Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934762AbZKYOID (ORCPT ); Wed, 25 Nov 2009 09:08:03 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S934668AbZKYOIB (ORCPT ); Wed, 25 Nov 2009 09:08:01 -0500 Received: from mail-pz0-f188.google.com ([209.85.222.188]:35418 "EHLO mail-pz0-f188.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934630AbZKYOH7 (ORCPT ); Wed, 25 Nov 2009 09:07:59 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:cc:subject:message-id:x-mailer:mime-version :content-type:content-transfer-encoding; b=e1Uh4FSPGCPHexXHZGnOJ5wSyjEAfIo0PHFNdnLcT58v5tKwhdEvSzW4ZZdQ/eU1TZ RuBwcD9b8pfC7cPc9He2wCmCfeLWi1sIyjxA1B38J7ngPNjYQCz5fbHOXnuufBZ6KDIp Gzv/t9g6SL+mi366SUb3GQaNijDf8uWrkcYys= Date: Wed, 25 Nov 2009 22:12:19 +0800 From: "Liuweni" To: "linux-kernel" Cc: "viro" , "akpm" , "jack" , "npiggin" , "linux-fsdevel" , "linux-kernel" , "strongzgy" , "xgr178" , "Liu Hui" Subject: [PATCH 2/3]fs/inode: iunique() Optimize Performance Message-ID: <200911252212166092236@gmail.com> X-mailer: Foxmail 6, 15, 201, 22 [cn] Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1304 Lines: 42 --- Change log: Change the hash operation from division to shift. It will cost less time. Also, I change the divisor from L1_CACHE_BYTES to L1_CACHE_SHIFT. In the cache.h, the most L1_CACHE_BYTES defined as "(1 << L1_CACHE_SHIFT)". --- Signed-off-by: Liuwenyi Cc: Alexander Viro Cc: Andrew Morton Cc: Jan Kara Cc: Nick Piggin Cc: linux-fsdevel@vger.kernel.org Cc: linux-kernel@vger.kernel.org --- diff --git a/fs/inode.c b/fs/inode.c index 4d8e3be..397d65f 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -605,8 +605,8 @@ static unsigned long hash(struct super_block *sb, unsigned long hashval) { unsigned long tmp; - tmp = (hashval * (unsigned long)sb) ^ (GOLDEN_RATIO_PRIME + hashval) / - L1_CACHE_BYTES; + tmp = (hashval * (unsigned long)sb) ^ (GOLDEN_RATIO_PRIME + hashval) >> + L1_CACHE_SHIFT; tmp = tmp ^ ((tmp ^ GOLDEN_RATIO_PRIME) >> I_HASHBITS); return tmp & I_HASHMASK; } -------------- Best Regards, Liuweni 2009-11-25 -- 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/