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Message-Id: <1438880084-18856-1-git-send-email-will.deacon@arm.com>
Date: Thu, 6 Aug 2015 17:54:36 +0100
From: Will Deacon <will.deacon@....com>
To: linux-arch@...r.kernel.org
Cc: Waiman.Long@...com, peterz@...radead.org,
linux-kernel@...r.kernel.org, paulmck@...ux.vnet.ibm.com,
mingo@...nel.org, Will Deacon <will.deacon@....com>
Subject: [PATCH v5 0/8] Add generic support for relaxed atomics
Hi all,
Here is version five of the patches previously posted here:
v1: https://lwn.net/Articles/650862/
v2: https://lwn.net/Articles/651293/
v3: https://lwn.net/Articles/652369/
v4: https://lwn.net/Articles/653388/
The series adds support for a family of relaxed atomics to the kernel.
More specifically:
- acquire/release/relaxed flavours of xchg, cmpxchg and {add,sub}_return
- atomic_read_acquire
- atomic_set_release
This came out of a separate patch series porting the (barrier-heavy)
qrwlock code to arm64. Rather than have arch-specific hooks littered
around the place, it makes more sense to define a core set of relaxed
atomics that can be used regardless of architecture.
Changes since v4 are:
* Drop the ret_t macro parameter in favour of typeof tricks (Peter Z)
* Add a missing acquire to the qrwlock code, as it was based on a
previous patch that I posted (Waiman Long)
Build tested on ARM, arm64, PowerPC and x86.
All feedback welcome,
Will
--->8
Will Deacon (8):
atomics: add acquire/release/relaxed variants of some atomic
operations
asm-generic: rework atomic-long.h to avoid bulk code duplication
asm-generic: add relaxed/acquire/release variants for atomic_long_t
lockref: remove homebrew cmpxchg64_relaxed macro definition
locking/qrwlock: implement queue_write_unlock using smp_store_release
locking/qrwlock: make use of acquire/release/relaxed atomics
include/llist: use linux/atomic.h instead of asm/cmpxchg.h
ARM: atomics: define our SMP atomics in terms of _relaxed operations
arch/arm/include/asm/atomic.h | 37 ++---
arch/arm/include/asm/cmpxchg.h | 47 +-----
arch/x86/include/asm/qrwlock.h | 10 --
include/asm-generic/atomic-long.h | 263 +++++++++++--------------------
include/asm-generic/qrwlock.h | 22 +--
include/linux/atomic.h | 323 ++++++++++++++++++++++++++++++++++++++
include/linux/llist.h | 2 +-
kernel/locking/qrwlock.c | 22 ++-
lib/lockref.c | 8 -
9 files changed, 462 insertions(+), 272 deletions(-)
--
2.1.4
--
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