vmalloc limits in PPC kernels ?
vroopcha at mcw.edu
Sat Feb 15 04:32:44 EST 2003
Thanks much for the information you provided below. Are there any
pointers/references as to why these changes were actually implemented,
or is it really a case of "the source being the guide" ? As I said,
this issue is really troubling for us, and I want to see if there is
a "clean" way to circumvent that limit without screwing up the MM
subsystem (at least not too badly :) ...
On Thu, 13 Feb 2003, Matt Porter wrote:
> All architectures have a limit. Its size is defined by
> VMALLOC_END-VMALLOC_START and further limited by the size of each
> preceding allocation (+ a PAGE_SIZE pad) before the allocation in
> question. Allocations also include ioremaps and on some architectures
> consistent memory allocations absorb vmalloc space.
> You can see the constraints in asm-ppc/pgtable.h. On PPC, it is possible
> to change the default parameters in order to expand the amount of vmalloc
> space available. This is accomplished via config options under the
> advanced kernel options menu. With PAGE_OFFSET at 0x40000000 and highmem,
> I've run a system with nearly 3GB of vmalloc space.
** Sent via the linuxppc-dev mail list. See http://lists.linuxppc.org/
More information about the Linuxppc-dev