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* powerpc: Make {cmp}xchg* and their atomic_ versions fully orderedBoqun Feng2016-01-311-8/+8
| | | | | | | | | | | | | | | | | | | | | | | | commit 81d7a3294de7e9828310bbf986a67246b13fa01e upstream. According to memory-barriers.txt, xchg*, cmpxchg* and their atomic_ versions all need to be fully ordered, however they are now just RELEASE+ACQUIRE, which are not fully ordered. So also replace PPC_RELEASE_BARRIER and PPC_ACQUIRE_BARRIER with PPC_ATOMIC_ENTRY_BARRIER and PPC_ATOMIC_EXIT_BARRIER in __{cmp,}xchg_{u32,u64} respectively to guarantee fully ordered semantics of atomic{,64}_{cmp,}xchg() and {cmp,}xchg(), as a complement of commit b97021f85517 ("powerpc: Fix atomic_xxx_return barrier semantics") This patch depends on patch "powerpc: Make value-returning atomics fully ordered" for PPC_ATOMIC_ENTRY_BARRIER definition. Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* arch: Remove __ARCH_HAVE_CMPXCHGThomas Gleixner2015-05-131-1/+0
| | | | | | | | We removed the only user of this define in the rtmutex code. Get rid of it. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
* powerpc: Add support for the optimised lockref implementationMichael Ellerman2014-01-281-0/+1
| | | | | | | | | | | | | | | | | | | | | | This commit adds the architecture support required to enable the optimised implementation of lockrefs. That's as simple as defining arch_spin_value_unlocked() and selecting the Kconfig option. We also define cmpxchg64_relaxed(), because the lockref code does not need the cmpxchg to have barrier semantics. Using Linus' test case[1] on one system I see a 4x improvement for the basic enablement, and a further 1.3x for cmpxchg64_relaxed(), for a total of 5.3x vs the baseline. On another system I see more like 2x improvement. [1]: http://marc.info/?l=linux-fsdevel&m=137782380714721&w=4 Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* Disintegrate asm/system.h for PowerPCDavid Howells2012-03-281-0/+309
Disintegrate asm/system.h for PowerPC. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> cc: linuxppc-dev@lists.ozlabs.org
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