Eric Lee / smarc-ti-linux-kernel

16 Jul, 2014

2 commits

  • 5db6c6fef   locking/rwsem: Add CONFIG_RWSEM_SPIN_ON_OWNER ... Browse Code »

    Just like with mutexes (CONFIG_MUTEX_SPIN_ON_OWNER),
    encapsulate the dependencies for rwsem optimistic spinning.
    No logical changes here as it continues to depend on both
    SMP and the XADD algorithm variant.

    Signed-off-by: Davidlohr Bueso
    Acked-by: Jason Low
    [ Also make it depend on ARCH_SUPPORTS_ATOMIC_RMW. ]
    Signed-off-by: Peter Zijlstra
    Link: http://lkml.kernel.org/r/1405112406-13052-2-git-send-email-davidlohr@hp.com
    Cc: aswin@hp.com
    Cc: Chris Mason
    Cc: Davidlohr Bueso
    Cc: Josef Bacik
    Cc: Linus Torvalds
    Cc: Waiman Long
    Signed-off-by: Ingo Molnar

    Signed-off-by: Ingo Molnar

    Davidlohr Bueso
     
  • 4badad352   locking/mutex: Disable optimistic spinning on some architectures ... Browse Code »
    37

    The optimistic spin code assumes regular stores and cmpxchg() play nice;
    this is found to not be true for at least: parisc, sparc32, tile32,
    metag-lock1, arc-!llsc and hexagon.

    There is further wreckage, but this in particular seemed easy to
    trigger, so blacklist this.

    Opt in for known good archs.

    Signed-off-by: Peter Zijlstra
    Reported-by: Mikulas Patocka
    Cc: David Miller
    Cc: Chris Metcalf
    Cc: James Bottomley
    Cc: Vineet Gupta
    Cc: Jason Low
    Cc: Waiman Long
    Cc: "James E.J. Bottomley"
    Cc: Paul McKenney
    Cc: John David Anglin
    Cc: James Hogan
    Cc: Linus Torvalds
    Cc: Davidlohr Bueso
    Cc: stable@vger.kernel.org
    Cc: Benjamin Herrenschmidt
    Cc: Catalin Marinas
    Cc: Russell King
    Cc: Will Deacon
    Cc: linux-arm-kernel@lists.infradead.org
    Cc: linux-kernel@vger.kernel.org
    Cc: linuxppc-dev@lists.ozlabs.org
    Cc: sparclinux@vger.kernel.org
    Link: http://lkml.kernel.org/r/20140606175316.GV13930@laptop.programming.kicks-ass.net
    Signed-off-by: Ingo Molnar

    Peter Zijlstra
     

06 Jun, 2014

1 commit

  • 70af2f8a4   locking/rwlocks: Introduce 'qrwlocks' - fair, queued rwlocks ... Browse Code »

    This rwlock uses the arch_spin_lock_t as a waitqueue, and assuming the
    arch_spin_lock_t is a fair lock (ticket,mcs etc..) the resulting
    rwlock is a fair lock.

    It fits in the same 8 bytes as the regular rwlock_t by folding the
    reader and writer count into a single integer, using the remaining 4
    bytes for the arch_spinlock_t.

    Architectures that can single-copy adress bytes can optimize
    queue_write_unlock() with a 0 write to the LSB (the write count).

    Performance as measured by Davidlohr Bueso (rwlock_t -> qrwlock_t):

    +--------------+-------------+---------------+
    | Workload | #users | delta |
    +--------------+-------------+---------------+
    | alltests | > 1400 | -4.83% |
    | custom | 0-100,> 100 | +1.43%,-1.57% |
    | high_systime | > 1000 | -2.61 |
    | shared | all | +0.32 |
    +--------------+-------------+---------------+

    http://www.stgolabs.net/qrwlock-stuff/aim7-results-vs-rwsem_optsin/

    Signed-off-by: Waiman Long
    [peterz: near complete rewrite]
    Signed-off-by: Peter Zijlstra
    Cc: Arnd Bergmann
    Cc: Linus Torvalds
    Cc: "Paul E.McKenney"
    Cc: linux-arch@vger.kernel.org
    Cc: linux-kernel@vger.kernel.org
    Link: http://lkml.kernel.org/n/tip-gac1nnl3wvs2ij87zv2xkdzq@git.kernel.org
    Signed-off-by: Ingo Molnar

    Waiman Long
     

28 May, 2013

1 commit

  • 4eedb77a9   locking: Fix copy/paste errors of "ARCH_INLINE_*_UNLOCK_BH" ... Browse Code »

