4854 Commits

Author SHA1 Message Date
Linus Torvalds
0234bf1d98 Merge branch 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  sched: rt-bandwidth accounting fix
  sched: fix sched_rt_rq_enqueue() resched idle
2008-08-28 12:31:12 -07:00
Linus Torvalds
e52c8857e0 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: update defconfigs
  x86: msr: fix bogus return values from rdmsr_safe/wrmsr_safe
  x86: cpuid: correct return value on partial operations
  x86: msr: correct return value on partial operations
  x86: cpuid: propagate error from smp_call_function_single()
  x86: msr: propagate errors from smp_call_function_single()
  smp: have smp_call_function_single() detect invalid CPUs
2008-08-28 12:30:59 -07:00
Rafael J. Wysocki
41108eb101 ftrace: disable tracing for hibernation
In accordance with commit f42ac38c59e0a03d6da0c24a63fb211393f484b0
("ftrace: disable tracing for suspend to ram"), disable tracing
around the suspend code in hibernation code paths.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-08-28 12:27:39 -07:00
Peter Zijlstra
cc2991cf15 sched: rt-bandwidth accounting fix
It fixes an accounting bug where we would continue accumulating runtime
even though the bandwidth control is disabled. This would lead to very long
throttle periods once bandwidth control gets turned on again.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-28 13:42:38 +02:00
Ingo Molnar
7940ca3605 sched: extract walk_tg_tree(), fix
fix:

 kernel/sched.c: In function '__rt_schedulable':
 kernel/sched.c:8771: error: implicit declaration of function 'walk_tg_tree'
 kernel/sched.c:8771: error: 'tg_nop' undeclared (first use in this function)
 kernel/sched.c:8771: error: (Each undeclared identifier is reported only once
 kernel/sched.c:8771: error: for each function it appears in.)

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-28 12:08:00 +02:00
Ingo Molnar
aef745fca0 sched: clean up __might_sleep()
add KERN_ to the printout and clean up the flow a bit.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-28 11:36:03 +02:00
Joe Korty
29cbef4869 make might_sleep() display the oopsing process
Expand might_sleep's printk to indicate the oopsing process.

Signed-off-by: Joe Korty <joe.korty@ccur.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-28 11:36:02 +02:00
Bharata B Rao
aec0a5142c sched: call resched_task() conditionally from new task wake up path
- During wake up of a new task, task_new_fair() can do a resched_task()
  on the current task. Later in the code path, check_preempt_curr() also ends
  up doing the same, which can be avoided. Check if TIF_NEED_RESCHED is
  already set for the current task.

- task_new_fair() does a resched_task() on the current task unconditionally.
  This can be done only in case when child runs before the parent.

So this is a small speedup.

Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-28 11:35:51 +02:00
John Blackwood
f3ade83780 sched: fix sched_rt_rq_enqueue() resched idle
When sysctl_sched_rt_runtime is set to something other than -1 and the
CONFIG_RT_GROUP_SCHED kernel parameter is NOT enabled, we get into a state
where we see one or more CPUs idling forvever even though there are
real-time
tasks in their rt runqueue that are able to run (no longer throttled).

The sequence is:

- A real-time task is running when the timer sets the rt runqueue
    to throttled, and the rt task is resched_task()ed and switched
    out, and idle is switched in since there are no non-rt tasks to
    run on that cpu.

- Eventually the do_sched_rt_period_timer() runs and un-throttles
    the rt runqueue, but we just exit the timer interrupt and go back
    to executing the idle task in the idle loop forever.

If we change the sched_rt_rq_enqueue() routine to use some of the code
from the CONFIG_RT_GROUP_SCHED enabled version of this same routine and
resched_task() the currently executing task (idle in our case) if it is
a lower priority task than the higher rt task in the now un-throttled
runqueue, the problem is no longer observed.

Signed-off-by: John Blackwood <john.blackwood@ccur.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-28 11:13:24 +02:00
Steven Rostedt
f42ac38c59 ftrace: disable tracing for suspend to ram
I've been painstakingly debugging the issue with suspend to ram and
ftraced. The 2.6.28 code does not have this issue, but since the mcount
recording is not going to be in 27, this must be solved for the ftrace
daemon version.

The resume from suspend to ram would reboot because it was triple
faulting. Debugging further, I found that calling the mcount function
itself was not an issue, but it would fault when it incremented
preempt_count. preempt_count is on the tasks info structure that is on the
low memory address of the task's stack.  For some reason, it could not
write to it. Resuming out of suspend to ram does quite a lot of funny
tricks to get to work, so it is not surprising at all that simply doing a
preempt_disable() would cause a fault.

