Eric Lee / smarc-fsl-linux-kernel

14 Aug, 2011

1 commit

  • 953bfcd10   sched: Implement hierarchical task accounting for SCHED_OTHER ... Browse Code »

    Introduce hierarchical task accounting for the group scheduling case in CFS, as
    well as promoting the responsibility for maintaining rq->nr_running to the
    scheduling classes.

    The primary motivation for this is that with scheduling classes supporting
    bandwidth throttling it is possible for entities participating in throttled
    sub-trees to not have root visible changes in rq->nr_running across activate
    and de-activate operations. This in turn leads to incorrect idle and
    weight-per-task load balance decisions.

    This also allows us to make a small fixlet to the fastpath in pick_next_task()
    under group scheduling.

    Note: this issue also exists with the existing sched_rt throttling mechanism.
    This patch does not address that.

    Signed-off-by: Paul Turner
    Reviewed-by: Hidetoshi Seto
    Signed-off-by: Peter Zijlstra
    Link: http://lkml.kernel.org/r/20110721184756.878333391@google.com
    Signed-off-by: Ingo Molnar

    Paul Turner
     

14 Apr, 2011

2 commits

  • 7608dec2c   sched: Drop the rq argument to sched_class::select_task_rq() ... Browse Code »

    In preparation of calling select_task_rq() without rq->lock held, drop
    the dependency on the rq argument.

    Reviewed-by: Frank Rowand
    Signed-off-by: Peter Zijlstra
    Cc: Mike Galbraith
    Cc: Nick Piggin
    Cc: Linus Torvalds
    Cc: Andrew Morton
    Link: http://lkml.kernel.org/r/20110405152729.031077745@chello.nl
    Signed-off-by: Ingo Molnar

    Peter Zijlstra
     
  • fd2f4419b   sched: Provide p->on_rq ... Browse Code »

    Provide a generic p->on_rq because the p->se.on_rq semantics are
    unfavourable for lockless wakeups but needed for sched_fair.

    In particular, p->on_rq is only cleared when we actually dequeue the
    task in schedule() and not on any random dequeue as done by things
    like __migrate_task() and __sched_setscheduler().

    This also allows us to remove p->se usage from !sched_fair code.

    Reviewed-by: Frank Rowand
    Cc: Mike Galbraith
    Cc: Nick Piggin
    Cc: Linus Torvalds
    Cc: Andrew Morton
    Signed-off-by: Ingo Molnar
    Signed-off-by: Peter Zijlstra
    Link: http://lkml.kernel.org/r/20110405152728.949545047@chello.nl

    Peter Zijlstra
     

23 Mar, 2011

1 commit

26 Jan, 2011

1 commit

  • da7a735e5   sched: Fix switch_from_fair() ... Browse Code »

    When a task is taken out of the fair class we must ensure the vruntime
    is properly normalized because when we put it back in it will assume
    to be normalized.

    The case that goes wrong is when changing away from the fair class
    while sleeping. Sleeping tasks have non-normalized vruntime in order
    to make sleeper-fairness work. So treat the switch away from fair as a
    wakeup and preserve the relative vruntime.

    Also update sysrq-n to call the ->switch_{to,from} methods.

    Reported-by: Onkalo Samu
    Signed-off-by: Peter Zijlstra
    LKML-Reference:
    Signed-off-by: Ingo Molnar

    Peter Zijlstra
     

11 Nov, 2010

2 commits

  • 1e5a74059   sched: Fix cross-sched-class wakeup preemption ... Browse Code »

    Instead of dealing with sched classes inside each check_preempt_curr()
    implementation, pull out this logic into the generic wakeup preemption
    path.

    This fixes a hang in KVM (and others) where we are waiting for the
    stop machine thread to run ...

    Reported-by: Markus Trippelsdorf
    Tested-by: Marcelo Tosatti
    Tested-by: Sergey Senozhatsky
    Signed-off-by: Peter Zijlstra
    LKML-Reference:
    Signed-off-by: Ingo Molnar

    Peter Zijlstra
     
  • 2d4670908   sched: Fix runnable condition for stoptask ... Browse Code »

    Heiko reported that the TASK_RUNNING check is not sufficient for
    CONFIG_PREEMPT=y since we can get preempted with !TASK_RUNNING.

    He suggested adding a ->se.on_rq test to the existing TASK_RUNNING
    one, however TASK_RUNNING will always have ->se.on_rq, so we might as
    well reduce that to a single test.

    [ stop tasks should never get preempted, but its good to handle
    this case correctly should this ever happen ]

    Reported-by: Heiko Carstens
    Signed-off-by: Peter Zijlstra
    LKML-Reference:
    Signed-off-by: Ingo Molnar

    Peter Zijlstra
     

19 Oct, 2010

1 commit

  • 34f971f6f   sched: Create special class for stop/migrate work ... Browse Code »

    In order to separate the stop/migrate work thread from the SCHED_FIFO
    implementation, create a special class for it that is of higher priority than
    SCHED_FIFO itself.

    This currently solves a problem where cpu-hotplug consumes so much cpu-time
    that the SCHED_FIFO class gets throttled, but has the bandwidth replenishment
    timer pending on the now dead cpu.

    It is also required for when we add the planned deadline scheduling class above
    SCHED_FIFO, as the stop/migrate thread still needs to transcent those tasks.

    Tested-by: Heiko Carstens
    Signed-off-by: Peter Zijlstra
    LKML-Reference:
    Signed-off-by: Ingo Molnar

    Peter Zijlstra