mm/sparse.c: wrong allocation for mem_section

In commit 83e3c48729d9 ("mm/sparsemem: Allocate mem_section at runtime
for CONFIG_SPARSEMEM_EXTREME=y") mem_section is allocated at runtime to
save memory.

It allocates the first dimension of array with sizeof(struct mem_section).

It costs extra memory, should be sizeof(struct mem_section *).

Fix it.

Link: http://lkml.kernel.org/r/[email protected]
Fixes: 83e3c48729 ("mm/sparsemem: Allocate mem_section at runtime for CONFIG_SPARSEMEM_EXTREME=y")
Signed-off-by: Baoquan He <[email protected]>
Tested-by: Dave Young <[email protected]>
Acked-by: Kirill A. Shutemov <[email protected]>
Cc: Kirill A. Shutemov <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Atsushi Kumagai <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

diff --git a/mm/sparse.c b/mm/sparse.c
index 7a5dacaa06e3f277c8543c502dba0e3c6a6a1a13..2609aba121e89cc5c8b656f4ef3539545c434091 100644 (file)
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -211,7 +211,7 @@ void __init memory_present(int nid, unsigned long start, unsigned long end)
        if (unlikely(!mem_section)) {
                unsigned long size, align;
 
-               size = sizeof(struct mem_section) * NR_SECTION_ROOTS;
+               size = sizeof(struct mem_section*) * NR_SECTION_ROOTS;
                align = 1 << (INTERNODE_CACHE_SHIFT);
                mem_section = memblock_virt_alloc(size, align);
        }