Currently, every event has its own trace_event structure. This is
fine since the structure is needed anyway. But the print function
structure (trace_event_functions) is now separate. Since the output
of the trace event is done by the class (with the exception of events
defined by DEFINE_EVENT_PRINT), it makes sense to have the class
define the print functions that all events in the class can use.
This makes a bigger deal with the syscall events since all syscall events
use the same class. The savings here is another 30K.
text data bss dec hex filename
4913961 1088356 861512 6863829 68bbd5 vmlinux.orig
4900382 1048964 861512 6810858 67ecea vmlinux.init
4900446 1049028 861512 6810986 67ed6a vmlinux.preprint
4895024 1023812 861512 6780348 6775bc vmlinux.print
To accomplish this, and to let the class know what event is being
printed, the event structure is embedded in the ftrace_event_call
structure. This should not be an issues since the event structure
was created for each event anyway.
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Acked-by: Masami Hiramatsu <mhiramat@redhat.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Multiple events may use the same method to print their data.
Instead of having all events have a pointer to their print funtions,
the trace_event structure now points to a trace_event_functions structure
that will hold the way to print ouf the event.
The event itself is now passed to the print function to let the print
function know what kind of event it should print.
This opens the door to consolidating the way several events print
their output.
text data bss dec hex filename
4913961 1088356 861512 6863829 68bbd5 vmlinux.orig
4900382 1048964 861512 6810858 67ecea vmlinux.init
4900446 1049028 861512 6810986 67ed6a vmlinux.preprint
This change slightly increases the size but is needed for the next change.
v3: Fix the branch tracer events to handle this change.
v2: Fix the new function graph tracer event calls to handle this change.
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Acked-by: Masami Hiramatsu <mhiramat@redhat.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The raw_init function pointer in the event is used to initialize
various kinds of events. The type of initialization needed is usually
classed to the kind of event it is.
Two events with the same class will always have the same initialization
function, so it makes sense to move this to the class structure.
Perhaps even making a special system structure would work since
the initialization is the same for all events within a system.
But since there's no system structure (yet), this will just move it
to the class.
text data bss dec hex filename
4913961 1088356 861512 6863829 68bbd5 vmlinux.orig
4900375 1053380 861512 6815267 67fe23 vmlinux.fields
4900382 1048964 861512 6810858 67ecea vmlinux.init
The text grew very slightly, but this is a constant growth that happened
with the changing of the C files that call the init code.
The bigger savings is the data which will be saved the more events share
a class.
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Acked-by: Masami Hiramatsu <mhiramat@redhat.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Move the defined fields from the event to the class structure.
Since the fields of the event are defined by the class they belong
to, it makes sense to have the class hold the information instead
of the individual events. The events of the same class would just
hold duplicate information.
After this change the size of the kernel dropped another 3K:
text data bss dec hex filename
4913961 1088356 861512 6863829 68bbd5 vmlinux.orig
4900252 1057412 861512 6819176 680d68 vmlinux.regs
4900375 1053380 861512 6815267 67fe23 vmlinux.fields
Although the text increased, this was mainly due to the C files
having to adapt to the change. This is a constant increase, where
new tracepoints will not increase the Text. But the big drop is
in the data size (as well as needed allocations to hold the fields).
This will give even more savings as more tracepoints are created.
Note, if just TRACE_EVENT()s are used and not DECLARE_EVENT_CLASS()
with several DEFINE_EVENT()s, then the savings will be lost. But
we are pushing developers to consolidate events with DEFINE_EVENT()
so this should not be an issue.
The kprobes define a unique class to every new event, but are dynamic
so it should not be a issue.
The syscalls however have a single class but the fields for the individual
events are different. The syscalls use a metadata to define the
fields. I moved the fields list from the event to the metadata and
added a "get_fields()" function to the class. This function is used
to find the fields. For normal events and kprobes, get_fields() just
returns a pointer to the fields list_head in the class. For syscall
events, it returns the fields list_head in the metadata for the event.
v2: Fixed the syscall fields. The syscall metadata needs a list
of fields for both enter and exit.
