Subject: [PATCH 00/17] powerpc: alternate queued spinlock implementation

From: Nicholas Piggin <[email-masked]>
Date: Thu, 28 Jul 2022 16:31:02 +1000

This replaces the generic queued spinlock code (like s390 does) with
our own implementation. There is an extra shim patch 1a here to get the
series to apply.

So far the microbenchmarks look okay, haven't really had time to write
up a good set of results. I hope to get some significant bigger
workloads some testing time in the next week or so so if those turn
out positive I may resubmit with any tweaks and some more details of
numbers.

Thanks,
Nick

Nicholas Piggin (17):
  powerpc/qspinlock: powerpc qspinlock implementation
  powerpc/qspinlock: add mcs queueing for contended waiters
  powerpc/qspinlock: use a half-word store to unlock to avoid larx/stcx.
  powerpc/qspinlock: convert atomic operations to assembly
  powerpc/qspinlock: allow new waiters to steal the lock before queueing
  powerpc/qspinlock: theft prevention to control latency
  powerpc/qspinlock: store owner CPU in lock word
  powerpc/qspinlock: paravirt yield to lock owner
  powerpc/qspinlock: implement option to yield to previous node
  powerpc/qspinlock: allow stealing when head of queue yields
  powerpc/qspinlock: allow propagation of yield CPU down the queue
  powerpc/qspinlock: add ability to prod new queue head CPU
  powerpc/qspinlock: trylock and initial lock attempt may steal
  powerpc/qspinlock: use spin_begin/end API
  powerpc/qspinlock: reduce remote node steal spins
  powerpc/qspinlock: allow indefinite spinning on a preempted owner
  powerpc/qspinlock: provide accounting and options for sleepy locks

 arch/powerpc/Kconfig                       |    1 -
 arch/powerpc/include/asm/qspinlock.h       |  130 ++-
 arch/powerpc/include/asm/qspinlock_types.h |   70 ++
 arch/powerpc/include/asm/spinlock_types.h  |    2 +-
 arch/powerpc/lib/Makefile                  |    4 +-
 arch/powerpc/lib/qspinlock.c               | 1009 ++++++++++++++++++++
 6 files changed, 1172 insertions(+), 44 deletions(-)
 create mode 100644 arch/powerpc/include/asm/qspinlock_types.h
 create mode 100644 arch/powerpc/lib/qspinlock.c

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2.35.1