Eric Lee / smarc-fsl-linux-kernel

14 Apr, 2011

1 commit

  • c6eb3dda2   mutex: Use p->on_cpu for the adaptive spin ... Browse Code »

    Since we now have p->on_cpu unconditionally available, use it to
    re-implement mutex_spin_on_owner.

    Requested-by: Thomas Gleixner
    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/20110405152728.826338173@chello.nl

    Peter Zijlstra
     

15 Dec, 2009

2 commits

  • c2f21ce2e   locking: Implement new raw_spinlock ... Browse Code »

    Now that the raw_spin name space is freed up, we can implement
    raw_spinlock and the related functions which are used to annotate the
    locks which are not converted to sleeping spinlocks in preempt-rt.

    A side effect is that only such locks can be used with the low level
    lock fsunctions which circumvent lockdep.

    For !rt spin_* functions are mapped to the raw_spin* implementations.

    Signed-off-by: Thomas Gleixner
    Acked-by: Peter Zijlstra
    Acked-by: Ingo Molnar

    Thomas Gleixner
     
  • 0199c4e68   locking: Convert __raw_spin* functions to arch_spin* ... Browse Code »

    Name space cleanup. No functional change.

    Signed-off-by: Thomas Gleixner
    Acked-by: Peter Zijlstra
    Acked-by: David S. Miller
    Acked-by: Ingo Molnar
    Cc: linux-arch@vger.kernel.org

    Thomas Gleixner
     

15 Jan, 2009

1 commit

  • 0d66bf6d3   mutex: implement adaptive spinning ... Browse Code »

    Change mutex contention behaviour such that it will sometimes busy wait on
    acquisition - moving its behaviour closer to that of spinlocks.

    This concept got ported to mainline from the -rt tree, where it was originally
    implemented for rtmutexes by Steven Rostedt, based on work by Gregory Haskins.

    Testing with Ingo's test-mutex application (http://lkml.org/lkml/2006/1/8/50)
    gave a 345% boost for VFS scalability on my testbox:

    # ./test-mutex-shm V 16 10 | grep "^avg ops"
    avg ops/sec: 296604

    # ./test-mutex-shm V 16 10 | grep "^avg ops"
    avg ops/sec: 85870

    The key criteria for the busy wait is that the lock owner has to be running on
    a (different) cpu. The idea is that as long as the owner is running, there is a
    fair chance it'll release the lock soon, and thus we'll be better off spinning
    instead of blocking/scheduling.

    Since regular mutexes (as opposed to rtmutexes) do not atomically track the
    owner, we add the owner in a non-atomic fashion and deal with the races in
    the slowpath.

    Furthermore, to ease the testing of the performance impact of this new code,
    there is means to disable this behaviour runtime (without having to reboot
    the system), when scheduler debugging is enabled (CONFIG_SCHED_DEBUG=y),
    by issuing the following command:

    # echo NO_OWNER_SPIN > /debug/sched_features

    This command re-enables spinning again (this is also the default):

    # echo OWNER_SPIN > /debug/sched_features

    Signed-off-by: Peter Zijlstra
    Signed-off-by: Ingo Molnar

    Peter Zijlstra
     

04 Jul, 2006

3 commits

  • 9a11b49a8   [PATCH] lockdep: better lock debugging ... Browse Code »

    Generic lock debugging:

    - generalized lock debugging framework. For example, a bug in one lock
    subsystem turns off debugging in all lock subsystems.

    - got rid of the caller address passing (__IP__/__IP_DECL__/etc.) from
    the mutex/rtmutex debugging code: it caused way too much prototype
    hackery, and lockdep will give the same information anyway.

    - ability to do silent tests

    - check lock freeing in vfree too.

    - more finegrained debugging options, to allow distributions to
    turn off more expensive debugging features.

    There's no separate 'held mutexes' list anymore - but there's a 'held locks'
    stack within lockdep, which unifies deadlock detection across all lock
    classes. (this is independent of the lockdep validation stuff - lockdep first
    checks whether we are holding a lock already)

    Here are the current debugging options:

    CONFIG_DEBUG_MUTEXES=y
    CONFIG_DEBUG_LOCK_ALLOC=y

    which do:

    config DEBUG_MUTEXES
    bool "Mutex debugging, basic checks"

    config DEBUG_LOCK_ALLOC
    bool "Detect incorrect freeing of live mutexes"

    Signed-off-by: Ingo Molnar
    Signed-off-by: Arjan van de Ven
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Ingo Molnar
     
  • 36596243d   [PATCH] lockdep: remove DEBUG_BUG_ON() ... Browse Code »

    cleanup: remove unused DEBUG_BUG_ON() defines.

    Signed-off-by: Ingo Molnar
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Ingo Molnar
     
  • 9e7f4d451   [PATCH] lockdep: rename DEBUG_WARN_ON() ... Browse Code »

    Rename DEBUG_WARN_ON() to the less generic DEBUG_LOCKS_WARN_ON() name, so that
    it's clear that this is a lock-debugging internal mechanism.

    Signed-off-by: Ingo Molnar
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Ingo Molnar
     

27 Jun, 2006

1 commit

10 Jan, 2006

1 commit