Looks good to me. And ia64 boots up with this patch too.
Thanks.
Acked-by: Yasunori Goto <[EMAIL PROTECTED]>
>
> vmemmap allocation current got
> [ffffe20000000000-ffffe200001fffff] PMD ->ffff810001400000 on node 0
> [ffffe20000200000-ffffe200003fffff] PMD ->ffff810001800000 on node 0
> [ffffe20000400000-ffffe200005fffff] PMD ->ffff810001c00000 on node 0
> [ffffe20000600000-ffffe200007fffff] PMD ->ffff810002000000 on node 0
> [ffffe20000800000-ffffe200009fffff] PMD ->ffff810002400000 on node 0
> ...
>
> there is 2M hole between them.
>
> the rootcause is that usemap (24 bytes) will be allocated after every 2M
> mem_map. and it will push next vmemmap (2M) to next align (2M).
>
> solution:
> try to allocate mem_map continously.
>
> after patch, will get
> [ffffe20000000000-ffffe200001fffff] PMD ->ffff810001400000 on node 0
> [ffffe20000200000-ffffe200003fffff] PMD ->ffff810001600000 on node 0
> [ffffe20000400000-ffffe200005fffff] PMD ->ffff810001800000 on node 0
> [ffffe20000600000-ffffe200007fffff] PMD ->ffff810001a00000 on node 0
> [ffffe20000800000-ffffe200009fffff] PMD ->ffff810001c00000 on node 0
> ...
> and usemap will share in page because of they are allocated continuously too.
> sparse_early_usemap_alloc: usemap = ffff810024e00000 size = 24
> sparse_early_usemap_alloc: usemap = ffff810024e00080 size = 24
> sparse_early_usemap_alloc: usemap = ffff810024e00100 size = 24
> sparse_early_usemap_alloc: usemap = ffff810024e00180 size = 24
> ...
>
> so we make the bootmem allocation more compact and use less memory for usemap.
>
> for power pc
> Badari Pulavarty <[EMAIL PROTECTED]> wrote:
>
> > You have to call sparse_init_one_section() on each pmap and usemap
> > as we allocate - since valid_section() depends on it (which is needed
> > by vmemmap_populate() to check if the section is populated or not).
> > On ppc, we need to call htab_bolted_mapping() on each section and
> > we need to skip existing sections.
>
> so try to allocate usemap at first altogether.
>
> v2 replace:
> [PATCH] mm: make mem_map allocation continuous.
> [PATCH] mm: allocate section_map for sparse_init
> [PATCH] mm: allocate usemap at first instead of mem_map in sparse_init
>
> Signed-off-by: Yinghai Lu <[EMAIL PROTECTED]>
>
> diff --git a/mm/sparse.c b/mm/sparse.c
> index f6a43c0..2881222 100644
> --- a/mm/sparse.c
> +++ b/mm/sparse.c
> @@ -294,22 +294,48 @@ void __init sparse_init(void)
> unsigned long pnum;
> struct page *map;
> unsigned long *usemap;
> + unsigned long **usemap_map;
> + int size;
> +
> + /*
> + * map is using big page (aka 2M in x86 64 bit)
> + * usemap is less one page (aka 24 bytes)
> + * so alloc 2M (with 2M align) and 24 bytes in turn will
> + * make next 2M slip to one more 2M later.
> + * then in big system, the memory will have a lot of holes...
> + * here try to allocate 2M pages continously.
> + *
> + * powerpc need to call sparse_init_one_section right after each
> + * sparse_early_mem_map_alloc, so allocate usemap_map at first.
> + */
> + size = sizeof(unsigned long *) * NR_MEM_SECTIONS;
> + usemap_map = alloc_bootmem(size);
> + if (!usemap_map)
> + panic("can not allocate usemap_map\n");
>
> for (pnum = 0; pnum < NR_MEM_SECTIONS; pnum++) {
> if (!present_section_nr(pnum))
> continue;
> + usemap_map[pnum] = sparse_early_usemap_alloc(pnum);
> + }
>
> - map = sparse_early_mem_map_alloc(pnum);
> - if (!map)
> + for (pnum = 0; pnum < NR_MEM_SECTIONS; pnum++) {
> + if (!present_section_nr(pnum))
> continue;
>
> - usemap = sparse_early_usemap_alloc(pnum);
> + usemap = usemap_map[pnum];
> if (!usemap)
> continue;
>
> + map = sparse_early_mem_map_alloc(pnum);
> + if (!map)
> + continue;
> +
> sparse_init_one_section(__nr_to_section(pnum), pnum, map,
> usemap);
> }
> +
> + free_bootmem(__pa(usemap_map), size);
> }
>
> #ifdef CONFIG_MEMORY_HOTPLUG
> --
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--
Yasunori Goto
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