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Acked-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This patch removes the register functions of TRACE_EVENT() to enable
and disable tracepoints. The registering of a event is now down
directly in the trace_events.c file. The tracepoint_probe_register()
is now called directly.
The prototypes are no longer type checked, but this should not be
an issue since the tracepoints are created automatically by the
macros. If a prototype is incorrect in the TRACE_EVENT() macro, then
other macros will catch it.
The trace_event_class structure now holds the probes to be called
by the callbacks. This removes needing to have each event have
a separate pointer for the probe.
To handle kprobes and syscalls, since they register probes in a
different manner, a "reg" field is added to the ftrace_event_class
structure. If the "reg" field is assigned, then it will be called for
enabling and disabling of the probe for either ftrace or perf. To let
the reg function know what is happening, a new enum (trace_reg) is
created that has the type of control that is needed.
With this new rework, the 82 kernel events and 618 syscall events
has their footprint dramatically lowered:
text data bss dec hex filename
4913961 1088356 861512 6863829 68bbd5 vmlinux.orig
4914025 1088868 861512 6864405 68be15 vmlinux.class
4918492 1084612 861512 6864616 68bee8 vmlinux.tracepoint
4900252 1057412 861512 6819176 680d68 vmlinux.regs
The size went from 6863829 to 6819176, that's a total of 44K
in savings. With tracepoints being continuously added, this is
critical that the footprint becomes minimal.
v5: Added #ifdef CONFIG_PERF_EVENTS around a reference to perf
specific structure in trace_events.c.
v4: Fixed trace self tests to check probe because regfunc no longer
exists.
v3: Updated to handle void *data in beginning of probe parameters.
Also added the tracepoint: check_trace_callback_type_##call().
v2: Changed the callback probes to pass void * and typecast the
value within the function.
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Acked-by: Masami Hiramatsu <mhiramat@redhat.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This patch adds data to be passed to tracepoint callbacks.
The created functions from DECLARE_TRACE() now need a mandatory data
parameter. For example:
DECLARE_TRACE(mytracepoint, int value, value)
Will create the register function:
int register_trace_mytracepoint((void(*)(void *data, int value))probe,
void *data);
As the first argument, all callbacks (probes) must take a (void *data)
parameter. So a callback for the above tracepoint will look like:
void myprobe(void *data, int value)
{
}
The callback may choose to ignore the data parameter.
This change allows callbacks to register a private data pointer along
with the function probe.
void mycallback(void *data, int value);
register_trace_mytracepoint(mycallback, mydata);
Then the mycallback() will receive the "mydata" as the first parameter
before the args.
A more detailed example:
DECLARE_TRACE(mytracepoint, TP_PROTO(int status), TP_ARGS(status));
/* In the C file */
DEFINE_TRACE(mytracepoint, TP_PROTO(int status), TP_ARGS(status));
[...]
trace_mytracepoint(status);
/* In a file registering this tracepoint */
int my_callback(void *data, int status)
{
struct my_struct my_data = data;
[...]
}
[...]
my_data = kmalloc(sizeof(*my_data), GFP_KERNEL);
init_my_data(my_data);
register_trace_mytracepoint(my_callback, my_data);
The same callback can also be registered to the same tracepoint as long
as the data registered is different. Note, the data must also be used
to unregister the callback:
unregister_trace_mytracepoint(my_callback, my_data);
Because of the data parameter, tracepoints declared this way can not have
no args. That is:
DECLARE_TRACE(mytracepoint, TP_PROTO(void), TP_ARGS());
will cause an error.
If no arguments are needed, a new macro can be used instead:
DECLARE_TRACE_NOARGS(mytracepoint);
Since there are no arguments, the proto and args fields are left out.
This is part of a series to make the tracepoint footprint smaller:
text data bss dec hex filename
4913961 1088356 861512 6863829 68bbd5 vmlinux.orig
4914025 1088868 861512 6864405 68be15 vmlinux.class
4918492 1084612 861512 6864616 68bee8 vmlinux.tracepoint
Again, this patch also increases the size of the kernel, but
lays the ground work for decreasing it.
v5: Fixed net/core/drop_monitor.c to handle these updates.
v4: Moved the DECLARE_TRACE() DECLARE_TRACE_NOARGS out of the
#ifdef CONFIG_TRACE_POINTS, since the two are the same in both
cases. The __DECLARE_TRACE() is what changes.
