From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755996Ab3BVANu (ORCPT ); Thu, 21 Feb 2013 19:13:50 -0500 Received: from mga03.intel.com ([143.182.124.21]:40283 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753577Ab3BVANt (ORCPT ); Thu, 21 Feb 2013 19:13:49 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.84,711,1355126400"; d="scan'208";a="205102007" From: Andi Kleen To: Dave Chinner Cc: Waiman Long , linux-fsdevel@vger.kernel.org, Alexander Viro , linux-kernel@vger.kernel.org Subject: Re: [PATCH 0/4] dcache: make Oracle more scalable on large systems References: <1361299859-27056-1-git-send-email-Waiman.Long@hp.com> <20130221233818.GM26694@dastard> Date: Thu, 21 Feb 2013 16:13:45 -0800 In-Reply-To: <20130221233818.GM26694@dastard> (Dave Chinner's message of "Fri, 22 Feb 2013 10:38:18 +1100") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Dave Chinner writes: > On Tue, Feb 19, 2013 at 01:50:55PM -0500, Waiman Long wrote: >> It was found that the Oracle database software issues a lot of call >> to the seq_path() kernel function which translates a (dentry, mnt) >> pair to an absolute path. The seq_path() function will eventually >> take the following two locks: > > Nobody should be doing reverse dentry-to-name lookups in a quantity > sufficient for it to become a performance limiting factor. What is > the Oracle DB actually using this path for? Yes calling d_path frequently is usually a bug elsewhere. Is that through /proc ? -Andi -- ak@linux.intel.com -- Speaking for myself only