method
tracing/probes: Move 'symbol' fetch method to kprobes
tracing/probes: Implement 'stack' fetch method for uprobes
...
In kernel/trace/trace.c we have this:
static void tracing_pipe_buf_release(struct pipe_inode_info *pipe,
struct pipe_buffer *buf)
{
__free_page(buf->page);
}
static const struct pipe_buf_operations tracing_pipe_buf_ops = {
.can_merge = 0,
.map = generic_pipe_buf_map,
.unmap = generic_pipe_buf_unmap,
.confirm = generic_pipe_buf_confirm,
.release = tracing_pipe_buf_release,
.steal = generic_pipe_buf_steal,
.get = generic_pipe_buf_get,
};
with
void generic_pipe_buf_get(struct pipe_inode_info *pipe, struct pipe_buffer *buf)
{
page_cache_get(buf->page);
}
and I don't see anything that would've prevented tee(2) called on the pipe
that got stuff spliced into it from that sucker. ->ops->get() will be
called, then buf gets copied into target pipe's ->bufs[] and eventually
readers get to both copies of the buffer. With
get_page(page)
look at that page
__free_page(page)
look at that page
__free_page(page)
which is not a good thing, to put it mildly. AFAICS, that ought to use
the normal generic_pipe_buf_release() (aka page_cache_release(buf->page)),
shouldn't it?
[
SDR - As trace_pipe just allocates the page with alloc_page(GFP_KERNEL),
and doesn't do anything special with it (no LRU logic). The __free_page()
should be fine, as it wont actually free a page with reference count.
Maybe there's a chance to leak memory? Anyway, This change is at a minimum
good for being symmetric with generic_pipe_buf_get, it is fine to add.
]
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
[ SDR - Removed no longer used tracing_pipe_buf_release ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The trace buffer has a descriptor pointer that goes back to the trace
array. But it was never assigned. Luckily, nothing uses it (yet), but
it will in the future.
Although nothing currently uses this, if any of the new features get
backported to older kernels, and because this is such a simple change,
I'm marking it for stable too.
Cc: stable@vger.kernel.org # v3.10+
Fixes: 12883efb67 "tracing: Consolidate max_tr into main trace_array structure"
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The synchronization needed after ftrace_ops are unregistered must happen
after the callback is disabled from becing called by functions.
The current location happens after the function is being removed from the
internal lists, but not after the function callbacks were disabled, leaving
the functions susceptible of being called after their callbacks are freed.
This affects perf and any externel users of function tracing (LTTng and
SystemTap).
Cc: stable@vger.kernel.org # 3.0+
Fixes: cdbe61bfe7 "ftrace: Allow dynamically allocated function tracers"
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Doing some different tests, I discovered that function graph tracing, when
filtered via the set_ftrace_filter and set_ftrace_notrace files, does
not always keep with them if another function ftrace_ops is registered
to trace functions.
The reason is that function graph just happens to trace all functions
that the function tracer enables. When there was only one user of
function tracing, the function graph tracer did not need to worry about
being called by functions that it did not want to trace. But now that there
are other users, this becomes a problem.
For example, one just needs to do the following:
# cd /sys/kernel/debug/tracing
# echo schedule > set_ftrace_filter
# echo function_graph > current_tracer
# cat trace
[..]
0) | schedule() {
------------------------------------------
0) <idle>-0 => rcu_pre-7
------------------------------------------
0) ! 2980.314 us | }
0) | schedule() {
------------------------------------------
0) rcu_pre-7 => <idle>-0
------------------------------------------
0) + 20.701 us | }
# echo 1 > /proc/sys/kernel/stack_tracer_enabled
# cat trace
[..]