Thanks to Frederic Weisbecker for pointing this out.
v3: Made all register_* functions require data to be passed and
all callbacks to take a void * parameter as its first argument.
This makes the calling functions comply with C standards.
Also added more comments to the modifications of DECLARE_TRACE().
v2: Made the DECLARE_TRACE() have the ability to pass arguments
and added a new DECLARE_TRACE_NOARGS() for tracepoints that
do not need any arguments.
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Acked-by: Masami Hiramatsu <mhiramat@redhat.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Neil Horman <nhorman@tuxdriver.com>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This patch creates a ftrace_event_class struct that event structs point to.
This class struct will be made to hold information to modify the
events. Currently the class struct only holds the events system name.
This patch slightly increases the size, but this change lays the ground work
of other changes to make the footprint of tracepoints smaller.
With 82 standard tracepoints, and 618 system call tracepoints
(two tracepoints per syscall: enter and exit):
text data bss dec hex filename
4913961 1088356 861512 6863829 68bbd5 vmlinux.orig
4914025 1088868 861512 6864405 68be15 vmlinux.class
This patch also cleans up some stale comments in ftrace.h.
v2: Fixed missing semi-colon in macro.
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Acked-by: Masami Hiramatsu <mhiramat@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
epoll should not touch flags in wait_queue_t. This patch introduces a new
function __add_wait_queue_exclusive(), for the users, who use wait queue as a
LIFO queue.
__add_wait_queue_tail_exclusive() is introduced too instead of
add_wait_queue_exclusive_locked(). remove_wait_queue_locked() is removed, as
it is a duplicate of __remove_wait_queue(), disliked by users, and with less
users.
Signed-off-by: Changli Gao <xiaosuo@gmail.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Paul Menage <menage@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Davide Libenzi <davidel@xmailserver.org>
Cc: <containers@lists.linux-foundation.org>
LKML-Reference: <1273214006-2979-1-git-send-email-xiaosuo@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This comment should have been removed together with uids_mutex
when removing user sched.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Dhaval Giani <dhaval.giani@gmail.com>
LKML-Reference: <4BE77C6B.5010402@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
For the ondemand cpufreq governor, it is desired that the iowait
time is microaccounted in a similar way as idle time is.
This patch introduces the infrastructure to account and expose
this information via the get_cpu_iowait_time_us() function.
[akpm@linux-foundation.org: fix CONFIG_NO_HZ=n build]
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Rik van Riel <riel@redhat.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: davej@redhat.com
LKML-Reference: <20100509082523.284feab6@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Now that the only user of ts->idle_lastupdate is
update_ts_time_stats(), the entire field can be eliminated.
In update_ts_time_stats(), idle_lastupdate is first set to
"now", and a few lines later, the only user is an if() statement
that assigns a variable either to "now" or to
ts->idle_lastupdate, which has the value of "now" at that point.
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Rik van Riel <riel@redhat.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: davej@redhat.com
LKML-Reference: <20100509082439.2fab0b4f@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This patch folds the updating of the last_update_time into the
update_ts_time_stats() function, and updates the callers.
This allows for further cleanups that are done in the next
patch.
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Rik van Riel <riel@redhat.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: davej@redhat.com
LKML-Reference: <20100509082403.60072967@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Right now, get_cpu_idle_time_us() only reports the idle
statistics upto the point the CPU entered last idle; not what is
valid right now.
This patch adds an update of the idle statistics to
get_cpu_idle_time_us(), so that calling this function always
returns statistics that are accurate at the point of the call.
This includes resetting the start of the idle time for
accounting purposes to avoid double accounting.
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Rik van Riel <riel@redhat.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: davej@redhat.com
LKML-Reference: <20100509082323.2d2f1945@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Currently, two places update the idle statistics (and more to
come later in this series).
This patch creates a helper function for updating these
statistics.
