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  1. 01 Feb, 2013 1 commit
    • Steven Rostedt (Red Hat)'s avatar
      tracing: Init current_trace to nop_trace and remove NULL checks · d840f718
      Steven Rostedt (Red Hat) authored 
      On early boot up, when the ftrace ring buffer is initialized, the
static variable current_trace is initialized to &nop_trace.
Before this initialization, current_trace is NULL and will never
become NULL again. It is always reassigned to a ftrace tracer.

Several places check if current_trace is NULL before it uses
it, and this check is frivolous, because at the point in time
when the checks are made the only way current_trace could be
NULL is if ftrace failed its allocations at boot up, and the
paths to these locations would probably not be possible.

By initializing current_trace to &nop_trace where it is declared,
current_trace will never be NULL, and we can remove all these
checks of current_trace being NULL which never needed to be
checked in the first place.

Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Hiraku Toyooka <hiraku.toyooka.gu@hitachi.com>
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      d840f718
  3. 30 Jan, 2013 5 commits
  5. 29 Jan, 2013 2 commits
    • Steven Rostedt (Red Hat)'s avatar
      tracing/fgraph: Adjust fgraph depth before calling trace return callback · 03274a3f
      Steven Rostedt (Red Hat) authored 
      While debugging the virtual cputime with the function graph tracer
with a max_depth of 1 (most common use of the max_depth so far),
I found that I was missing kernel execution because of a race condition.

The code for the return side of the function has a slight race:

	ftrace_pop_return_trace(&trace, &ret, frame_pointer);
	trace.rettime = trace_clock_local();
	ftrace_graph_return(&trace);
	barrier();
	current->curr_ret_stack--;

The ftrace_pop_return_trace() initializes the trace structure for
the callback. The ftrace_graph_return() uses the trace structure
for its own use as that structure is on the stack and is local
to this function. Then the curr_ret_stack is decremented which
is what the trace.depth is set to.

If an interrupt comes in after the ftrace_graph_return() but
before the curr_ret_stack, then the called function will get
a depth of 2. If max_depth is set to 1 this function will be
ignored.

The problem is that the trace has already been called, and the
timestamp for that trace will not reflect the time the function
was about to re-enter userspace. Calls to the interrupt will not
be traced because the max_depth has prevented this.

To solve this issue, the ftrace_graph_return() can safely be
moved after the current->curr_ret_stack has been updated.
This way the timestamp for the return callback will reflect
the actual time.

If an interrupt comes in after the curr_ret_stack update and
ftrace_graph_return(), it will be traced. It may look a little
confusing to see it within the other function, but at least
it will not be lost.

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      03274a3f
    • Jovi Zhang's avatar
      tracing: Remove second iterator initializer · 38dbe0b1
      Jovi Zhang authored 
      The trace iterator is already initialized by trace_init_global_iter(),
so there is no need to initialize it again.

Link: http://lkml.kernel.org/r/CACV3sb+G1YnO6168JhY3dEadmJi58pA5-2cSZT8E0WVHJNFt9Q@mail.gmail.comSigned-off-by: default avatarJovi Zhang <bookjovi@gmail.com>
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      38dbe0b1
  7. 26 Jan, 2013 1 commit
  9. 25 Jan, 2013 2 commits
  11. 24 Jan, 2013 10 commits
  13. 23 Jan, 2013 19 commits
    • Greg Kroah-Hartman's avatar
      MAINTAINERS: Someone needs to watch over the serial drivers · 5e30bbb7
      Greg Kroah-Hartman authored 
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      5e30bbb7
    • Linus Torvalds's avatar
      Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/geert/linux-m68k · 248152b6
      Linus Torvalds authored 
      Pull m68k fixes from Geert Uytterhoeven:
 "The asm-generic changeset has been ack'ed by Arnd."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/geert/linux-m68k:
  m68k: Wire up finit_module
  asm-generic/dma-mapping-broken.h: Provide dma_alloc_attrs()/dma_free_attrs()
  m68k: Provide dma_alloc_attrs()/dma_free_attrs()
      248152b6
    • Linus Torvalds's avatar
      Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/cmarinas/linux-aarch64 · c1b84144
      Linus Torvalds authored 
      Pull arm64 fixes from Catalin Marinas:
 - ELF coredump fix (more registers dumped than what user space expects)
 - SUBARCH name generation (s/aarch64/arm64/)

