Commit Graph

4776 Commits

Author SHA1 Message Date
Linus Torvalds b922df7383 Merge branch 'rcu-v28-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'rcu-v28-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (21 commits)
  rcu: RCU-based detection of stalled CPUs for Classic RCU, fix
  rcu: RCU-based detection of stalled CPUs for Classic RCU
  rcu: add rcu_read_lock_sched() / rcu_read_unlock_sched()
  rcu: fix sparse shadowed variable warning
  doc/RCU: fix pseudocode in rcuref.txt
  rcuclassic: fix compiler warning
  rcu: use irq-safe locks
  rcuclassic: fix compilation NG
  rcu: fix locking cleanup fallout
  rcu: remove redundant ACCESS_ONCE definition from rcupreempt.c
  rcu: fix classic RCU locking cleanup lockdep problem
  rcu: trace fix possible mem-leak
  rcu: just rename call_rcu_bh instead of making it a macro
  rcu: remove list_for_each_rcu()
  rcu: fixes to include/linux/rcupreempt.h
  rcu: classic RCU locking and memory-barrier cleanups
  rcu: prevent console flood when one CPU sees another AWOL via RCU
  rcu, debug: detect stalled grace periods, cleanups
  rcu, debug: detect stalled grace periods
  rcu classic: new algorithm for callbacks-processing(v2)
  ...
2008-10-10 13:10:51 -07:00
Ingo Molnar a5d8c3483a sched debug: add name to sched_domain sysctl entries
add /proc/sys/kernel/sched_domain/cpu0/domain0/name, to make
it easier to see which specific scheduler domain remained at
that entry.

Since we process the scheduler domain tree and
simplify it, it's not always immediately clear during debugging
which domain came from where.

depends on CONFIG_SCHED_DEBUG=y.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-09 17:13:06 +02:00
Ingo Molnar cdbb92b31d Merge branch 'linus' into core/rcu 2008-10-09 00:17:25 +02:00
Peter Zijlstra 2fb7635c4c sched: sync wakeups vs avg_overlap
While looking at the code I wondered why we always do:

  sync && avg_overlap < migration_cost

Which is a bit odd, since the overlap test was meant to detect sync wakeups
so using it to specialize sync wakeups doesn't make much sense.

Hence change the code to do:

  sync || avg_overlap < migration_cost

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-08 12:20:26 +02:00
Ingo Molnar 990d0f2ced Merge branches 'sched/devel', 'sched/cpu-hotplug', 'sched/cpusets' and 'sched/urgent' into sched/core 2008-10-08 11:31:02 +02:00
Jason Wessel cc1e0f4f7a kgdb: call touch_softlockup_watchdog on resume
The softlockup watchdog needs to be touched when resuming the from the
kgdb stopped state to avoid the printk that a CPU is stuck if the
debugger was active for longer than the softlockup threshold.

Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
2008-10-06 13:50:59 -05:00
Li Zefan 34b3ede235 sched: remove redundant code in cpu_cgroup_create()
css will be initialized by cgroup core.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-06 08:13:34 +02:00
Ingo Molnar 2c10c22af0 Merge branch 'linus' into sched/devel 2008-10-06 08:13:18 +02:00
Dario Faggioli f6121f4f87 sched_rt.c: resch needed in rt_rq_enqueue() for the root rt_rq
While working on the new version of the code for SCHED_SPORADIC I
noticed something strange in the present throttling mechanism. More
specifically in the throttling timer handler in sched_rt.c
(do_sched_rt_period_timer()) and in rt_rq_enqueue().

The problem is that, when unthrottling a runqueue, rt_rq_enqueue() only
asks for rescheduling if the runqueue has a sched_entity associated to
it (i.e., rt_rq->rt_se != NULL).
Now, if the runqueue is the root rq (which has a rt_se = NULL)
rescheduling does not take place, and it is delayed to some undefined
instant in the future.

