Commit Graph

4870 Commits

Author SHA1 Message Date
Alan Cox
9c9f4ded90 tty: Add a kref count
Introduce a kref to the tty structure and use it to protect the tty->signal
tty references. For now we don't introduce it for anything else.

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-13 09:51:40 -07:00
David S. Miller
56c5d900db Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/torvalds/linux-2.6
Conflicts:

	sound/core/memalloc.c
2008-10-11 12:39:35 -07:00
Linus Torvalds
ead9d23d80 Merge phase #4 (X2APIC, APIC unification, CPU identification unification) of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'x86-v28-for-linus-phase4-D' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (186 commits)
  x86, debug: print more information about unknown CPUs
  x86 setup: handle more than 8 CPU flag words
  x86: cpuid, fix typo
  x86: move transmeta cap read to early_init_transmeta()
  x86: identify_cpu_without_cpuid v2
  x86: extended "flags" to show virtualization HW feature in /proc/cpuinfo
  x86: move VMX MSRs to msr-index.h
  x86: centaur_64.c remove duplicated setting of CONSTANT_TSC
  x86: intel.c put workaround for old cpus together
  x86: let intel 64-bit use intel.c
  x86: make intel_64.c the same as intel.c
  x86: make intel.c have 64-bit support code
  x86: little clean up of intel.c/intel_64.c
  x86: make 64 bit to use amd.c
  x86: make amd_64 have 32 bit code
  x86: make amd.c have 64bit support code
  x86: merge header in amd_64.c
  x86: add srat_detect_node for amd64
  x86: remove duplicated force_mwait
  x86: cpu make amd.c more like amd_64.c v2
  ...
2008-10-11 11:51:16 -07:00
Ingo Molnar
0afe2db213 Merge branch 'x86/unify-cpu-detect' into x86-v28-for-linus-phase4-D
Conflicts:
	arch/x86/kernel/cpu/common.c
	arch/x86/kernel/signal_64.c
	include/asm-x86/cpufeature.h
2008-10-11 20:23:20 +02:00
Ingo Molnar
d84705969f Merge branch 'x86/apic' into x86-v28-for-linus-phase4-B
Conflicts:
	arch/x86/kernel/apic_32.c
	arch/x86/kernel/apic_64.c
	arch/x86/kernel/setup.c
	drivers/pci/intel-iommu.c
	include/asm-x86/cpufeature.h
	include/asm-x86/dma-mapping.h
2008-10-11 20:17:36 +02:00
Linus Torvalds
bf6f51e3a4 Merge phase #3 (IOMMU) of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'x86-v28-for-linus-phase3-B' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (74 commits)
  AMD IOMMU: use iommu_device_max_index, fix
  AMD IOMMU: use iommu_device_max_index
  x86: add PCI IDs for AMD Barcelona PCI devices
  x86/iommu: use __GFP_ZERO instead of memset for GART
  x86/iommu: convert GART need_flush to bool
  x86/iommu: make GART driver checkpatch clean
  x86 gart: remove unnecessary initialization
  x86: restore old GART alloc_coherent behavior
  revert "x86: make GART to respect device's dma_mask about virtual mappings"
  x86: export pci-nommu's alloc_coherent
  iommu: remove fullflush and nofullflush in IOMMU generic option
  x86: remove set_bit_string()
  iommu: export iommu_area_reserve helper function
  AMD IOMMU: use coherent_dma_mask in alloc_coherent
  add AMD IOMMU tree to MAINTAINERS file
  AMD IOMMU: use cmd_buf_size when freeing the command buffer
  AMD IOMMU: calculate IVHD size with a function
  AMD IOMMU: remove unnecessary cast to u64 in the init code
  AMD IOMMU: free domain bitmap with its allocation order
  AMD IOMMU: simplify dma_mask_to_pages
  ...
2008-10-11 11:03:12 -07:00
Ingo Molnar
5b16a2212f Merge branch 'sched/clock' into sched/urgent 2008-10-11 18:50:45 +02:00
Linus Torvalds
098ef215b1 Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/davej/cpufreq
* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/davej/cpufreq:
  [CPUFREQ] Fix BUG: using smp_processor_id() in preemptible code
  [CPUFREQ] Don't export governors for default governor
  [CPUFREQ][6/6] cpufreq: Add idle microaccounting in ondemand governor
  [CPUFREQ][5/6] cpufreq: Changes to get_cpu_idle_time_us(), used by ondemand governor
  [CPUFREQ][4/6] cpufreq_ondemand: Parameterize down differential
  [CPUFREQ][3/6] cpufreq: get_cpu_idle_time() changes in ondemand for idle-microaccounting
  [CPUFREQ][2/6] cpufreq: Change load calculation in ondemand for software coordination
  [CPUFREQ][1/6] cpufreq: Add cpu number parameter to __cpufreq_driver_getavg()
  [CPUFREQ] use deferrable delayed work init in conservative governor
  [CPUFREQ] drivers/cpufreq/cpufreq.c: Adjust error handling code involving cpufreq_cpu_put
  [CPUFREQ] add error handling for cpufreq_register_governor() error
  [CPUFREQ] acpi-cpufreq: add error handling for cpufreq_register_driver() error
  [CPUFREQ] Coding style fixes to arch/x86/kernel/cpu/cpufreq/powernow-k6.c
  [CPUFREQ] Coding style fixes to arch/x86/kernel/cpu/cpufreq/elanfreq.c
2008-10-11 08:49:34 -07:00
Greg Kroah-Hartman
061b1bd394 Staging: add TAINT_CRAP for all drivers/staging code
We need to add a flag for all code that is in the drivers/staging/
directory to prevent all other kernel developers from worrying about
issues here, and to notify users that the drivers might not be as good
as they are normally used to.

