Re: Please don't beat me up (was Re: Bugs and wishes in memory management area)

Ingo Molnar (
Wed, 27 Nov 1996 16:07:02 +0100 (MET)

On Wed, 27 Nov 1996, Mike Jagdis wrote:

> > IMHO, the problem is that once a pointer is given out, you cannot
> > reogranize your logical->physical memory mappings. With the page table
> > solution you can. It's a CPU hardware feature that is hard to emulate.
> But you don't need to reorganize, you don't need paging and you don't
> need to emulate it.

i dont get it [it must be me]. How would you allocate 2 consecutive pages
in this 5-page pool which has 3 free pages? :

page 1 -------> free
page 2 -------> used by the Ethernet driver
page 3 -------> free
page 4 -------> used by the SCSI driver
page 5 -------> free

[ sure we are not at page granularity with the buddy system, but the
original poster proposed an >additional< mechanizm for multipage
vmalloc() calls, maybe by using paging ]

now i need 2 pages in the above situation ... from an IRQ handler, to get
8192 bytes off the networking card for example. How would you do it?

-- mingo