1) + 20.825 us | }
1) + 21.651 us | }
1) + 30.924 us | } /* SyS_ioctl */
1) | do_page_fault() {
1) | __do_page_fault() {
1) 0.274 us | down_read_trylock();
1) 0.098 us | find_vma();
1) | handle_mm_fault() {
1) | _raw_spin_lock() {
1) 0.102 us | preempt_count_add();
1) 0.097 us | do_raw_spin_lock();
1) 2.173 us | }
1) | do_wp_page() {
1) 0.079 us | vm_normal_page();
1) 0.086 us | reuse_swap_page();
1) 0.076 us | page_move_anon_rmap();
1) | unlock_page() {
1) 0.082 us | page_waitqueue();
1) 0.086 us | __wake_up_bit();
1) 1.801 us | }
1) 0.075 us | ptep_set_access_flags();
1) | _raw_spin_unlock() {
1) 0.098 us | do_raw_spin_unlock();
1) 0.105 us | preempt_count_sub();
1) 1.884 us | }
1) 9.149 us | }
1) + 13.083 us | }
1) 0.146 us | up_read();
When the stack tracer was enabled, it enabled all functions to be traced, which
now the function graph tracer also traces. This is a side effect that should
not occur.
To fix this a test is added when the function tracing is changed, as well as when
the graph tracer is enabled, to see if anything other than the ftrace global_ops
function tracer is enabled. If so, then the graph tracer calls a test trampoline
that will look at the function that is being traced and compare it with the
filters defined by the global_ops.
As an optimization, if there's no other function tracers registered, or if
the only registered function tracers also use the global ops, the function
graph infrastructure will call the registered function graph callback directly
and not go through the test trampoline.
Cc: stable@vger.kernel.org # 3.3+
Fixes: d2d45c7a03 "tracing: Have stack_tracer use a separate list of functions"
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Some method to deal with rt-mutexes and make sched_dl interact with
the current PI-coded is needed, raising all but trivial issues, that
needs (according to us) to be solved with some restructuring of
the pi-code (i.e., going toward a proxy execution-ish implementation).
This is under development, in the meanwhile, as a temporary solution,
what this commits does is:
- ensure a pi-lock owner with waiters is never throttled down. Instead,
when it runs out of runtime, it immediately gets replenished and it's
deadline is postponed;
- the scheduling parameters (relative deadline and default runtime)
used for that replenishments --during the whole period it holds the
pi-lock-- are the ones of the waiting task with earliest deadline.
Acting this way, we provide some kind of boosting to the lock-owner,
still by using the existing (actually, slightly modified by the previous
commit) pi-architecture.
We would stress the fact that this is only a surely needed, all but
clean solution to the problem. In the end it's only a way to re-start
discussion within the community. So, as always, comments, ideas, rants,
etc.. are welcome! :-)
Signed-off-by: Dario Faggioli <raistlin@linux.it>
Signed-off-by: Juri Lelli <juri.lelli@gmail.com>
[ Added !RT_MUTEXES build fix. ]
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1383831828-15501-11-git-send-email-juri.lelli@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
It is very likely that systems that wants/needs to use the new
SCHED_DEADLINE policy also want to have the scheduling latency of
the -deadline tasks under control.
For this reason a new version of the scheduling wakeup latency,
called "wakeup_dl", is introduced.
As a consequence of applying this patch there will be three wakeup
latency tracer:
* "wakeup", that deals with all tasks in the system;
* "wakeup_rt", that deals with -rt and -deadline tasks only;
* "wakeup_dl", that deals with -deadline tasks only.
Signed-off-by: Dario Faggioli <raistlin@linux.it>
Signed-off-by: Juri Lelli <juri.lelli@gmail.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1383831828-15501-9-git-send-email-juri.lelli@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
ftrace_trace_function is a variable that holds what function will be called
directly by the assembly code (mcount). If just a single function is
registered and it handles recursion itself, then the assembly will call that
function directly without any helper function. It also passes in the
ftrace_op that was registered with the callback. The ftrace_op to send is
stored in the function_trace_op variable.
The ftrace_trace_function and function_trace_op needs to be coordinated such
that the called callback wont be called with the wrong ftrace_op, otherwise
bad things can happen if it expected a different op. Luckily, there's no
callback that doesn't use the helper functions that requires this. But
there soon will be and this needs to be fixed.
Use a set_function_trace_op to store the ftrace_op to set the
function_trace_op to when it is safe to do so (during the update function
within the breakpoint or stop machine calls). Or if dynamic ftrace is not
being used (static tracing) then we have to do a bit more synchronization
when the ftrace_trace_function is set as that takes affect immediately
(as oppose to dynamic ftrace doing it with the modification of the trampoline).
