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From: arnd@arndb.de (Arnd Bergmann)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 3/3] reset: socfpga: use readl/writel_relaxed
Date: Tue, 05 Jul 2016 13:20:29 +0200	[thread overview]
Message-ID: <10266400.9nrl73J4sT@wuerfel> (raw)
In-Reply-To: <1467713872-4051-3-git-send-email-p.zabel@pengutronix.de>

On Tuesday, July 5, 2016 12:17:52 PM CEST Philipp Zabel wrote:
> This just removes the rmb()/wmb() pair between register read and
> write. Since no relevant reads follow the rmb and no relevant writes
> precede the wmb, they should be safe to remove.
> 
> Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>

We should only do this if you are fixing a bug (which you don't mention
in the changelog), or if you can show a relevant performance
improvement. Is this code ever used in a fast path? If it is,
wouldn't that indicate a problem in some driver?

	Arnd

  reply	other threads:[~2016-07-05 11:20 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-07-05 10:17 [PATCH 1/3] reset: socfpga: no need to store modrst_offset Philipp Zabel
2016-07-05 10:17 ` [PATCH 2/3] reset: sunxi: use readl/writel_relaxed Philipp Zabel
2016-07-05 10:17 ` [PATCH 3/3] reset: socfpga: " Philipp Zabel
2016-07-05 11:20   ` Arnd Bergmann [this message]
2016-07-05 11:40     ` Philipp Zabel
2016-07-05 12:59       ` Arnd Bergmann
2016-07-05 13:20         ` Philipp Zabel
2016-07-06 16:06 ` [PATCH 1/3] reset: socfpga: no need to store modrst_offset Dinh Nguyen
2016-07-06 16:26   ` Philipp Zabel

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