[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <20100907153813.936db0c6.akpm@linux-foundation.org>
Date: Tue, 7 Sep 2010 15:38:13 -0700
From: Andrew Morton <akpm@...ux-foundation.org>
To: Anton Vorontsov <avorontsov@...sta.com>
Cc: Wolfram Sang <w.sang@...gutronix.de>,
Albert Herranz <albert_herranz@...oo.es>,
Matt Fleming <matt@...sole-pimps.org>,
Ben Dooks <ben-linux@...ff.org>,
Pierre Ossman <pierre@...man.eu>, linux-mmc@...r.kernel.org,
linux-kernel@...r.kernel.org, linuxppc-dev@...abs.org
Subject: Re: [PATCH 0/8] sdhci: Move real work out of an atomic context
On Wed, 14 Jul 2010 17:07:28 +0400
Anton Vorontsov <avorontsov@...sta.com> wrote:
> Hi all,
>
> Currently the sdhci driver does everything in the atomic context.
> And what is worse, PIO transfers are made from the IRQ handler.
>
> This causes huge latencies (up to 120 ms). On some P2020 SOCs,
> DMA and card detection is broken, which means that kernel polls
> for the card via PIO transfers every second. Needless to say
> that this is quite bad.
>
> So, this patch set reworks sdhci code to avoid atomic context,
> almost completely. We only do two device memory operations
> in the atomic context, and all the rest is threaded.
>
> I noticed no throughput drop neither with PIO transfers nor
> with DMA (tested on MPC8569E CPU), while latencies should be
> greatly improved.
>
This patchset isn't causing any problems yet, but may do so in the
future and will impact the validity of any testing. It seems to be
kind of stuck. Should I drop it all?
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists