From: Arnd Bergmann <arnd@arndb.de>
To: Peter Zijlstra <peterz@infradead.org>
Cc: "Will Deacon" <will@kernel.org>,
"Boqun Feng" <boqun.feng@gmail.com>,
"Ingo Molnar" <mingo@kernel.org>,
"Waiman Long" <longman@redhat.com>,
"Arnd Bergmann" <arnd@arndb.de>,
linux-arch <linux-arch@vger.kernel.org>,
"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
"Guo Ren" <guoren@kernel.org>,
"Palmer Dabbelt" <palmerdabbelt@google.com>,
"Anup Patel" <anup@brainfault.org>,
linux-riscv <linux-riscv@lists.infradead.org>,
"Christoph Müllner" <christophm30@gmail.com>,
"Stafford Horne" <shorne@gmail.com>
Subject: Re: [PATCH] locking: Generic ticket lock
Date: Thu, 21 Oct 2021 15:49:51 +0200 [thread overview]
Message-ID: <CAK8P3a2+=9jjyqN5dMOb4+bYJy=q5G3CxFaCW+=4xryz-S=zYA@mail.gmail.com> (raw)
In-Reply-To: <YXFli3mzMishRpEq@hirez.programming.kicks-ass.net>
On Thu, Oct 21, 2021 at 3:05 PM Peter Zijlstra <peterz@infradead.org> wrote:
>
> Therefore provide ticket locks, which depend on a single atomic
> operation (fetch_add) while still providing fairness.
Nice!
Aside from the qspinlock vs ticket-lock question, can you describe the
tradeoffs between this generic ticket lock and a custom implementation
in architecture code? Should we convert most architectures over
to the generic code in the long run, or is there something they
can usually do better with an inline asm based ticket lock or
a trivial test-and-set?
> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> ---
> include/asm-generic/qspinlock.h | 30 +++++++++
> include/asm-generic/ticket_lock_types.h | 11 +++
> include/asm-generic/ticket_lock.h | 97 ++++++++++++++++++++++++++++++++
> 3 files changed, 138 insertions(+)
If anyone wants to use this for their architecture, feel free to add
Acked-by: Arnd Bergmann <arnd@arndb.de>
to merge it through the respective architecture git tree. If there is more
than one architecture that wants it right now, I could also take them
all through
the asm-generic tree.
Arnd
next prev parent reply other threads:[~2021-10-21 13:50 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-21 13:05 [PATCH] locking: Generic ticket lock Peter Zijlstra
2021-10-21 13:12 ` Peter Zijlstra
2021-10-21 13:50 ` Stafford Horne
2021-10-21 13:49 ` Arnd Bergmann [this message]
2021-10-21 15:14 ` Peter Zijlstra
2021-10-21 15:31 ` Arnd Bergmann
2021-10-21 16:28 ` Peter Zijlstra
2021-10-21 18:04 ` Waiman Long
2021-10-22 15:19 ` Boqun Feng
2021-10-22 2:04 ` Guo Ren
2021-10-22 9:23 ` Mark Rutland
2021-10-22 12:31 ` Peter Zijlstra
2021-12-14 15:40 ` Will Deacon
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