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Message-Id: <20220424072918.2596899-1-guoren@kernel.org>
Date: Sun, 24 Apr 2022 15:29:15 +0800
From: guoren@...nel.org
To: guoren@...nel.org, arnd@...db.de, mark.rutland@....com,
boqun.feng@...il.com, peterz@...radead.org, will@...nel.org
Cc: linux-arch@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-csky@...r.kernel.org, Guo Ren <guoren@...ux.alibaba.com>
Subject: [PATCH V4 0/3] csky: Optimize atomic_ops & cmpxchg
From: Guo Ren <guoren@...ux.alibaba.com>
Optimize arch_xchg|cmpxchg|cmpxchg_local with ASM acquire|release
instructions instead of previous C based.
The generic atomic.h used cmpxchg to implement the atomic
operations, it will cause daul loop to reduce the forward
guarantee. The patch implement csky custom atomic operations with
ldex/stex instructions for the best performance.
Changes in V4:
- Remove RELEASE_FENCE in ldex/stex loop by Buoqun's advice
Changes in V3:
- Add arch_atomic_(fetch_add_unless, inc_unless_negative,
dec_unless_positive, dec_if_positive)
Changes in V2:
- Fixup use of acquire + release for barrier semantics by Rutland.
Guo Ren (3):
csky: atomic: Optimize cmpxchg with acquire & release
csky: atomic: Add custom atomic.h implementation
csky: atomic: Add conditional atomic operations' optimization
arch/csky/include/asm/atomic.h | 237 ++++++++++++++++++++++++++++++++
arch/csky/include/asm/barrier.h | 11 +-
arch/csky/include/asm/cmpxchg.h | 64 ++++++++-
3 files changed, 304 insertions(+), 8 deletions(-)
create mode 100644 arch/csky/include/asm/atomic.h
--
2.25.1
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