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  1. 04 Nov, 2008 5 commits
    • Peter Zijlstra's avatar
      ftrace: sysctl typo · 3299b4dd
      Peter Zijlstra authored 
      Impact: fix sysctl name typo

Steve must have needed more coffee ;-)
Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      3299b4dd
    • Peter Zijlstra's avatar
      ftrace: sysrq-z to dump the buffers · 69f698ad
      Peter Zijlstra authored 
      Impact: add SysRq-z support to dump trace buffers

Allows one to force an ftrace dump from sysrq
Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: default avatarSteven Rostedt <srostedt@redhat.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      69f698ad
    • Steven Rostedt's avatar
      ftrace: function tracer with irqs disabled · b2a866f9
      Steven Rostedt authored 
      Impact: disable interrupts during trace entry creation (as opposed to preempt)

To help with performance, I set the ftracer to not disable interrupts,
and only to disable preemption. If an interrupt occurred, it would not
be traced, because the function tracer protects itself from recursion.
This may be faster, but the trace output might miss some traces.

This patch makes the fuction trace disable interrupts, but it also
adds a runtime feature to disable preemption instead. It does this by
having two different tracer functions. When the function tracer is
enabled, it will check to see which version is requested (irqs disabled
or preemption disabled). Then it will use the corresponding function
as the tracer.

Irq disabling is the default behaviour, but if the user wants better
performance, with the chance of missing traces, then they can choose
the preempt disabled version.

Running hackbench 3 times with the irqs disabled and 3 times with
the preempt disabled function tracer yielded:

tracing type       times            entries recorded
------------      --------          ----------------
irq disabled      43.393            166433066
                  43.282            166172618
                  43.298            166256704

preempt disabled  38.969            159871710
                  38.943            159972935
                  39.325            161056510

Average:

   irqs disabled:  43.324           166287462
preempt disabled:  39.079           160300385

 preempt is 10.8 percent faster than irqs disabled.

I wrote a patch to count function trace recursion and reran hackbench.

With irq disabled: 1,150 times the function tracer did not trace due to
  recursion.
with preempt disabled: 5,117,718 times.

The thousand times with irq disabled could be due to NMIs, or simply a case
where it called a function that was not protected by notrace.

But we also see that a large amount of the trace is lost with the
preempt version.
Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      b2a866f9
    • Steven Rostedt's avatar
      ftrace: insert in the ftrace_preempt_disable()/enable() functions · 182e9f5f
      Steven Rostedt authored 
      Impact: use new, consolidated APIs in ftrace plugins

This patch replaces the schedule safe preempt disable code with the
ftrace_preempt_disable() and ftrace_preempt_enable() safe functions.
Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      182e9f5f
    • Steven Rostedt's avatar
      ftrace: introduce ftrace_preempt_disable()/enable() · 8f0a056f
      Steven Rostedt authored 
      Impact: add new ftrace-plugin internal APIs

Parts of the tracer needs to be careful about schedule recursion.
If the NEED_RESCHED flag is set, a preempt_enable will call schedule.
Inside the schedule function, the NEED_RESCHED flag is cleared.

The problem arises when a trace happens in the schedule function but before
NEED_RESCHED is cleared. The race is as follows:

schedule()
  >> tracer called

    trace_function()
       preempt_disable()
       [ record trace ]
       preempt_enable()  <<- here's the issue.

         [check NEED_RESCHED]
          schedule()
          [ Repeat the above, over and over again ]

The naive approach is simply to use preempt_enable_no_schedule instead.
The problem with that approach is that, although we solve the schedule
recursion issue, we now might lose a preemption check when not in the
schedule function.

  trace_function()
    preempt_disable()
    [ record trace ]
    [Interrupt comes in and sets NEED_RESCHED]
    preempt_enable_no_resched()
    [continue without scheduling]

The way ftrace handles this problem is with the following approach:

	int resched;

	resched = need_resched();
	preempt_disable_notrace();
	[record trace]
	if (resched)
		preempt_enable_no_sched_notrace();
	else
		preempt_enable_notrace();

This may seem like the opposite of what we want. If resched is set
then we call the "no_sched" version??  The reason we do this is because
if NEED_RESCHED is set before we disable preemption, there's two reasons
for that:

  1) we are in an atomic code path
  2) we are already on our way to the schedule function, and maybe even
     in the schedule function, but have yet to clear the flag.

