https://github.com/torvalds/linux
Revision 23316316c1af0677a041c81f3ad6efb9dc470b33 authored by Paul Mackerras on 21 October 2015, 05:03:14 UTC, committed by Michael Ellerman on 21 October 2015, 09:50:30 UTC
This reverts commit 9678cdaae939 ("Use the POWER8 Micro Partition
Prefetch Engine in KVM HV on POWER8") because the original commit had
multiple, partly self-cancelling bugs, that could cause occasional
memory corruption.
In fact the logmpp instruction was incorrectly using register r0 as the
source of the buffer address and operation code, and depending on what
was in r0, it would either do nothing or corrupt the 64k page pointed to
by r0.
The logmpp instruction encoding and the operation code definitions could
be corrected, but then there is the problem that there is no clearly
defined way to know when the hardware has finished writing to the
buffer.
The original commit attempted to work around this by aborting the
write-out before starting the prefetch, but this is ineffective in the
case where the virtual core is now executing on a different physical
core from the one where the write-out was initiated.
These problems plus advice from the hardware designers not to use the
function (since the measured performance improvement from using the
feature was actually mostly negative), mean that reverting the code is
the best option.
Fixes: 9678cdaae939 ("Use the POWER8 Micro Partition Prefetch Engine in KVM HV on POWER8")
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
1 parent abb39bc
Tip revision: 23316316c1af0677a041c81f3ad6efb9dc470b33 authored by Paul Mackerras on 21 October 2015, 05:03:14 UTC
powerpc: Revert "Use the POWER8 Micro Partition Prefetch Engine in KVM HV on POWER8"
powerpc: Revert "Use the POWER8 Micro Partition Prefetch Engine in KVM HV on POWER8"
Tip revision: 2331631
Kconfig.locks
#
# The ARCH_INLINE foo is necessary because select ignores "depends on"
#
config ARCH_INLINE_SPIN_TRYLOCK
bool
config ARCH_INLINE_SPIN_TRYLOCK_BH
bool
config ARCH_INLINE_SPIN_LOCK
bool
config ARCH_INLINE_SPIN_LOCK_BH
bool
config ARCH_INLINE_SPIN_LOCK_IRQ
bool
config ARCH_INLINE_SPIN_LOCK_IRQSAVE
bool
config ARCH_INLINE_SPIN_UNLOCK
bool
config ARCH_INLINE_SPIN_UNLOCK_BH
bool
config ARCH_INLINE_SPIN_UNLOCK_IRQ
bool
config ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE
bool
config ARCH_INLINE_READ_TRYLOCK
bool
config ARCH_INLINE_READ_LOCK
bool
config ARCH_INLINE_READ_LOCK_BH
bool
config ARCH_INLINE_READ_LOCK_IRQ
bool
config ARCH_INLINE_READ_LOCK_IRQSAVE
bool
config ARCH_INLINE_READ_UNLOCK
bool
config ARCH_INLINE_READ_UNLOCK_BH
bool
config ARCH_INLINE_READ_UNLOCK_IRQ
bool
config ARCH_INLINE_READ_UNLOCK_IRQRESTORE
bool
config ARCH_INLINE_WRITE_TRYLOCK
bool
config ARCH_INLINE_WRITE_LOCK
bool
config ARCH_INLINE_WRITE_LOCK_BH
bool
config ARCH_INLINE_WRITE_LOCK_IRQ
bool
config ARCH_INLINE_WRITE_LOCK_IRQSAVE
bool
config ARCH_INLINE_WRITE_UNLOCK
bool
config ARCH_INLINE_WRITE_UNLOCK_BH
bool
config ARCH_INLINE_WRITE_UNLOCK_IRQ
bool
config ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE
bool
config UNINLINE_SPIN_UNLOCK
bool
#
# lock_* functions are inlined when:
# - DEBUG_SPINLOCK=n and GENERIC_LOCKBREAK=n and ARCH_INLINE_*LOCK=y
#
# trylock_* functions are inlined when:
# - DEBUG_SPINLOCK=n and ARCH_INLINE_*LOCK=y
#
# unlock and unlock_irq functions are inlined when:
# - DEBUG_SPINLOCK=n and ARCH_INLINE_*LOCK=y
# or
# - DEBUG_SPINLOCK=n and PREEMPT=n
#
# unlock_bh and unlock_irqrestore functions are inlined when:
# - DEBUG_SPINLOCK=n and ARCH_INLINE_*LOCK=y
#
if !DEBUG_SPINLOCK