This imply some random bandwidth usage by the RT tasks under throttling.
For instance, setting rt_runtime_us/rt_period_us = 950ms/1000ms an RT
task will get less than 95%. In our tests we got something varying
between 70% to 95%.
Using smaller time values, e.g., 95ms/100ms, things are even worse, and
I can see values also going down to 20-25%!!

The tests we performed are simply running 'yes' as a SCHED_FIFO task,
and checking the CPU usage with top, but we can investigate thoroughly
if you think it is needed.

Things go much better, for us, with the attached patch... Don't know if
it is the best approach, but it solved the issue for us.

Signed-off-by: Dario Faggioli <raistlin@linux.it>
Signed-off-by: Michael Trimarchi <trimarchimichael@yahoo.it>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: <stable@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-04 14:31:54 +02:00
Thomas Gleixner 07454bfff1 clockevents: check broadcast tick device not the clock events device
Impact: jiffies increment too fast.

Hugh Dickins noted that with NOHZ=n and HIGHRES=n jiffies get
incremented too fast. The reason is a wrong check in the broadcast
enter/exit code, which keeps the local apic timer in periodic mode
when the switch happens.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-10-04 10:51:07 +02:00
Frederic Weisbecker d294eb83d8 cpusets: scan_for_empty_cpusets(), cpuset doesn't seem to be so const
This fixes a warning on latest -tip:

 kernel/cpuset.c: Dans la fonction «scan_for_empty_cpusets» :
 kernel/cpuset.c:1932: attention : passing argument 1 of «list_add_tail» discards qualifiers from pointer target type

Actually the struct cpuset *root passed in parameter to scan_for_empty_cpusets
is not supposed to be const since an entry is added on the tail of its list.
Just correct the qualifier.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-03 13:39:50 +02:00
Ingo Molnar 2ec2b482b1 rcu: RCU-based detection of stalled CPUs for Classic RCU, fix
fix the !CONFIG_RCU_CPU_STALL_DETECTOR path:

 kernel/rcuclassic.c: In function '__rcu_pending':
 kernel/rcuclassic.c:609: error: too few arguments to function 'check_cpu_stall'

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-03 10:41:00 +02:00
Paul E. McKenney 2133b5d7ff rcu: RCU-based detection of stalled CPUs for Classic RCU
This patch adds stalled-CPU detection to Classic RCU.  This capability
is enabled by a new config variable CONFIG_RCU_CPU_STALL_DETECTOR, which
defaults disabled.

This is a debugging feature to detect infinite loops in kernel code, not
something that non-kernel-hackers would be expected to care about.

This feature can detect looping CPUs in !PREEMPT builds and looping CPUs
with preemption disabled in PREEMPT builds.  This is essentially a port of
this functionality from the treercu patch, replacing the stall debug patch
that is already in tip/core/rcu (commit 67182ae1c4).

The changes from the patch in tip/core/rcu include making the config
variable name match that in treercu, changing from seconds to jiffies to
avoid spurious warnings, and printing a boot message when this feature
is enabled.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-03 10:36:08 +02:00
Ingo Molnar b5259d9442 Merge commit 'v2.6.27-rc8' into core/rcu 2008-10-03 10:34:36 +02:00
Dan Carpenter aa94fbd5cc fix error-path NULL deref in alloc_posix_timer()
Found by static checker (http://repo.or.cz/w/smatch.git).

Signed-off-by: Dan Carpenter <error27@gmail.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-02 15:53:13 -07:00
Linus Torvalds cf4b0b2c95 Merge branch 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  hrtimer: prevent migration of per CPU hrtimers
  hrtimer: mark migration state
  hrtimer: fix migration of CB_IRQSAFE_NO_SOFTIRQ hrtimers
  hrtimer: migrate pending list on cpu offline

Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Tested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2008-09-30 08:39:28 -07:00
Amit K. Arora 64b9e0294d sched: minor optimizations in wake_affine and select_task_rq_fair
This patch does following:
o Removes unused variable and argument "rq".
o Optimizes one of the "if" conditions in wake_affine() - i.e.  if
  "balanced" is true, we need not do rest of the calculations in the
  condition.
o If this cpu is same as the previous cpu (on which woken up task
  was running when it went to sleep), no need to call wake_affine at all.