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Rik van Riel <riel@redhat.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: davej@redhat.com
LKML-Reference: <20100509082245.163e67ed@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The exported function get_cpu_idle_time_us() has no comment
describing it; add a kerneldoc comment
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Rik van Riel <riel@redhat.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: davej@redhat.com
LKML-Reference: <20100509082208.7cb721f0@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
When !CONFIG_SMP, cpu_stop functions weren't defined at all which
could lead to build failures if UP code uses cpu_stop facility. Add
dummy cpu_stop implementation for UP. The waiting variants execute
the work function directly with preempt disabled and
stop_one_cpu_nowait() schedules a workqueue work.
Makefile and ifdefs around stop_machine implementation are updated to
accomodate CONFIG_SMP && !CONFIG_STOP_MACHINE case.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Ingo Molnar <mingo@elte.hu>
struct rq isn't visible outside of sched.o so its near useless to
expose the pointer, also there are no users of it, so remove it.
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1272997616.1642.207.camel@laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
If synchronize_sched_expedited() is ever to be called from within
kernel/sched.c in a !SMP PREEMPT kernel, the !SMP implementation needs
a barrier().
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
The memory barriers must be in the SMP case, not in the !SMP case.
Also add a barrier after the atomic_inc() in order to ensure that
other CPUs see post-synchronize_sched_expedited() actions as following
the expedited grace period.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
The paranoid check which verifies that the cpu_stop callback is
actually called on all online cpus is completely superflous. It's
guaranteed by cpu_stop facility and if it didn't work as advertised
other things would go horribly wrong and trying to recover using
synchronize_sched() wouldn't be very meaningful.
Kill the paranoid check. Removal of this feature is done as a
separate step so that it can serve as a bisection point if something
actually goes wrong.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Dipankar Sarma <dipankar@in.ibm.com>
Cc: Josh Triplett <josh@freedesktop.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Dimitri Sivanich <sivanich@sgi.com>
Currently migration_thread is serving three purposes - migration
pusher, context to execute active_load_balance() and forced context
switcher for expedited RCU synchronize_sched. All three roles are
hardcoded into migration_thread() and determining which job is
scheduled is slightly messy.
This patch kills migration_thread and replaces all three uses with
cpu_stop. The three different roles of migration_thread() are
splitted into three separate cpu_stop callbacks -
migration_cpu_stop(), active_load_balance_cpu_stop() and
synchronize_sched_expedited_cpu_stop() - and each use case now simply
asks cpu_stop to execute the callback as necessary.
synchronize_sched_expedited() was implemented with private
preallocated resources and custom multi-cpu queueing and waiting
logic, both of which are provided by cpu_stop.
synchronize_sched_expedited_count is made atomic and all other shared
resources along with the mutex are dropped.
synchronize_sched_expedited() also implemented a check to detect cases
where not all the callback got executed on their assigned cpus and
fall back to synchronize_sched(). If called with cpu hotplug blocked,
cpu_stop already guarantees that and the condition cannot happen;
otherwise, stop_machine() would break. However, this patch preserves
the paranoid check using a cpumask to record on which cpus the stopper
ran so that it can serve as a bisection point if something actually
goes wrong theree.
Because the internal execution state is no longer visible,
rcu_expedited_torture_stats() is removed.
This patch also renames cpu_stop threads to from "stopper/%d" to
"migration/%d". The names of these threads ultimately don't matter
and there's no reason to make unnecessary userland visible changes.
With this patch applied, stop_machine() and sched now share the same
resources. stop_machine() is faster without wasting any resources and
sched migration users are much cleaner.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Dipankar Sarma <dipankar@in.ibm.com>
Cc: Josh Triplett <josh@freedesktop.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Dimitri Sivanich <sivanich@sgi.com>
Reimplement stop_machine using cpu_stop. As cpu stoppers are
guaranteed to be available for all online cpus,
stop_machine_create/destroy() are no longer necessary and removed.
With resource management and synchronization handled by cpu_stop, the
new implementation is much simpler. Asking the cpu_stop to execute
the stop_cpu() state machine on all online cpus with cpu hotplug
disabled is enough.
stop_machine itself doesn't need to manage any global resources
anymore, so all per-instance information is rolled into struct
stop_machine_data and the mutex and all static data variables are
removed.