Thanks to Rafael for suggesting to add a "while (1);" to find the place in
resuming that is causing the fault. I would place the loop somewhere in
the code, compile and reboot and see if it would either reboot (hit the
fault) or simply hang (hit the loop).  Doing this over and over again, I
narrowed it down that it was happening in enable_nonboot_cpus.

At this point, I found that it is easier to simply disable tracing around
the suspend code, instead of searching for the particular function that
can not handle doing a preempt_disable.

This patch disables the tracer as it suspends and reenables it on resume.

I tested this patch on my Laptop, and it can resume fine with the patch.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Acked-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-08-27 13:54:20 -07:00
Hiroshi Shimamoto
0cd418ddb1 rcuclassic: fix compiler warning
CC      kernel/rcuclassic.o
kernel/rcuclassic.c: In function 'rcu_init_percpu_data':
kernel/rcuclassic.c:705: warning: comparison of distinct pointer types lacks a cast
kernel/rcuclassic.c:713: warning: comparison of distinct pointer types lacks a cast

flags should be unsigned long.

Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-27 09:28:07 +02:00
Steve VanDeBogart
2633f0e57b exit signals: use of uninitialized field notify_count
task->signal->notify_count is only initialized if
task->signal->group_exit_task is not NULL.  Reorder a conditional so
that uninitialised memory is not used.  Found by Valgrind.

Signed-off-by: Steve VanDeBogart <vandebo-lkml@nerdbox.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-27 09:10:09 +02:00
Zhu Yi
7487017282 lockdep: fix invalid list_del_rcu in zap_class
The problem is found during iwlagn driver testing on
v2.6.27-rc4-176-gb8e6c91 kernel, but it turns out to be a lockdep bug.
In our testing, we frequently load and unload the iwlagn driver
(>50 times). Then the MAX_STACK_TRACE_ENTRIES is reached (expected
behaviour?). The error message with the call trace is as below.

BUG: MAX_STACK_TRACE_ENTRIES too low!
turning off the locking correctness validator.
Pid: 4895, comm: iwlagn Not tainted 2.6.27-rc4 #13

Call Trace:
 [<ffffffff81014aa1>] save_stack_trace+0x22/0x3e
 [<ffffffff8105390a>] save_trace+0x8b/0x91
 [<ffffffff81054e60>] mark_lock+0x1b0/0x8fa
 [<ffffffff81056f71>] __lock_acquire+0x5b9/0x716
 [<ffffffffa00d818a>] ieee80211_sta_work+0x0/0x6ea [mac80211]
 [<ffffffff81057120>] lock_acquire+0x52/0x6b
 [<ffffffff81045f0e>] run_workqueue+0x97/0x1ed
 [<ffffffff81045f5e>] run_workqueue+0xe7/0x1ed
 [<ffffffff81045f0e>] run_workqueue+0x97/0x1ed
 [<ffffffff81046ae4>] worker_thread+0xd8/0xe3
 [<ffffffff81049503>] autoremove_wake_function+0x0/0x2e
 [<ffffffff81046a0c>] worker_thread+0x0/0xe3
 [<ffffffff810493ec>] kthread+0x47/0x73
 [<ffffffff8128e3ab>] trace_hardirqs_on_thunk+0x3a/0x3f
 [<ffffffff8100cea9>] child_rip+0xa/0x11
 [<ffffffff8100c4df>] restore_args+0x0/0x30
 [<ffffffff810316e1>] finish_task_switch+0x0/0xcc
 [<ffffffff810493a5>] kthread+0x0/0x73
 [<ffffffff8100ce9f>] child_rip+0x0/0x11

Although the above is harmless, when the ilwagn module is removed
later lockdep will trigger a kernel oops as below.

