5508 Commits

Author SHA1 Message Date
Serge E. Hallyn
94d6a5f734 user namespaces: document CFS behavior
Documented the currently bogus state of support for CFS user groups with
user namespaces.  In particular, all users in a user namespace should be
children of the user which created the user namespace.  This is yet to
be implemented.

Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Acked-by: Dhaval Giani <dhaval@linux.vnet.ibm.com>

Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
2008-12-09 09:25:53 +11:00
Ingo Molnar
e726f5f91e tracing/function-graph-tracer: fix 'flags' variable mismatch
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>
2008-12-08 16:55:53 +01:00
Vaidyanathan Srinivasan
efbe027e95 sched: idle_balance() does not call load_balance_newidle()
Impact: fix SD_BALANCE_NEWIDLEand broaden its use

load_balance_newidle() does not get called if SD_BALANCE_NEWIDLE is
set at higher level domain (3-CPU) and not in low level domain (2-MC).

pulled_task is initialised to -1 and checked for non-zero which is
always true if the lowest level sched_domain does not have
SD_BALANCE_NEWIDLE flag set.

Signed-off-by: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-12-08 16:48:00 +01:00
Frederic Weisbecker
380c4b1411 tracing/function-graph-tracer: append the tracing_graph_flag
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>
2008-12-08 15:11:45 +01:00
Frederic Weisbecker
8e1b82e086 tracing/function-graph-tracer: turn tracing_selftest_running into an int
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>
2008-12-08 15:11:44 +01:00
Frederic Weisbecker
8b96f01198 tracing/function-graph-tracer: introduce __notrace_funcgraph to filter special functions
Impact: trace more functions

When the function graph tracer is configured, three more files are not
traced to prevent only four functions to be traced. And this impacts the
normal function tracer too.

arch/x86/kernel/process_64/32.c:

I had crashes when I let this file traced. After some debugging, I saw
that the "current" task point was changed inside__swtich_to(), ie:
"write_pda(pcurrent, next_p);" inside process_64.c Since the tracer store
the original return address of the function inside current, we had
crashes. Only __switch_to() has to be excluded from tracing.

kernel/module.c and kernel/extable.c:

Because of a function used internally by the function graph tracer:
__kernel_text_address()

To let the other functions inside these files to be traced, this patch
introduces the __notrace_funcgraph function prefix which is __notrace if
function graph tracer is configured and nothing if not.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-12-08 15:11:44 +01:00
Ken Chen
5436499e60 sched: fix sd_parent_degenerate on non-numa smp machine
Impact: optimize the sched domains tree some more

The addition of SD_SERIALIZE flag added to SD_NODE_INIT prevented top level
dummy numa sched_domain to be properly degenerated on non-numa smp machine.
The reason is that in sd_parent_degenerate(), it found that the child and
parent does not have comon sched_domain flags due to SD_SERIALIZE.  However,
for non-numa smp box, the top level is a dummy with a single sched_group.

Filter out SD_SERIALIZE if it is on non-numa machine to properly degenerate
top level node sched_domain.  this will cut back some of the sd domain walk
in the load balancer code.

Signed-off-by: Ken Chen <kenchen@google.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-12-08 13:52:44 +01:00
Ingo Molnar
4d117c5c6b Merge branch 'sched/urgent' into sched/core 2008-12-08 13:52:00 +01:00
Frederic Weisbecker
decbec3838 tracing/function-graph-tracer: implement a print_headers function
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>
2008-12-08 13:24:52 +01:00
Serge E. Hallyn
7657d90497 user namespaces: require cap_set{ug}id for CLONE_NEWUSER
While ideally CLONE_NEWUSER will eventually require no
privilege, the required permission checks are currently
not there.  As a result, CLONE_NEWUSER has the same effect
as a setuid(0)+setgroups(1,"0").  While we already require
CAP_SYS_ADMIN, requiring CAP_SETUID and CAP_SETGID seems
appropriate.

Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: James Morris <jmorris@namei.org>
2008-12-08 09:16:27 +11:00
Serge E. Hallyn
c37bbb0fdc user namespaces: let user_ns be cloned with fairsched
(These two patches are in the next-unacked branch of
git://git.kernel.org/pub/scm/linux/kernel/git/sergeh/userns-2.6.
If they get some ACKs, then I hope to feed this into security-next.
After these two, I think we're ready to tackle userns+capabilities)

Fairsched creates a per-uid directory under /sys/kernel/uids/.
So when you clone(CLONE_NEWUSER), it tries to create
/sys/kernel/uids/0, which already exists, and you get back
-ENOMEM.

This was supposed to be fixed by sysfs tagging, but that
was postponed (ok, rejected until sysfs locking is fixed).
So, just as with network namespaces, we just don't create
those directories for user namespaces other than the init.

Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
2008-12-08 09:16:22 +11:00
Steven Rostedt
21bbecdaae ftrace: use init_struct_pid as swapper pid
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>
2008-12-05 14:51:29 +01:00
Frederic Weisbecker
21a8c466f9 tracing/ftrace: provide the macro task_curr_ret_stack()
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>
2008-12-05 14:47:44 +01:00
Frederic Weisbecker
77d683f3e0 tracing/ftrace: fix the check of ftrace_trace_task
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>
2008-12-05 14:47:43 +01:00
Frederic Weisbecker
ff32504fdc tracing/ftrace: don't insert TRACE_PRINT during selftests
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>
2008-12-05 14:47:43 +01:00
Ingo Molnar
970987beb9 Merge branches 'tracing/ftrace', 'tracing/function-graph-tracer' and 'tracing/urgent' into tracing/core 2008-12-05 14:45:22 +01:00
Linus Torvalds
bbeba4c35c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/bdev
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/bdev:
  [PATCH] fix bogus argument of blkdev_put() in pktcdvd
  [PATCH 2/2] documnt FMODE_ constants
  [PATCH 1/2] kill FMODE_NDELAY_NOW
  [PATCH] clean up blkdev_get a little bit
  [PATCH] Fix block dev compat ioctl handling
  [PATCH] kill obsolete temporary comment in swsusp_close()
2008-12-04 21:45:44 -08:00
Linus Torvalds
4857339d7c Merge branch 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  time: catch xtime_nsec underflows and fix them
  posix-cpu-timers: fix clock_gettime with CLOCK_PROCESS_CPUTIME_ID
2008-12-04 21:40:29 -08:00
Linus Torvalds
3b666ce6a2 Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  check_hung_task(): unsigned sysctl_hung_task_warnings cannot be less than 0
  documentation: local_ops fix on_each_cpu
2008-12-04 21:39:41 -08:00
Al Viro
50c396d38c [PATCH] kill obsolete temporary comment in swsusp_close()
it had been put there to mark the call of blkdev_put() that
needed proper argument propagated to it; later patch in the
same series had done just that.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-12-04 04:22:54 -05:00
Frederic Weisbecker
1fd8f2a3f9 tracing/function-graph-tracer: handle ftrace_printk entries
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>
2008-12-04 10:18:39 +01:00
Liming Wang
faec2ec505 ftrace: avoid duplicated function when writing set_graph_function
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>
2008-12-04 09:42:35 +01:00
Ingo Molnar
6b2539302b tracing: fix typo and missing inline function
Impact: fix build bugs

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-12-04 09:33:01 +01:00
Steven Rostedt
e32d895691 ftrace: add ability to only trace swapper tasks
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>
2008-12-04 09:09:38 +01:00
Steven Rostedt
978f3a45d9 ftrace: use struct pid
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>
2008-12-04 09:09:37 +01:00
Steven Rostedt
804a685162 ftrace: trace single pid for function graph tracer
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>
2008-12-04 09:09:36 +01:00
Steven Rostedt
0ef8cde56a ftrace: use task struct trace flag to filter on pid
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>
2008-12-04 09:09:35 +01:00
Steven Rostedt
ea4e2bc4d9 ftrace: graph of a single function
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>
2008-12-04 09:09:34 +01:00
Ingo Molnar
b29144c317 Merge branches 'tracing/ftrace' and 'tracing/function-graph-tracer' into tracing/core 2008-12-04 09:07:44 +01:00
Ingo Molnar
b8307db247 Merge commit 'v2.6.28-rc7' into tracing/core 2008-12-04 09:07:19 +01:00
john stultz
6c9bacb41c time: catch xtime_nsec underflows and fix them
Impact: fix time warp bug

Alex Shi, along with Yanmin Zhang have been noticing occasional time
inconsistencies recently. Through their great diagnosis, they found that
the xtime_nsec value used in update_wall_time was occasionally going
negative. After looking through the code for awhile, I realized we have
the possibility for an underflow when three conditions are met in
update_wall_time():

  1) We have accumulated a second's worth of nanoseconds, so we
     incremented xtime.tv_sec and appropriately decrement xtime_nsec.
     (This doesn't cause xtime_nsec to go negative, but it can cause it
      to be small).

  2) The remaining offset value is large, but just slightly less then
     cycle_interval.

  3) clocksource_adjust() is speeding up the clock, causing a
     corrective amount (compensating for the increase in the multiplier
     being multiplied against the unaccumulated offset value) to be
     subtracted from xtime_nsec.

This can cause xtime_nsec to underflow.

Unfortunately, since we notify the NTP subsystem via second_overflow()
whenever we accumulate a full second, and this effects the error
accumulation that has already occured, we cannot simply revert the
accumulated second from xtime nor move the second accumulation to after
the clocksource_adjust call without a change in behavior.

This leaves us with (at least) two options:

1) Simply return from clocksource_adjust() without making a change if we
   notice the adjustment would cause xtime_nsec to go negative.

