[PATCH v2 0/3] locking/spinlock_debug: Change it to a mostly fair lock

From: Waiman Long
Date: Wed Feb 01 2017 - 16:14:38 EST


v1->v2:
- Pack lockup and break_lock into a single 4-byte slot so as not
to in increase spinlock size when GENERIC_LOCKBREAK is
on. Hopefully that will be enough to fix a frame size too large
warning in 0-day build.
- Add a new patch to disable GENERIC_LOCKBREAK when DEBUG_LOCK_ALLOC
is on.

The current debug spinlock implementation is a TATAS unfair lock. This
can occasionally lead to system lockup with a debug kernel because
of the unfairness of the lock rather than inherent locking problem.

This patch set changes the debug spinlock implementation to a
mostly fair spinlock based on the MCS lock similar to what is done
in qspinlock.

Waiman Long (3):
locking/spinlock_debug: Reduce lockup suspected message clutter
locking/spinlock_debug: Reduce lock cacheline contention
locking/spinlock: Disable GENERIC_LOCKBREAK when DEBUG_LOCK_ALLOC is
on

arch/m32r/Kconfig | 2 +-
arch/parisc/Kconfig | 2 +-
arch/powerpc/Kconfig | 2 +-
arch/s390/Kconfig | 2 +-
arch/sh/Kconfig | 2 +-
arch/sparc/Kconfig | 2 +-
include/linux/spinlock_types.h | 9 +++--
kernel/locking/spinlock_debug.c | 73 ++++++++++++++++++++++++++++++-----------
8 files changed, 65 insertions(+), 29 deletions(-)

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1.8.3.1