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Commit Graph

119921 Commits

Author SHA1 Message Date
Frederic Weisbecker
da485e0cb1 tracing/fastboot: include missing headers
For now include/trace/boot.h doesn't need to include necessary headers
for its functions and structures because the files that include it already
do it.

But boot.h could be needed as well for further uses on other files.
So, this patch adds the necessary headers for future purposes...

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-12-12 09:26:13 +01:00
Stephen Rothwell
8001530d5a tracing/fastboot: fix len of func buffer
Impact: fix possible stack overrun

This is a port of a patch included in the mainline (KSYM_SYMBOL_LEN fixes).
The current func len is not large enough to contain the max symbol len, the
right size must be KSYM_SYMBOL_LEN.

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-12-12 09:26:12 +01:00
Ingo Molnar
f3134de606 Merge branches 'tracing/function-graph-tracer' and 'tracing/ring-buffer' into tracing/core 2008-12-12 07:40:08 +01:00
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
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
Lai Jiangshan
361b73d5c3 ring_buffer: fix comments
Impact: comments cleanup

fix incorrect comments for enum ring_buffer_type

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-12-08 13:54:05 +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
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
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
5ef6476190 pid: fix the do_each_pid_task() macro
Impact: macro side-effects fix

This patch adds parenthesis around 'pid' in the do_each_pid_task
macro to allow callers to pass in more complex parameters.

e.g.  do_each_pid_task(*pid, type, task)

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
Linus Torvalds
feaf3848a8 Merge branch 'for-linus' of git://git.kernel.dk/linux-2.6-block
* 'for-linus' of git://git.kernel.dk/linux-2.6-block:
  block: fix setting of max_segment_size and seg_boundary mask
  block: internal dequeue shouldn't start timer
  block: set disk->node_id before it's being used
  When block layer fails to map iov, it calls bio_unmap_user to undo
2008-12-03 16:45:56 -08:00
Linus Torvalds
a771132783 Merge branch 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc
* 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc:
  powerpc/83xx: Fix MCU support merge issue in mpc8349emitx.dts
  powerpc: Fix dma_map_sg() cache flushing on non coherent platforms
2008-12-03 16:41:15 -08:00
Linus Torvalds
2433c41789 Merge branch 'for-2.6.28' of git://linux-nfs.org/~bfields/linux
* 'for-2.6.28' of git://linux-nfs.org/~bfields/linux:
  NLM: client-side nlm_lookup_host() should avoid matching on srcaddr
  nfsd: use of unitialized list head on error exit in nfs4recover.c
  Add a reference to sunrpc in svc_addsock
  nfsd: clean up grace period on early exit
2008-12-03 16:40:37 -08:00
Linus Torvalds
cd92a17eec iTCO_wdt: fix typo when setting TCO_EN bit
The code used '&= 0x00002000' when it tried to set the TCO_EN bit, which
obviously didn't set that bit at all, but instead just reset all the
other bits in the SMI_EN register.

This bug seemingly caused various random behavior, with Frans Pop
reporting that X.org just silently hung at startup and Rafael Wysocki
reports the fan spinning with full speed.

See
	http://lkml.org/lkml/2008/12/3/178
	http://bugzilla.kernel.org/show_bug.cgi?id=12162

The problem seems to have been triggered by "[WATCHDOG] iTCO_wdt :
problem with rebooting on new ICH9 based motherboards" (commit
7cd5b08be3), but the bogus code existed
before that too (in the "supermicro_old_pre_stop()" function), it just
apparently never showed up due to different logic.

In that commit the broken code got moved around and now gets executed
much more.

Reported-by: Rafael J. Wysocki <rjw@sisk.pl>
Tested-by: Frans Pop <elendil@planet.nl>
Cc: Wim Van Sebroeck <wim@iguana.be>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-12-03 16:20:19 -08:00
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
Anton Vorontsov
dafdb61313 powerpc/83xx: Fix MCU support merge issue in mpc8349emitx.dts
Just found the merge issue in 442746989d
("powerpc/83xx: Add support for MCU microcontroller in .dts files"):
the commit adds the MCU controller node into the DMA node, which is
wrong because the MCU sits on the I2C bus. Fix this by moving the MCU
node into the I2C controller node.

The original patch[1] was OK though. ;-)

Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
2008-12-03 09:56:02 -06:00
Milan Broz
0e435ac26e block: fix setting of max_segment_size and seg_boundary mask
Fix setting of max_segment_size and seg_boundary mask for stacked md/dm
devices.

When stacking devices (LVM over MD over SCSI) some of the request queue
parameters are not set up correctly in some cases by default, namely
max_segment_size and and seg_boundary mask.

If you create MD device over SCSI, these attributes are zeroed.

Problem become when there is over this mapping next device-mapper mapping
- queue attributes are set in DM this way:

request_queue   max_segment_size  seg_boundary_mask
SCSI                65536             0xffffffff
MD RAID1                0                      0
LVM                 65536                 -1 (64bit)

Unfortunately bio_add_page (resp.  bio_phys_segments) calculates number of
physical segments according to these parameters.

During the generic_make_request() is segment cout recalculated and can
increase bio->bi_phys_segments count over the allowed limit.  (After
bio_clone() in stack operation.)