This would work, but I'm concerned that if a large adjustment was needed
(due to the error being large), it may be possible to get stuck with an
ever increasing error that becomes too large to correct (since it may
always force xtime_nsec negative). This may just be paranoia on my part.

2) Catch xtime_nsec if it is negative, then add back the amount its
   negative to both xtime_nsec and the error.

This second method is consistent with how we've handled earlier rounding
issues, and also has the benefit that the error being added is always in
the oposite direction also always equal or smaller then the correction
being applied. So the risk of a corner case where things get out of
control is lessened.

This patch fixes bug 11970, as tested by Yanmin Zhang
http://bugzilla.kernel.org/show_bug.cgi?id=11970

Reported-by: alex.shi@intel.com
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Acked-by: "Zhang, Yanmin" <yanmin_zhang@linux.intel.com>
Tested-by: "Zhang, Yanmin" <yanmin_zhang@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-12-04 08:43:02 +01:00
James Morris
ec98ce480a Merge branch 'master' into next
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>
2008-12-04 17:16:36 +11:00
Steven Rostedt
e8e1abe92f ftrace: fix race in function graph during fork
Impact: graph tracer race/crash fix

There is a nasy race in startup of a new process running the
function graph tracer. In fork.c:

	total_forks++;
	spin_unlock(&current->sighand->siglock);
	write_unlock_irq(&tasklist_lock);
	ftrace_graph_init_task(p);
	proc_fork_connector(p);
	cgroup_post_fork(p);
	return p;

The new task is free to run as soon as the tasklist_lock is released.
This is before the ftrace_graph_init_task. If the task does run
it will be using the same ret_stack and curr_ret_stack as the parent.
This will cause crashes that are difficult to debug.

This patch moves the ftrace_graph_init_task to just after the alloc_pid
code. This fixes the above race.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-12-03 17:15:03 +01:00
Steven Rostedt
0a37119d96 trace: fix output of stack trace
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>
2008-12-03 17:15:02 +01:00
Ingo Molnar
764f3b9513 tracing/function-graph-tracer: enabled by default
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>
2008-12-03 10:33:58 +01:00
Roel Kluin
201955463a check_hung_task(): unsigned sysctl_hung_task_warnings cannot be less than 0
Impact: fix warnings-limit cutoff check for debug feature

unsigned sysctl_hung_task_warnings cannot be less than 0

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-12-03 10:11:51 +01:00
Frederic Weisbecker
166d3c7994 tracing/function-graph-tracer: improve duration output
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>
2008-12-03 09:09:42 +01:00
Frederic Weisbecker
11e84acc40 tracing/function-graph-tracer: display unified style cmdline and pid
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>
2008-12-03 09:09:41 +01:00
Steven Rostedt
e49dc19c6a ftrace: function graph return for function entry
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>
2008-12-03 08:56:26 +01:00
Steven Rostedt
044fa782eb ring-buffer: change "page" variable names to "bpage"
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>
2008-12-03 08:56:24 +01:00
Steven Rostedt
14a866c567 ftrace: add ftrace_graph_stop()
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>
2008-12-03 08:56:23 +01:00
Steven Rostedt
8789a9e7df ring-buffer: read page interface
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>
2008-12-03 08:56:21 +01:00
Steven Rostedt
abc9b56d66 ring-buffer: move some metadata into buffer page
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>
2008-12-03 08:56:20 +01:00
Steven Rostedt
a5e25883a4 ftrace: replace raw_local_irq_save with local_irq_save
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>
2008-12-03 08:56:19 +01:00
Ingo Molnar
dfdc5437bd Merge commit 'v2.6.28-rc7'; branch 'x86/dumpstack' into tracing/ftrace
Merge x86/dumpstack into tracing/ftrace because upcoming ftrace changes
depend on cleanups already in x86/dumpstack.

Also merge to latest upstream -rc.
2008-12-03 08:55:34 +01:00
Ingo Molnar
f0461d0146 Merge branches 'tracing/ftrace' and 'tracing/function-graph-tracer' into tracing/core 2008-12-03 08:49:21 +01:00
Frederic Weisbecker
48d68b20d0 tracing/function-graph-tracer: support for x86-64
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>
2008-12-02 09:47:48 +01:00
Liming Wang
66eafebc10 function trace: fix a bug of single thread function trace
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>
2008-12-02 09:23:24 +01:00
Ingo Molnar
222658e08f Merge branches 'tracing/branch-tracer', 'tracing/ftrace', 'tracing/function-graph-tracer', 'tracing/markers', 'tracing/powerpc', 'tracing/stack-tracer' and 'tracing/tracepoints' into tracing/core 2008-12-02 09:20:44 +01:00
Arjan van de Ven
a800599283 taint: add missing comment
The description for 'D' was missing in the comment...  (causing me a
minute of WTF followed by looking at more of the code)

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-12-01 19:55:24 -08:00