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  1. 11 4月, 2011 4 次提交
    • S
      sched: Eliminate dead code from wakeup_gran() · f4ad9bd2
      由 Shaohua Li 提交于 
      calc_delta_fair() checks NICE_0_LOAD already, delete duplicate check.

Signed-off-by: Shaohua Li<shaohua.li@intel.com>
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Link: http://lkml.kernel.org/r/1302238389.3981.92.camel@sli10-conroeSigned-off-by: NIngo Molnar <mingo@elte.hu>
      f4ad9bd2
    • K
      sched: Fix erroneous all_pinned logic · b30aef17
      由 Ken Chen 提交于 
      The scheduler load balancer has specific code to deal with cases of
unbalanced system due to lots of unmovable tasks (for example because of
hard CPU affinity). In those situation, it excludes the busiest CPU that
has pinned tasks for load balance consideration such that it can perform
second 2nd load balance pass on the rest of the system.

This all works as designed if there is only one cgroup in the system.

However, when we have multiple cgroups, this logic has false positives and
triggers multiple load balance passes despite there are actually no pinned
tasks at all.

The reason it has false positives is that the all pinned logic is deep in
the lowest function of can_migrate_task() and is too low level:

load_balance_fair() iterates each task group and calls balance_tasks() to
migrate target load. Along the way, balance_tasks() will also set a
all_pinned variable. Given that task-groups are iterated, this all_pinned
variable is essentially the status of last group in the scanning process.
Task group can have number of reasons that no load being migrated, none
due to cpu affinity. However, this status bit is being propagated back up
to the higher level load_balance(), which incorrectly think that no tasks
were moved.  It kick off the all pinned logic and start multiple passes
attempt to move load onto puller CPU.

To fix this, move the all_pinned aggregation up at the iterator level.
This ensures that the status is aggregated over all task-groups, not just
last one in the list.
Signed-off-by: NKen Chen <kenchen@google.com>
Cc: stable@kernel.org
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/BANLkTi=ernzNawaR5tJZEsV_QVnfxqXmsQ@mail.gmail.comSigned-off-by: NIngo Molnar <mingo@elte.hu>
      b30aef17
    • K
      sched: Fix sched-domain avg_load calculation · b0432d8f
      由 Ken Chen 提交于 
      In function find_busiest_group(), the sched-domain avg_load isn't
calculated at all if there is a group imbalance within the domain. This
will cause erroneous imbalance calculation.

The reason is that calculate_imbalance() sees sds->avg_load = 0 and it
will dump entire sds->max_load into imbalance variable, which is used
later on to migrate entire load from busiest CPU to the puller CPU.

This has two really bad effect:

1. stampede of task migration, and they won't be able to break out
   of the bad state because of positive feedback loop: large load
   delta -> heavier load migration -> larger imbalance and the cycle
   goes on.

2. severe imbalance in CPU queue depth.  This causes really long
   scheduling latency blip which affects badly on application that
   has tight latency requirement.

The fix is to have kernel calculate domain avg_load in both cases. This
will ensure that imbalance calculation is always sensible and the target
is usually half way between busiest and puller CPU.
Signed-off-by: NKen Chen <kenchen@google.com>
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: <stable@kernel.org>
Link: http://lkml.kernel.org/r/20110408002322.3A0D812217F@elm.corp.google.comSigned-off-by: NIngo Molnar <mingo@elte.hu>
      b0432d8f
    • L
      Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6 · 4263a2f1
      由 Linus Torvalds 提交于 
      * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6:
  ALSA: hda - Don't query connections for widgets have no connections
  ALSA: HDA: Fix single internal mic on ALC275 (Sony Vaio VPCSB1C5E)
  ALSA: hda - HDMI: Fix MCP7x audio infoframe checksums
  ALSA: usb-audio: define another USB ID for a buggy USB MIDI cable
  ALSA: HDA: Fix dock mic for Lenovo X220-tablet
  ASoC: format_register_str: Don't clip register values
  ASoC: PXA: Fix oops in __pxa2xx_pcm_prepare
  ASoC: zylonite: set .codec_dai_name in initializer
      4263a2f1
  3. 10 4月, 2011 1 次提交
    • L
      Merge git://git.infradead.org/mtd-2.6 · 510ec7bc
      由 Linus Torvalds 提交于 
      * git://git.infradead.org/mtd-2.6:
  mtd: atmel_nand: use CPU I/O when buffer is in vmalloc(ed) region
  mtd: atmel_nand: modify test case for using DMA operations
  mtd: atmel_nand: fix support for CPUs that do not support DMA access
  mtd: atmel_nand: trivial: change DMA usage information trace
  mtd: mtdswap: fix printk format warning
      510ec7bc
  5. 09 4月, 2011 4 次提交
  7. 08 4月, 2011 15 次提交
  9. 07 4月, 2011 16 次提交