Based on code from Andreas Gruenbacher and Jeff Mahoney to provide a
TAINT flag for the support level of a kernel module in the Novell
enterprise kernel release.

This is the kernel portion of this feature, the ability for the flag to
be set needs to be done in the build process and will happen in a
follow-up patch.

Cc: Andreas Gruenbacher <agruen@suse.de>
Cc: Jeff Mahoney <jeffm@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2008-10-10 15:31:05 -07:00
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
725c25819e Merge branches 'core/iommu', 'x86/amd-iommu' and 'x86/iommu' into x86-v28-for-linus-phase3-B
Conflicts:
	arch/x86/kernel/pci-gart_64.c
	include/asm-x86/dma-mapping.h
2008-10-10 19:47:12 +02:00
Dave Kleikamp
5b7dba4ff8 sched_clock: prevent scd->clock from moving backwards
When sched_clock_cpu() couples the clocks between two cpus, it may
increment scd->clock beyond the GTOD tick window that __update_sched_clock()
uses to clamp the clock.  A later call to __update_sched_clock() may move
the clock back to scd->tick_gtod + TICK_NSEC, violating the clock's
monotonic property.

This patch ensures that scd->clock will not be set backward.

Signed-off-by: Dave Kleikamp <shaggy@linux.vnet.ibm.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-10 11:17:04 +02:00
Alexey Dobriyan
3bbfe05967 proc: remove kernel.maps_protect
After commit 831830b5a2 aka
"restrict reading from /proc/<pid>/maps to those who share ->mm or can ptrace"
sysctl stopped being relevant because commit moved security checks from ->show
time to ->start time (mm_for_maps()).

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Acked-by: Kees Cook <kees.cook@canonical.com>
2008-10-10 04:24:51 +04:00
Lai Jiangshan
a6bebbc87a [PATCH] signal, procfs: some lock_task_sighand() users do not need rcu_read_lock()
lock_task_sighand() make sure task->sighand is being protected,
so we do not need rcu_read_lock().
[ exec() will get task->sighand->siglock before change task->sighand! ]

But code using rcu_read_lock() _just_ to protect lock_task_sighand()
only appear in procfs. (and some code in procfs use lock_task_sighand()
without such redundant protection.)

Other subsystem may put lock_task_sighand() into rcu_read_lock()
critical region, but these rcu_read_lock() are used for protecting
"for_each_process()", "find_task_by_vpid()" etc. , not for protecting
lock_task_sighand().

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
[ok from Oleg]
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
2008-10-10 04:18:57 +04:00
venkatesh.pallipadi@intel.com
8083e4ad97 [CPUFREQ][5/6] cpufreq: Changes to get_cpu_idle_time_us(), used by ondemand governor
export get_cpu_idle_time_us() for it to be used in ondemand governor.
Last update time can be current time when the CPU is currently non-idle,
accounting for the busy time since last idle.

