Messages in this thread Patch in this message | | | Date | Sun, 13 Apr 2008 11:51:06 -0700 | From | "Yinghai Lu" <> | Subject | replace patch about memmap |
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Ingo,
please use attached one to replace the two in x86.git/testing.
commit 68d0f2167481190d02947d35cb9693a76545eb28 Author: Yinghai Lu <yhlu.kernel@gmail.com> Date: Mon Mar 10 23:22:47 2008 -0700
mm: make mem_map allocation continuous.
commit 8871127b4a54a480f172de39deb5e29c482956be Author: Yinghai Lu <yhlu.kernel@gmail.com> Date: Tue Mar 18 12:47:59 2008 -0700
mm: allocate section_map for sparse_init
Andrew already put the updated one in -mm
YH [PATCH] mm: make mem_map allocation continuous v2.
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 <pbadari@us.ibm.com> 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 <yhlu.kernel@gmail.com>
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 | |