From mboxrd@z Thu Jan 1 00:00:00 1970 From: Phillip Susi Subject: readahead on directories Date: Mon, 19 Apr 2010 11:51:33 -0400 Message-ID: <4BCC7C05.8000803@cfl.rr.com> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit To: linux-fsdevel@vger.kernel.org, Linux-kernel Return-path: Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org I have been trying to improve boot times with ureadahead and have identified a period of time of almost zero IO throughput caused by calls to open() blocking during name lookup while fetching directory blocks. At first I thought this could simply be fixed by calling readahead() on the directories first before open()ing all of the normal files for readahead. Unfortunately it seems that readahead() fails when called on a directory. I was wondering if I could get some help understanding why this is, and how it could be fixed.