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Dave Jones <davej@redhat.com>
2008-10-09 13:52:44 -04:00
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
Frederic Weisbecker
77af7e3403 softirq, warning fix: correct a format to avoid a warning
Last -tip gives this warning:

kernel/softirq.c: Dans la fonction «__do_softirq» :
kernel/softirq.c:216: attention : format «%ld» expects type «long int», but argument 2 has type «int»

This patch corrects the format type, and a small mistake in the "softirq" word.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-03 11:41:41 +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
Thomas Gleixner
8e85b4b553 softirqs, debug: preemption check
if a preempt count leaks out of a softirq handler it can be very hard
to figure it out. Add a debug check for this.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-02 10:58:04 +02:00
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
Thomas Petazzoni
bfcd17a6c5 Configure out file locking features
This patch adds the CONFIG_FILE_LOCKING option which allows to remove
support for advisory locks. With this patch enabled, the flock()
system call, the F_GETLK, F_SETLK and F_SETLKW operations of fcntl()
and NFS support are disabled. These features are not necessarly needed
on embedded systems. It allows to save ~11 Kb of kernel code and data:

   text          data     bss     dec     hex filename
1125436        118764  212992 1457192  163c28 vmlinux.old
1114299        118564  212992 1445855  160fdf vmlinux
 -11137    -200       0  -11337   -2C49 +/-

This patch has originally been written by Matt Mackall
<mpm@selenic.com>, and is part of the Linux Tiny project.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Matt Mackall <mpm@selenic.com>
Cc: matthew@wil.cx
Cc: linux-fsdevel@vger.kernel.org
Cc: mpm@selenic.com
Cc: akpm@linux-foundation.org
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
2008-09-29 17:56:57 -04:00
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
Ingo Molnar
13eb83754b IO resources, x86: ioremap sanity check to catch mapping requests exceeding, fix
fix this build error:

 kernel/resource.c: In function 'iomem_map_sanity_check':
 kernel/resource.c:842: error: implicit declaration of function 'r_next'
 kernel/resource.c:842: warning: assignment makes pointer from integer without a cast

r_next() was only available if CONFIG_PROCFS was enabled.

and fix this build warning:

 kernel/resource.c:855: warning: format '%llx' expects type 'long long unsigned int', but argument 2 has type 'resource_size_t'
 kernel/resource.c:855: warning: format '%llx' expects type 'long long unsigned int', but argument 3 has type 'long unsigned int'
 kernel/resource.c:855: warning: format '%llx' expects type 'long long unsigned int', but argument 4 has type 'resource_size_t'
 kernel/resource.c:855: warning: format '%llx' expects type 'long long unsigned int', but argument 5 has type 'resource_size_t'

resource_t can be 32 bits.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-26 10:10:12 +02:00
Suresh Siddha
379daf6290 IO resources, x86: ioremap sanity check to catch mapping requests exceeding the BAR sizes
Go through the iomem resource tree to check if any of the ioremap()
requests span more than any slot in the iomem resource tree and do
a WARN_ON() if we hit this check.

This will raise a red-flag, if some driver is mapping more than what
is needed. And hopefully identify possible corruptions much earlier.

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-26 09:42:20 +02:00
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
David S. Miller
2e57572a50 Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/sparc-2.6
Conflicts:

	arch/sparc64/kernel/pci_psycho.c
2008-09-16 14:11:43 -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
Ingo Molnar
9dfed08eb4 Merge commit 'v2.6.27-rc6' into core/resources 2008-09-14 17:23:29 +02:00
Ingo Molnar
6e03f99803 Merge branch 'linus' into x86/iommu
Conflicts:
	lib/swiotlb.c

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-14 14:07:00 +02:00
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
David S. Miller
17f04fbb0f sysctl: Use header file for sysctl knob declarations on sparc.
This also takes care of a sparse warning as scons_pwroff's definition
point.

Signed-off-by: David S. Miller <davem@davemloft.net>
2008-09-11 23:33:53 -07:00
David S. Miller
72c57ed506 sysctl: Use CONFIG_SPARC instead of __sparc__ for ifdef tests.
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-09-11 23:29:54 -07:00
Ingo Molnar
09b22a2f67 Merge commit 'v2.6.27-rc6' into sched/devel 2008-09-11 13:37:28 +02:00
Hiroshi Shimamoto
ec5d498991 sched: fix deadlock in setting scheduler parameter to zero
Andrei Gusev wrote:

