From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sasha Levin Subject: Re: [PATCH] kvm tools: mmap guest kernel instead of reading it into memory Date: Mon, 12 Dec 2011 19:47:35 +0200 Message-ID: <1323712055.3269.1.camel@lappy> References: <1323701258-17443-1-git-send-email-levinsasha928@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: mingo@elte.hu, gorcunov@gmail.com, asias.hejun@gmail.com, kvm@vger.kernel.org, ajsween@sandia.gov To: Pekka Enberg Return-path: Received: from mail-bw0-f46.google.com ([209.85.214.46]:37486 "EHLO mail-bw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751026Ab1LLPsF (ORCPT ); Mon, 12 Dec 2011 10:48:05 -0500 Received: by bkcjm19 with SMTP id jm19so1577363bkc.19 for ; Mon, 12 Dec 2011 07:48:03 -0800 (PST) In-Reply-To: Sender: kvm-owner@vger.kernel.org List-ID: On Mon, 2011-12-12 at 16:54 +0200, Pekka Enberg wrote: > On Mon, Dec 12, 2011 at 4:47 PM, Sasha Levin wrote: > > This patch mmaps guest kernel into it's own memory slot instead of reading > > it into the memory. > > > > The advantages are: > > - Smaller memory footprint (same effect as KSM if running multiple guests) > > KSM isn't free so it's smaller footprint with less CPU cycles. It's > mostly useful for the special case of running tons of guests using the > same kernel image. Another usecase which I've only first heard about couple of days ago is loading extremely large bzImages. Those images are 300MB+ in size and come with built in filesystem. Apparently it's some sort of a livecd variant. -- Sasha.