Signed-off-by: Amit K Arora <aarora@linux.vnet.ibm.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-30 15:25:44 +02:00
Balbir Singh 31a78f23ba mm owner: fix race between swapoff and exit
There's a race between mm->owner assignment and swapoff, more easily
seen when task slab poisoning is turned on.  The condition occurs when
try_to_unuse() runs in parallel with an exiting task.  A similar race
can occur with callers of get_task_mm(), such as /proc/<pid>/<mmstats>
or ptrace or page migration.

CPU0                                    CPU1
                                        try_to_unuse
                                        looks at mm = task0->mm
                                        increments mm->mm_users
task 0 exits
mm->owner needs to be updated, but no
new owner is found (mm_users > 1, but
no other task has task->mm = task0->mm)
mm_update_next_owner() leaves
                                        mmput(mm) decrements mm->mm_users
task0 freed
                                        dereferencing mm->owner fails

The fix is to notify the subsystem via mm_owner_changed callback(),
if no new owner is found, by specifying the new task as NULL.

Jiri Slaby:
mm->owner was set to NULL prior to calling cgroup_mm_owner_callbacks(), but
must be set after that, so as not to pass NULL as old owner causing oops.

Daisuke Nishimura:
mm_update_next_owner() may set mm->owner to NULL, but mem_cgroup_from_task()
and its callers need to take account of this situation to avoid oops.

Hugh Dickins:
Lockdep warning and hang below exec_mmap() when testing these patches.
exit_mm() up_reads mmap_sem before calling mm_update_next_owner(),
so exec_mmap() now needs to do the same.  And with that repositioning,
there's now no point in mm_need_new_owner() allowing for NULL mm.

Reported-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-09-29 08:41:47 -07:00
Thomas Gleixner ccc7dadf73 hrtimer: prevent migration of per CPU hrtimers
Impact: per CPU hrtimers can be migrated from a dead CPU

The hrtimer code has no knowledge about per CPU timers, but we need to
prevent the migration of such timers and warn when such a timer is
active at migration time.

Explicitely mark the timers as per CPU and use a more understandable
mode descriptor for the interrupts safe unlocked callback mode, which
is used by hrtimer_sleeper and the scheduler code.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-09-29 17:09:14 +02:00
Thomas Gleixner b00c1a99e7 hrtimer: mark migration state
Impact: during migration active hrtimers can be seen as inactive

The migration code removes the hrtimers from the queues of the dead
CPU and sets the state temporary to INACTIVE. The enqueue code sets it
to ACTIVE/PENDING again.

Prevent that the wrong state can be seen by using a separate migration
state bit.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-09-29 17:09:14 +02:00
Thomas Gleixner 41e1022eae hrtimer: fix migration of CB_IRQSAFE_NO_SOFTIRQ hrtimers
Impact: Stale timers after a CPU went offline.

commit 37bb6cb409
       hrtimer: unlock hrtimer_wakeup

changed the hrtimer sleeper callback mode to CB_IRQSAFE_NO_SOFTIRQ due
to locking problems. A result of this change is that when enqueue is
called for an already expired hrtimer the callback function is not
longer called directly from the enqueue code. The normal callers have
been fixed in the code, but the migration code which moves hrtimers
from a dead CPU to a live CPU was not made aware of this.

This can be fixed by checking the timer state after the call to
enqueue in the migration code.


Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-09-29 17:09:14 +02:00
Thomas Gleixner 7659e34967 hrtimer: migrate pending list on cpu offline
Impact: hrtimers which are on the pending list are not migrated at cpu
	offline and can be stale forever

Add the pending list migration when CONFIG_HIGH_RES_TIMERS is enabled

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-09-29 17:09:13 +02:00
Jason Wessel d7161a6534 kgdb, x86, arm, mips, powerpc: ignore user space single stepping
On the x86 arch, user space single step exceptions should be ignored
if they occur in the kernel space, such as ptrace stepping through a
system call.

