Commit 4ca644d9 authored by Dave Hansen's avatar Dave Hansen Committed by Linus Torvalds
Browse files

[PATCH] memory hotplug prep: __section_nr helper



A little helper that we use in the hotplug code.
Signed-off-by: default avatarDave Hansen <haveblue@us.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent ed8ece2e
......@@ -509,6 +509,7 @@ static inline struct mem_section *__nr_to_section(unsigned long nr)
return NULL;
return &mem_section[SECTION_NR_TO_ROOT(nr)][nr & SECTION_ROOT_MASK];
}
extern int __section_nr(struct mem_section* ms);
/*
* We use the lower bits of the mem_map pointer to store
......
......@@ -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)
{
......
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