From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Fri, 15 Jul 2005 23:47:01 +0200 From: Andi Kleen Subject: Re: [NUMA] Display and modify the memory policy of a process through /proc//numa_policy Message-ID: <20050715214700.GJ15783@wotan.suse.de> References: <200507150452.j6F4q9g10274@unix-os.sc.intel.com> <20050714230501.4a9df11e.pj@sgi.com> <20050715140437.7399921f.pj@sgi.com> <20050715211210.GI15783@wotan.suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org Return-Path: To: Christoph Lameter Cc: Andi Kleen , Paul Jackson , kenneth.w.chen@intel.com, linux-mm@kvack.org, linux-ia64@vger.kernel.org List-ID: > It is very useful to a batch scheduler that can dynamically move memory > between nodes. It needs to know exactly where the pages are including the > vma information. You mean for relative placement in node groups? Ray's code was supposed to handle that in the kernel. You pass an mapping array to the syscall and it does the rest. We had a big discussion about that some months ago; I suggest you review it. So for what does that batch monstrosity need to know about the VMAs? > It is also of utmost importance to a sysadmin that wants > to control the memory placement of an important application to have > information about the process and be able to influence future allocations > as well as to move existing pages. I don't believe any admin will mess with virtual addresses. I added the capability to numactl for shared memory areas because I first thought it would be useful, but as far as I know nobody was interested in it. (will probably remove it again) But for "uncooperative" programs working on bigger objects like threads/files/shm areas/processes makes much more sense. And gives much cleaner interfaces too. Now I can see some people being interested in more fine grained policy, but the only sane way to do that is to change the source code and use libnuma. Basically to mess with finegrained virtual addresses you need code access, and when you have that you can as well do it well and add libnuma and recompile. -Andi -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: aart@kvack.org