Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752499AbbHUXyP (ORCPT ); Fri, 21 Aug 2015 19:54:15 -0400 Received: from mail-ig0-f176.google.com ([209.85.213.176]:34528 "EHLO mail-ig0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751792AbbHUXyN (ORCPT ); Fri, 21 Aug 2015 19:54:13 -0400 MIME-Version: 1.0 In-Reply-To: References: <1415089784-28779-1-git-send-email-daniel@numascale.com> <1415089784-28779-4-git-send-email-daniel@numascale.com> <20150821181910.GA31378@agluck-desk.sc.intel.com> <20150821202707.GA920@agluck-desk.sc.intel.com> Date: Fri, 21 Aug 2015 16:54:12 -0700 Message-ID: Subject: Re: [PATCH v4 4/4] Use 2GB memory block size on large-memory x86-64 systems From: Tony Luck To: Yinghai Lu Cc: Daniel J Blueman , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Bjorn Helgaas , "the arch/x86 maintainers" , Linux Kernel Mailing List , "linux-pci@vger.kernel.org" , Steffen Persvold Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1036 Lines: 26 On Fri, Aug 21, 2015 at 1:50 PM, Yinghai Lu wrote: >> It seems that many systems with large amounts of memory >> will have a nicely aligned max_pfn ... so they will get >> the 2GB block size. If they don't have a well aligned >> max_pfn, then they need to use a smaller size to avoid >> the crash I saw. > > Good to me. Still stuff going on that I don't understand here. I increased the amount of mirrored memory in this machine which moved max_pfn to 0x7560000 and probe_memory_block_size() picked 512MB as the memory_block_size, which seemed plausible. But my kernel still crashed during boot with this value. :-( Forcing the block size to 128M made the system boot. Maybe all the holes in the e820 map matter too (specifically the alignment of the holes)? -Tony -- 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/