Re: [Patch] fix MTD CFI/LPDDR flash driver huge latency bug

From: Stefani Seibold
Date: Sat Mar 13 2010 - 07:35:27 EST


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@xxxxxxxxxxx> 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.



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