From: Peter Zijlstra <peterz@infradead.org>
To: Arnd Bergmann <arnd@arndb.de>
Cc: Randy Dunlap <rdunlap@infradead.org>,
Mark Rutland <mark.rutland@arm.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
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Yoshinori Sato <ysato@users.sourceforge.jp>
Subject: Re: [PATCH v2 00/33] locking/atomic: convert all architectures to ARCH_ATOMIC
Date: Wed, 30 Jun 2021 09:55:55 +0200 [thread overview]
Message-ID: <YNwji8yPUfQp/ErQ@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <CAK8P3a2yH+dSWrS=1E0UbwcRhYJEThgrk2i9=omCQvcMMQZcww@mail.gmail.com>
On Tue, Jun 29, 2021 at 09:36:23AM +0200, Arnd Bergmann wrote:
> For the specific case of cmpxchg64(), I do think it would make sense to either
> have a Kconfig symbol that controls the few users, or to provide a spinlock
> based fallback for those that don't have a native implementation.
My preference goes to a Kconfig based solution; I so detest spinlock
based atomics. I dream of the day we can kill the lot of 'em
(sparc32-smp, parisc-smp are always the ones that come to mind).
This is doubly true for the xchg/cmpxchg/cmpxchg64 family of functions
that are supposed to work together with READ_ONCE/WRITE_ONCE but don't
(when 'emulated', we'd need WRITE_ONCE to also be spinlock based in
that case).
That is, at least for atomic64_*() the whole API is self contained so we
can (and do) frob atomic64_set() to behave sanely vs atomic64_cmpxchg().
next prev parent reply other threads:[~2021-06-30 7:57 UTC|newest]
Thread overview: 82+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-25 14:01 Mark Rutland
2021-05-25 14:02 ` [PATCH v2 01/33] locking/atomic: make ARCH_ATOMIC a Kconfig symbol Mark Rutland
2021-05-26 11:24 ` [tip: locking/core] " tip-bot2 for Mark Rutland
2021-05-25 14:02 ` [PATCH v2 02/33] locking/atomic: net: use linux/atomic.h for xchg & cmpxchg Mark Rutland
2021-05-26 11:24 ` [tip: locking/core] " tip-bot2 for Mark Rutland
2021-05-25 14:02 ` [PATCH v2 03/33] locking/atomic: h8300: use asm-generic exclusively Mark Rutland
2021-05-26 11:24 ` [tip: locking/core] " tip-bot2 for Mark Rutland
2021-05-25 14:02 ` [PATCH v2 04/33] locking/atomic: microblaze: " Mark Rutland
2021-05-26 11:24 ` [tip: locking/core] " tip-bot2 for Mark Rutland
2021-05-31 12:31 ` [PATCH v2 04/33] " Michal Simek
2021-05-25 14:02 ` [PATCH v2 05/33] locking/atomic: openrisc: avoid asm-generic/atomic.h Mark Rutland
2021-05-26 11:24 ` [tip: locking/core] " tip-bot2 for Mark Rutland
2021-05-25 14:02 ` [PATCH v2 06/33] locking/atomic: atomic: remove stale comments Mark Rutland
2021-05-26 11:24 ` [tip: locking/core] " tip-bot2 for Mark Rutland
2021-05-25 14:02 ` [PATCH v2 07/33] locking/atomic: atomic: remove redundant include Mark Rutland
2021-05-26 11:24 ` [tip: locking/core] " tip-bot2 for Mark Rutland
2021-05-25 14:02 ` [PATCH v2 08/33] locking/atomic: atomic: simplify ifdeffery Mark Rutland
2021-05-26 11:24 ` [tip: locking/core] " tip-bot2 for Mark Rutland
2021-05-25 14:02 ` [PATCH v2 09/33] locking/atomic: atomic: support ARCH_ATOMIC Mark Rutland
2021-05-26 11:24 ` [tip: locking/core] " tip-bot2 for Mark Rutland
2021-05-25 14:02 ` [PATCH v2 10/33] locking/atomic: atomic64: " Mark Rutland
2021-05-26 11:24 ` [tip: locking/core] " tip-bot2 for Mark Rutland
2021-05-25 14:02 ` [PATCH v2 11/33] locking/atomic: cmpxchg: make `generic` a prefix Mark Rutland
2021-05-26 11:24 ` [tip: locking/core] " tip-bot2 for Mark Rutland
2021-05-25 14:02 ` [PATCH v2 12/33] locking/atomic: cmpxchg: support ARCH_ATOMIC Mark Rutland
2021-05-26 11:24 ` [tip: locking/core] " tip-bot2 for Mark Rutland
