Re: [PATCH] x86 Boot NUMA kernels on non-NUMA hardware with DISCONTIG memory model

2007-08-25 Thread Andy Whitcroft
Andi Kleen wrote: > On Fri, Aug 24, 2007 at 06:44:38PM +0100, Mel Gorman wrote: >> On (24/08/07 19:38), Andi Kleen didst pronounce: Other than the fact that the memmap must be PMD aligned to use hugepage entries for the memmap. >>> Why is that so? mem_map should be just part of lowmem a

Re: [PATCH] x86 Boot NUMA kernels on non-NUMA hardware with DISCONTIG memory model

2007-08-24 Thread Mel Gorman
On (24/08/07 19:53), Andi Kleen didst pronounce: > On Fri, Aug 24, 2007 at 06:44:38PM +0100, Mel Gorman wrote: > > On (24/08/07 19:38), Andi Kleen didst pronounce: > > > > Other than the fact that the memmap must be PMD aligned to use hugepage > > > > entries for the memmap. > > > > > > Why is th

Re: [PATCH] x86 Boot NUMA kernels on non-NUMA hardware with DISCONTIG memory model

2007-08-24 Thread Andi Kleen
On Fri, Aug 24, 2007 at 06:44:38PM +0100, Mel Gorman wrote: > On (24/08/07 19:38), Andi Kleen didst pronounce: > > > Other than the fact that the memmap must be PMD aligned to use hugepage > > > entries for the memmap. > > > > Why is that so? mem_map should be just part of lowmem anyways. > > >

Re: [PATCH] x86 Boot NUMA kernels on non-NUMA hardware with DISCONTIG memory model

2007-08-24 Thread Mel Gorman
On (24/08/07 19:38), Andi Kleen didst pronounce: > > Other than the fact that the memmap must be PMD aligned to use hugepage > > entries for the memmap. > > Why is that so? mem_map should be just part of lowmem anyways. > Not in this case. memmap is allocated node local and mapped in the virtu

Re: [PATCH] x86 Boot NUMA kernels on non-NUMA hardware with DISCONTIG memory model

2007-08-24 Thread Andi Kleen
> Other than the fact that the memmap must be PMD aligned to use hugepage > entries for the memmap. Why is that so? mem_map should be just part of lowmem anyways. > It could be mapped with small pages in corner cases > but the complexity worth it? You don't need to map it with small pages in t

Re: [PATCH] x86 Boot NUMA kernels on non-NUMA hardware with DISCONTIG memory model

2007-08-24 Thread Mel Gorman
On (24/08/07 19:07), Andi Kleen didst pronounce: > On Fri, Aug 24, 2007 at 05:52:31PM +0100, Andy Whitcroft wrote: > > Andi Kleen wrote: > > >> This reserved portion of the KVA must be PMD aligned. > > > > > > Why do they need to be PMD aligned? > > > > That comes from the fact that the KVA in

Re: [PATCH] x86 Boot NUMA kernels on non-NUMA hardware with DISCONTIG memory model

2007-08-24 Thread Andi Kleen
On Fri, Aug 24, 2007 at 05:52:31PM +0100, Andy Whitcroft wrote: > Andi Kleen wrote: > >> This reserved portion of the KVA must be PMD aligned. > > > > Why do they need to be PMD aligned? > > That comes from the fact that the KVA in x86 has traditionally been Where does this KVA acronym come f

Re: [PATCH] x86 Boot NUMA kernels on non-NUMA hardware with DISCONTIG memory model

2007-08-24 Thread Andy Whitcroft
Andi Kleen wrote: >> This reserved portion of the KVA must be PMD aligned. > > Why do they need to be PMD aligned? That comes from the fact that the KVA in x86 has traditionally been mapped with huge pages where at all possible, for performance reasons. The purpose of the remap itself always h

Re: [PATCH] x86 Boot NUMA kernels on non-NUMA hardware with DISCONTIG memory model

2007-08-24 Thread Andi Kleen
> This reserved portion of the KVA must be PMD aligned. Why do they need to be PMD aligned? -Andi - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please re

[PATCH] x86 Boot NUMA kernels on non-NUMA hardware with DISCONTIG memory model

2007-08-24 Thread Mel Gorman
Currently NUMA kernels generally do not boot on non-NUMA machines in some situations. This patch addresses one such boot problem on x86 machines running a NUMA kernel with the DISCONTIG memory model. On 32-bit NUMA, the memmap representing struct pages on each node is allocated from node-local mem