linux-stable.git/arch/arm/include/asm/atomic.h, branch linux-4.3.y Linux kernel stable tree locking, ARM, atomics: Define our SMP atomics in terms of _relaxed() operations 2015-08-12T09:59:10+00:00 Will Deacon will.deacon@arm.com 2015-08-06T16:54:44+00:00 0ca326de7aa9cb253db9c1a3eb3f0487c8dbf912 By defining our SMP atomics in terms of relaxed operations, we gain a small reduction in code size and have acquire/release/fence variants generated automatically by the core code. Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Waiman.Long@hp.com Cc: paulmck@linux.vnet.ibm.com Link: http://lkml.kernel.org/r/1438880084-18856-9-git-send-email-will.deacon@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org> 
By defining our SMP atomics in terms of relaxed operations, we gain
a small reduction in code size and have acquire/release/fence variants
generated automatically by the core code.

Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Waiman.Long@hp.com
Cc: paulmck@linux.vnet.ibm.com
Link: http://lkml.kernel.org/r/1438880084-18856-9-git-send-email-will.deacon@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
atomic: Provide atomic_{or,xor,and} 2015-07-27T12:06:24+00:00 Peter Zijlstra peterz@infradead.org 2014-04-23T17:32:50+00:00 e6942b7de2dfe44ebde9bae57dadece5abca9de8 Implement atomic logic ops -- atomic_{or,xor,and}. These will replace the atomic_{set,clear}_mask functions that are available on some archs. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> 
Implement atomic logic ops -- atomic_{or,xor,and}.

These will replace the atomic_{set,clear}_mask functions that are
available on some archs.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
arm: Provide atomic_{or,xor,and} 2015-07-27T12:06:21+00:00 Peter Zijlstra peterz@infradead.org 2014-04-23T18:04:39+00:00 125897908c718972351b589da89b7f990892d4df Implement atomic logic ops -- atomic_{or,xor,and}. These will replace the atomic_{set,clear}_mask functions that are available on some archs. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> 
Implement atomic logic ops -- atomic_{or,xor,and}.

These will replace the atomic_{set,clear}_mask functions that are
available on some archs.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
locking,arch: Use ACCESS_ONCE() instead of cast to volatile in atomic_read() 2014-10-03T04:06:23+00:00 Pranith Kumar bobby.prani@gmail.com 2014-09-23T14:29:50+00:00 2291059c852706c6f5ffb400366042b7625066cd Use the much more reader friendly ACCESS_ONCE() instead of the cast to volatile. This is purely a stylistic change. Signed-off-by: Pranith Kumar <bobby.prani@gmail.com> Acked-by: Jesper Nilsson <jesper.nilsson@axis.com> Acked-by: Hans-Christian Egtvedt <egtvedt@samfundet.no> Acked-by: Max Filippov <jcmvbkbc@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: linux-arch@vger.kernel.org Link: http://lkml.kernel.org/r/1411482607-20948-1-git-send-email-bobby.prani@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org> 
Use the much more reader friendly ACCESS_ONCE() instead of the cast to volatile.
This is purely a stylistic change.

Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
Acked-by: Jesper Nilsson <jesper.nilsson@axis.com>
Acked-by: Hans-Christian Egtvedt <egtvedt@samfundet.no>
Acked-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-arch@vger.kernel.org
Link: http://lkml.kernel.org/r/1411482607-20948-1-git-send-email-bobby.prani@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
locking,arch,arm: Fold atomic_ops 2014-08-14T10:48:04+00:00 Peter Zijlstra peterz@infradead.org 2014-03-23T15:38:18+00:00 aee9a55452f0371258e18b41649ce650ff344090 Many of the atomic op implementations are the same except for one instruction; fold the lot into a few CPP macros and reduce LoC. This also prepares for easy addition of new ops. Requires the asm_op because of eor. Signed-off-by: Peter Zijlstra <peterz@infradead.org> Acked-by: Will Deacon <will.deacon@arm.com> Cc: Chen Gang <gang.chen@asianux.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Nicolas Pitre <nico@linaro.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Albin Tonnerre <albin.tonnerre@arm.com> Cc: Victor Kamensky <victor.kamensky@linaro.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: linux-arm-kernel@lists.infradead.org Link: http://lkml.kernel.org/r/20140508135851.939725247@infradead.org Signed-off-by: Ingo Molnar <mingo@kernel.org> 
Many of the atomic op implementations are the same except for one
instruction; fold the lot into a few CPP macros and reduce LoC.

This also prepares for easy addition of new ops.

Requires the asm_op because of eor.