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/cmarinas/linux-aarch64:
  arm64: makefile: fix uname munging when setting ARCH on native machine
  arm64: elf: fix core dumping to match what glibc expects
      c1b84144
    • Alan Stern's avatar
      USB: EHCI: fix build error in ehci-mxc · dba63b2f
      Alan Stern authored 
      This patch (as1643b) fixes a build error in ehci-hcd when compiling for
ARM with allmodconfig:

drivers/usb/host/ehci-hcd.c:1285:0: warning: "PLATFORM_DRIVER" redefined [enabled by default]
drivers/usb/host/ehci-hcd.c:1255:0: note: this is the location of the previous definition
drivers/usb/host/ehci-mxc.c:280:31: warning: 'ehci_mxc_driver' defined but not used [-Wunused-variable]
drivers/usb/host/ehci-hcd.c:1285:0: warning: "PLATFORM_DRIVER" redefined [enabled by default]
drivers/usb/host/ehci-hcd.c:1255:0: note: this is the location of the previous definition

The fix is to convert ehci-mxc over to the new "ehci-hcd is a library"
scheme so that it can coexist peacefully with the ehci-platform
driver.  As part of the conversion the ehci_mxc_priv data structure,
which was allocated dynamically, is now placed where it belongs: in
the private area at the end of struct ehci_hcd.
Signed-off-by: default avatarAlan Stern <stern@rowland.harvard.edu>
Tested-by: default avatarShawn Guo <shawn.guo@linaro.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      dba63b2f
    • Linus Torvalds's avatar
      Merge tag 'sound-3.8' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound · db233669
      Linus Torvalds authored 
      Pull sound fixes from Takashi Iwai:
 "Only a few small HD-audio fixes:
   - Addition of new Conexant codec IDs
   - Two one-liners to add fixups for Realtek codecs
   - A last-minute regression fix for auto-mute with power-saving mode
     (regressed since 3.8-rc1)"

* tag 'sound-3.8' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
  ALSA: hda - Fix inconsistent pin states after resume
  ALSA: hda - Add Conexant CX20755/20756/20757 codec IDs
  ALSA: hda - Add fixup for Acer AO725 laptop
  ALSA: hda - Fix mute led for another HP machine
      db233669
    • Alan Cox's avatar
      MAINTAINERS: remove me · 6d26b3a1
      Alan Cox authored 
      Signed-off-by: default avatarAlan Cox <alan@linux.intel.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      6d26b3a1
    • Takashi Iwai's avatar
      ALSA: hda - Fix inconsistent pin states after resume · 31614bb8
      Takashi Iwai authored 
      The commit [26a6cb6c: ALSA: hda - Implement a poll loop for jacks as a
module parameter] introduced the polling jack detection code, but it
also moved the call of snd_hda_jack_set_dirty_all() in the resume path
after resume/init ops call.  This caused a regression when the jack
state has been changed during power-down (e.g. in the power save
mode).  Since the driver doesn't probe the new jack state but keeps
using the cached value due to no dirty flag, the pin state remains
also as if the jack is still plugged.

The fix is simply moving snd_hda_jack_set_dirty_all() to the original
position.
Reported-by: default avatarManolo Díaz <diaz.manolo@gmail.com>
Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
      31614bb8
    • Steven Rostedt's avatar
      ring-buffer: Remove trace.h from ring_buffer.c · 0b07436d
      Steven Rostedt authored 
      ring_buffer.c use to require declarations from trace.h, but
these have moved to the generic header files. There's nothing
in trace.h that ring_buffer.c requires.

There's some headers that trace.h included that ring_buffer.c
needs, but it's best that it includes them directly, and not
include trace.h.

Also, some things may use ring_buffer.c without having tracing
configured. This removes the dependency that may come in the
future.
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      0b07436d
    • Steven Rostedt's avatar
      ring-buffer: User context bit recursion checking · 567cd4da
      Steven Rostedt authored 
      Using context bit recursion checking, we can help increase the
performance of the ring buffer.

