Re: [PATCH v2] Make VM_MAX_READAHEAD a kernel parameter

From: Dave Chinner
Date: Mon Feb 22 2010 - 21:25:48 EST


On Sun, Feb 21, 2010 at 10:26:00PM +0800, Wu Fengguang wrote:
> Nikanth,
>
> > > > + readahead= Default readahead value for block devices.
> > > > +
> > >
> > > I think the description should define the units (kb) and valid value
> > > ranges e.g. page size to something not excessive - say 65536kb. The
> > > above description is, IMO, useless without refering to the source to
> > > find out this information....
> > >
> >
> > The parameter can be specified with/without any suffix(k/m/g) that memparse()
> > helper function can accept. So it can take 1M, 1024k, 1050620. I checked other
> > parameters that use memparse() to get similar values and they didn't document
> > it. May be this should be described here.
>
> Hope this helps clarify things to user:
>
> + readahead=nn[KM]
> + Default max readahead size for block devices.
> + Range: 0; 4k - 128m

Yes, that is exactly what I was thinÄing of. Thanks.

Cheers,

Dave.
--
Dave Chinner
david@xxxxxxxxxxxxx
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