Re: [Fwd: Re: connector is missing in 2.6.12-rc2-mm1]

[Evgeniy Polyakov <johnpol@2ka.mipt.ru>]

On Fri, 2005-04-08 at 09:19 +0400, Evgeniy Polyakov wrote:
> On Fri, 2005-04-08 at 15:08 +1000, Herbert Xu wrote:
> > On Fri, Apr 08, 2005 at 09:11:56AM +0400, Evgeniy Polyakov wrote:
> > >
> > > > Yes but what will go wrong on uni-processor MIPS when you don't do the
> > > > sync in atomic_sub_return?
> > > 
> > > Sync synchornizes cached mamory access,
> > > without it new value may be stored only into cache,
> > > but not into memory.
> > 
> > I know, the same thing holds for most architectures, including i386.
> > However, this is not an issue for uni-processor kernels anywhere else,
> > so what's so special about MIPS?
> 
> Does i386 or ppc has cached and uncached memory?
> No, i386, ppc and others do not require sync on uncached memory access,
> and only instruction not data cache sync on SMP.

Ugh, now I see your point :)
For UP we may have some nitpics with DMA, 
but I doubt anyone will use atomic pointer for DMA.
sync will not be an issue in atomic ops.

> > Cheers,
-- 
        Evgeniy Polyakov

Crash is better than data corruption -- Arthur Grabowski

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