linux-toradex.git/arch/powerpc/include/asm/cmpxchg.h, branch v4.4.65 Linux kernel for Apalis and Colibri modules powerpc: Make {cmp}xchg* and their atomic_ versions fully ordered 2016-01-31T19:29:03+00:00 Boqun Feng boqun.feng@gmail.com 2015-11-02T01:30:32+00:00 badc688439f09f440e8d3dcd5d23457e54dfa8eb 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> 
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_CMPXCHG 2015-05-13T08:55:42+00:00 Thomas Gleixner tglx@linutronix.de 2015-05-13T08:54:25+00:00 a22e5f579b98f16e24b7184d01c35de26eb5a7f7 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> 
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 implementation 2014-01-28T03:45:43+00:00 Michael Ellerman mpe@ellerman.id.au 2014-01-15T07:14:28+00:00 3405d230b374b6923878b21b8d708d7db1f734ef 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> 
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 PowerPC 2012-03-28T17:30:02+00:00 David Howells dhowells@redhat.com 2012-03-28T17:30:02+00:00 ae3a197e3d0bfe3f4bf1693723e82dc018c096f3 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 
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