Re: [PATCH 07/07] i386: numa emulation on pc

Dave Hansen
2005-09-30T18:55:15Z

On Fri, 2005-09-30 at 16:33 +0900, Magnus Damm wrote:
> void __init nid_zone_sizes_init(int nid)
> {
> unsigned long zones_size[MAX_NR_ZONES] = {0, 0, 0};
> - unsigned long max_dma;
> + unsigned long max_dma = min(max_hardware_dma_pfn(), max_low_pfn);
> unsigned long start = node_start_pfn[nid];
> unsigned long end = node_end_pfn[nid];
>
> if (node_has_online_mem(nid)){
> - if (nid_starts_in_highmem(nid)) {
> - zones_size[ZONE_HIGHMEM] = nid_size_pages(nid);
> - } else {
> - max_dma = min(max_hardware_dma_pfn(), max_low_pfn);
> - zones_size[ZONE_DMA] = max_dma;
> - zones_size[ZONE_NORMAL] = max_low_pfn - max_dma;
> - zones_size[ZONE_HIGHMEM] = end - max_low_pfn;
> + if (start < max_dma) {
> + zones_size[ZONE_DMA] = min(end, max_dma) - start;
> + }
> + if (start < max_low_pfn && max_dma < end) {
> + zones_size[ZONE_NORMAL] = min(end, max_low_pfn) - max(start, max_dma);
> + }
> + if (max_low_pfn <= end) {
> + zones_size[ZONE_HIGHMEM] = end - max(start, max_low_pfn);
> }
> }

That is a decent cleanup all by itself. You might want to break it out.
Take a look at the patches I just sent out. They do some similar things
to the same code.

> @@ -1270,7 +1273,12 @@ void __init setup_bootmem_allocator(void
> /*
> * Initialize the boot-time allocator (with low memory only):
> */
> +#ifdef CONFIG_NUMA_EMU
> + bootmap_size = init_bootmem(max(min_low_pfn, node_start_pfn[0]),
> + min(max_low_pfn, node_end_pfn[0]));
> +#else
> bootmap_size = init_bootmem(min_low_pfn, max_low_pfn);
> +#endif

This shouldn't be necessary. Again, take a look at my discontig
separation patches and see if what I did works for you here.

> register_bootmem_low_pages(max_low_pfn);
>
> --- from-0006/arch/i386/mm/numa.c
> +++ to-work/arch/i386/mm/numa.c 2005-09-28 17:49:53.000000000 +0900
> @@ -165,3 +165,103 @@ int early_pfn_to_nid(unsigned long pfn)
>
> return 0;
> }
> +
> +#ifdef CONFIG_NUMA_EMU
...
> +#endif

Ewwwwww :) No real need to put new function in a big #ifdef like that.
Can you just create a new file for NUMA emulation?

> --- from-0001/include/asm-i386/numnodes.h
> +++ to-work/include/asm-i386/numnodes.h 2005-09-28 17:49:53.000000000 +0900
> @@ -8,7 +8,7 @@
> /* Max 16 Nodes */
> #define NODES_SHIFT 4
>
> -#elif defined(CONFIG_ACPI_SRAT)
> +#elif defined(CONFIG_ACPI_SRAT) || defined(CONFIG_NUMA_EMU)
>
> /* Max 8 Nodes */
> #define NODES_SHIFT 3

Geez. We should probably just do those in the Kconfig files. Would
look much simpler. But, that's a patch for another day. This is fine
by itself.

-- Dave