Messages in this thread Patch in this message | | | Subject | [RFC][PATCH 2/6] sparsemem: hotplug support | From | Dave Hansen <> | Date | Wed, 16 Mar 2005 16:28:11 -0800 |
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Make sparse's initalization be accessible at runtime. This allows sparse mappings to be created after boot in a hotplug situation.
This patch is separated from the previous one just to give an indication how much of the sparse infrastructure is *just* for hotplug memory.
Signed-off-by: Dave Hansen <haveblue@us.ibm.com> ---
memhotplug-dave/include/linux/mmzone.h | 2 memhotplug-dave/mm/sparse.c | 72 ++++++++++++++++++++++++--------- 2 files changed, 56 insertions(+), 18 deletions(-)
diff -puN mm/sparse.c~B-sparse-152-sparse-hotplug mm/sparse.c --- memhotplug/mm/sparse.c~B-sparse-152-sparse-hotplug 2005-03-16 15:46:39.000000000 -0800 +++ memhotplug-dave/mm/sparse.c 2005-03-16 15:46:39.000000000 -0800 @@ -52,6 +52,40 @@ unsigned long __init node_memmap_size_by return nr_pages * sizeof(struct page); } +static int sparse_init_one_section(struct mem_section *ms, int pnum, struct page *mem_map) +{ + if (ms->section_mem_map && + (ms->section_mem_map != SECTION_MARKED_PRESENT)) + return -EEXIST; + /* + * Subtle, we encode the real pfn into the mem_map such that + * the identity pfn - section_mem_map will return the actual + * physical page frame number. + */ + ms->section_mem_map = mem_map - (pnum << PFN_SECTION_SHIFT); + + return 1; +} + +static struct page *sparse_early_mem_map_alloc(int pnum) +{ + struct page *map; + int nid = early_pfn_to_nid(pnum << PFN_SECTION_SHIFT); + + map = alloc_remap(nid, sizeof(struct page) * PAGES_PER_SECTION); + if (map) + return map; + + map = alloc_bootmem_node(NODE_DATA(nid), + sizeof(struct page) * PAGES_PER_SECTION); + if (map) + return map; + + printk(KERN_WARNING "%s: allocation failed\n", __FUNCTION__); + mem_section[pnum].section_mem_map = 0; + return NULL; +} + /* * Allocate the accumulated non-linear sections, allocate a mem_map * for each and record the physical to section mapping. @@ -60,28 +94,30 @@ void sparse_init(void) { int pnum; struct page *map; - int nid; for (pnum = 0; pnum < NR_MEM_SECTIONS; pnum++) { if (!mem_section[pnum].section_mem_map) continue; - nid = early_pfn_to_nid(pnum << PFN_SECTION_SHIFT); - map = alloc_remap(nid, sizeof(struct page) * PAGES_PER_SECTION); - if (!map) - map = alloc_bootmem_node(NODE_DATA(nid), - sizeof(struct page) * PAGES_PER_SECTION); - if (!map) { - mem_section[pnum].section_mem_map = 0; - continue; - } - - /* - * Subtle, we encode the real pfn into the mem_map such that - * the identity pfn - section_mem_map will return the actual - * physical page frame number. - */ - mem_section[pnum].section_mem_map = map - - (pnum << PFN_SECTION_SHIFT); + map = sparse_early_mem_map_alloc(pnum); + if (map) + sparse_init_one_section(&mem_section[pnum], pnum, map); } } + +/* + * returns the number of sections whose mem_maps were properly + * set. If this is <=0, then that means that the passed-in + * map was not consumed and must be freed. + */ +int sparse_add_one_section(int start_pfn, int nr_pages, struct page *map) +{ + struct mem_section *ms = __pfn_to_section(start_pfn); + + if (ms->section_mem_map & SECTION_MARKED_PRESENT) + return -EEXIST; + + ms->section_mem_map |= SECTION_MARKED_PRESENT; + + return sparse_init_one_section(ms, start_pfn >> PFN_SECTION_SHIFT, map); +} diff -puN include/linux/mmzone.h~B-sparse-152-sparse-hotplug include/linux/mmzone.h --- memhotplug/include/linux/mmzone.h~B-sparse-152-sparse-hotplug 2005-03-16 15:46:39.000000000 -0800 +++ memhotplug-dave/include/linux/mmzone.h 2005-03-16 15:46:39.000000000 -0800 @@ -445,6 +445,8 @@ struct mem_section { extern struct mem_section mem_section[NR_MEM_SECTIONS]; +#define SECTION_MARKED_PRESENT ((void *)-1) + /* * Given a kernel address, find the home node of the underlying memory. */ _ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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