First check if it is kgdb that is executing a single step, then ensure
it is not an accidental traversal into the user space, while in kgdb,
any other time the TIF_SINGLESTEP is set, kgdb should ignore the
exception.

On x86, arm, mips and powerpc, the kgdb_contthread usage was
inconsistent with the way single stepping is implemented in the kgdb
core.  The arch specific stub should always set the
kgdb_cpu_doing_single_step correctly if it is single stepping.  This
allows kgdb to correctly process an instruction steps if ptrace
happens to be requesting an instruction step over a system call.

Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
2008-09-26 10:36:41 -05:00
Atsuo Igarashi 18d6522b86 kgdb: could not write to the last of valid memory with kgdb
On the ARM architecture, kgdb will crash the kernel if the last byte
of valid memory is written due to a flush_icache_range flushing
beyond the memory boundary.

Signed-off-by: Atsuo Igarashi <atsuo_igarashi@tripeaks.co.jp>
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
2008-09-26 10:36:41 -05:00
Bharata B Rao b87f17242d sched: maintain only task entities in cfs_rq->tasks list
cfs_rq->tasks list is used by the load balancer to iterate
over all the tasks. Currently it holds all the entities
(both task and group entities) because of which there is
a need to check for group entities explicitly during load
balancing. This patch changes the cfs_rq->tasks list to
hold only task entities.

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>
2008-09-25 11:24:11 +02:00
Linus Torvalds 8553f321e0 Merge branch 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  timers: fix build error in !oneshot case
  x86: c1e_idle: don't mark TSC unstable if CPU has invariant TSC
  x86: prevent C-states hang on AMD C1E enabled machines
  clockevents: prevent mode mismatch on cpu online
  clockevents: check broadcast device not tick device
  clockevents: prevent stale tick_next_period for onlining CPUs
  x86: prevent stale state of c1e_mask across CPU offline/online
  clockevents: prevent cpu online to interfere with nohz
2008-09-23 14:57:36 -07:00
Linus Torvalds be3be89058 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: fix init_hrtick() section mismatch warning
2008-09-23 14:57:22 -07:00
Jonathan Steel f9092f358b kexec: fix segmentation fault in kimage_add_entry
A segmentation fault can occur in kimage_add_entry in kexec.c when loading
a kernel image into memory.  The fault occurs because a page is requested
by calling kimage_alloc_page with gfp_mask GFP_KERNEL and the function may
actually return a page with gfp_mask GFP_HIGHUSER.  The high mem page is
returned because it was swapped with the kernel page due to the kernel
page being a page that will shortly be copied to.

This patch ensures that kimage_alloc_page returns a page that was created
with the correct gfp flags.

I have verified the change and fixed the whitespace damage of the original
patch.  Jonathan did a great job of tracking this down after he hit the
problem.  -- Eric

Signed-off-by: Jonathan Steel <jon.steel@esentire.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Acked-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-09-23 08:09:14 -07:00
Peter Zijlstra 57fdc26d4a sched: fixup buddy selection
We should set the buddy even though we might already have the
TIF_RESCHED flag set.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-23 16:23:17 +02:00
Peter Zijlstra 4653f803e6 sched: more sanity checks on the bandwidth settings
While playing around with it, I noticed we missed some sanity checks.
Also add some comments while we're there.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-23 16:23:16 +02:00
Peter Zijlstra 78333cdd0e sched: add some comments to the bandwidth code
Hopefully clarify some of this code a little.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-23 16:23:16 +02:00
Peter Zijlstra 940959e939 sched: fixlet for group load balance
We should not only correct the increment for the initial group, but should
be consistent and do so for all the groups we encounter.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-23 16:23:15 +02:00
Ingo Molnar 63e5c39859 Merge branches 'sched/urgent' and 'sched/rt' into sched/devel 2008-09-23 16:23:05 +02:00
Peter Zijlstra 6956985009 sched: rework wakeup preemption
Rework the wakeup preemption to work on real runtime instead of
the virtual runtime. This greatly simplifies the code.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-23 14:54:23 +02:00
Ingo Molnar f8e256c687 timers: fix build error in !oneshot case
kernel/time/tick-common.c: In function ‘tick_setup_periodic’:
 kernel/time/tick-common.c:113: error: implicit declaration of function ‘tick_broadcast_oneshot_active’

