Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753849Ab3FYS6J (ORCPT ); Tue, 25 Jun 2013 14:58:09 -0400 Received: from relay3.sgi.com ([192.48.152.1]:33848 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752641Ab3FYS6G (ORCPT ); Tue, 25 Jun 2013 14:58:06 -0400 Message-ID: <51C9E83A.8070700@sgi.com> Date: Tue, 25 Jun 2013 11:58:02 -0700 From: Mike Travis User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:17.0) Gecko/20130509 Thunderbird/17.0.6 MIME-Version: 1.0 To: "H. Peter Anvin" CC: Yinghai Lu , Greg KH , Nathan Zimmer , Robin Holt , Rob Landley , Thomas Gleixner , Ingo Molnar , Andrew Morton , the arch/x86 maintainers , linux-doc@vger.kernel.org, Linux Kernel Mailing List Subject: Re: [RFC 0/2] Delay initializing of large sections of memory References: <1371831934-156971-1-git-send-email-nzimmer@sgi.com> <20130621165142.GA32125@kroah.com> <51C48745.9030304@zytor.com> <20130621185056.GA23473@kroah.com> <51C4C5F3.3050800@sgi.com> <51C9D4ED.5070805@sgi.com> <51C9DEC1.6030602@zytor.com> <51C9E523.7000803@zytor.com> In-Reply-To: <51C9E523.7000803@zytor.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1376 Lines: 36 On 6/25/2013 11:44 AM, H. Peter Anvin wrote: > On 06/25/2013 11:40 AM, Yinghai Lu wrote: >> On Tue, Jun 25, 2013 at 11:17 AM, H. Peter Anvin wrote: >>> On 06/25/2013 10:35 AM, Mike Travis wrote: >> >>> However, please consider Ingo's counterproposal of doing this via the >>> buddy allocator, i.e. hugepages being broken on demand. That is a >>> *very* powerful model, although would require more infrastructure. >> >> Can you or Ingo elaborate more about the buddy allocator proposal? >> > > Start by initializing 1G hyperpages only, but mark them so that the > allocator knows that if it needs to break them apart it has to > initialize the page structures for the 2M subpages. > > Same thing with 2M -> 4K. > > -hpa > > It is worth experimenting with but the big question would be, if it still avoids the very expensive "memmap_init_zone" and it's sub-functions using huge expanses of memory. I'll do some experimenting as soon as I can. Our 32TB system is being brought back to 16TB (we found a number of problems as we get closer and closer to the 64TB limit), but that's still a significant size. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/