On Wed, May 23, 2007 at 09:03:02PM -0700, Christoph Lameter wrote:
> On Thu, 24 May 2007, Paul Mackerras wrote:
> > Also there is the problem that some drivers use ZONE_DMA allocations
> > because their device can only generate addresses below some limit, but
> > on a platform with an IOMMU there i
> Also there is the problem that some drivers use ZONE_DMA allocations
> because their device can only generate addresses below some limit, but
> on a platform with an IOMMU there is in fact no restriction on what
> memory the device can access.
Bzt - have to call your bluff on that one
The I
On Wed, May 23, 2007 at 04:07:12PM -0700, Christoph Lameter wrote:
> On Wed, 23 May 2007, Russell King wrote:
> > At the end of the day, it is _far_ simpler from an architectural point
> > of view for memory to live in the DMA zone and disable the normal and
> > highmem zones than it is to selectiv
On Thu, 24 May 2007, Paul Mackerras wrote:
> That is (presumably) true today, but is in fact a redefinition of what
> ZONE_DMA historically was for.
I do not know too much about the history but when I tried to correlate
all the different ways that arches use the zone this definition was the
most
Christoph Lameter writes:
> > The DMA zone is for memory allocations _for_ _DMA_. If all your memory
> > is DMA-able then it belongs in the DMA zone.
>
> Nope. The DMA zone is for crappy DMA devices that can only use a portion
> of memory.
That is (presumably) true today, but is in fact a rede
On Wed, 23 May 2007, Russell King wrote:
> > GFP_DMA allocations are an exception and that exception can be removed
> > from the core VM by not defining ZONE_DMA. You cannot switch off the
> > NORMAL zone.
>
> I'd like to be able to switch off the normal and highmem zones and leave
> just the D
On Wed, May 23, 2007 at 10:15:10AM -0700, Christoph Lameter wrote:
> On Wed, 23 May 2007, Russell King wrote:
>
> > > That is wrong. ppc should have ZONE_NORMAL and no ZONE_DMA.
> > > Otherwise you cannot switch off ZONE_DMA and you cannot switch off
> > > bounce. ZONE_DMA is a zone for exception
On Wed, 23 May 2007, Russell King wrote:
> > That is wrong. ppc should have ZONE_NORMAL and no ZONE_DMA.
> > Otherwise you cannot switch off ZONE_DMA and you cannot switch off
> > bounce. ZONE_DMA is a zone for exceptional allocs. If you do not have
> > those then you only have normal allocs ->
On Mon, May 21, 2007 at 10:27:16PM -0700, Christoph Lameter wrote:
> On Tue, 22 May 2007, KAMEZAWA Hiroyuki wrote:
>
> > > +config BOUNCE
> > > + def_bool y
> > > + depends on BLOCK && MMU && (ZONE_DMA || HIGHMEM)
> > > +
> >
> > AFAIK, ppc has only ZONE_DMA and it never needs bounce.
> > Is this
On Mon, May 21 2007, Christoph Lameter wrote:
> The bounce buffer logic is included on systems that do not need it.
> If a system does not have zones like ZONE_DMA and ZONE_HIGHMEM that
> can lead to the use of bounce buffers then there is no need to reserve
> memory pools etc etc. This is true f.
On Tue, 22 May 2007, KAMEZAWA Hiroyuki wrote:
> > +config BOUNCE
> > + def_bool y
> > + depends on BLOCK && MMU && (ZONE_DMA || HIGHMEM)
> > +
>
> AFAIK, ppc has only ZONE_DMA and it never needs bounce.
> Is this ok ?
That is wrong. ppc should have ZONE_NORMAL and no ZONE_DMA.
Otherwise you
On Mon, 21 May 2007 21:03:40 -0700 (PDT)
Christoph Lameter <[EMAIL PROTECTED]> wrote:
> The bounce buffer logic is included on systems that do not need it.
> If a system does not have zones like ZONE_DMA and ZONE_HIGHMEM that
> can lead to the use of bounce buffers then there is no need to reserve
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