From: Stefani Seibold <stefani@seibold.net>
To: Jamie Lokier <jamie@shareable.org>
Cc: linux-mtd@lists.infradead.org,
Andrew Morton <akpm@linux-foundation.org>,
David Woodhouse <dwmw2@infradead.org>,
"Kreuzer, Michael \(NSN - DE/Ulm\)" <michael.kreuzer@nsn.com>,
linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [Patch] fix MTD CFI/LPDDR flash driver huge latency bug
Date: Sat, 13 Mar 2010 13:35:44 +0100 [thread overview]
Message-ID: <1268483744.6339.25.camel@wall-e> (raw)
In-Reply-To: <20100312233820.GH6491@shareable.org>
Am Freitag, den 12.03.2010, 23:38 +0000 schrieb Jamie Lokier:
> Andrew Morton wrote:
> > On Sat, 06 Mar 2010 17:48:57 +0100
> > Stefani Seibold <stefani@seibold.net> wrote:
> >
> > > The patch change all the use of spin_lock operations for xxxx->mutex
> > > into mutex operations, which is exact what the name says and means.
>
> It would be even better if it also split the critical sections into
> smaller ones with cond_resched() between, so that non-preemptible
> kernels benefit too.
>
The problem is the memcpy operation which is very slow. A cond_resched
wouldn't help, since the cpu bus is blocked during the transfer of the
word.
WARNING: multiple messages have this Message-ID (diff)
From: Stefani Seibold <stefani@seibold.net>
To: Jamie Lokier <jamie@shareable.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
David Woodhouse <dwmw2@infradead.org>,
"Kreuzer, Michael (NSN - DE/Ulm)" <michael.kreuzer@nsn.com>,
linux-mtd@lists.infradead.org,
linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [Patch] fix MTD CFI/LPDDR flash driver huge latency bug
Date: Sat, 13 Mar 2010 13:35:44 +0100 [thread overview]
Message-ID: <1268483744.6339.25.camel@wall-e> (raw)
In-Reply-To: <20100312233820.GH6491@shareable.org>
Am Freitag, den 12.03.2010, 23:38 +0000 schrieb Jamie Lokier:
> Andrew Morton wrote:
> > On Sat, 06 Mar 2010 17:48:57 +0100
> > Stefani Seibold <stefani@seibold.net> wrote:
> >
> > > The patch change all the use of spin_lock operations for xxxx->mutex
> > > into mutex operations, which is exact what the name says and means.
>
> It would be even better if it also split the critical sections into
> smaller ones with cond_resched() between, so that non-preemptible
> kernels benefit too.
>
The problem is the memcpy operation which is very slow. A cond_resched
wouldn't help, since the cpu bus is blocked during the transfer of the
word.
next prev parent reply other threads:[~2010-03-13 12:35 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-03-06 16:48 [Patch] fix MTD CFI/LPDDR flash driver huge latency bug Stefani Seibold
2010-03-06 16:48 ` Stefani Seibold
2010-03-12 22:23 ` Andrew Morton
2010-03-12 22:23 ` Andrew Morton
2010-03-12 23:38 ` Jamie Lokier
2010-03-12 23:38 ` Jamie Lokier
2010-03-13 12:35 ` Stefani Seibold [this message]
2010-03-13 12:35 ` Stefani Seibold
2010-03-15 3:03 ` Jamie Lokier
2010-03-15 3:03 ` Jamie Lokier
2010-03-15 6:15 ` Stefani Seibold
2010-03-15 6:15 ` Stefani Seibold
2010-03-15 14:24 ` Jamie Lokier
2010-03-15 14:24 ` Jamie Lokier
2010-03-19 8:29 ` David Woodhouse
2010-03-19 8:29 ` David Woodhouse
2010-03-19 8:40 ` Jamie Lokier
2010-03-19 8:40 ` Jamie Lokier
2010-03-13 12:31 ` Stefani Seibold
2010-03-13 12:31 ` Stefani Seibold
2010-03-13 11:25 ` Andrew Morton
2010-03-13 11:25 ` Andrew Morton
2010-03-13 17:00 ` Stefani Seibold
2010-03-13 17:00 ` Stefani Seibold
-- strict thread matches above, loose matches on Subject: below --
2010-02-28 17:00 Stefani Seibold
2010-02-28 17:00 ` Stefani Seibold
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