From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Chen, Kenneth W" Date: Thu, 12 Oct 2006 21:40:25 +0000 Subject: RE: [PATCH 4/4] vmm: Use a static memory map Message-Id: <000001c6ee47$0764e7e0$db34030a@amr.corp.intel.com> List-Id: References: <20061012191828.21498.95831.sendpatchset@schroedinger.engr.sgi.com> In-Reply-To: <20061012191828.21498.95831.sendpatchset@schroedinger.engr.sgi.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-ia64@vger.kernel.org Christoph Lameter wrote on Thursday, October 12, 2006 12:18 PM > IA64 currently uses a dynamically configured memory map that is taken off > the end of VMALLOC space. This means that we do some tweaking with some > core constants that now refer to variables and we keep having to > get the address of the virtual memory map and the limits from memory. > This patch makes pfn_to_page and page_to_pfn possible without referencing > any memory location. > > So, the size of the virtual memory map is always less than 8 Terabyte. > > I think its reasonable to take these 8 Terabyte away from the 128 Terabyte > that we currently reserve for support for VMALLOC space. > > Advantages: > - virt_to_page, page_address, pfn_to_page, page_to_pfn become simple address > calculations without a memory reference. I like the concept a lot. > - This patch will enable later patches to move the virtual memory map into > another region with a larger page size. Larger page sizes will reduce > TLB pressure. I like that even more, which region are you going to move it to?