Re: [11/36] Use page_cache_xxx in fs/buffer.c

Christoph Lameter
2007-08-31T15:22:58Z

On Fri, 31 Aug 2007, Jens Axboe wrote:

> > Ok. So another solution maybe to limit the blocksizes that can be used
> > with a device?
>
> That'd work for creation, but not for moving things around.

What do you mean by moving things around? Creation binds a filesystem to a
device.

> > Hmmmm.. We could keep the existing scheme too and check that device
> > drivers split things up if they are too large? Isnt it possible today
> > to create a huge bio of 2M for huge pages and send it to a device?
>
> Not sure, aren't the constituents of compound pages the basis for IO?

get_user_pages() serializes compound pages into the base pages. But doesnt
the I/O layer coalesce these later into 2M chunks again?