Re: 0-order allocation failed in 2.4.10-pre8

[Jens Axboe]

On Sun, Sep 16 2001, Daniel Phillips wrote:
> On September 16, 2001 10:03 am, Jens Axboe wrote:
> > On Sun, Sep 16 2001, Daniel Phillips wrote:
> > > > Use the
> > > > 
> > > > 
> *.kernel.org/pub/linux/kernel/people/axboe/patches/2.4.9/block-highmem-all
> > > > 
> > > > patch and you can use highmem without having to worry about failed
> > > > 0-order bounce pages allocations.
> > > 
> > > Right, by using 64 bit DMA instead of bounce buffers.  But aren't there 
> cases
> > > where the 64 bit capable hardware isn't there but somebody still wants to 
> use
> > > highmem?
> > 
> > Yes of course. The common case is not 64-bit dma here though, it's just
> > being able to DMA to highmem pages (just full 32-bit dma instead of low
> > memory dma). And that should cover most systems out there.
> 
> Right, but that does not mean we can forget about bounce buffers, does it.  
> Most users will probably be able to use full 32-bit dma and users with more 
> than 4 GB of memory really should go to the effort of making sure their 
> hardware supports 64 bit dma.  But there will still be a few people who have 
> to use bounce buffers.

Of course. My point was merely what with the block-highmem patch, most
users will never need bounce -> it would therefore solve the posters
issue.

> I'm just confirming that we really do have to push on and get bounce buffers 
> working reliably, even if most people will be able to use your far nicer 
> alternative.

Agreed. It will be much less important, but there will still be a need
for it.

-- 
Jens Axboe