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-23 12:57:00 +02:00
Thomas Gleixner 27ce4cb4a0 clockevents: prevent mode mismatch on cpu online
Impact: timer hang on CPU online observed on AMD C1E systems

When a CPU is brought online then the broadcast machinery can
be in the one shot state already. Check this and setup the timer 
device of the new CPU in one shot mode so the broadcast code
can pick up the next_event value correctly.

Another AMD C1E oddity, as we switch to broadcast immediately and
not after the full bring up via the ACPI cpu idle code.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-09-23 11:38:53 +02:00
Thomas Gleixner 302745699c clockevents: check broadcast device not tick device
Impact: Possible hang on CPU online observed on AMD C1E machines.

The broadcast setup code looks at the mode of the tick device to
determine whether it needs to be shut down or setup. This is wrong
when the broadcast mode is set to one shot already. This can happen
when a CPU is brought online as it goes through the periodic setup
first.

The problem went unnoticed as sane systems do not call into that code
before the switch to one shot for the clock event device happens.
The AMD C1E idle routine switches over immediately and thereby shuts
down the just setup device before the first interrupt happens.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-09-23 11:38:53 +02:00
Thomas Gleixner 49d670fb8d clockevents: prevent stale tick_next_period for onlining CPUs
Impact: possible hang on CPU onlining in timer one shot mode.

The tick_next_period variable is only used during boot on nohz/highres
enabled systems, but for CPU onlining it needs to be maintained when
the per cpu clock events device operates in one shot mode.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-09-23 11:38:53 +02:00
Thomas Gleixner 6441402b1f clockevents: prevent cpu online to interfere with nohz
Impact: rare hang which can be triggered on CPU online.

tick_do_timer_cpu keeps track of the CPU which updates jiffies
via do_timer. The value -1 is used to signal, that currently no
CPU is doing this. There are two cases, where the variable can 
have this state:

 boot:
    necessary for systems where the boot cpu id can be != 0

 nohz long idle sleep:
    When the CPU which did the jiffies update last goes into
    a long idle sleep it drops the update jiffies duty so
    another CPU which is not idle can pick it up and keep
    jiffies going.

Using the same value for both situations is wrong, as the CPU online
code can see the -1 state when the timer of the newly onlined CPU is
setup. The setup for a newly onlined CPU goes through periodic mode
and can pick up the do_timer duty without being aware of the nohz /
highres mode of the already running system.

Use two separate states and make them constants to avoid magic
numbers confusion. 

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-09-23 11:38:52 +02:00
Harvey Harrison 3a72dc8eb5 rcu: fix sparse shadowed variable warning
kernel/rcuclassic.c:564:18: warning: symbol 'flags' shadows an earlier one
kernel/rcuclassic.c:527:16: originally declared here

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-23 11:04:30 +02:00
Andrew Morton 006c75f146 sched: clarify ifdef tangle
- Add some comments to try to make the ifdef puzzle a bit clearer

- Explicitly inline one of the three init_hrtick() implementations.

Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-23 11:02:31 +02:00
Rakib Mullick fa74820317 sched: fix init_hrtick() section mismatch warning
LD      kernel/built-in.o
WARNING: kernel/built-in.o(.text+0x326): Section mismatch in reference
from the function init_hrtick() to the variable
.cpuinit.data:hotplug_hrtick_nb.8
The function init_hrtick() references
the variable __cpuinitdata hotplug_hrtick_nb.8.
This is often because init_hrtick lacks a __cpuinitdata
annotation or the annotation of hotplug_hrtick_nb.8 is wrong.

