From: Thorsten Glaser <t.glaser@tarent.de>
To: Mark Rutland <mark.rutland@arm.com>
Cc: linux-kernel@vger.kernel.org, ardb@kernel.org, arnd@arndb.de,
boqun.feng@gmail.com, peterz@infradead.org, will@kernel.org
Subject: Re: [PATCH v2] atomics: fix atomic64_{read_acquire,set_release} fallbacks
Date: Sat, 5 Nov 2022 00:05:30 +0100 (CET) [thread overview]
Message-ID: <fcafd6d9-7d3e-67b0-3176-5fb8e9c322ef@tarent.de> (raw)
In-Reply-To: <20220203161243.3955547-1-mark.rutland@arm.com>
On Thu, 3 Feb 2022, Mark Rutland wrote:
> - smp_store_release(&(v)->counter, i);
> + if (__native_word(atomic_t)) {
> + smp_store_release(&(v)->counter, i);
> + } else {
> + __atomic_release_fence();
> + arch_atomic_set(v, i);
> + }
Shouldn’t this also update Documentation/atomic_t.txt which
currently states:
| The non-RMW ops are (typically) regular LOADs and STOREs and are canonically
| implemented using READ_ONCE(), WRITE_ONCE(), smp_load_acquire() and
| smp_store_release() respectively. Therefore, if you find yourself only using
| the Non-RMW operations of atomic_t, you do not in fact need atomic_t at all
| and are doing it wrong.
With this, direct use of atomic64_set_release() and atomic64_read_acquire()
is (IIUC) not “doing it wrong” any more?
bye,
//mirabilos
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next prev parent reply other threads:[~2022-11-04 23:14 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-03 16:12 Mark Rutland
2022-02-03 16:18 ` Ard Biesheuvel
2022-02-04 0:20 ` Boqun Feng
2022-02-04 11:16 ` Mark Rutland
2022-02-04 15:45 ` Boqun Feng
2022-02-06 14:06 ` Peter Zijlstra
2022-11-04 23:05 ` Thorsten Glaser [this message]
2022-11-07 10:37 ` Mark Rutland
2022-11-07 11:14 ` Thorsten Glaser
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