Messages in this thread Patch in this message | | | From | hawkes@sgi ... | Date | Wed, 15 Mar 2006 09:36:39 -0800 | Subject | [PATCH] fix alloc_large_system_hash roundup |
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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 <hawkes@sgi.com>
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) { - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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