Thi is specially problem in CCISS driver, where it produce OOPS here

    BUG_ON(creq->nr_phys_segments > MAXSGENTRIES);

(MAXSEGENTRIES is 31 by default.)

Sometimes even this command is enough to cause oops:

  dd iflag=direct if=/dev/<vg>/<lv> of=/dev/null bs=128000 count=10

This command generates bios with 250 sectors, allocated in 32 4k-pages
(last page uses only 1024 bytes).

For LVM layer, it allocates bio with 31 segments (still OK for CCISS),
unfortunatelly on lower layer it is recalculated to 32 segments and this
violates CCISS restriction and triggers BUG_ON().

The patch tries to fix it by:

 * initializing attributes above in queue request constructor
   blk_queue_make_request()

 * make sure that blk_queue_stack_limits() inherits setting

 (DM uses its own function to set the limits because it
 blk_queue_stack_limits() was introduced later.  It should probably switch
 to use generic stack limit function too.)

 * sets the default seg_boundary value in one place (blkdev.h)

 * use this mask as default in DM (instead of -1, which differs in 64bit)

Bugs related to this:
https://bugzilla.redhat.com/show_bug.cgi?id=471639
http://bugzilla.kernel.org/show_bug.cgi?id=8672

Signed-off-by: Milan Broz <mbroz@redhat.com>
Reviewed-by: Alasdair G Kergon <agk@redhat.com>
Cc: Neil Brown <neilb@suse.de>
Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Tejun Heo <htejun@gmail.com>
Cc: Mike Miller <mike.miller@hp.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-12-03 12:55:55 +01:00
Tejun Heo
53a08807c0 block: internal dequeue shouldn't start timer
blkdev_dequeue_request() and elv_dequeue_request() are equivalent and
both start the timeout timer.  Barrier code dequeues the original
barrier request but doesn't passes the request itself to lower level
driver, only broken down proxy requests; however, as the original
barrier code goes through the same dequeue path and timeout timer is
started on it.  If barrier sequence takes long enough, this timer
expires but the low level driver has no idea about this request and
oops follows.

Timeout timer shouldn't have been started on the original barrier
request as it never goes through actual IO.  This patch unexports
elv_dequeue_request(), which has no external user anyway, and makes it
operate on elevator proper w/o adding the timer and make
blkdev_dequeue_request() call elv_dequeue_request() and add timer.
Internal users which don't pass the request to driver - barrier code
and end_that_request_last() - are converted to use
elv_dequeue_request().

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Mike Anderson <andmike@linux.vnet.ibm.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-12-03 12:41:26 +01:00
Cheng Renquan
bf91db18ac block: set disk->node_id before it's being used
disk->node_id will be refered in allocating in disk_expand_part_tbl, so we
should set it before disk->node_id is refered.

Signed-off-by: Cheng Renquan <crquan@gmail.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-12-03 12:41:20 +01:00
Petr Vandrovec
53cc0b2948 When block layer fails to map iov, it calls bio_unmap_user to undo
mapping.  Which is good if pages were mapped - but if they were provided
by someone else and just copied then bad things happen - pages are
released once here, and once by caller, leading to user triggerable BUG
at include/linux/mm.h:246.

Signed-off-by: Petr Vandrovec <petr@vandrovec.name>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-12-03 12:41:20 +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
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
62679efe0a ftrace: add checks on ret stack in function graph
Import: robustness checks

Add more checks in the function graph code to detect errors and
perhaps print out better information if a bug happens.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-12-03 08:56:27 +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
7ee991fbc6 ftrace: print real return in dumpstack for function graph
Impact: better dumpstack output

I noticed in my crash dumps and even in the stack tracer that a
lot of functions listed in the stack trace are simply
return_to_handler which is ftrace graphs way to insert its own
call into the return of a function.

But we lose out where the actually function was called from.

This patch adds in hooks to the dumpstack mechanism that detects
this and finds the real function to print. Both are printed to
let the user know that a hook is still in place.

This does give a funny side effect in the stack tracer output:

        Depth   Size      Location    (80 entries)
        -----   ----      --------
  0)     4144      48   save_stack_trace+0x2f/0x4d
  1)     4096     128   ftrace_call+0x5/0x2b
  2)     3968      16   mempool_alloc_slab+0x16/0x18
  3)     3952     384   return_to_handler+0x0/0x73
  4)     3568    -240   stack_trace_call+0x11d/0x209
  5)     3808     144   return_to_handler+0x0/0x73
  6)     3664    -128   mempool_alloc+0x4d/0xfe
  7)     3792     128   return_to_handler+0x0/0x73
  8)     3664     -32   scsi_sg_alloc+0x48/0x4a [scsi_mod]

As you can see, the real functions are now negative. This is due
to them not being found inside the stack.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-12-03 08:56:25 +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
bb4304c71c ftrace: have function graph use mcount caller address
Impact: consistency change for function graph

This patch makes function graph record the mcount caller address
the same way the function tracer does.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-12-03 08:56:22 +01:00
Steven Rostedt
347fdd9dd4 ftrace: clean up function graph asm
Impact: clean up

There exists macros for x86 asm to handle x86_64 and i386.
This patch updates function graph asm to use them.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-12-03 08:56:21 +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