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  1. Mar 17, 2008
  2. Mar 16, 2008
  3. Mar 15, 2008
  4. Mar 14, 2008
    • Ingo Molnar's avatar
      sched: simplify sched_slice() · 6a6029b8
      Ingo Molnar authored
      
      Use the existing calc_delta_mine() calculation for sched_slice(). This
      saves a divide and simplifies the code because we share it with the
      other /cfs_rq->load users.
      
      It also improves code size:
      
            text    data     bss     dec     hex filename
           42659    2740     144   45543    b1e7 sched.o.before
           42093    2740     144   44977    afb1 sched.o.after
      
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
      6a6029b8
    • Ingo Molnar's avatar
      sched: fix fair sleepers · e22ecef1
      Ingo Molnar authored
      
      Fair sleepers need to scale their latency target down by runqueue
      weight. Otherwise busy systems will gain ever larger sleep bonus.
      
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
      e22ecef1
    • Peter Zijlstra's avatar
      sched: fix overload performance: buddy wakeups · aa2ac252
      Peter Zijlstra authored
      
      Currently we schedule to the leftmost task in the runqueue. When the
      runtimes are very short because of some server/client ping-pong,
      especially in over-saturated workloads, this will cycle through all
      tasks trashing the cache.
      
      Reduce cache trashing by keeping dependent tasks together by running
      newly woken tasks first. However, by not running the leftmost task first
      we could starve tasks because the wakee can gain unlimited runtime.
      
      Therefore we only run the wakee if its within a small
      (wakeup_granularity) window of the leftmost task. This preserves
      fairness, but does alternate server/client task groups.
      
      Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      aa2ac252
    • Ingo Molnar's avatar
      sched: fix calc_delta_mine() · 27d11726
      Ingo Molnar authored
      
      lw->weight can be 0 for a short time during bootup.
      
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
      27d11726
    • Ingo Molnar's avatar
      sched: fix update_load_add()/sub() · e89996ae
      Ingo Molnar authored
      
      Clear the cached inverse value when updating load. This is needed for
      calc_delta_mine() to work correctly when using the rq load.
      
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
      e89996ae
    • Peter Zijlstra's avatar
      sched: min_vruntime fix · 3fe69747
      Peter Zijlstra authored
      
      Current min_vruntime tracking is incorrect and will cause serious
      problems when we don't run the leftmost task for some reason.
      
      min_vruntime does two things; 1) it's used to determine a forward
      direction when the u64 vruntime wraps, 2) it's used to track the
      leftmost vruntime to position newly enqueued tasks from.
      
      The current logic advances min_vruntime whenever the current task's
      vruntime advance. Because the current task may pass the leftmost task
      still waiting we're failing the second goal. This causes new tasks to be
      placed too far ahead and thus penalizes their runtime.
      
      Fix this by making min_vruntime the min_vruntime of the waiting tasks by
      tracking it in enqueue/dequeue, and compare against current's vruntime
      to obtain the absolute minimum when placing new tasks.
      
      Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      3fe69747
    • Hiroshi Shimamoto's avatar
      sched: fix race in schedule() · 0e1f3483
      Hiroshi Shimamoto authored
      
      Fix a hard to trigger crash seen in the -rt kernel that also affects
      the vanilla scheduler.
      
      There is a race condition between schedule() and some dequeue/enqueue
      functions; rt_mutex_setprio(), __setscheduler() and sched_move_task().
      
      When scheduling to idle, idle_balance() is called to pull tasks from
      other busy processor. It might drop the rq lock. It means that those 3
      functions encounter on_rq=0 and running=1. The current task should be
      put when running.
      
      Here is a possible scenario:
      
         CPU0                               CPU1
          |                              schedule()
          |                              ->deactivate_task()
          |                              ->idle_balance()
          |                              -->load_balance_newidle()
      rt_mutex_setprio()                     |
          |                              --->double_lock_balance()
          *get lock                          *rel lock
          * on_rq=0, ruuning=1               |
          * sched_class is changed           |
          *rel lock                          *get lock
          :                                  |
                                             :
                                         ->put_prev_task_rt()
                                         ->pick_next_task_fair()
                                             => panic
      
      The current process of CPU1(P1) is scheduling. Deactivated P1, and the
      scheduler looks for another process on other CPU's runqueue because CPU1
      will be idle. idle_balance(), load_balance_newidle() and
      double_lock_balance() are called and double_lock_balance() could drop
      the rq lock. On the other hand, CPU0 is trying to boost the priority of
      P1. The result of boosting only P1's prio and sched_class are changed to
      RT. The sched entities of P1 and P1's group are never put. It makes
      cfs_rq invalid, because the cfs_rq has curr and no leaf, but
      pick_next_task_fair() is called, then the kernel panics.
      
      Signed-off-by: default avatarHiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
      Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      0e1f3483
    • Linus Torvalds's avatar
      Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394-2.6 · 4faa8496
      Linus Torvalds authored
      * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394-2.6:
        firewire: fw-ohci: shut up false compiler warning on PPC32
        firewire: fw-ohci: use dma_alloc_coherent for ar_buffer
        ieee1394: sbp2: fix for SYM13FW500 bridge (Datafab disk)
        firewire: fw-sbp2: fix for SYM13FW500 bridge (Datafab disk)
        firewire: update Kconfig help text
        firewire: warn on fatal condition in topology code
        firewire: fw-sbp2: set single-phase retry_limit
        firewire: fw-ohci: Apple UniNorth 1st generation support
        firewire: fw-ohci: PPC PMac platform code
        firewire: endianess annotations
        firewire: endianess fix
      4faa8496
    • J. Bruce Fields's avatar
      nfsd: fix oops on access from high-numbered ports · b663c6fd
      J. Bruce Fields authored
      
      This bug was always here, but before my commit 6fa02839
      ("recheck for secure ports in fh_verify"), it could only be triggered by
      failure of a kmalloc().  After that commit it could be triggered by a
      client making a request from a non-reserved port for access to an export
      marked "secure".  (Exports are "secure" by default.)
      
      The result is a struct svc_export with a reference count one too low,
      resulting in likely oopses next time the export is accessed.
      
      The reference counting here is not straightforward; a later patch will
      clean up fh_verify().
      
      Thanks to Lukas Hejtmanek for the bug report and followup.
      
      Signed-off-by: default avatarJ. Bruce Fields <bfields@citi.umich.edu>
      Cc: Lukas Hejtmanek <xhejtman@ics.muni.cz>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      b663c6fd
    • Marc Dionne's avatar
      struct export_operations: adjust comments to match current members · 9b89ca7a
      Marc Dionne authored
      
      The comments in the definition of struct export_operations don't match the
      current members.
      
      Add a comment for the 2 new functions and remove 2 comments for unused ones.
      
      Signed-off-by: default avatarMarc Dionne <marc.c.dionne@gmail.com>
      Acked-by: default avatarDavid Howells <dhowells@redhat.com>
      Acked-by: default avatarChristoph Hellwig <hch@lst.de>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      9b89ca7a
  5. Mar 13, 2008
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