From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262339AbUEAQSh (ORCPT ); Sat, 1 May 2004 12:18:37 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262311AbUEAQSh (ORCPT ); Sat, 1 May 2004 12:18:37 -0400 Received: from rrcs-central-24-123-144-118.biz.rr.com ([24.123.144.118]:16737 "EHLO zso-proxy.zeusinc.com") by vger.kernel.org with ESMTP id S262422AbUEAQP5 (ORCPT ); Sat, 1 May 2004 12:15:57 -0400 Subject: Re: Large page support in the Linux Kernel? From: Tom Sightler To: Buddy Lumpkin Cc: Linux-Kernel In-Reply-To: References: Content-Type: text/plain Message-Id: <1083428150.3810.18.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.4.6 (1.4.6-1) Date: Sat, 01 May 2004 12:15:50 -0400 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 2004-05-01 at 05:28, Buddy Lumpkin wrote: > Lastly, I know I have mentioned Oracle and Solaris a lot. Please don't flame > me for this, I think the points I am trying to make are reasonable. The only reason to be flamed is that you didn't seem to do much research before posting. RHEL 2.1 has supported a feature called "BigPages" specifically used for Oracle for quite a while. Good documentation on how to set this up can be found from Redhat, Oracle, and a quick Google search. See http://www.puschitz.com/TuningLinuxForOracle.shtml#UsingLargeMemoryPages for instructions on how to set it up. Basically you pass a kernel parameter to tell the system how much memory to allocate as big pages and the kernel reserves this memory for it's use. RHEL 3.0 and current 2.6 kernel support a newer variant called Hugetlb which seems similar from a user perspective but I'm not sure of the implementation details. It more dynamic, you can decrease or increase memory allocated to Hugetlb's via /proc athough, you can't always grow it (the kernel has to be able to allocate contiguous segments to grow the system). I'm not aware of any instruction in the community about how to set this up, but Oracle's Metalink provides complete instructions. I'm already using it on my five production Oracle instances and have had no problems with it. Later, Tom