Hi Linus, I just updated the patch set to include your suggested changes.
You can also pull the three patches from git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux.git lockref Original part of description that still matters: enabling the new lockless lockref variant on s390 would have been trivial until Tony Luck added a cpu_relax() call into the CMPXCHG_LOOP(), with d472d9d9 "lockref: Relax in cmpxchg loop". As already mentioned cpu_relax() is very expensive on s390 since it yields() the current virtual cpu. So we are talking of several thousand cycles. Considering this enabling the lockless lockref variant would contradict the intention of the new semantics. And also some quick measurements show performance regressions of 50% and more. Simply removing the cpu_relax() call again seems also not very desireable since Waiman Long reported that for some workloads the call improved performance by 5%. Heiko Carstens (3): mutex: replace CONFIG_HAVE_ARCH_MUTEX_CPU_RELAX with simple ifdef lockref: use arch_mutex_cpu_relax() in CMPXCHG_LOOP() s390: enable ARCH_USE_CMPXCHG_LOCKREF arch/Kconfig | 3 --- arch/s390/Kconfig | 2 +- arch/s390/include/asm/mutex.h | 2 -- arch/s390/include/asm/processor.h | 2 ++ arch/s390/include/asm/spinlock.h | 5 +++++ include/linux/mutex.h | 6 +++--- lib/lockref.c | 10 +++++++++- 7 files changed, 20 insertions(+), 10 deletions(-) -- 1.8.3.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