> I played witch scheduler settings. After doing something like:
> echo -n 1000000 >sched_rt_period_us
>
> command is locked. I found in kernel.log:
>
> Sep 11 00:39:34 zaratustra
> Sep 11 00:39:34 zaratustra Pid: 4495, comm: bash Tainted: G        W
> (2.6.26.3 #12)
> Sep 11 00:39:34 zaratustra EIP: 0060:[<c0213fc7>] EFLAGS: 00210246 CPU: 0
> Sep 11 00:39:34 zaratustra EIP is at div64_u64+0x57/0x80
> Sep 11 00:39:34 zaratustra EAX: 0000389f EBX: 00000000 ECX: 00000000
> EDX: 00000000
> Sep 11 00:39:34 zaratustra ESI: d9800000 EDI: d9800000 EBP: 0000389f
> ESP: ea7a6edc
> Sep 11 00:39:34 zaratustra DS: 007b ES: 007b FS: 0000 GS: 0033 SS: 0068
> Sep 11 00:39:34 zaratustra Process bash (pid: 4495, ti=ea7a6000
> task=ea744000 task.ti=ea7a6000)
> Sep 11 00:39:34 zaratustra Stack: 00000000 000003e8 d9800000 0000389f
> c0119042 00000000 00000000 00000001
> Sep 11 00:39:34 zaratustra 00000000 00000000 ea7a6f54 00010000 00000000
> c04d2e80 00000001 000e7ef0
> Sep 11 00:39:34 zaratustra c01191a3 00000000 00000000 ea7a6fa0 00000001
> ffffffff c04d2e80 ea5b2480
> Sep 11 00:39:34 zaratustra Call Trace:
> Sep 11 00:39:34 zaratustra [<c0119042>] __rt_schedulable+0x52/0x130
> Sep 11 00:39:34 zaratustra [<c01191a3>] sched_rt_handler+0x83/0x120
> Sep 11 00:39:34 zaratustra [<c01a76a6>] proc_sys_call_handler+0xb6/0xd0
> Sep 11 00:39:34 zaratustra [<c01a76c0>] proc_sys_write+0x0/0x20
> Sep 11 00:39:34 zaratustra [<c01a76d9>] proc_sys_write+0x19/0x20
> Sep 11 00:39:34 zaratustra [<c016cc68>] vfs_write+0xa8/0x140
> Sep 11 00:39:34 zaratustra [<c016cdd1>] sys_write+0x41/0x80
> Sep 11 00:39:34 zaratustra [<c0103051>] sysenter_past_esp+0x6a/0x91
> Sep 11 00:39:34 zaratustra =======================
> Sep 11 00:39:34 zaratustra Code: c8 41 0f ad f3 d3 ee f6 c1 20 0f 45 de
> 31 f6 0f ad ef d3 ed f6 c1 20 0f 45 fd 0f 45 ee 31 c9 39 eb 89 fe 89 ea
> 77 08 89 e8 31 d2 <f7> f3 89 c1 89 f0 8b 7c 24 08 f7 f3 8b 74 24 04 89
> ca 8b 1c 24
> Sep 11 00:39:34 zaratustra EIP: [<c0213fc7>] div64_u64+0x57/0x80 SS:ESP
> 0068:ea7a6edc
> Sep 11 00:39:34 zaratustra ---[ end trace 4eaa2a86a8e2da22 ]---

fix the boundary condition.

sysctl_sched_rt_period=0 makes exception at to_ratio().

Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-11 09:39:18 +02:00
Zhang, Yanmin
baf25731e5 sched: fix 2.6.27-rc5 couldn't boot on tulsa machine randomly
On my tulsa x86-64 machine, kernel 2.6.25-rc5 couldn't boot randomly.

Basically, function __enable_runtime forgets to reset rt_rq->rt_throttled
to 0. When every cpu is up, per-cpu migration_thread is created and it runs
very fast, sometimes to mark the corresponding rt_rq->rt_throttled to 1 very
quickly. After all cpus are up, with below calling chain:

   sched_init_smp => arch_init_sched_domains => build_sched_domains => ...
=> cpu_attach_domain => rq_attach_root => set_rq_online => ...
=> _enable_runtime

_enable_runtime is called against every rt_rq again, so rt_rq->rt_time is
reset to 0, but rt_rq->rt_throttled might be still 1. Later on function
do_sched_rt_period_timer couldn't reset it, and all RT tasks couldn't be
scheduled to run on that cpu. here is RT task migration_thread which is
woken up when a task is migrated to another cpu.