Both the above cases we do not want to schedule.

This solution has already been implemented within the ftrace infrastructure.
But the problem is that it has been implemented several times. This patch
encapsulates this code to two nice functions.

  resched = ftrace_preempt_disable();
  [ record trace]
  ftrace_preempt_enable(resched);

This way the tracers do not need to worry about getting it right.
Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      8f0a056f
  3. 03 Nov, 2008 6 commits
  5. 02 Nov, 2008 19 commits
  7. 01 Nov, 2008 10 commits
    • Al Viro's avatar
      sparc32: kernel/trace/trace.c wants DIE_OOPS · c10555fa
      Al Viro authored 
      Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      c10555fa
    • Al Viro's avatar
      el3_common_init() should be __devinit, not __init · 37b2a179
      Al Viro authored 
      Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      37b2a179
    • Al Viro's avatar
      missing dependencies on HAVE_CLK in drivers/mfd · 9ca68233
      Al Viro authored 
      Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      9ca68233
    • Al Viro's avatar
      section fixes for cirrusfb · f5ee051e
      Al Viro authored 
      cirrusfb_zorro_unmap() may be called both from __devexit and (on
cleanup path) from __devinit.  So it needs to be a normal function,
same as for cirrusfb_pci_unmap()
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      f5ee051e
    • Al Viro's avatar
      PM_TEST_SUSPEND should depend on RTC_CLASS, not RTC_LIB · 28959742
      Al Viro authored 
      Insufficient dependency - we really want CONFIG_RTC_CLASS=y there.
That will give us CONFIG_RTC_LIB=y, so the old dependency can be
simply replaced.
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      28959742
    • Al Viro's avatar
      oss: fix O_NONBLOCK in dmasound_core · 4b30fbde
      Al Viro authored 
      We broke O_NONBLOCK handling in OSS dmasound_core in 2.3.11-pre3 - the
original code copied f_flags to open_mode and then checked for
O_NONBLOCK in there, but that got changed to copying f_mode and
O_NONBLOCK has not reached that field in any kernel version.

Since we do not care for any other bits, the fix is obvious...
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      4b30fbde
    • Linus Torvalds's avatar
      Merge branch 'x86-fixes-for-linus' of... · 67d11284
      Linus Torvalds authored 
      Merge branch 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86: fix AMDC1E and XTOPOLOGY conflict in cpufeature
  x86: build fix
      67d11284
    • Huang Weiyi's avatar
      init/do_mounts_md.c: remove duplicated #include · d3f15800
      Huang Weiyi authored 
      Removed duplicated #include <linux/delay.h> in init/do_mounts_md.c.

The same compile error ("error: implicit declaration of function
'msleep'") got fixed twice:

 - f8b77d39 ("init/do_mounts_md.c:
   msleep compile fix")

 - 73b4a24f ("init/do_mounts_md.c must
   #include <linux/delay.h>")

by people adding the <linux/delay.h> include in two slightly different
places.  Andrew's quilt scripts happily ignore the fuzz, and will
re-apply the patch even though they had conflicts.
Signed-off-by: default avatarHuang Weiyi <weiyi.huang@gmail.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      d3f15800
    • Linus Torvalds's avatar
      x86: Clean up late e820 resource allocation · 1f987577
      Linus Torvalds authored 
      This makes the late e820 resources use 'insert_resource_expand_to_fit()'
instead of doing a 'reserve_region_with_split()', and also avoids
marking them as IORESOURCE_BUSY.

This results in us being perfectly happy to use pre-existing PCI
resources even if they were marked as being in a reserved region, while
still avoiding any _new_ allocations in the reserved regions.  It also
makes for a simpler and more accurate resource tree.

Example resource allocation from Jonathan Corbet, who has firmware that
has an e820 reserved entry that covered a big range (e0000000-fed003ff),
and that had various PCI resources in it set up by firmware.