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Will Deacon <will.deacon@arm.com>
Cc: Chen Gang <gang.chen@asianux.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nicolas Pitre <nico@linaro.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Albin Tonnerre <albin.tonnerre@arm.com>
Cc: Victor Kamensky <victor.kamensky@linaro.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/20140508135851.939725247@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
arch,arm: Convert smp_mb__*() 2014-04-18T09:40:32+00:00 Peter Zijlstra peterz@infradead.org 2014-03-12T16:11:00+00:00 030d0178bdbd237c1f0577f03bbc1d7140a75044 ARM uses ll/sc primitives that do not imply barriers for all regular atomic ops, therefore smp_mb__{before,after} need be a full barrier. Since ARM doesn't use asm-generic/barrier.h include the required definitions in its asm/barrier.h Signed-off-by: Peter Zijlstra <peterz@infradead.org> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Link: http://lkml.kernel.org/n/tip-yijo7sglsl7uusbp13upcuvo@git.kernel.org Cc: Albin Tonnerre <albin.tonnerre@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Chen Gang <gang.chen@asianux.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Nicolas Pitre <nico@linaro.org> Cc: Russell King <linux@arm.linux.org.uk> Cc: Victor Kamensky <victor.kamensky@linaro.org> Cc: Will Deacon <will.deacon@arm.com> Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org> 
ARM uses ll/sc primitives that do not imply barriers for all regular
atomic ops, therefore smp_mb__{before,after} need be a full barrier.

Since ARM doesn't use asm-generic/barrier.h include the required
definitions in its asm/barrier.h

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/n/tip-yijo7sglsl7uusbp13upcuvo@git.kernel.org
Cc: Albin Tonnerre <albin.tonnerre@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chen Gang <gang.chen@asianux.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nicolas Pitre <nico@linaro.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Victor Kamensky <victor.kamensky@linaro.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
ARM: 7983/1: atomics: implement a better __atomic_add_unless for v6+ 2014-02-25T11:35:08+00:00 Will Deacon will.deacon@arm.com 2014-02-21T16:01:48+00:00 db38ee874c48713d0723221d08332242e0088970 Looking at perf profiles of multi-threaded hackbench runs, a significant performance hit appears to manifest from the cmpxchg loop used to implement the 32-bit atomic_add_unless function. This can be mitigated by writing a direct implementation of __atomic_add_unless which doesn't require iteration outside of the atomic operation. Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> 
Looking at perf profiles of multi-threaded hackbench runs, a significant
performance hit appears to manifest from the cmpxchg loop used to
implement the 32-bit atomic_add_unless function. This can be mitigated
by writing a direct implementation of __atomic_add_unless which doesn't
require iteration outside of the atomic operation.

Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
ARM: 7984/1: prefetch: add prefetchw invocations for barriered atomics 2014-02-25T11:30:20+00:00 Will Deacon will.deacon@arm.com 2014-02-21T16:01:48+00:00 c32ffce0f66e5d1d4856254516e24f5ef275cd00 After a bunch of benchmarking on the interaction between dmb and pldw, it turns out that issuing the pldw *after* the dmb instruction can give modest performance gains (~3% atomic_add_return improvement on a dual A15). This patch adds prefetchw invocations to our barriered atomic operations including cmpxchg, test_and_xxx and futexes. Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> 
After a bunch of benchmarking on the interaction between dmb and pldw,
it turns out that issuing the pldw *after* the dmb instruction can
give modest performance gains (~3% atomic_add_return improvement on a
dual A15).

This patch adds prefetchw invocations to our barriered atomic operations
including cmpxchg, test_and_xxx and futexes.

Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Merge branch 'devel-stable' into for-next 2013-11-12T10:58:59+00:00 Russell King rmk+kernel@arm.linux.org.uk 2013-11-12T10:58:59+00:00 df762eccbadf87850fbee444d729e0f1b1e946f1 Conflicts: arch/arm/include/asm/atomic.h arch/arm/include/asm/hardirq.h arch/arm/kernel/smp.c 
Conflicts:
	arch/arm/include/asm/atomic.h
	arch/arm/include/asm/hardirq.h
	arch/arm/kernel/smp.c
ARM: 7868/1: arm/arm64: remove atomic_clear_mask() in "include/asm/atomic.h" 2013-11-09T00:00:13+00:00 Chen Gang gang.chen@asianux.com 2013-10-26T14:07:41+00:00 aed3a4ed7222ae37860ae33cbad3ea7a6b2eaf8e In current kernel wide source code, except other architectures, only s390 scsi drivers use atomic_clear_mask(), and arm/arm64 need not support s390 drivers. So remove atomic_clear_mask() from "arm[64]/include/asm/atomic.h". Signed-off-by: Chen Gang <gang.chen@asianux.com> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> 
In current kernel wide source code, except other architectures, only
s390 scsi drivers use atomic_clear_mask(), and arm/arm64 need not
support s390 drivers.

So remove atomic_clear_mask() from "arm[64]/include/asm/atomic.h".

Signed-off-by: Chen Gang <gang.chen@asianux.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>