Below patch fixes it against 2.6.27-rc5.

Signed-off-by: Zhang Yanmin <yanmin_zhang@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-11 09:34:28 +02:00
Ingo Molnar
59c37bf892 Merge commit 'v2.6.27-rc6' into x86/unify-cpu-detect
Conflicts:
	arch/x86/kernel/cpu/amd.c
	arch/x86/kernel/cpu/common.c
	arch/x86/kernel/cpu/common_64.c
	arch/x86/kernel/cpu/feature_names.c
	include/asm-x86/cpufeature.h

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-10 14:00:45 +02:00
Ingo Molnar
e92b4fdacc Merge commit 'v2.6.27-rc6' into x86/iommu 2008-09-10 11:32:52 +02:00
Ingo Molnar
429b022af4 Merge commit 'v2.6.27-rc6' into core/rcu 2008-09-10 08:35:40 +02:00
Thomas Gleixner
61c22c34c6 clockevents: remove WARN_ON which was used to gather information
The issue of the endless reprogramming loop due to a too small
min_delta_ns was fixed with the previous updates of the clock events
code, but we had no information about the spread of this problem. I
added a WARN_ON to get automated information via kerneloops.org and to
get some direct reports, which allowed me to analyse the affected
machines.

The WARN_ON has served its purpose and would be annoying for a release
kernel. Remove it and just keep the information about the increase of
the min_delta_ns value.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-09-09 22:20:01 +02:00
Linus Torvalds
e1d7bf1499 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: arch_reinit_sched_domains() must destroy domains to force rebuild
  sched, cpuset: rework sched domains and CPU hotplug handling (v4)
2008-09-08 15:47:21 -07:00
Manfred Spraul
e545a6140b kernel/cpu.c: create a CPU_STARTING cpu_chain notifier
Right now, there is no notifier that is called on a new cpu, before the new
cpu begins processing interrupts/softirqs.
Various kernel function would need that notification, e.g. kvm works around
by calling smp_call_function_single(), rcu polls cpu_online_map.

The patch adds a CPU_STARTING notification. It also adds a helper function
that sends the message to all cpu_chain handlers.

Tested on x86-64.
All other archs are untested. Especially on sparc, I'm not sure if I got
it right.

Signed-off-by: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-08 19:25:24 +02:00
Linus Torvalds
f532522565 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:
  clocksource, acpi_pm.c: check for monotonicity
  clocksource, acpi_pm.c: use proper read function also in errata mode
  ntp: fix calculation of the next jiffie to trigger RTC sync
  x86: HPET: read back compare register before reading counter
  x86: HPET fix moronic 32/64bit thinko
  clockevents: broadcast fixup possible waiters
  HPET: make minimum reprogramming delta useful
  clockevents: prevent endless loop lockup
  clockevents: prevent multiple init/shutdown
  clockevents: enforce reprogram in oneshot setup
  clockevents: prevent endless loop in periodic broadcast handler
  clockevents: prevent clockevent event_handler ending up handler_noop
2008-09-06 19:33:26 -07:00
Ingo Molnar
291c54ff76 Merge branch 'sched/cpuset' into sched/urgent 2008-09-06 21:03:16 +02:00
Alexey Dobriyan
978b0116cd softirq: allocate less vectors
We don't need whole 32 of them, only NR_SOFTIRQS.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-06 20:04:36 +02:00
Max Krasnyansky
dfb512ec48 sched: arch_reinit_sched_domains() must destroy domains to force rebuild
What I realized recently is that calling rebuild_sched_domains() in
arch_reinit_sched_domains() by itself is not enough when cpusets are enabled.
partition_sched_domains() code is trying to avoid unnecessary domain rebuilds
and will not actually rebuild anything if new domain masks match the old ones.

What this means is that doing
     echo 1 > /sys/devices/system/cpu/sched_mc_power_savings
on a system with cpusets enabled will not take affect untill something changes
in the cpuset setup (ie new sets created or deleted).

This patch fixes restore correct behaviour where domains must be rebuilt in
order to enable MC powersaving flags.

Test on quad-core Core2 box with both CONFIG_CPUSETS and !CONFIG_CPUSETS.
Also tested on dual-core Core2 laptop. Lockdep is happy and things are working
as expected.