The previous implementation created and destroyed RT workqueues as
necessary which made stop_machine() calls highly expensive on very
large machines. According to Dimitri Sivanich, preventing the dynamic
creation/destruction makes booting faster more than twice on very
large machines. cpu_stop resources are preallocated for all online
cpus and should have the same effect.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Dimitri Sivanich <sivanich@sgi.com>
Implement a simplistic per-cpu maximum priority cpu monopolization
mechanism. A non-sleeping callback can be scheduled to run on one or
multiple cpus with maximum priority monopolozing those cpus. This is
primarily to replace and unify RT workqueue usage in stop_machine and
scheduler migration_thread which currently is serving multiple
purposes.
Four functions are provided - stop_one_cpu(), stop_one_cpu_nowait(),
stop_cpus() and try_stop_cpus().
This is to allow clean sharing of resources among stop_cpu and all the
migration thread users. One stopper thread per cpu is created which
is currently named "stopper/CPU". This will eventually replace the
migration thread and take on its name.
* This facility was originally named cpuhog and lived in separate
files but Peter Zijlstra nacked the name and thus got renamed to
cpu_stop and moved into stop_machine.c.
* Better reporting of preemption leak as per Peter's suggestion.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Dimitri Sivanich <sivanich@sgi.com>
When sleep_time is off the function profiler ignores the time that a task
is scheduled out. When the task is scheduled out a timestamp is taken.
When the task is scheduled back in, the timestamp is compared to the
current time and the saved calltimes are adjusted accordingly.
But when stopping the function profiler, the sched switch hook that
does this adjustment was stopped before shutting down the tracer.
This allowed some tasks to not get their timestamps set when they
scheduled out. When the function profiler started again, this would
skew the times of the scheduler functions.
This patch moves the stopping of the sched switch to after the function
profiler is stopped. It also ignores zero set calltimes, which may
happen on start up.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
When combined with function graph tracing the ftrace function profiler
also prints the average run time of functions. While this gives us some
good information, it doesn't tell us anything about the variance of the
run times of the function. This change prints out the s^2 sample
standard deviation alongside the average.
This change adds one entry to the profile record structure. This
increases the memory footprint of the function profiler by 1/3 on a
32-bit system, and by 1/5 on a 64-bit system when function graphing is
enabled, though the memory is only allocated when the profiler is turned
on. During the profiling, one extra line of code adds the squared
calltime to the new record entry, so this should not adversly affect
performance.
Note that the square of the sample standard deviation is printed because
there is no sqrt implementation for unsigned long long in the kernel.
Signed-off-by: Chase Douglas <chase.douglas@canonical.com>
LKML-Reference: <1272304925-2436-1-git-send-email-chase.douglas@canonical.com>
[ fixed comment about ns^2 -> us^2 conversion ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
With the addition of the "missed events" flags that is stored in the
commit field of the ring buffer page, the ring_buffer_benchmark
was not updated to handle this. If events are missed, then the
missed events flag is set in the ring buffer page, the benchmark
will count that flag as part of the size of the page and will hit the BUG()
when it tries to read beyond the page.
The solution is simply to have the ring buffer benchmark mask off
the extra bits.
Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
When performing a non-consuming read, a synchronize_sched() is
performed once for every cpu which is actively tracing.
This is very expensive, and can make it take several seconds to open
up the 'trace' file with lots of cpus.
Only one synchronize_sched() call is actually necessary. What is
desired is for all cpus to see the disabling state change. So we
transform the existing sequence:
for_each_cpu() {
ring_buffer_read_start();
}
where each ring_buffer_start() call performs a synchronize_sched(),
into the following:
for_each_cpu() {
ring_buffer_read_prepare();
}
ring_buffer_read_prepare_sync();
for_each_cpu() {
ring_buffer_read_start();
}
wherein only the single ring_buffer_read_prepare_sync() call needs to
do the synchronize_sched().
The first phase, via ring_buffer_read_prepare(), allocates the 'iter'
memory and increments ->record_disabled.
