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From: guoren@kernel.org
To: guoren@kernel.org, arnd@arndb.de, mark.rutland@arm.com,
	boqun.feng@gmail.com, peterz@infradead.org, will@kernel.org
Cc: linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-csky@vger.kernel.org, Guo Ren <guoren@linux.alibaba.com>
Subject: [PATCH V3 0/3] csky: Optimize with acquire & release for atomic & cmpxchg
Date: Sun, 17 Apr 2022 16:32:01 +0800	[thread overview]
Message-ID: <20220417083204.2048364-1-guoren@kernel.org> (raw)

From: Guo Ren <guoren@linux.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.

Important reference commit:
8e86f0b409a4 ("arm64: atomics: fix use of acquire + release for
full barrier semantics")

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: cmpxchg: Optimize with acquire & release
  csky: atomic: Add custom atomic.h implementation
  csky: atomic: Add conditional atomic operations' optimization

 arch/csky/include/asm/atomic.h  | 249 ++++++++++++++++++++++++++++++++
 arch/csky/include/asm/barrier.h |  11 +-
 arch/csky/include/asm/cmpxchg.h |  64 +++++++-
 3 files changed, 316 insertions(+), 8 deletions(-)
 create mode 100644 arch/csky/include/asm/atomic.h

-- 
2.25.1


             reply	other threads:[~2022-04-17  8:32 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-04-17  8:32 guoren [this message]
2022-04-17  8:32 ` [PATCH V3 1/3] csky: cmpxchg: Optimize with acquire & release guoren
2022-04-22  3:20   ` Boqun Feng
2022-04-22  3:45     ` Guo Ren
2022-04-17  8:32 ` [PATCH V3 2/3] csky: atomic: Add custom atomic.h implementation guoren
2022-04-17  8:32 ` [PATCH V3 3/3] csky: atomic: Add conditional atomic operations' optimization guoren

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