Signed-off-by: Max Krasnyansky <maxk@qualcomm.com>
Tested-by: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-06 19:22:15 +02:00
Manfred Spraul
3ba35573ad kernel/cpu.c: Move the CPU_DYING notifiers
When a cpu is taken offline, the CPU_DYING notifiers are called on the
dying cpu. According to <linux/notifiers.h>, the cpu should be "not
running any task, not handling interrupts, soon dead".

For the current implementation, this is not true:
- __cpu_disable can fail. If it fails, then the cpu will remain alive
  and happy.
- At least on x86, __cpu_disable() briefly enables the local interrupts
  to handle any outstanding interrupts.

What about moving CPU_DYING down a few lines, behind the __cpu_disable()
line?
There are only two CPU_DYING handlers in the kernel right now: one in
kvm, one in the scheduler. Both should work with the patch applied
[and: I'm not sure if either one handles a failing __cpu_disable()]

The patch survives simple offlining a cpu. kvm untested due to lack
of a test setup.

Signed-off-By: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-06 19:13:59 +02:00
Gautham R Shenoy
38736f4750 sched: fix __load_balance_iterator() for cfq with only one task
The __load_balance_iterator() returns a NULL when there's only one
sched_entity which is a task. It is caused by the following code-path.

	/* Skip over entities that are not tasks */
	do {
		se = list_entry(next, struct sched_entity, group_node);
		next = next->next;
	} while (next != &cfs_rq->tasks && !entity_is_task(se));

	if (next == &cfs_rq->tasks)
		return NULL;
	^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
      This will return NULL even when se is a task.

As a side-effect, there was a regression in sched_mc behavior since 2.6.25,
since iter_move_one_task() when it calls load_balance_start_fair(),
would not get any tasks to move!

Fix this by checking if the last entity was a task or not.

Signed-off-by: Gautham R Shenoy <ego@in.ibm.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-06 16:53:34 +02:00
Ingo Molnar
7f79d852ed Merge branch 'linus' into sched/devel 2008-09-06 16:51:57 +02:00
Maciej W. Rozycki
4ff4b9e19a ntp: fix calculation of the next jiffie to trigger RTC sync
We have a bug in the calculation of the next jiffie to trigger the RTC
synchronisation.  The aim here is to run sync_cmos_clock() as close as
possible to the middle of a second.  Which means we want this function to
be called less than or equal to half a jiffie away from when now.tv_nsec
equals 5e8 (500000000).

If this is not the case for a given call to the function, for this purpose
instead of updating the RTC we calculate the offset in nanoseconds to the
next point in time where now.tv_nsec will be equal 5e8.  The calculated
offset is then converted to jiffies as these are the unit used by the
timer.

Hovewer timespec_to_jiffies() used here uses a ceil()-type rounding mode,
where the resulting value is rounded up.  As a result the range of
now.tv_nsec when the timer will trigger is from 5e8 to 5e8 + TICK_NSEC
rather than the desired 5e8 - TICK_NSEC / 2 to 5e8 + TICK_NSEC / 2.

As a result if for example sync_cmos_clock() happens to be called at the
time when now.tv_nsec is between 5e8 + TICK_NSEC / 2 and 5e8 to 5e8 +
TICK_NSEC, it will simply be rescheduled HZ jiffies later, falling in the
same range of now.tv_nsec again.  Similarly for cases offsetted by an
integer multiple of TICK_NSEC.

This change addresses the problem by subtracting TICK_NSEC / 2 from the
nanosecond offset to the next point in time where now.tv_nsec will be
equal 5e8, effectively shifting the following rounding in
timespec_to_jiffies() so that it produces a rounded-to-nearest result.

Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-06 15:31:48 +02:00
Krzysztof Helt
c8bfff6dd4 sched: compilation fix with gcc 3.4.6
I found that 2.6.27-rc5-mm1 does not compile with gcc 3.4.6.
The error is:
  CC      kernel/sched.o
kernel/sched.c: In function `start_rt_bandwidth':
kernel/sched.c:208: sorry, unimplemented: inlining failed in call to 'rt_bandwidth_enabled': function body not available
kernel/sched.c:214: sorry, unimplemented: called from here
make[1]: *** [kernel/sched.o] Error 1
make: *** [kernel] Error 2

It seems that the gcc 3.4.6 requires full inline definition before first usage.
The patch below fixes the compilation problem.