2021-05-25 14:02 ` [PATCH v2 13/33] locking/atomic: alpha: move to ARCH_ATOMIC Mark Rutland
2021-05-26 11:24 ` [tip: locking/core] " tip-bot2 for Mark Rutland
2021-05-25 14:02 ` [PATCH v2 14/33] locking/atomic: arc: " Mark Rutland
2021-05-26 11:24 ` [tip: locking/core] " tip-bot2 for Mark Rutland
2021-05-25 14:02 ` [PATCH v2 15/33] locking/atomic: arm: " Mark Rutland
2021-05-26 11:24 ` [tip: locking/core] " tip-bot2 for Mark Rutland
2021-05-25 14:02 ` [PATCH v2 16/33] locking/atomic: csky: " Mark Rutland
2021-05-26 11:24 ` [tip: locking/core] " tip-bot2 for Mark Rutland
2021-05-25 14:02 ` [PATCH v2 17/33] locking/atomic: h8300: " Mark Rutland
2021-05-26 11:24 ` [tip: locking/core] " tip-bot2 for Mark Rutland
2021-05-25 14:02 ` [PATCH v2 18/33] locking/atomic: hexagon: " Mark Rutland
2021-05-26 11:24 ` [tip: locking/core] " tip-bot2 for Mark Rutland
2021-05-25 14:02 ` [PATCH v2 19/33] locking/atomic: ia64: " Mark Rutland
2021-05-26 11:24 ` [tip: locking/core] " tip-bot2 for Mark Rutland
2021-05-25 14:02 ` [PATCH v2 20/33] locking/atomic: m68k: " Mark Rutland
2021-05-26 11:24 ` [tip: locking/core] " tip-bot2 for Mark Rutland
2021-05-25 14:02 ` [PATCH v2 21/33] locking/atomic: microblaze: " Mark Rutland
2021-05-26 11:24 ` [tip: locking/core] " tip-bot2 for Mark Rutland
2021-05-31 12:31 ` [PATCH v2 21/33] " Michal Simek
2021-05-25 14:02 ` [PATCH v2 22/33] locking/atomic: mips: " Mark Rutland
2021-05-26 11:24 ` [tip: locking/core] " tip-bot2 for Mark Rutland
2021-05-25 14:02 ` [PATCH v2 23/33] locking/atomic: nds32: " Mark Rutland
2021-05-26 11:24 ` [tip: locking/core] " tip-bot2 for Mark Rutland
2021-05-25 14:02 ` [PATCH v2 24/33] locking/atomic: nios2: " Mark Rutland
2021-05-26 11:24 ` [tip: locking/core] " tip-bot2 for Mark Rutland
2021-05-25 14:02 ` [PATCH v2 25/33] locking/atomic: openrisc: " Mark Rutland
2021-05-26 11:24 ` [tip: locking/core] " tip-bot2 for Mark Rutland
2021-05-25 14:02 ` [PATCH v2 26/33] locking/atomic: parisc: " Mark Rutland
2021-05-26 11:24 ` [tip: locking/core] " tip-bot2 for Mark Rutland
2021-05-25 14:02 ` [PATCH v2 27/33] locking/atomic: powerpc: " Mark Rutland
2021-05-26 11:24 ` [tip: locking/core] " tip-bot2 for Mark Rutland
2021-05-25 14:02 ` [PATCH v2 28/33] locking/atomic: riscv: " Mark Rutland
2021-05-26 11:24 ` [tip: locking/core] " tip-bot2 for Mark Rutland
2021-05-25 14:02 ` [PATCH v2 29/33] locking/atomic: sh: " Mark Rutland
2021-05-26 11:24 ` [tip: locking/core] " tip-bot2 for Mark Rutland
2021-05-25 14:02 ` [PATCH v2 30/33] locking/atomic: sparc: " Mark Rutland
2021-05-26 11:24 ` [tip: locking/core] " tip-bot2 for Mark Rutland
2021-05-25 14:02 ` [PATCH v2 31/33] locking/atomic: xtensa: " Mark Rutland
2021-05-26 11:24 ` [tip: locking/core] " tip-bot2 for Mark Rutland
2021-05-25 14:02 ` [PATCH v2 32/33] locking/atomic: delete !ARCH_ATOMIC remnants Mark Rutland
2021-05-26 11:24 ` [tip: locking/core] " tip-bot2 for Mark Rutland
2021-05-25 14:02 ` [PATCH v2 33/33] locking/atomics: atomic-instrumented: simplify ifdeffery Mark Rutland
2021-05-26 11:24 ` [tip: locking/core] " tip-bot2 for Mark Rutland
2021-05-26 11:30 ` [PATCH v2 00/33] locking/atomic: convert all architectures to ARCH_ATOMIC Peter Zijlstra
2021-05-26 12:29 ` Junio C Hamano
2021-05-26 14:19 ` Peter Zijlstra
2021-06-05 5:56 ` Randy Dunlap
2021-06-18 8:48 ` Mark Rutland
2021-06-27 21:47 ` Randy Dunlap
2021-06-28 21:22 ` Randy Dunlap
2021-06-28 22:13 ` Peter Zijlstra
2021-06-28 22:21 ` Vineet Gupta
2021-06-28 22:21 ` Randy Dunlap
2021-06-29 7:36 ` Arnd Bergmann
2021-06-30 7:55 ` Peter Zijlstra [this message]
2021-06-30 12:24 ` Arnd Bergmann
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