The "rounded up to nearest power of 2 in size" algorithm in
alloc_large_system_hash is not correct. As coded, it takes an otherwise
acceptable power-of-2 value and doubles it. For example, we see the
error if we boot with thash_entries=2097152 which produces a hash
table with 4194304 entries.
Signed-off-by: John Hawkes <[email protected]>
Index: linux/mm/page_alloc.c
===================================================================
--- linux.orig/mm/page_alloc.c 2006-03-14 15:25:40.000000000 -0800
+++ linux/mm/page_alloc.c 2006-03-14 16:06:48.000000000 -0800
@@ -2686,7 +2686,7 @@ void *__init alloc_large_system_hash(con
numentries <<= (PAGE_SHIFT - scale);
}
/* rounded up to nearest power of 2 in size */
- numentries = 1UL << (long_log2(numentries) + 1);
+ numentries = 1UL << (long_log2(2*numentries - 1));
/* limit allocation size to 1/16 total memory by default */
if (max == 0) {
-
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