Signed-off-by: Krzysztof Helt <krzysztof.h1@wp.pl> (if needed>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-06 15:17:09 +02:00
Thomas Gleixner
7300711e8c clockevents: broadcast fixup possible waiters
Until the C1E patches arrived there where no users of periodic broadcast
before switching to oneshot mode. Now we need to trigger a possible
waiter for a periodic broadcast when switching to oneshot mode.
Otherwise we can starve them for ever.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-09-06 07:21:17 +02:00
Balbir Singh
49048622ea sched: fix process time monotonicity
Spencer reported a problem where utime and stime were going negative despite
the fixes in commit b27f03d4bd. The suspected
reason for the problem is that signal_struct maintains it's own utime and
stime (of exited tasks), these are not updated using the new task_utime()
routine, hence sig->utime can go backwards and cause the same problem
to occur (sig->utime, adds tsk->utime and not task_utime()). This patch
fixes the problem

TODO: using max(task->prev_utime, derived utime) works for now, but a more
generic solution is to implement cputime_max() and use the cputime_gt()
function for comparison.

Reported-by: spencer@bluehost.com
Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-05 18:14:35 +02:00
Peter Zijlstra
56c7426b39 sched_clock: fix NOHZ interaction
If HLT stops the TSC, we'll fail to account idle time, thereby inflating the
actual process times. Fix this by re-calibrating the clock against GTOD when
leaving nohz mode.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Tested-by: Avi Kivity <avi@qumranet.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-05 18:14:08 +02:00
Thomas Gleixner
1fb9b7d29d clockevents: prevent endless loop lockup
The C1E/HPET bug reports on AMDX2/RS690 systems where tracked down to a
too small value of the HPET minumum delta for programming an event.

The clockevents code needs to enforce an interrupt event on the clock event
device in some cases. The enforcement code was stupid and naive, as it just
added the minimum delta to the current time and tried to reprogram the device.
When the minimum delta is too small, then this loops forever.

Add a sanity check. Allow reprogramming to fail 3 times, then print a warning
and double the minimum delta value to make sure, that this does not happen again.
Use the same function for both tick-oneshot and tick-broadcast code.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-05 11:11:53 +02:00
Thomas Gleixner
9c17bcda99 clockevents: prevent multiple init/shutdown
While chasing the C1E/HPET bugreports I went through the clock events
code inch by inch and found that the broadcast device can be initialized
and shutdown multiple times. Multiple shutdowns are not critical, but
useless waste of time. Multiple initializations are simply broken. Another
CPU might have the device in use already after the first initialization and
the second init could just render it unusable again.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-05 11:11:52 +02:00
Thomas Gleixner
7205656ab4 clockevents: enforce reprogram in oneshot setup
In tick_oneshot_setup we program the device to the given next_event,
but we do not check the return value. We need to make sure that the
device is programmed enforced so the interrupt handler engine starts
working. Split out the reprogramming function from tick_program_event()
and call it with the device, which was handed in to tick_setup_oneshot().
Set the force argument, so the devices is firing an interrupt.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-05 11:11:52 +02:00
Thomas Gleixner
d4496b3955 clockevents: prevent endless loop in periodic broadcast handler
The reprogramming of the periodic broadcast handler was broken,
when the first programming returned -ETIME. The clockevents code
stores the new expiry value in the clock events device next_event field
only when the programming time has not been elapsed yet. The loop in
question calculates the new expiry value from the next_event value
and therefor never increases.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-05 11:11:51 +02:00
Venkatesh Pallipadi
7c1e768974 clockevents: prevent clockevent event_handler ending up handler_noop
There is a ordering related problem with clockevents code, due to which
clockevents_register_device() called after tickless/highres switch
will not work. The new clockevent ends up with clockevents_handle_noop as
event handler, resulting in no timer activity.

The problematic path seems to be

* old device already has hrtimer_interrupt as the event_handler
* new clockevent device registers with a higher rating
* tick_check_new_device() is called
  * clockevents_exchange_device() gets called
    * old->event_handler is set to clockevents_handle_noop
  * tick_setup_device() is called for the new device
    * which sets new->event_handler using the old->event_handler which is noop.

Change the ordering so that new device inherits the proper handler.

This does not have any issue in normal case as most likely all the clockevent
devices are setup before the highres switch. But, can potentially be affecting
some corner case where HPET force detect happens after the highres switch.
This was a problem with HPET in MSI mode code that we have been experimenting
with.

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-05 11:11:51 +02:00
Ingo Molnar
0c8c708a7e Merge branch 'x86/core' into x86/unify-cpu-detect 2008-09-05 09:27:23 +02:00