From: Catalin Marinas <catalin.marinas@arm.com>
To: Julien Grall <julien.grall@arm.com>
Cc: linux-rt-users@vger.kernel.org, suzuki.poulose@arm.com,
bigeasy@linutronix.de, will.deacon@arm.com,
linux-kernel@vger.kernel.org, rostedt@goodmis.org,
tglx@linutronix.de, dave.martin@arm.com,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] arm64/cpufeature: Convert hook_lock to raw_spin_lock_t in cpu_enable_ssbs()
Date: Tue, 4 Jun 2019 14:49:01 +0100 [thread overview]
Message-ID: <20190604134901.GE6610@arrakis.emea.arm.com> (raw)
In-Reply-To: <20190530113058.1988-1-julien.grall@arm.com>
On Thu, May 30, 2019 at 12:30:58PM +0100, Julien Grall wrote:
> cpu_enable_ssbs() is called via stop_machine() as part of the cpu_enable
> callback. A spin lock is used to ensure the hook is registered before
> the rest of the callback is executed.
>
> On -RT spin_lock() may sleep. However, all the callees in stop_machine()
> are expected to not sleep. Therefore a raw_spin_lock() is required here.
>
> Given this is already done under stop_machine() and the work done under
> the lock is quite small, the latency should not increase too much.
>
> Signed-off-by: Julien Grall <julien.grall@arm.com>
Queued for 5.3. Thanks.
--
Catalin
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prev parent reply other threads:[~2019-06-04 13:49 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-30 11:30 [PATCH] arm64/cpufeature: Convert hook_lock to raw_spin_lock_t in cpu_enable_ssbs() Julien Grall
2019-05-30 12:01 ` Will Deacon
2019-05-30 13:55 ` Julien Grall
2019-06-04 13:49 ` Catalin Marinas [this message]
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