Signed-off-by: Md.Rakib H. Mullick <rakib.mullick@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-23 11:02:13 +02:00
Chris Friesen caea8a0370 sched: fix list traversal to use _rcu variant
load_balance_fair() calls rcu_read_lock() but then traverses the list
 using the regular list traversal routine.  This patch converts the
list traversal to use the _rcu version.

Signed-off-by: Chris Friesen <cfriesen@nortel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-22 19:43:10 +02:00
Ingo Molnar f681bbd656 sched: turn off WAKEUP_OVERLAP
WAKEUP_OVERLAP is not a winner on a 16way box, running psql+sysbench:

       .27-rc7-NO_WAKEUP_OVERLAP  .27-rc7-WAKEUP_OVERLAP
-------------------------------------------------
    1:             694              811    +14.39%
    2:            1454             1427    -1.86%
    4:            3017             3070    +1.70%
    8:            5694             5808    +1.96%
   16:           10592            10612    +0.19%
   32:            9693             9647    -0.48%
   64:            8507             8262    -2.97%
  128:            8402             7087    -18.55%
  256:            8419             5124    -64.30%
  512:            7990             3671    -117.62%
-------------------------------------------------
  SUM:           64466            55524    -16.11%

... so turn it off by default.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-22 16:29:00 +02:00
Peter Zijlstra 15afe09bf4 sched: wakeup preempt when small overlap
Lin Ming reported a 10% OLTP regression against 2.6.27-rc4.

The difference seems to come from different preemption agressiveness,
which affects the cache footprint of the workload and its effective
cache trashing.

Aggresively preempt a task if its avg overlap is very small, this should
avoid the task going to sleep and find it still running when we schedule
back to it - saving a wakeup.

Reported-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-22 16:28:32 +02:00
Linus Torvalds b4df9d88a6 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: fix deadlock in setting scheduler parameter to zero
  sched: fix 2.6.27-rc5 couldn't boot on tulsa machine randomly
2008-09-19 16:17:12 -07:00
Linus Torvalds 902f2ac9da Merge branch 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  clockevents: make device shutdown robust
  clocksource, acpi_pm.c: fix check for monotonicity
  clockevents: remove WARN_ON which was used to gather information
2008-09-19 16:16:50 -07:00
Thomas Gleixner 2344abbcbd clockevents: make device shutdown robust
The device shut down does not cleanup the next_event variable of the
clock event device. So when the device is reactivated the possible
stale next_event value can prevent the device to be reprogrammed as it
claims to wait on a event already.

This is the root cause of the resurfacing suspend/resume problem,
where systems need key press to come back to life.

Fix this by setting next_event to KTIME_MAX when the device is shut
down. Use a separate function for shutdown which takes care of that
and only keep the direct set mode call in the broadcast code, where we
can not touch the next_event value.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-09-16 13:47:02 -07:00
Li Zefan 4e74339af6 cpuset: avoid changing cpuset's cpus when -errno returned
After the patch:

commit 0b2f630a28
Author: Miao Xie <miaox@cn.fujitsu.com>
Date:   Fri Jul 25 01:47:21 2008 -0700

    cpusets: restructure the function update_cpumask() and update_nodemask()

It might happen that 'echo 0 > /cpuset/sub/cpus' returned failure but 'cpus'
has been changed, because cpus was changed before calling heap_init() which
may return -ENOMEM.

This patch restores the orginal behavior.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Paul Menage <menage@google.com>
Cc: Paul Jackson <pj@sgi.com>
Cc: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-09-13 14:41:50 -07:00
Ingo Molnar 09b22a2f67 Merge commit 'v2.6.27-rc6' into sched/devel 2008-09-11 13:37:28 +02:00