From: Will Deacon <will.deacon@arm.com>
To: linux-arch@vger.kernel.org
Cc: Waiman.Long@hp.com, peterz@infradead.org,
linux-kernel@vger.kernel.org, paulmck@linux.vnet.ibm.com,
Will Deacon <will.deacon@arm.com>
Subject: [PATCH 0/5] Add generic support for relaxed atomics
Date: Mon, 13 Jul 2015 13:31:22 +0100 [thread overview]
Message-ID: <1436790687-11984-1-git-send-email-will.deacon@arm.com> (raw)
Hello,
This patch 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.
For now, the definitions simply take on the existing (i.e. full-barrier)
semantics, but there is a direct mapping onto arm64 and even architectures
with explicit memory barrier instructions (e.g. powerpc, arm) can benefit,
as they do from the existing smp_load_acquire/smp_store_release macros.
The final patch is a proof-of-concept port of the qrwlock over to the
new atomics. It's based on some of the pending patches from me and Waiman,
so it won't apply to mainline but I think it illustrates the usage well
enough.
All feedback welcome,
Will
--->8
Will Deacon (5):
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: make use of acquire/release/relaxed atomics
Documentation/atomic_ops.txt | 4 +-
include/asm-generic/atomic-long.h | 263 ++++++++++++++------------------------
include/asm-generic/qrwlock.h | 13 +-
include/linux/atomic.h | 140 ++++++++++++++++++++
kernel/locking/qrwlock.c | 12 +-
lib/lockref.c | 8 --
6 files changed, 248 insertions(+), 192 deletions(-)
--
2.1.4
next reply other threads:[~2015-07-13 12:33 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-13 12:31 Will Deacon [this message]
2015-07-13 12:31 ` [PATCH 1/5] atomics: add acquire/release/relaxed variants of some atomic operations Will Deacon
2015-07-14 10:25 ` Peter Zijlstra
2015-07-14 10:32 ` Will Deacon
2015-07-14 10:58 ` Peter Zijlstra
2015-07-14 11:08 ` Will Deacon
2015-07-14 11:24 ` Peter Zijlstra
2015-07-14 11:31 ` Will Deacon
2015-07-14 11:38 ` Peter Zijlstra
2015-07-14 15:55 ` Will Deacon
2015-07-13 12:31 ` [PATCH 2/5] asm-generic: rework atomic-long.h to avoid bulk code duplication Will Deacon
2015-07-13 12:31 ` [PATCH 3/5] asm-generic: add relaxed/acquire/release variants for atomic_long_t Will Deacon
2015-07-13 12:31 ` [PATCH 4/5] lockref: remove homebrew cmpxchg64_relaxed macro definition Will Deacon
2015-07-13 12:31 ` [PATCH 5/5] locking/qrwlock: make use of acquire/release/relaxed atomics Will Deacon
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1436790687-11984-1-git-send-email-will.deacon@arm.com \
--to=will.deacon@arm.com \
--cc=Waiman.Long@hp.com \
--cc=linux-arch@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=paulmck@linux.vnet.ibm.com \
--cc=peterz@infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.