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authorZhou Chengming <zhouchengming1@huawei.com>2016-07-28 15:48:35 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-07-28 16:07:41 -0700
commit91fd8b95d656dcd3f0a4e17b6583e7b0220b0747 (patch)
tree8e33bf623881a0471ff611f3176f603cc27efe7d /mm/sparse.c
parent98c42d945238c55ab56e5716e89553fb7de45b66 (diff)
make __section_nr() more efficient
When CONFIG_SPARSEMEM_EXTREME is disabled, __section_nr can get the section number with a subtraction directly. Link: http://lkml.kernel.org/r/1468988310-11560-1-git-send-email-zhouchengming1@huawei.com Signed-off-by: Zhou Chengming <zhouchengming1@huawei.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Tejun Heo <tj@kernel.org> Cc: Hanjun Guo <guohanjun@huawei.com> Cc: Li Bin <huawei.libin@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/sparse.c')
-rw-r--r--mm/sparse.c12
1 files changed, 7 insertions, 5 deletions
diff --git a/mm/sparse.c b/mm/sparse.c
index 5d0cf4540364..36d7bbb80e49 100644
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -100,11 +100,7 @@ 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 because
- * NR_SECTION_ROOTS==NR_MEM_SECTIONS.
- */
+#ifdef CONFIG_SPARSEMEM_EXTREME
int __section_nr(struct mem_section* ms)
{
unsigned long root_nr;
@@ -123,6 +119,12 @@ int __section_nr(struct mem_section* ms)
return (root_nr * SECTIONS_PER_ROOT) + (ms - root);
}
+#else
+int __section_nr(struct mem_section* ms)
+{
+ return (int)(ms - mem_section[0]);
+}
+#endif
/*
* During early boot, before section_mem_map is used for an actual