BUG: unable to handle kernel NULL pointer dereference at
0000000000000008
IP: [<ffffffff810531e1>] zap_class+0x24/0x82
PGD 73128067 PUD 7448c067 PMD 0
Oops: 0002 [1] SMP
CPU 0
Modules linked in: rfcomm l2cap bluetooth autofs4 sunrpc
nf_conntrack_ipv6 xt_state nf_conntrack xt_tcpudp ip6t_ipv6header
ip6t_REJECT ip6table_filter ip6_tables x_tables ipv6 cpufreq_ondemand
acpi_cpufreq dm_mirror dm_log dm_multipath dm_mod snd_hda_intel sr_mod
snd_seq_dummy snd_seq_oss snd_seq_midi_event battery snd_seq
snd_seq_device cdrom button snd_pcm_oss snd_mixer_oss snd_pcm
snd_timer snd_page_alloc e1000e snd_hwdep sg iTCO_wdt
iTCO_vendor_support ac pcspkr i2c_i801 i2c_core snd soundcore video
output ata_piix ata_generic libata sd_mod scsi_mod ext3 jbd mbcache
uhci_hcd ohci_hcd ehci_hcd [last unloaded: mac80211]
Pid: 4941, comm: modprobe Not tainted 2.6.27-rc4 #10
RIP: 0010:[<ffffffff810531e1>]  [<ffffffff810531e1>]
zap_class+0x24/0x82
RSP: 0000:ffff88007bcb3eb0  EFLAGS: 00010046
RAX: 0000000000068ee8 RBX: ffffffff8192a0a0 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000001dfb RDI: ffffffff816e70b0
RBP: ffffffffa00cd000 R08: ffffffff816818f8 R09: ffff88007c923558
R10: ffffe20002ad2408 R11: ffffffff811028ec R12: ffffffff8192a0a0
R13: 000000000002bd90 R14: 0000000000000000 R15: 0000000000000296
FS:  00007f9d1cee56f0(0000) GS:ffffffff814a58c0(0000)
knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 0000000000000008 CR3: 0000000073047000 CR4: 00000000000006e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process modprobe (pid: 4941, threadinfo ffff88007bcb2000, task
ffff8800758d1fc0)
Stack:  ffffffff81057376 0000000000000000 ffffffffa00f7b00
0000000000000000
 0000000000000080 0000000000618278 00007fff24f16720 0000000000000000
 ffffffff8105d37a ffffffffa00f7b00 ffffffff8105d591 313132303863616d
Call Trace:
 [<ffffffff81057376>] ? lockdep_free_key_range+0x61/0xf5
 [<ffffffff8105d37a>] ? free_module+0xd4/0xe4
 [<ffffffff8105d591>] ? sys_delete_module+0x1de/0x1f9
 [<ffffffff8106dbfa>] ? audit_syscall_entry+0x12d/0x160
 [<ffffffff8100be2b>] ? system_call_fastpath+0x16/0x1b

Code: b2 00 01 00 00 00 c3 31 f6 49 c7 c0 10 8a 61 81 eb 32 49 39 38
75 26 48 98 48 6b c0 38 48 8b 90 08 8a 61 81 48 8b 88 00 8a 61 81 <48>
89 51 08 48 89 0a 48 c7 80 08 8a 61 81 00 02 20 00 48 ff c6
RIP  [<ffffffff810531e1>] zap_class+0x24/0x82
 RSP <ffff88007bcb3eb0>
CR2: 0000000000000008
---[ end trace a1297e0c4abb0f2e ]---

The root cause for this oops is in add_lock_to_list() when
save_trace() fails due to MAX_STACK_TRACE_ENTRIES is reached,
entry->class is assigned but entry is never added into any lock list.
This makes the list_del_rcu() in zap_class() oops later when the
module is unloaded. This patch fixes the problem by assigning
entry->class after save_trace() returns success.

Signed-off-by: Zhu Yi <yi.zhu@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-27 08:40:36 +02:00
Joe Korty
04148b73b8 lockstat: repair erronous contention statistics
Fix bad contention counting in /proc/lock_stat.

/proc/lockstat tries to gather per-ip contention
statistics per-lock.  This was failing due to
a garbage per-ip index selector being used.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-26 10:37:47 +02:00
Joe Korty
2189459d25 lockstat: fix numerical output rounding error
Fix rounding error in /proc/lock_stat numerical output.

On occasion the two digit fractional part contains the three
digit value '100'.  This is due to a bug in the rounding algorithm
which pushes values in the range '95..99' to '100' rather than
to '00' + an increment to the integer part.  For example,

	- 123456.100      old display
	+ 123457.00	  new display

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-26 10:37:46 +02:00
Kevin Diggs
65eb3dc609 sched: add kernel doc for the completion, fix kernel-doc-nano-HOWTO.txt
This patch adds kernel doc for the completion feature.

An error in the split-man.pl PERL snippet in kernel-doc-nano-HOWTO.txt is
also fixed.

