[PATCH v2 0/5] locking/pvqspinlock: Fix missed PV wakeup & support PPC

From: Waiman Long
Date: Tue May 31 2016 - 13:02:13 EST

- Adds a patch to make pv_unhash() atomic to prevent racing.
- Adds 2 more patches to update the pvstat code.

Patch 1 separates the wait_again and spurious wakeup stat counters
so that the former is for the queue head only and the latter is for
the non-head queue nodes.

Patch 2 fixes the missed PV wakeup problem as reported by Pan Xinhui.

Patch 3 makes pv_unhash() atomic to fix another potential racing problem
reported by Boqun Feng.

Patch 4 adds a new pvstat counter to track the rare _Q_SLOW_VAL racing.

Patch 5 adds a new argument to pv_wait() to provide better support
for PPC.

Waiman Long (5):
locking/pvstat: Separate wait_again and spurious wakeup stats
locking/pvqspinlock: Fix missed PV wakeup problem
locking/pvqspinlock: Make pv_unhash() atomic
locking/pvstat: Add stat counter to track _Q_SLOW_VAL race
locking/pvqspinlock: Add lock holder CPU argument to pv_wait()

arch/x86/include/asm/paravirt.h | 4 +-
arch/x86/include/asm/paravirt_types.h | 2 +-
arch/x86/kernel/kvm.c | 2 +-
arch/x86/xen/spinlock.c | 2 +-
kernel/locking/qspinlock.c | 5 +-
kernel/locking/qspinlock_paravirt.h | 189 ++++++++++++++++++++++++---------
kernel/locking/qspinlock_stat.h | 17 ++--
7 files changed, 159 insertions(+), 62 deletions(-)