    The Kconfig symbols ARCH_INLINE_READ_UNLOCK_IRQ,
    ARCH_INLINE_SPIN_UNLOCK_IRQ, and ARCH_INLINE_WRITE_UNLOCK_IRQ were added
    in v2.6.33, but have never actually been used. Ingo Molnar spotted that
    this is caused by three identical copy/paste erros. Eg, the Kconfig
    entry for

    INLINE_READ_UNLOCK_IRQ

    has an (optional) dependency on:

    ARCH_INLINE_READ_UNLOCK_BH

    were it apparently should depend on:

    ARCH_INLINE_READ_UNLOCK_IRQ

    instead. Likewise for the Kconfig entries for INLINE_SPIN_UNLOCK_IRQ and
    INLINE_WRITE_UNLOCK_IRQ. Fix these three errors.

    This never really caused any real problems as these symbols are set (or
    unset) in a group - but it's worth fixing it nevertheless.

    Reported-by: Ingo Molnar
    Signed-off-by: Paul Bolle
    Signed-off-by: Peter Zijlstra
    Link: http://lkml.kernel.org/r/1368780693.1350.228.camel@x61.thuisdomein
    Signed-off-by: Ingo Molnar

    Paul Bolle
     

13 Sep, 2012

1 commit

  • 4fe84fb8c   locking: Adjust spin lock inlining Kconfig options ... Browse Code »

    Break out the DEBUG_SPINLOCK dependency (requires moving up
    UNINLINE_SPIN_UNLOCK, as this was the only one in that block not
    depending on that option).

    Avoid putting values not selected into the resulting .config -
    they are not useful for anything, make the output less legible,
    and just consume space: Use "depends on" rather than directly
    setting the default from the combined dependency values.

    Signed-off-by: Jan Beulich
    Cc: Linus Torvalds
    Cc: Peter Zijlstra
    Link: http://lkml.kernel.org/r/504DF2AC020000780009A2DF@nat28.tlf.novell.com
    Signed-off-by: Ingo Molnar

    Jan Beulich
     

23 Mar, 2012

1 commit

  • e335e3eb8   locking/kconfig: Simplify INLINE_SPIN_UNLOCK usage ... Browse Code »

    Get rid of INLINE_SPIN_UNLOCK entirely replacing it with
    UNINLINE_SPIN_UNLOCK instead of the reverse meaning.

    Whoever wants to change the default spinlock inlining
    behavior and uninline the spinlocks for some weird reason,
    such as spinlock debugging, paravirt etc. can now all just
    select UNINLINE_SPIN_UNLOCK

    Original discussion at: https://lkml.org/lkml/2012/3/21/357

    Suggested-by: Linus Torvalds
    Signed-off-by: Raghavendra K T
    Cc: Linus Torvalds
    Cc: Ralf Baechle
    Cc: Chris Metcalf
    Cc: Chris Zankel
    Cc: linux-mips@linux-mips.org
    Link: http://lkml.kernel.org/r/20120322095502.30866.75756.sendpatchset@codeblue
    [ tidied up the changelog a bit ]
    Signed-off-by: Ingo Molnar

    Raghavendra K T
     

10 Apr, 2011

1 commit

03 Dec, 2009

1 commit

14 Nov, 2009

1 commit

  • 6beb00092   locking: Make inlining decision Kconfig based ... Browse Code »

    commit 892a7c67 (locking: Allow arch-inlined spinlocks) implements the
    selection of which lock functions are inlined based on defines in
    arch/.../spinlock.h: #define __always_inline__LOCK_FUNCTION

    Despite of the name __always_inline__* the lock functions can be built
    out of line depending on config options. Also if the arch does not set
    some inline defines the generic code might set them; again depending on
    config options.

    This makes it unnecessary hard to figure out when and which lock
    functions are inlined. Aside of that it makes it way harder and
    messier for -rt to manipulate the lock functions.

    Convert the inlining decision to CONFIG switches. Each lock function
    is inlined depending on CONFIG_INLINE_*. The configs implement the
    existing dependencies. The architecture code can select ARCH_INLINE_*
    to signal that it wants the corresponding lock function inlined.
    ARCH_INLINE_* is necessary as Kconfig ignores "depends on"
    restrictions when a config element is selected.

    No functional change.

    Signed-off-by: Thomas Gleixner
    LKML-Reference:
    Acked-by: Heiko Carstens
    Reviewed-by: Ingo Molnar
    Acked-by: Peter Zijlstra

    Thomas Gleixner