Signed-off-by: Kevin Diggs <kevdig@hypersurf.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-26 10:26:54 +02:00
Ingo Molnar
3cf430b063 Merge branch 'linus' into sched/devel 2008-08-26 10:25:59 +02:00
H. Peter Anvin
f73be6dedf smp: have smp_call_function_single() detect invalid CPUs
Have smp_call_function_single() return invalid CPU indicies and return
-ENXIO.  This function is already executed inside a
get_cpu()..put_cpu() which locks out CPU removal, so rather than
having the higher layers doing another layer of locking to guard
against unplugged CPUs do the test here.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2008-08-25 17:45:48 -07:00
Linus Torvalds
cc556c5c92 Merge branch 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  sched_clock: fix cpu_clock()
2008-08-25 11:26:02 -07:00
Linus Torvalds
ffb4ba76a2 [module] Don't let gcc inline load_module()
'load_module()' is a complex function that contains all the ELF section
logic, and inlining it is utterly insane.  But gcc will do it, simply
because there is only one call-site.  As a result, all the stack space
that is allocated for all the work to load the module will still be
active when we actually call the module init sequence, and the deep call
chain makes stack overflows happen.

And stack overflows are really hard to debug, because they not only
corrupt random pages below the stack, but also corrupt the thread_info
structure that is allocated under the stack.

In this case, Alan Brunelle reported some crazy oopses at bootup, after
loading the processor module that ends up doing complex ACPI stuff and
has quite a deep callchain.  This should fix it, and is the sane thing
to do regardless.

Cc: Alan D. Brunelle <Alan.Brunelle@hp.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-08-25 11:10:26 -07:00
Peter Zijlstra
354879bb97 sched_clock: fix cpu_clock()
This patch fixes 3 issues:

a) it removes the dependency on jiffies, because jiffies are incremented
   by a single CPU, and the tick is not synchronized between CPUs. Therefore
   relying on it to calculate a window to clip whacky TSC values doesn't work
   as it can drift around.

   So instead use [GTOD, GTOD+TICK_NSEC) as the window.

b) __update_sched_clock() did (roughly speaking):

   delta = sched_clock() - scd->tick_raw;
   clock += delta;

   Which gives exponential growth, instead of linear.

c) allows the sched_clock_cpu() value to warp the u64 without breaking.

the results are more reliable sched_clock() deltas:

           before       after   sched_clock

cpu_clock: 15750        51312   51488
cpu_clock: 59719        51052   50947
cpu_clock: 15879        51249   51061
cpu_clock: 1            50933   51198
cpu_clock: 1            50931   51039
cpu_clock: 1            51093   50981
cpu_clock: 1            51043   51040
cpu_clock: 1            50959   50938
cpu_clock: 1            50981   51011
cpu_clock: 1            51364   51212
cpu_clock: 1            51219   51273
cpu_clock: 1            51389   51048
cpu_clock: 1            51285   51611
cpu_clock: 1            50964   51137
cpu_clock: 1            50973   50968
cpu_clock: 1            50967   50972
cpu_clock: 1            58910   58485
cpu_clock: 1            51082   51025
cpu_clock: 1            50957   50958
cpu_clock: 1            50958   50957
cpu_clock: 1006128      51128   50971
cpu_clock: 1            51107   51155
cpu_clock: 1            51371   51081
cpu_clock: 1            51104   51365
cpu_clock: 1            51363   51309
cpu_clock: 1            51107   51160
cpu_clock: 1            51139   51100
cpu_clock: 1            51216   51136
cpu_clock: 1            51207   51215
cpu_clock: 1            51087   51263
cpu_clock: 1            51249   51177
cpu_clock: 1            51519   51412
cpu_clock: 1            51416   51255
cpu_clock: 1            51591   51594
cpu_clock: 1            50966   51374
cpu_clock: 1            50966   50966
cpu_clock: 1            51291   50948
cpu_clock: 1            50973   50867
cpu_clock: 1            50970   50970
cpu_clock: 998306       50970   50971
cpu_clock: 1            50971   50970
cpu_clock: 1            50970   50970
cpu_clock: 1            50971   50971
cpu_clock: 1            50970   50970
cpu_clock: 1            51351   50970
cpu_clock: 1            50970   51352
cpu_clock: 1            50971   50970
cpu_clock: 1            50970   50970
cpu_clock: 1            51321   50971
cpu_clock: 1            50974   51324

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-25 17:39:57 +02:00
Adrian Bunk
7a8fc9b248 removed unused #include <linux/version.h>'s
This patch lets the files using linux/version.h match the files that
#include it.

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-08-23 12:14:12 -07:00
Linus Torvalds
43cc071db8 Merge branch 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  sched: enable LB_BIAS by default
2008-08-22 08:36:55 -07:00
Linus Torvalds
05f57f50e0 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:
  rcu: fix synchronize_rcu() so that kernel-doc works
2008-08-22 08:36:42 -07:00
Oleg Nesterov
93dcf55f82 wait_task_inactive: "improve" the returned value for ->nvcsw == 0
wait_task_inactive() returns 1 when p->nvcsw == 0 || p->nvcsw == 1.  This
means that two subsequent calls can return the same number while the task
was scheduled in between.

