From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Wed, 3 Jan 2007 06:03:22 +0900 From: Paul Mundt Subject: [PATCH] Sanely size hash tables when using large base pages. take 2. Message-ID: <20070102210322.GA20697@linux-sh.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Sender: owner-linux-mm@kvack.org Return-Path: To: linux-kernel@vger.kernel.org, linux-mm@kvack.org List-ID: This is a resubmission of the earlier patch with the pidhash bits dropped. At the moment the inode/dentry cache hash tables (common by way of alloc_large_system_hash()) are incorrectly sized by their respective detection logic when we attempt to use large base pages on systems with little memory. This results in odd behaviour when using a 64kB PAGE_SIZE, such as: Dentry cache hash table entries: 8192 (order: -1, 32768 bytes) Inode-cache hash table entries: 4096 (order: -2, 16384 bytes) The mount cache hash table is seemingly the only one that gets this right by directly taking PAGE_SIZE in to account. The following patch attempts to catch the bogus values and round it up to at least 0-order. Signed-off-by: Paul Mundt -- mm/page_alloc.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 8c1a116..4a9a83f 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -3321,6 +3321,10 @@ void *__init alloc_large_system_hash(con numentries >>= (scale - PAGE_SHIFT); else numentries <<= (PAGE_SHIFT - scale); + + /* Make sure we've got at least a 0-order allocation.. */ + if (unlikely((numentries * bucketsize) < PAGE_SIZE)) + numentries = PAGE_SIZE / bucketsize; } numentries = roundup_pow_of_two(numentries); -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org