From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andi Kleen Subject: Re: [PATCH 0/4] dcache: make Oracle more scalable on large systems Date: Thu, 21 Feb 2013 16:13:45 -0800 Message-ID: References: <1361299859-27056-1-git-send-email-Waiman.Long@hp.com> <20130221233818.GM26694@dastard> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Waiman Long , linux-fsdevel@vger.kernel.org, Alexander Viro , linux-kernel@vger.kernel.org To: Dave Chinner Return-path: In-Reply-To: <20130221233818.GM26694@dastard> (Dave Chinner's message of "Fri, 22 Feb 2013 10:38:18 +1100") Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-fsdevel.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