From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754898AbZEEFz3 (ORCPT ); Tue, 5 May 2009 01:55:29 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752618AbZEEFzT (ORCPT ); Tue, 5 May 2009 01:55:19 -0400 Received: from mga10.intel.com ([192.55.52.92]:43879 "EHLO fmsmga102.fm.intel.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751965AbZEEFzT (ORCPT ); Tue, 5 May 2009 01:55:19 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.40,295,1239001200"; d="scan'208";a="687534908" Subject: Re: [PATCH] Fix early panic issue on machines with memless node From: "Zhang, Yanmin" To: David Rientjes Cc: Jack Steiner , alex.shi@intel.com, LKML , Ingo Molnar , Andi Kleen In-Reply-To: References: <1241493327.27664.17.camel@ymzhang> Content-Type: text/plain; charset=UTF-8 Date: Tue, 05 May 2009 13:55:41 +0800 Message-Id: <1241502941.27664.19.camel@ymzhang> Mime-Version: 1.0 X-Mailer: Evolution 2.22.1 (2.22.1-2.fc9) Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2009-05-04 at 20:32 -0700, David Rientjes wrote: > On Tue, 5 May 2009, Zhang, Yanmin wrote: > > > Kernel 2.6.30-rc4 panic with boot parameter mem=2G on Nehalem machine. > > The machines has 2 nodes and every node has about 3G memory. > > > > Alex Shi did a good bisect and located the bad patch. > > > > commit dc098551918093901d8ac8936e9d1a1b891b56ed > > Author: Jack Steiner > > Date: Fri Apr 17 09:22:42 2009 -0500 > > > > x86/uv: fix init of memory-less nodes > > > > Add support for nodes that have cpus but no memory. > > The current code was failing to add these nodes > > to the nodes_present_map. > > > > v2: Fixes case caught by David Rientjes - missed support > > for the x2apic SRAT table. > > > > [ Impact: fix potential boot crash on memory-less UV nodes. ] > > > > Reported-by: David Rientjes > > Signed-off-by: Jack Steiner > > LKML-Reference: <20090417142242.GA23743@sgi.com> > > Signed-off-by: Ingo Molnar > > > > > > > > With earlyprintk boot parameter, we captured below dump info. > > > > <6>bootmem::alloc_bootmem_core nid=0 size=0 [0 pages] align=1000 goal=1000000 lim0 > > PANIC: early exception 06 rip 10:ffffffff80a2fbe4 error 0 cr2 0 > > Pid: 0, comm: swapper Not tainted 2.6.30-rc4-ymz #3 > > Call Trace: > > [] ? early_idt_handler+0x55/0x68 > > [] ? alloc_bootmem_core+0x91/0x2ae > > [] ? alloc_bootmem_core+0x89/0x2ae > > [] ? ___alloc_bootmem_nopanic+0x73/0xab > > [] ? early_node_mem+0x54/0x78 > > [] ? setup_node_bootmem+0x156/0x282 > > [] ? acpi_scan_nodes+0x207/0x303 > > [] ? initmem_init+0x3c/0x14c > > [] ? setup_arch+0x5ba/0x760 > > [] ? cgroup_init_subsys+0xfc/0x105 > > [] ? cgroup_init_early+0x152/0x163 > > [] ? start_kernel+0x84/0x35e > > [] ? x86_64_start_kernel+0xe5/0xeb > > RIP alloc_bootmem_core+0x91/0x2ae > > > > Consider below call chain: > > acpi_scan_nodes => > > setup_node_bootmem > >  (twice) => early_node_mem > > > > At begining, acpi_scan_nodes filters out memless nodes by calling > > unparse_node. Patch dc098551918 adds the node back actually. > > acpi_scan_nodes has many comments around unparse_node. > > > > Below patch fixes it with node memory checking. Another method is just > > to revert the bad patch. > > > > David Rientjes, Jack Steiner, > > Would you check if below patch satisfy your original objective? > > > > Could you try this instead? > > > srat: do not register nodes beyond e820 map > > The mem= option will truncate the memory map at a specified address so > it's not possible to register nodes with memory beyond the e820 upper > bound. > > unparse_node() is only called when then node had memory associated with > it, although with the mem= option it is no longer addressable. > > Signed-off-by: David Rientjes Your patch does fix the hang issue. > --- > diff --git a/arch/x86/mm/srat_64.c b/arch/x86/mm/srat_64.c > --- a/arch/x86/mm/srat_64.c > +++ b/arch/x86/mm/srat_64.c > @@ -361,6 +361,7 @@ static void __init unparse_node(int node) > { > int i; > node_clear(node, nodes_parsed); > + node_clear(node, cpu_nodes_parsed); > for (i = 0; i < MAX_LOCAL_APIC; i++) { > if (apicid_to_node[i] == node) > apicid_to_node[i] = NUMA_NO_NODE;