Change the code to return "nvcsw | LONG_MIN" instead of "nvcsw ?: 1", now
the overlap always needs LONG_MAX schedules.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-22 15:17:31 +02:00
Oleg Nesterov
f31e11d87a wait_task_inactive(): don't consider task->nivcsw
If wait_task_inactive() returns success the task was deactivated.  In that
case schedule() always increments ->nvcsw which alone can be used as a
"generation counter".

If the next call returns the same number, we can be sure that the task was
unscheduled.  Otherwise, because we know that .on_rq == 0 again, ->nvcsw
should have been changed in between.

Q: perhaps it is better to do "ncsw = (p->nvcsw << 1) | 1" ?  This
decreases the possibility of "was it unscheduled" false positive when
->nvcsw == 0.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-22 15:17:29 +02:00
Oleg Nesterov
94d3d8247d sched: do_wait_for_common: use signal_pending_state()
Change do_wait_for_common() to use signal_pending_state() instead of open
coding.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-22 15:17:28 +02:00
Ingo Molnar
a38409fbb5 dma-coherent: export dma_[alloc|release]_from_coherent methods
fixes modular builds:

  ERROR: "dma_alloc_from_coherent" [sound/core/snd-page-alloc.ko] undefined!
  ERROR: "dma_release_from_coherent" [sound/core/snd-page-alloc.ko] undefined!

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-22 08:34:53 +02:00
Paul E. McKenney
275a89bdd3 rcu: use irq-safe locks
Some earlier tip/core/rcu patches caused RCU to incorrectly enable irqs
too early in boot.  This caused Yinghai's repeated-kexec testing to
hit oopses, presumably due to so that device interrupts left over from
the prior kernel instance (which would oops the newly booting kernel
before it got a chance to reset said devices).  This patch therefore
converts all the local_irq_disable()s in rcuclassic.c to local_irq_save().

Besides, I never did like local_irq_disable() anyway.  ;-)

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-21 16:01:02 +02:00
Miao Xie
3c4fbe5e01 nohz: fix wrong event handler after online an offlined cpu
On the tickless system(CONFIG_NO_HZ=y and CONFIG_HIGH_RES_TIMERS=n), after
I made an offlined cpu online, I found this cpu's event handler was
tick_handle_periodic, not tick_nohz_handler.

After debuging, I found this bug was caused by the wrong tick mode.  the
tick mode is not changed to NOHZ_MODE_INACTIVE when the cpu is offline.

This patch fixes this bug.

Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-21 09:54:06 +02:00
Randy Dunlap
01dcb0443e rcu: fix synchronize_rcu() so that kernel-doc works
Fix RCU's synchronize_rcu() so that it looks like a C function, enabling
it to be recognized as a function with kernel-doc annotation.

Warning(linux-2.6.26-git11//kernel/rcupdate.c:81): No description found for parameter 'synchronize_rcu'
Warning(linux-2.6.26-git11//kernel/rcupdate.c:81): No description found for parameter 'call_rcu'

[akpm@linux-foundation.org: fix comment]
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-21 09:31:44 +02:00
Peter Zijlstra
efc2dead2c sched: enable LB_BIAS by default
Yanmin reported a significant regression on his 16-core machine due to:

  commit 93b75217df39e6d75889cc6f8050343286aff4a5
  Author: Peter Zijlstra <a.p.zijlstra@chello.nl>
  Date:   Fri Jun 27 13:41:33 2008 +0200

Flip back to the old behaviour.

Reported-by: "Zhang, Yanmin" <yanmin_zhang@linux.intel.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-21 08:18:02 +02:00
Ken Chen
2d70b68d42 fix setpriority(PRIO_PGRP) thread iterator breakage
When user calls sys_setpriority(PRIO_PGRP ...) on a NPTL style multi-LWP
process, only the task leader of the process is affected, all other
sibling LWP threads didn't receive the setting.  The problem was that the
iterator used in sys_setpriority() only iteartes over one task for each
process, ignoring all other sibling thread.

Introduce a new macro do_each_pid_thread / while_each_pid_thread to walk
each thread of a process.  Convert 4 call sites in {set/get}priority and
ioprio_{set/get}.

