From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <4FE8D54F.7060805@xenomai.org> Date: Mon, 25 Jun 2012 23:17:03 +0200 From: Gilles Chanteperdrix MIME-Version: 1.0 References: <20120625182334.GH32727@csclub.uwaterloo.ca> In-Reply-To: <20120625182334.GH32727@csclub.uwaterloo.ca> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Subject: Re: [Xenomai] memory size List-Id: Discussions about the Xenomai project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Lennart Sorensen Cc: xenomai@xenomai.org On 06/25/2012 08:23 PM, Lennart Sorensen wrote: > On Mon, Jun 25, 2012 at 06:51:53PM +0430, ali hagigat wrote: >> My computer has 3G bytes RAM. I have disabled "high memory", PAE and >> 64-bit memory and I/O resources for the Xenomai kernel and the memory >> size is nearly 900M (Why the memory size became smaller than 1G? By >> disabling those options the size should be still 3G!) : > > Linux supports 900MB ram on x86, unless you have highmem support (which > supports up to 4GB), or PAE (which supports up to 64GB). > > It has been that way for many many years. > Not exactly, you can increase the kernel-space memory, by decreasing the user-space applications address space, using CONFIG_VMSPLIT_2G or even CONFIG_VMSPLIT_1G. But if your machine is a 64 bits machine, you should probably simply compile a 64 bits kernel. But anyway, people elsewhere, know better than we do. See for instance: http://linux-mm.org/HighMemory -- Gilles.