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From: Paolo Bonzini <pbonzini@redhat.com>
To: "Emilio G. Cota" <cota@braap.org>, qemu-devel@nongnu.org
Cc: "Peter Crosthwaite" <crosthwaite.peter@gmail.com>,
	"Richard Henderson" <rth@twiddle.net>,
	"Eduardo Habkost" <ehabkost@redhat.com>,
	"Alex Bennée" <alex.bennee@linaro.org>
Subject: Re: [Qemu-devel] [PATCH 1/6] qsp: drop atomics when using the seqlock
Date: Mon, 10 Sep 2018 01:32:15 +0200	[thread overview]
Message-ID: <e0055fc2-778d-c9cd-c157-29032085e2e7@redhat.com> (raw)
In-Reply-To: <20180903171831.15446-2-cota@braap.org>

On 03/09/2018 19:18, Emilio G. Cota wrote:
> Using atomics here is a mistake since they're not guaranteed
> to compile.

But isn't it technically a C11 data race if you don't use atomics?
Could we make nocheck read/set degrade to just a volatile access when
used on a variable that is bigger than pointers, or perhaps always
except when using tsan?

Paolo

> Signed-off-by: Emilio G. Cota <cota@braap.org>
> ---
>  util/qsp.c | 16 ++++++++++------
>  1 file changed, 10 insertions(+), 6 deletions(-)
> 

  reply	other threads:[~2018-09-09 23:32 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-09-03 17:18 [Qemu-devel] [PATCH 0/6] i386 + x86_64 mttcg Emilio G. Cota
2018-09-03 17:18 ` [Qemu-devel] [PATCH 1/6] qsp: drop atomics when using the seqlock Emilio G. Cota
2018-09-09 23:32   ` Paolo Bonzini [this message]
2018-09-10 15:44     ` Emilio G. Cota
2018-09-11 11:11       ` Paolo Bonzini
2018-09-03 17:18 ` [Qemu-devel] [PATCH 2/6] test-rcu-list: avoid torn accesses to n_reclaims and n_nodes_removed Emilio G. Cota
2018-09-04 17:37   ` Murilo Opsfelder Araujo
2018-09-04 19:35     ` Emilio G. Cota
2018-09-04 20:56       ` Murilo Opsfelder Araujo
2018-09-04 21:32         ` Emilio G. Cota
2018-09-11 11:25         ` Paolo Bonzini
2018-09-03 17:18 ` [Qemu-devel] [PATCH 3/6] atomic: fix comment s/x64_64/x86_64/ Emilio G. Cota
2018-09-10  9:12   ` Alex Bennée
2018-09-03 17:18 ` [Qemu-devel] [PATCH 4/6] cpus: initialize timers_state.vm_clock_lock Emilio G. Cota
2018-09-10  9:13   ` Alex Bennée
2018-09-03 17:18 ` [Qemu-devel] [PATCH 5/6] target/i386/translate: use thread-local storage in !user-mode Emilio G. Cota
2018-09-10  9:17   ` Alex Bennée
2018-09-10 12:30     ` Emilio G. Cota
2018-09-10 13:43       ` Alex Bennée
2018-09-11 11:24       ` Paolo Bonzini
2018-09-11 17:21         ` Emilio G. Cota
2018-09-03 17:18 ` [Qemu-devel] [PATCH 6/6] configure: enable mttcg for i386 and x86_64 Emilio G. Cota
2018-09-11 11:25 ` [Qemu-devel] [PATCH 0/6] i386 + x86_64 mttcg Paolo Bonzini

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