Signed-off-by: Ken Chen <kenchen@google.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-08-20 15:40:32 -07:00
Jiri Kosina
1fa63a817d printk: robustify printk, update comment
Remove the comment describing the possibility of printk() deadlocking on
runqueue lock.

Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-20 15:39:59 +02:00
Peter Zijlstra
fa33507a22 printk: robustify printk, fix #2
Dmitry Adamushko reported:

> [*] btw., with DEBUG being enabled, pr_debug() generates [1] when
> debug_smp_processor_id() is used (CONFIG_DEBUG_PREEMPT).
>
> the problem seems to be caused by the following commit:
> commit b845b517b5e3706a3729f6ea83b88ab85f0725b0
> Author: Peter Zijlstra <a.p.zijlstra@chello.nl>
> Date:   Fri Aug 8 21:47:09 2008 +0200
>
>     printk: robustify printk
>
>
> wake_up_klogd() -> __get_cpu_var() -> smp_processor_id()
>
> and that's being called from release_console_sem() which is, in turn,
> said to be "may be called from any context" [2]
>
> and in this case, it seems to be called from some non-preemptible
> context (although, it can't be printk()...
> although, I haven't looked carefully yet).
>
> Provided [2], __get_cpu_var() is perhaps not the right solution there.
>
>
> [1]
>
> [ 7697.942005] BUG: using smp_processor_id() in preemptible [00000000] code: syslogd/3542
> [ 7697.942005] caller is wake_up_klogd+0x1b/0x50
> [ 7697.942005] Pid: 3542, comm: syslogd Not tainted 2.6.27-rc3-tip-git #2
> [ 7697.942005] Call Trace:
> [ 7697.942005]  [<ffffffff8036b398>] debug_smp_processor_id+0xe8/0xf0
> [ 7697.942005]  [<ffffffff80239d3b>] wake_up_klogd+0x1b/0x50
> [ 7697.942005]  [<ffffffff8023a047>] release_console_sem+0x1e7/0x200
> [ 7697.942005]  [<ffffffff803c0f17>] do_con_write+0xb7/0x1f30
> [ 7697.942005]  [<ffffffff8020d920>] ? show_trace+0x10/0x20
> [ 7697.942005]  [<ffffffff8020dc42>] ? dump_stack+0x72/0x80
> [ 7697.942005]  [<ffffffff8036392d>] ? __ratelimit+0xbd/0xe0
> [ 7697.942005]  [<ffffffff8036b398>] ? debug_smp_processor_id+0xe8/0xf0
> [ 7697.942005]  [<ffffffff80239d3b>] ? wake_up_klogd+0x1b/0x50
> [ 7697.942005]  [<ffffffff8023a047>] ? release_console_sem+0x1e7/0x200
> [ 7697.942005]  [<ffffffff803c2de9>] con_write+0x19/0x30
> [ 7697.942005]  [<ffffffff803b37b6>] write_chan+0x276/0x3c0
> [ 7697.942005]  [<ffffffff80232b20>] ? default_wake_function+0x0/0x10
> [ 7697.942005]  [<ffffffff804cb872>] ? _spin_lock_irqsave+0x22/0x50
> [ 7697.942005]  [<ffffffff803b1334>] tty_write+0x194/0x260
> [ 7697.942005]  [<ffffffff803b3540>] ? write_chan+0x0/0x3c0
> [ 7697.942005]  [<ffffffff803b14a4>] redirected_tty_write+0xa4/0xb0
> [ 7697.942005]  [<ffffffff803b1400>] ? redirected_tty_write+0x0/0xb0
> [ 7697.942005]  [<ffffffff802a88c2>] do_loop_readv_writev+0x52/0x80
> [ 7697.942005]  [<ffffffff802a939d>] do_readv_writev+0x1bd/0x1d0
> [ 7697.942005]  [<ffffffff802a93e9>] vfs_writev+0x39/0x60
> [ 7697.942005]  [<ffffffff802a9870>] sys_writev+0x50/0x90
> [ 7697.942005]  [<ffffffff8020bb3b>] system_call_fastpath+0x16/0x1b

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reported-by: Dmitry Adamushko <dmitry.adamushko@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-20 12:22:37 +02:00
Roland McGrath
1b04624f93 tracehook: fix SA_NOCLDWAIT
I outwitted myself again in commit 2b2a1ff64afbadac842bbc58c5166962cf4f7664,
and broke the SA_NOCLDWAIT behavior so it leaks zombies.  This fixes it.

