[PATCH v2 00/13] kernel/locking: qspinlock improvements
From: Will Deacon
Date: Wed Apr 11 2018 - 14:02:12 EST
Hi all,
Here's v2 of the qspinlock patches I posted last week:
https://lkml.org/lkml/2018/4/5/496
Changes since v1 include:
* Use WRITE_ONCE to clear the pending bit if we set it erroneously
* Report pending and slowpath acquisitions via the qspinlock stat
mechanism [Waiman Long]
* Spin for a bounded duration while lock is observed in the
pending->locked transition
* Use try_cmpxchg to get better codegen on x86
* Reword comments
All comments welcome,
Will
--->8
Jason Low (1):
locking/mcs: Use smp_cond_load_acquire() in mcs spin loop
Waiman Long (1):
locking/qspinlock: Add stat tracking for pending vs slowpath
Will Deacon (11):
barriers: Introduce smp_cond_load_relaxed and atomic_cond_read_relaxed
locking/qspinlock: Bound spinning on pending->locked transition in
slowpath
locking/qspinlock/x86: Increase _Q_PENDING_LOOPS upper bound
locking/qspinlock: Remove unbounded cmpxchg loop from locking slowpath
locking/qspinlock: Kill cmpxchg loop when claiming lock from head of
queue
locking/qspinlock: Use atomic_cond_read_acquire
locking/qspinlock: Use smp_cond_load_relaxed to wait for next node
locking/qspinlock: Merge struct __qspinlock into struct qspinlock
locking/qspinlock: Make queued_spin_unlock use smp_store_release
locking/qspinlock: Elide back-to-back RELEASE operations with
smp_wmb()
locking/qspinlock: Use try_cmpxchg instead of cmpxchg when locking
arch/x86/include/asm/qspinlock.h | 21 ++-
arch/x86/include/asm/qspinlock_paravirt.h | 3 +-
include/asm-generic/atomic-long.h | 2 +
include/asm-generic/barrier.h | 27 +++-
include/asm-generic/qspinlock.h | 2 +-
include/asm-generic/qspinlock_types.h | 32 +++-
include/linux/atomic.h | 2 +
kernel/locking/mcs_spinlock.h | 10 +-
kernel/locking/qspinlock.c | 247 ++++++++++++++----------------
kernel/locking/qspinlock_paravirt.h | 41 ++---
kernel/locking/qspinlock_stat.h | 9 +-
11 files changed, 209 insertions(+), 187 deletions(-)
--
2.1.4