With old kernels, the reserved range would force us to re-allocate all
pre-existing PCI resources, and his reserved range would end up looking
like this:

	e0000000-fed003ff : reserved
	  fec00000-fec00fff : IOAPIC 0
	  fed00000-fed003ff : HPET 0

where only the pre-allocated special regions (IOAPIC and HPET) were kept
around.

With 2.6.28-rc2, which uses 'reserve_region_with_split()', Jonathan's
resource tree looked like this:

	e0000000-fe7fffff : reserved
	fe800000-fe8fffff : PCI Bus 0000:01
	 fe800000-fe8fffff : reserved
	fe900000-fe9d9aff : reserved
	fe9d9b00-fe9d9bff : 0000:00:1f.3
	 fe9d9b00-fe9d9bff : reserved
	fe9d9c00-fe9d9fff : 0000:00:1a.7
	 fe9d9c00-fe9d9fff : reserved
	fe9da000-fe9dafff : 0000:00:03.3
	 fe9da000-fe9dafff : reserved
	fe9db000-fe9dbfff : 0000:00:19.0
	 fe9db000-fe9dbfff : reserved
	fe9dc000-fe9dffff : 0000:00:1b.0
	 fe9dc000-fe9dffff : reserved
	fe9e0000-fe9fffff : 0000:00:19.0
	 fe9e0000-fe9fffff : reserved
	fea00000-fea7ffff : 0000:00:02.0
	 fea00000-fea7ffff : reserved
	fea80000-feafffff : 0000:00:02.1
	 fea80000-feafffff : reserved
	feb00000-febfffff : 0000:00:02.0
	 feb00000-febfffff : reserved
	fec00000-fed003ff : reserved
	 fec00000-fec00fff : IOAPIC 0
	 fed00000-fed003ff : HPET 0

and because the reserved entry had been split and moved into the
individual resources, and because it used the IORESOURCE_BUSY flag, the
drivers that actually wanted to _use_ those resources couldn't actually
attach to them:

	e1000e 0000:00:19.0: BAR 0: can't reserve mem region [0xfe9e0000-0xfe9fffff]
	HDA Intel 0000:00:1b.0: BAR 0: can't reserve mem region [0xfe9dc000-0xfe9dffff]

with this patch, the resource tree instead becomes

	e0000000-fed003ff : reserved
	  fe800000-fe8fffff : PCI Bus 0000:01
	  fe9d9b00-fe9d9bff : 0000:00:1f.3
	  fe9d9c00-fe9d9fff : 0000:00:1a.7
	    fe9d9c00-fe9d9fff : ehci_hcd
	  fe9da000-fe9dafff : 0000:00:03.3
	  fe9db000-fe9dbfff : 0000:00:19.0
	    fe9db000-fe9dbfff : e1000e
	  fe9dc000-fe9dffff : 0000:00:1b.0
	    fe9dc000-fe9dffff : ICH HD audio
	  fe9e0000-fe9fffff : 0000:00:19.0
	    fe9e0000-fe9fffff : e1000e
	  fea00000-fea7ffff : 0000:00:02.0
	  fea80000-feafffff : 0000:00:02.1
	  feb00000-febfffff : 0000:00:02.0
	  fec00000-fec00fff : IOAPIC 0
	  fed00000-fed003ff : HPET 0

ie the one reserved region now ends up surrounding all the PCI resources
that were allocated inside of it by firmware, and because it is not
marked BUSY, drivers have no problem attaching to the pre-allocated
resources.
Reported-and-tested-by: default avatarJonathan Corbet <corbet@lwn.net>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Robert Hancock <hancockr@shaw.ca>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      1f987577
    • Linus Torvalds's avatar
      reserve_region_with_split: Fix GFP_KERNEL usage under spinlock · 42c02023
      Linus Torvalds authored 
      This one apparently doesn't generate any warnings, because the function
is only used during system bootup, when the warnings are disabled.  But
it's still very wrong.

The __reserve_region_with_split() function is called with the
resource_lock held for writing, so it must only ever do GFP_ATOMIC
allocations.
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      42c02023
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