Reported-by: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Roland McGrath <roland@redhat.com>
2008-08-19 20:37:07 -07:00
Peter Zijlstra
9a7e0b180d sched: rt-bandwidth fixes
The last patch allows sysctl_sched_rt_runtime to disable bandwidth accounting
for the group scheduler - however it doesn't deal with sched_setscheduler(),
which will keep tasks out of groups that have no assigned runtime.

If we relax this, we get into the situation where RT tasks can get into a group
when we disable bandwidth control, and then starve them by enabling it again.

Rework the schedulability code to check for this condition and fail to turn
on bandwidth control with -EBUSY when this situation is found.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-19 13:10:12 +02:00
Peter Zijlstra
eb755805f2 sched: extract walk_tg_tree()
Extract walk_tg_tree() and make it a little more generic so we can use it
in the schedulablity test.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-19 13:10:11 +02:00
Peter Zijlstra
0b148fa048 sched: rt-bandwidth group disable fixes
More extensive disable of bandwidth control. It allows sysctl_sched_rt_runtime
to disable full group bandwidth control.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-19 13:10:10 +02:00
Peter Zijlstra
6f0d5c390e sched: rt-bandwidth accounting fix
It fixes an accounting bug where we would continue accumulating runtime
even though the bandwidth control is disabled. This would lead to very long
throttle periods once bandwidth control gets turned on again.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-19 13:10:09 +02:00
Peter Zijlstra
af4491e516 sched: rt-bandwidth for user grouping interface
rt_runtime is a signed value

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-19 13:10:09 +02:00
Hiroshi Shimamoto
0c925d7923 rcuclassic: fix compilation NG
fix:

  CC      kernel/rcuclassic.o
kernel/rcuclassic.c: In function '__rcu_process_callbacks':
kernel/rcuclassic.c:561: error: 'flags' undeclared (first use in this function)
kernel/rcuclassic.c:561: error: (Each undeclared identifier is reported only once
kernel/rcuclassic.c:561: error: for each function it appears in.)

Declare missing variable flags.

Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-19 11:03:33 +02:00
Paul E. McKenney
eff9b713ee rcu: fix locking cleanup fallout
Given that the rcp->lock is now acquired from call_rcu(), which can be
invoked from irq-disable regions, all acquisitions need to disable irqs.
The following patch fixes this.

Although I don't have any reason to believe that this is the cause of
Yinghai's oops, it does need to be fixed.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-19 04:15:36 +02:00
Paul E. McKenney
ded00a56e9 rcu: remove redundant ACCESS_ONCE definition from rcupreempt.c
Remove the redundant definition of ACCESS_ONCE() from rcupreempt.c in
favor of the one in compiler.h.  Also merge the comment header from
rcupreempt.c's definition into that in compiler.h.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-18 09:45:22 +02:00
Dmitry Baryshkov
6951b12a0f lockdep: fix spurious 'inconsistent lock state' warning
Since f82b217e3513fe3af342c0f3ee1494e86250c21c lockdep can output spurious
warnings related to hwirqs due to hardirq_off shrinkage from int to bit-sized
flag. Guard it with double negation to fix the warning.