In the second phase, ring_buffer_read_prepare_sync() makes sure this
->record_disabled state is visible fully to all cpus.
And in the final third phase, the ring_buffer_read_start() calls reset
the 'iter' objects allocated in the first phase since we now know that
none of the cpus are adding trace entries any more.
This makes openning the 'trace' file nearly instantaneous on a
sparc64 Niagara2 box with 128 cpus tracing.
Signed-off-by: David S. Miller <davem@davemloft.net>
LKML-Reference: <20100420.154711.11246950.davem@davemloft.net>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Add function graph output to irqsoff tracer.
The graph output is enabled by setting new 'display-graph' trace option.
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
LKML-Reference: <1270227683-14631-4-git-send-email-jolsa@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Let the function graph tracer have custom flags passed to its
output functions.
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
LKML-Reference: <1270227683-14631-3-git-send-email-jolsa@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Add ftrace events for graph tracer, so the graph output could be shared
with other tracers.
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
LKML-Reference: <1270227683-14631-2-git-send-email-jolsa@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
On ppc64 you get this error:
$ setarch ppc -R true
setarch: ppc: Unrecognized architecture
because uname still reports ppc64 as the machine.
So mask off the personality flags when checking for PER_LINUX32.
Signed-off-by: Andreas Schwab <schwab@linux-m68k.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Issues in the current select_idle_sibling() logic in select_task_rq_fair()
in the context of a task wake-up:
a) Once we select the idle sibling, we use that domain (spanning the cpu that
the task is currently woken-up and the idle sibling that we found) in our
wake_affine() decisions. This domain is completely different from the
domain(we are supposed to use) that spans the cpu that the task currently
woken-up and the cpu where the task previously ran.
b) We do select_idle_sibling() check only for the cpu that the task is
currently woken-up on. If select_task_rq_fair() selects the previously run
cpu for waking the task, doing a select_idle_sibling() check
for that cpu also helps and we don't do this currently.
c) In the scenarios where the cpu that the task is woken-up is busy but
with its HT siblings are idle, we are selecting the task be woken-up
on the idle HT sibling instead of a core that it previously ran
and currently completely idle. i.e., we are not taking decisions based on
wake_affine() but directly selecting an idle sibling that can cause
an imbalance at the SMT/MC level which will be later corrected by the
periodic load balancer.
Fix this by first going through the load imbalance calculations using
wake_affine() and once we make a decision of woken-up cpu vs previously-ran cpu,
then choose a possible idle sibling for waking up the task on.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1270079265.7835.8.camel@sbs-t61.sc.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Dave reported that his large SPARC machines spend lots of time in
hweight64(), try and optimize some of those needless cpumask_weight()
invocations (esp. with the large offstack cpumasks these are very
expensive indeed).
Reported-by: David Miller <davem@davemloft.net>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Chase reported that due to us decrementing calc_load_task prematurely
(before the next LOAD_FREQ sample), the load average could be scewed
by as much as the number of CPUs in the machine.
This patch, based on Chase's patch, cures the problem by keeping the
delta of the CPU going into NO_HZ idle separately and folding that in
on the next LOAD_FREQ update.
This restores the balance and we get strict LOAD_FREQ period samples.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Chase Douglas <chase.douglas@canonical.com>
LKML-Reference: <1271934490.1776.343.camel@laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
creds_are_invalid() reads both cred->usage and cred->subscribers and then
compares them to make sure the number of processes subscribed to a cred struct
never exceeds the refcount of that cred struct.
The problem is that this can cause a race with both copy_creds() and
exit_creds() as the two counters, whilst they are of atomic_t type, are only
atomic with respect to themselves, and not atomic with respect to each other.
This means that if creds_are_invalid() can read the values on one CPU whilst
they're being modified on another CPU, and so can observe an evolving state in
which the subscribers count now is greater than the usage count a moment
before.
Switching the order in which the counts are read cannot help, so the thing to
do is to remove that particular check.
I had considered rechecking the values to see if they're in flux if the test
fails, but I can't guarantee they won't appear the same, even if they've
changed several times in the meantime.