config INLINE_SPIN_TRYLOCK
def_bool y
depends on ARCH_INLINE_SPIN_TRYLOCK
config INLINE_SPIN_TRYLOCK_BH
def_bool y
depends on ARCH_INLINE_SPIN_TRYLOCK_BH
config INLINE_SPIN_LOCK
def_bool y
depends on !GENERIC_LOCKBREAK && ARCH_INLINE_SPIN_LOCK
config INLINE_SPIN_LOCK_BH
def_bool y
depends on !GENERIC_LOCKBREAK && ARCH_INLINE_SPIN_LOCK_BH
config INLINE_SPIN_LOCK_IRQ
def_bool y
depends on !GENERIC_LOCKBREAK && ARCH_INLINE_SPIN_LOCK_IRQ
config INLINE_SPIN_LOCK_IRQSAVE
def_bool y
depends on !GENERIC_LOCKBREAK && ARCH_INLINE_SPIN_LOCK_IRQSAVE
config INLINE_SPIN_UNLOCK_BH
def_bool y
depends on ARCH_INLINE_SPIN_UNLOCK_BH
config INLINE_SPIN_UNLOCK_IRQ
def_bool y
depends on !PREEMPT || ARCH_INLINE_SPIN_UNLOCK_IRQ
config INLINE_SPIN_UNLOCK_IRQRESTORE
def_bool y
depends on ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE
config INLINE_READ_TRYLOCK
def_bool y
depends on ARCH_INLINE_READ_TRYLOCK
config INLINE_READ_LOCK
def_bool y
depends on !GENERIC_LOCKBREAK && ARCH_INLINE_READ_LOCK
config INLINE_READ_LOCK_BH
def_bool y
depends on !GENERIC_LOCKBREAK && ARCH_INLINE_READ_LOCK_BH
config INLINE_READ_LOCK_IRQ
def_bool y
depends on !GENERIC_LOCKBREAK && ARCH_INLINE_READ_LOCK_IRQ
config INLINE_READ_LOCK_IRQSAVE
def_bool y
depends on !GENERIC_LOCKBREAK && ARCH_INLINE_READ_LOCK_IRQSAVE
config INLINE_READ_UNLOCK
def_bool y
depends on !PREEMPT || ARCH_INLINE_READ_UNLOCK
config INLINE_READ_UNLOCK_BH
def_bool y
depends on ARCH_INLINE_READ_UNLOCK_BH
config INLINE_READ_UNLOCK_IRQ
def_bool y
depends on !PREEMPT || ARCH_INLINE_READ_UNLOCK_IRQ
config INLINE_READ_UNLOCK_IRQRESTORE
def_bool y
depends on ARCH_INLINE_READ_UNLOCK_IRQRESTORE
config INLINE_WRITE_TRYLOCK
def_bool y
depends on ARCH_INLINE_WRITE_TRYLOCK
config INLINE_WRITE_LOCK
def_bool y
depends on !GENERIC_LOCKBREAK && ARCH_INLINE_WRITE_LOCK
config INLINE_WRITE_LOCK_BH
def_bool y
depends on !GENERIC_LOCKBREAK && ARCH_INLINE_WRITE_LOCK_BH
config INLINE_WRITE_LOCK_IRQ
def_bool y
depends on !GENERIC_LOCKBREAK && ARCH_INLINE_WRITE_LOCK_IRQ
config INLINE_WRITE_LOCK_IRQSAVE
def_bool y
depends on !GENERIC_LOCKBREAK && ARCH_INLINE_WRITE_LOCK_IRQSAVE
config INLINE_WRITE_UNLOCK
def_bool y
depends on !PREEMPT || ARCH_INLINE_WRITE_UNLOCK
config INLINE_WRITE_UNLOCK_BH
def_bool y
depends on ARCH_INLINE_WRITE_UNLOCK_BH
config INLINE_WRITE_UNLOCK_IRQ
def_bool y
depends on !PREEMPT || ARCH_INLINE_WRITE_UNLOCK_IRQ
config INLINE_WRITE_UNLOCK_IRQRESTORE
def_bool y
depends on ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE
endif
config ARCH_SUPPORTS_ATOMIC_RMW
bool
config MUTEX_SPIN_ON_OWNER
def_bool y
depends on SMP && !DEBUG_MUTEXES && ARCH_SUPPORTS_ATOMIC_RMW
config RWSEM_SPIN_ON_OWNER
def_bool y
depends on SMP && RWSEM_XCHGADD_ALGORITHM && ARCH_SUPPORTS_ATOMIC_RMW
config LOCK_SPIN_ON_OWNER
def_bool y
depends on MUTEX_SPIN_ON_OWNER || RWSEM_SPIN_ON_OWNER
config ARCH_USE_QUEUED_SPINLOCKS
bool
config QUEUED_SPINLOCKS
def_bool y if ARCH_USE_QUEUED_SPINLOCKS
depends on SMP
config ARCH_USE_QUEUED_RWLOCKS
bool
config QUEUED_RWLOCKS
def_bool y if ARCH_USE_QUEUED_RWLOCKS
depends on SMP
Computing file changes ...