Before this patch:

 # echo function > /debug/tracing/current_tracer
 # for i in `seq 10`; do ./hackbench 50; done
Time: 10.285
Time: 10.407
Time: 10.243
Time: 10.372
Time: 10.380
Time: 10.198
Time: 10.272
Time: 10.354
Time: 10.248
Time: 10.253

(average: 10.3012)

Now we have:

 # echo function > /debug/tracing/current_tracer
 # for i in `seq 10`; do ./hackbench 50; done
Time: 9.712
Time: 9.824
Time: 9.861
Time: 9.827
Time: 9.962
Time: 9.905
Time: 9.886
Time: 10.088
Time: 9.861
Time: 9.834

(average: 9.876)

 a 4% savings!
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      567cd4da
    • Steven Rostedt's avatar
      ftrace: Use only the preempt version of function tracing · 897f68a4
      Steven Rostedt authored 
      The function tracer had two different versions of function tracing.

The disabling of irqs version and the preempt disable version.

As function tracing in very intrusive and can cause nasty recursion
issues, it has its own recursion protection. But the old method to
do this was a flat layer. If it detected that a recursion was happening
then it would just return without recording.

This made the preempt version (much faster than the irq disabling one)
not very useful, because if an interrupt were to occur after the
recursion flag was set, the interrupt would not be traced at all,
because every function that was traced would think it recursed on
itself (due to the context it preempted setting the recursive flag).

Now that we have a recursion flag for every context level, we
no longer need to worry about that. We can disable preemption,
set the current context recursion check bit, and go on. If an
interrupt were to come along, it would check its own context bit
and happily continue to trace.

As the preempt version is faster than the irq disable version,
there's no more reason to keep the preempt version around.
And the irq disable version still had an issue with missing
out on tracing NMI code.

Remove the irq disable function tracer version and have the
preempt disable version be the default (and only version).

Before this patch we had from running:

 # echo function > /debug/tracing/current_tracer
 # for i in `seq 10`; do ./hackbench 50; done
Time: 12.028
Time: 11.945
Time: 11.925
Time: 11.964
Time: 12.002
Time: 11.910
Time: 11.944
Time: 11.929
Time: 11.941
Time: 11.924

(average: 11.9512)

Now we have:

 # echo function > /debug/tracing/current_tracer
 # for i in `seq 10`; do ./hackbench 50; done
Time: 10.285
Time: 10.407
Time: 10.243
Time: 10.372
Time: 10.380
Time: 10.198
Time: 10.272
Time: 10.354
Time: 10.248
Time: 10.253

(average: 10.3012)

 a 13.8% savings!
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      897f68a4
    • Steven Rostedt's avatar
      tracing: Avoid unnecessary multiple recursion checks · edc15caf
      Steven Rostedt authored 
      When function tracing occurs, the following steps are made:
  If arch does not support a ftrace feature:
   call internal function (uses INTERNAL bits) which calls...
  If callback is registered to the "global" list, the list
   function is called and recursion checks the GLOBAL bits.
   then this function calls...
  The function callback, which can use the FTRACE bits to
   check for recursion.

Now if the arch does not suppport a feature, and it calls
the global list function which calls the ftrace callback
all three of these steps will do a recursion protection.
There's no reason to do one if the previous caller already
did. The recursion that we are protecting against will
go through the same steps again.

To prevent the multiple recursion checks, if a recursion
bit is set that is higher than the MAX bit of the current
check, then we know that the check was made by the previous
caller, and we can skip the current check.
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      edc15caf
    • Steven Rostedt's avatar
      tracing: Make the trace recursion bits into enums · e46cbf75
      Steven Rostedt authored 
      Convert the bits into enums which makes the code a little easier
to maintain.
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      e46cbf75
    • Steven Rostedt's avatar
      ftrace: Add context level recursion bit checking · c29f122c
      Steven Rostedt authored 
      Currently for recursion checking in the function tracer, ftrace
tests a task_struct bit to determine if the function tracer had
recursed or not. If it has, then it will will return without going
further.

But this leads to races. If an interrupt came in after the bit
was set, the functions being traced would see that bit set and
think that the function tracer recursed on itself, and would return.