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Currently there's no way to know what triggers exist on a kernel without
looking at the source of the kernel or randomly trying out triggers.
Instead of creating another file in the debugfs system, simply show
what available triggers are there when cat'ing the trigger file when
it has no events:
[root /sys/kernel/debug/tracing]# cat events/sched/sched_switch/trigger
# Available triggers:
# traceon traceoff snapshot stacktrace enable_event disable_event
This stays consistent with other debugfs files where meta data like
this is always proceeded with a '#' at the start of the line so that
tools can strip these out.
Link: http://lkml.kernel.org/r/20140107103548.0a84536d@gandalf.local.home
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The event trigger code that checks for callback triggers before and
after recording of an event has lots of flags checks. This code is
duplicated throughout the ftrace events, kprobes and system calls.
They all do the exact same checks against the event flags.
Added helper functions ftrace_trigger_soft_disabled(),
event_trigger_unlock_commit() and event_trigger_unlock_commit_regs()
that consolidated the code and these are used instead.
Link: http://lkml.kernel.org/r/20140106222703.5e7dbba2@gandalf.local.home
Acked-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Tested-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The counters for the traceon and traceoff are only suppose to decrement
when the trigger enables or disables tracing. It is not suppose to decrement
every time the event is hit.
Only decrement the counter if the trigger actually did something.
Link: http://lkml.kernel.org/r/20140106223124.0e5fd0b4@gandalf.local.home
Acked-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
There's no reason to use double-underscores for any variable name in
ftrace_syscall_enter()/exit(), since those functions aren't generated
and there's no need to avoid namespace collisions as with the event
macros, which is where the original invocation code came from.
Link: http://lkml.kernel.org/r/0b489c9d1f7ee315cff60fa0e4c2b433ade8ae0d.1389036657.git.tom.zanussi@linux.intel.com
Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Add code to the kprobe/kretprobe event functions that will invoke any
event triggers associated with a probe's ftrace_event_file.
The code to do this is very similar to the invocation code already
used to invoke the triggers associated with static events and
essentially replaces the existing soft-disable checks with a superset
that preserves the original behavior but adds the bits needed to
support event triggers.
Link: http://lkml.kernel.org/r/f2d49f157b608070045fdb26c9564d5a05a5a7d0.1389036657.git.tom.zanussi@linux.intel.com
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
When kprobe-based dynamic event tracer is not enabled, it caused
following build error:
kernel/built-in.o: In function `traceprobe_update_arg':
(.text+0x10c8dd): undefined reference to `fetch_symbol_u8'
kernel/built-in.o: In function `traceprobe_update_arg':
(.text+0x10c8e9): undefined reference to `fetch_symbol_u16'
kernel/built-in.o: In function `traceprobe_update_arg':
(.text+0x10c8f5): undefined reference to `fetch_symbol_u32'
kernel/built-in.o: In function `traceprobe_update_arg':
(.text+0x10c901): undefined reference to `fetch_symbol_u64'
kernel/built-in.o: In function `traceprobe_update_arg':
(.text+0x10c909): undefined reference to `fetch_symbol_string'
kernel/built-in.o: In function `traceprobe_update_arg':
(.text+0x10c913): undefined reference to `fetch_symbol_string_size'
...
It was due to the fetch methods are referred from CHECK_FETCH_FUNCS
macro and since it was only defined in trace_kprobe.c. Move NULL
definition of such fetch functions to the header file.
Note, it also requires CONFIG_BRANCH_PROFILING enabled to trigger
this failure as well. This is because the "fetch_symbol_*" variables
are referenced in a "else if" statement that will only call
update_symbol_cache(), which is a static inline stub function
when CONFIG_KPROBE_EVENT is not enabled. gcc is smart enough
to optimize this "else if" out and that also removes the code that
references the undefined variables.
But when BRANCH_PROFILING is enabled, it fools gcc into keeping
the if statement around and thus references the undefined symbols
and fails to build.
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Enable to fetch data from a file offset. Currently it only supports
fetching from same binary uprobe set. It'll translate the file offset
to a proper virtual address in the process.
The syntax is "@+OFFSET" as it does similar to normal memory fetching
(@ADDR) which does no address translation.
Suggested-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
