From: Palmer Dabbelt <palmer@rivosinc.com>
To: Arnd Bergmann <arnd@arndb.de>
Cc: guoren@kernel.org, peterz@infradead.org, mingo@redhat.com,
Will Deacon <will@kernel.org>,
longman@redhat.com, boqun.feng@gmail.com, jonas@southpole.se,
stefan.kristiansson@saunalahti.fi, shorne@gmail.com,
Paul Walmsley <paul.walmsley@sifive.com>,
Palmer Dabbelt <palmer@dabbelt.com>,
aou@eecs.berkeley.edu, Arnd Bergmann <arnd@arndb.de>,
macro@orcam.me.uk, Greg KH <gregkh@linuxfoundation.org>,
sudipm.mukherjee@gmail.com, jszhang@kernel.org,
linux-csky@vger.kernel.org, linux-kernel@vger.kernel.org,
openrisc@lists.librecores.org, linux-riscv@lists.infradead.org,
linux-arch@vger.kernel.org, linux-riscv@lists.infradead.org,
linux-kernel@vger.kernel.org,
Palmer Dabbelt <palmer@rivosinc.com>
Subject: [PATCH v5 3/7] asm-generic: qrwlock: Document the spinlock fairness requirements
Date: Mon, 9 May 2022 15:29:52 -0700 [thread overview]
Message-ID: <20220509222956.2886-4-palmer@rivosinc.com> (raw)
In-Reply-To: <20220509222956.2886-1-palmer@rivosinc.com>
From: Palmer Dabbelt <palmer@rivosinc.com>
I could only find the fairness requirements documented as the C code,
this calls them out in a comment just to be a bit more explicit.
Reviewed-by: Arnd Bergmann <arnd@arndb.de
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
---
include/asm-generic/qrwlock.h | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/include/asm-generic/qrwlock.h b/include/asm-generic/qrwlock.h
index 7ae0ece07b4e..24ae09c1db9f 100644
--- a/include/asm-generic/qrwlock.h
+++ b/include/asm-generic/qrwlock.h
@@ -2,6 +2,10 @@
/*
* Queue read/write lock
*
+ * These use generic atomic and locking routines, but depend on a fair spinlock
+ * implementation in order to be fair themselves. The implementation in
+ * asm-generic/spinlock.h meets these requirements.
+ *
* (C) Copyright 2013-2014 Hewlett-Packard Development Company, L.P.
*
* Authors: Waiman Long <waiman.long@hp.com>
--
2.34.1
next prev parent reply other threads:[~2022-05-09 22:32 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-09 22:29 [PATCH v5 0/7] Generic Ticket Spinlocks Palmer Dabbelt
2022-05-09 22:29 ` [PATCH v5 1/7] asm-generic: ticket-lock: New generic ticket-based spinlock Palmer Dabbelt
2022-05-09 22:29 ` [PATCH v5 2/7] asm-generic: qspinlock: Indicate the use of mixed-size atomics Palmer Dabbelt
2022-05-09 22:29 ` Palmer Dabbelt [this message]
2022-05-09 22:29 ` [PATCH v5 4/7] openrisc: Move to ticket-spinlock Palmer Dabbelt
2022-05-09 22:29 ` [PATCH v5 5/7] RISC-V: Move to generic spinlocks Palmer Dabbelt
2022-05-09 22:29 ` [PATCH v5 6/7] RISC-V: Move to queued RW locks Palmer Dabbelt
2022-05-09 22:29 ` [PATCH v5 7/7] csky: Move to generic ticket-spinlock Palmer Dabbelt
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