Re: Getting big areas of memory, in 2.3.x?

William J. Earl
1999-12-09T22:13:39Z

Ingo Molnar writes:
> On Thu, 9 Dec 1999, Jeff Garzik wrote:
>
> > > hm, does anyone have any conceptual problem with a new
> > > allocate_largemem(pages) interface in page_alloc.c? It's not terribly hard
> > > to scan all bitmaps for available RAM and mark the large memory area
> > > allocated and remove all pages from the freelists. Such areas can only be
> > > freed via free_largemem(pages). Both calls will be slow, so should be only
> > > used at driver initialization time and such.
> >
> > Would this interface swap out user pages if necessary? That sort of
> > interface would be great, and kill a number of hacks floating around out
> > there.
>
> not at the moment - but it's not really necessery because this is ment for
> driver initialization time, which usually happens at boot time.
...

That is not the case for loadable (modular) drivers. Loading st
as a module, for example, after boot time sometimes works and sometimes does
not, especially if you set the maximum buffer size larger (to, say, 128K,
as is needed on some drives for good space efficiency).