Note that this can only happen if CONFIG_DEBUG_CREDENTIALS is enabled.
The problem is only likely to occur with multithreaded programs, and can be
tested by the tst-eintr1 program from glibc's "make check". The symptoms look
like:
CRED: Invalid credentials
CRED: At include/linux/cred.h:240
CRED: Specified credentials: ffff88003dda5878 [real][eff]
CRED: ->magic=43736564, put_addr=(null)
CRED: ->usage=766, subscr=766
CRED: ->*uid = { 0,0,0,0 }
CRED: ->*gid = { 0,0,0,0 }
CRED: ->security is ffff88003d72f538
CRED: ->security {359, 359}
------------[ cut here ]------------
kernel BUG at kernel/cred.c:850!
...
RIP: 0010:[<ffffffff81049889>] [<ffffffff81049889>] __invalid_creds+0x4e/0x52
...
Call Trace:
[<ffffffff8104a37b>] copy_creds+0x6b/0x23f
Note the ->usage=766 and subscr=766. The values appear the same because
they've been re-read since the check was made.
Reported-by: Roland McGrath <roland@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
The ftrace_dump_on_oops kernel parameter, sysctl and sysrq let one
dump every cpu buffers when an oops or panic happens.
It's nice when you have few cpus but it may take ages if have many,
plus you miss the real origin of the problem in all the cpu traces.
Sometimes, all you need is to dump the cpu buffer that triggered the
opps, most of the time it is our main interest.
This patch modifies ftrace_dump_on_oops to handle this choice.
The ftrace_dump_on_oops kernel parameter, when it comes alone, has
the same behaviour than before. But ftrace_dump_on_oops=orig_cpu
will only dump the buffer of the cpu that oops'ed.
Similarly, sysctl kernel.ftrace_dump_on_oops=1 and
echo 1 > /proc/sys/kernel/ftrace_dump_on_oops keep their previous
behaviour. But setting 2 jumps into cpu origin dump mode.
v2: Fix double setup
v3: Fix spelling issues reported by Randy Dunlap
v4: Also update __ftrace_dump in the selftests
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Patch 570b8fb505896e007fd3bb07573ba6640e51851d:
Author: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Date: Tue Mar 30 00:04:00 2010 +0100
Subject: CRED: Fix memory leak in error handling
attempts to fix a memory leak in the error handling by making the offending
return statement into a jump down to the bottom of the function where a
kfree(tgcred) is inserted.
This is, however, incorrect, as it does a kfree() after doing put_cred() if
security_prepare_creds() fails. That will result in a double free if 'error'
is jumped to as put_cred() will also attempt to free the new tgcred record by
virtue of it being pointed to by the new cred record.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
The lockdep facility temporarily disables lockdep checking by
incrementing the current->lockdep_recursion variable. Such
disabling happens in NMIs and in other situations where lockdep
might expect to recurse on itself.
This patch therefore checks current->lockdep_recursion, disabling RCU
lockdep splats when this variable is non-zero. In addition, this patch
removes the "likely()", as suggested by Lai Jiangshan.
Reported-by: Frederic Weisbecker <fweisbec@gmail.com>
Reported-by: David Miller <davem@davemloft.net>
Tested-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: laijs@cn.fujitsu.com
Cc: dipankar@in.ibm.com
Cc: mathieu.desnoyers@polymtl.ca
Cc: josh@joshtriplett.org
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: peterz@infradead.org
Cc: rostedt@goodmis.org
Cc: Valdis.Kletnieks@vt.edu
Cc: dhowells@redhat.com
Cc: eric.dumazet@gmail.com
LKML-Reference: <20100415195039.GA22623@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
update_avg() is only used for SMP builds, move it to the nearest
SMP block.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
LKML-Reference: <1271309399.14779.17.camel@marge.simson.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
When CONFIG_DEBUG_BLOCK_EXT_DEVT is set we decode the device
improperly by old_decode_dev and it results in an error while
hibernating with s2disk.
All users already pass the new device number, so switch to
new_decode_dev().
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Reported-and-tested-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: "Rafael J. Wysocki" <rjw@sisk.pl>
Steven Rostedt