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| author | Dave Hansen <haveblue@us.ibm.com> | 2005-10-29 18:16:51 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2005-10-29 21:40:44 -0700 |
| commit | 4ca644d970bf2542623228a4624af356d20ca267 (patch) | |
| tree | 1040782e8799d5531a5ee1d5f1143e26e8781e9d /mm/sparse.c | |
| parent | ed8ece2ec8d3c2031b1a1a0737568bb0d49454e0 (diff) | |
| download | lwn-4ca644d970bf2542623228a4624af356d20ca267.tar.gz lwn-4ca644d970bf2542623228a4624af356d20ca267.zip | |
[PATCH] memory hotplug prep: __section_nr helper
A little helper that we use in the hotplug code.
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'mm/sparse.c')
| -rw-r--r-- | mm/sparse.c | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/mm/sparse.c b/mm/sparse.c index 347249a4917a..0d3bd4bf3aaa 100644 --- a/mm/sparse.c +++ b/mm/sparse.c @@ -72,6 +72,31 @@ static inline int sparse_index_init(unsigned long section_nr, int nid) } #endif +/* + * Although written for the SPARSEMEM_EXTREME case, this happens + * to also work for the flat array case becase + * NR_SECTION_ROOTS==NR_MEM_SECTIONS. + */ +int __section_nr(struct mem_section* ms) +{ + unsigned long root_nr; + struct mem_section* root; + + for (root_nr = 0; + root_nr < NR_MEM_SECTIONS; + root_nr += SECTIONS_PER_ROOT) { + root = __nr_to_section(root_nr); + + if (!root) + continue; + + if ((ms >= root) && (ms < (root + SECTIONS_PER_ROOT))) + break; + } + + return (root_nr * SECTIONS_PER_ROOT) + (ms - root); +} + /* Record a memory area against a node. */ void memory_present(int nid, unsigned long start, unsigned long end) { |