Instead add a bit for each context (normal, softirq, irq and nmi).

A check of which context the task is in is made before testing the
associated bit. Now if an interrupt preempts the function tracer
after the previous context has been set, the interrupt functions
can still be traced.
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      c29f122c
    • Steven Rostedt's avatar
      ftrace: Optimize the function tracer list loop · 0a016409
      Steven Rostedt authored 
      There is lots of places that perform:

       op = rcu_dereference_raw(ftrace_control_list);
       while (op != &ftrace_list_end) {

Add a helper macro to do this, and also optimize for a single
entity. That is, gcc will optimize a loop for either no iterations
or more than one iteration. But usually only a single callback
is registered to the function tracer, thus the optimized case
should be a single pass. to do this we now do:

	op = rcu_dereference_raw(list);
	do {
		[...]
	} while (likely(op = rcu_dereference_raw((op)->next)) &&
	       unlikely((op) != &ftrace_list_end));

An op is always registered (ftrace_list_end when no callbacks is
registered), thus when a single callback is registered, the link
list looks like:

 top => callback => ftrace_list_end => NULL.

The likely(op = op->next) still must be performed due to the race
of removing the callback, where the first op assignment could
equal ftrace_list_end. In that case, the op->next would be NULL.
But this is unlikely (only happens in a race condition when
removing the callback).

But it is very likely that the next op would be ftrace_list_end,
unless more than one callback has been registered. This tells
gcc what the most common case is and makes the fast path with
the least amount of branches.
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      0a016409
    • Steven Rostedt's avatar
      ftrace: Fix function tracing recursion self test · 9640388b
      Steven Rostedt authored 
      The function tracing recursion self test should not crash
the machine if the resursion test fails. If it detects that
the function tracing is recursing when it should not be, then
bail, don't go into an infinite recursive loop.
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      9640388b
    • Steven Rostedt's avatar
      ftrace: Fix global function tracers that are not recursion safe · 63503794
      Steven Rostedt authored 
      If one of the function tracers set by the global ops is not recursion
safe, it can still be called directly without the added recursion
supplied by the ftrace infrastructure.
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      63503794
    • Steven Rostedt's avatar
      tracing: Fix selftest function recursion accounting · 05cbbf64
      Steven Rostedt authored 
      The test that checks function recursion does things differently
if the arch does not support all ftrace features. But that really
doesn't make a difference with how the test runs, and either way
the count variable should be 2 at the end.

Currently the test wrongly fails for archs that don't support all
the ftrace features.
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      05cbbf64
    • Steven Rostedt's avatar
      tracing: Fix race with max_tr and changing tracers · 34600f0e
      Steven Rostedt authored 
      There's a race condition between the setting of a new tracer and
the update of the max trace buffers (the swap). When a new tracer
is added, it sets current_trace to nop_trace before disabling
the old tracer. At this moment, if the old tracer uses update_max_tr(),
the update may trigger the warning against !current_trace->use_max-tr,
as nop_trace doesn't have that set.

As update_max_tr() requires that interrupts be disabled, we can
add a check to see if current_trace == nop_trace and bail if it
does. Then when disabling the current_trace, set it to nop_trace
and run synchronize_sched(). This will make sure all calls to
update_max_tr() have completed (it was called with interrupts disabled).

As a clean up, this commit also removes shrinking and recreating
the max_tr buffer if the old and new tracers both have use_max_tr set.
The old way use to always shrink the buffer, and then expand it
for the next tracer. This is a waste of time.
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      34600f0e
    • Luciano Coelho's avatar
      Revert "drivers/misc/ti-st: remove gpio handling" · a7e2ca17
      Luciano Coelho authored 
      This reverts commit eccf2979.

The reason is that it broke TI WiLink shared transport on Panda.
Also, callback functions should not be added to board files anymore,
so revert to implementing the power functions in the driver itself.

Additionally, changed a variable name ('status' to 'err') so that this
revert compiles properly.

Cc: stable <stable@vger.kernel.org> [3.7]
Acked-by: default avatarTony Lindgren <tony@atomide.com>
Signed-off-by: default avatarLuciano Coelho <coelho@ti.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      a7e2ca17
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