Signed-off-by: Dmitry Baryshkov <dbaryshkov@gmail.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-18 09:42:31 +02:00
Paul E. McKenney
cd95851785 rcu: fix classic RCU locking cleanup lockdep problem
On Fri, Aug 15, 2008 at 04:24:30PM +0200, Ingo Molnar wrote:
>
> Paul,
>
> one of your two recent RCU patches caused this lockdep splat in -tip
> testing:
>
> ------------------->
> Brought up 2 CPUs
> Total of 2 processors activated (6850.87 BogoMIPS).
> PM: Adding info for No Bus:platform
> khelper used greatest stack depth: 3124 bytes left
>
> =================================
> [ INFO: inconsistent lock state ]
> 2.6.27-rc3-tip #1
> ---------------------------------
> inconsistent {softirq-on-W} -> {in-softirq-W} usage.
> ksoftirqd/0/4 [HC0[0]:SC1[1]:HE1:SE0] takes:
>  (&rcu_ctrlblk.lock){-+..}, at: [<c016d91c>] __rcu_process_callbacks+0x1ac/0x1f0
> {softirq-on-W} state was registered at:
>   [<c01528e4>] __lock_acquire+0x3f4/0x5b0
>   [<c0152b29>] lock_acquire+0x89/0xc0
>   [<c076142b>] _spin_lock+0x3b/0x70
>   [<c016d649>] rcu_init_percpu_data+0x29/0x80
>   [<c075e43f>] rcu_cpu_notify+0xaf/0xd0
>   [<c076458d>] notifier_call_chain+0x2d/0x60
>   [<c0145ede>] __raw_notifier_call_chain+0x1e/0x30
>   [<c075db29>] _cpu_up+0x79/0x110
>   [<c075dc0d>] cpu_up+0x4d/0x70
>   [<c0a769e1>] kernel_init+0xb1/0x200
>   [<c01048a3>] kernel_thread_helper+0x7/0x10
>   [<ffffffff>] 0xffffffff
> irq event stamp: 14
> hardirqs last  enabled at (14): [<c01534db>] trace_hardirqs_on+0xb/0x10
> hardirqs last disabled at (13): [<c014dbeb>] trace_hardirqs_off+0xb/0x10
> softirqs last  enabled at (0): [<c012b186>] copy_process+0x276/0x1190
> softirqs last disabled at (11): [<c0105c0a>] call_on_stack+0x1a/0x30
>
> other info that might help us debug this:
> no locks held by ksoftirqd/0/4.
>
> stack backtrace:
> Pid: 4, comm: ksoftirqd/0 Not tainted 2.6.27-rc3-tip #1
>  [<c01504dc>] print_usage_bug+0x16c/0x1b0
>  [<c0152455>] mark_lock+0xa75/0xb10
>  [<c0108b75>] ? sched_clock+0x15/0x30
>  [<c015289d>] __lock_acquire+0x3ad/0x5b0
>  [<c0152b29>] lock_acquire+0x89/0xc0
>  [<c016d91c>] ? __rcu_process_callbacks+0x1ac/0x1f0
>  [<c076142b>] _spin_lock+0x3b/0x70
>  [<c016d91c>] ? __rcu_process_callbacks+0x1ac/0x1f0
>  [<c016d91c>] __rcu_process_callbacks+0x1ac/0x1f0
>  [<c016d986>] rcu_process_callbacks+0x26/0x50
>  [<c0132305>] __do_softirq+0x95/0x120
>  [<c0132270>] ? __do_softirq+0x0/0x120
>  [<c0105c0a>] call_on_stack+0x1a/0x30
>  [<c0132426>] ? ksoftirqd+0x96/0x110
>  [<c0132390>] ? ksoftirqd+0x0/0x110
>  [<c01411f7>] ? kthread+0x47/0x80
>  [<c01411b0>] ? kthread+0x0/0x80
>  [<c01048a3>] ? kernel_thread_helper+0x7/0x10
>  =======================
> calling  init_cpufreq_transition_notifier_list+0x0/0x20
> initcall init_cpufreq_transition_notifier_list+0x0/0x20 returned 0 after 0 msecs
> calling  net_ns_init+0x0/0x190
> net_namespace: 676 bytes
> initcall net_ns_init+0x0/0x190 returned 0 after 0 msecs
> calling  cpufreq_tsc+0x0/0x20
> initcall cpufreq_tsc+0x0/0x20 returned 0 after 0 msecs
> calling  reboot_init+0x0/0x20
> initcall reboot_init+0x0/0x20 returned 0 after 0 msecs
> calling  print_banner+0x0/0x10
> Booting paravirtualized kernel on bare hardware
>
> <-----------------------
>
> my guess is on:
>
>  commit 1f7b94cd3d564901f9e04a8bc5832ae7bfd690a0
>  Author: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
>  Date:   Tue Aug 5 09:21:44 2008 -0700
>
>     rcu: classic RCU locking and memory-barrier cleanups
>
> 	Ingo

Fixes a problem detected by lockdep in which rcu->lock was acquired
both in irq context and in process context, but without disabling from
process context.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-17 17:38:01 +02:00
Linus Torvalds
406703f8de 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:
  lockdep: fix build if CONFIG_PROVE_LOCKING not defined
  lockdep: use WARN() in kernel/lockdep.c
  lockdep: spin_lock_nest_lock(), checkpatch fixes
  lockdep: build fix
2008-08-16 17:16:07 -07:00
Linus Torvalds
c100548d46 Merge branch 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  sched: scale sysctl_sched_shares_ratelimit with nr_cpus
  sched: fix rt-bandwidth hotplug race
  sched: fix the race between walk_tg_tree and sched_create_group
2008-08-16 17:15:32 -07:00
Linus Torvalds
71ef2a46fc Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6:
  security: Fix setting of PF_SUPERPRIV by __capable()
2008-08-15 15:32:13 -07:00
Stephen Hemminger
df60a84418 lockdep: fix build if CONFIG_PROVE_LOCKING not defined
If CONFIG_PROVE_LOCKING not defined, then no dependency information
is available.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-15 19:22:04 +02:00