From: Will Deacon <will.deacon@arm.com>
To: Larry Bassel <larry.bassel@linaro.org>
Cc: Catalin Marinas <Catalin.Marinas@arm.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"linaro-kernel@lists.linaro.org" <linaro-kernel@lists.linaro.org>,
"khilman@linaro.org" <khilman@linaro.org>
Subject: Re: [PATCH] arm64: Support arch_irq_work_raise() via self IPIs
Date: Tue, 6 May 2014 13:30:20 +0100 [thread overview]
Message-ID: <20140506123020.GC30234@arm.com> (raw)
In-Reply-To: <1399322907-21280-1-git-send-email-larry.bassel@linaro.org>
On Mon, May 05, 2014 at 09:48:27PM +0100, Larry Bassel wrote:
> Support for arch_irq_work_raise() was missing from
> arm64 (a prerequisite for FULL_NOHZ).
>
> This patch is based on the arm32 patch ARM 7872/1
> which ports cleanly.
>
> commit bf18525fd793101df42a1344ecc48b49b62e48c9
> Author: Stephen Boyd <sboyd@codeaurora.org>
> Date: Tue Oct 29 20:32:56 2013 +0100
>
> ARM: 7872/1: Support arch_irq_work_raise() via self IPIs
>
> By default, IRQ work is run from the tick interrupt (see
> irq_work_run() in update_process_times()). When we're in full
> NOHZ mode, restarting the tick requires the use of IRQ work and
> if the only place we run IRQ work is in the tick interrupt we
> have an unbreakable cycle. Implement arch_irq_work_raise() via
> self IPIs to break this cycle and get the tick started again.
> Note that we implement this via IPIs which are only available on
> SMP builds. This shouldn't be a problem because full NOHZ is only
> supported on SMP builds anyway.
>
> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
> Reviewed-by: Kevin Hilman <khilman@linaro.org>
> Cc: Frederic Weisbecker <fweisbec@gmail.com>
> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
>
> Signed-off-by: Larry Bassel <larry.bassel@linaro.org>
> Reviewed-by: Kevin Hilman <khilman@linaro.org>
Looks fine to me, thanks.
Will
next prev parent reply other threads:[~2014-05-06 12:30 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-05 20:48 [PATCH] arm64: Support arch_irq_work_raise() via self IPIs Larry Bassel
2014-05-06 12:30 ` Will Deacon [this message]
2014-05-09 15:57 ` Catalin Marinas
2014-05-10 21:42 ` Larry Bassel
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