From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755360AbZEEDcx (ORCPT ); Mon, 4 May 2009 23:32:53 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751807AbZEEDco (ORCPT ); Mon, 4 May 2009 23:32:44 -0400 Received: from smtp-out.google.com ([216.239.45.13]:47904 "EHLO smtp-out.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751569AbZEEDcn (ORCPT ); Mon, 4 May 2009 23:32:43 -0400 DomainKey-Signature: a=rsa-sha1; s=beta; d=google.com; c=nofws; q=dns; h=date:from:x-x-sender:to:cc:subject:in-reply-to:message-id: references:user-agent:mime-version:content-type:x-system-of-record; b=MDUX6Dm+On2lE+c6VUjU3RrgnHUWW2GwbdcSkcqeDe8sfYBFJwZeZjkV2ZF9kCR6j OIEbhmuMH9LbwaNVMPDHA== Date: Mon, 4 May 2009 20:32:36 -0700 (PDT) From: David Rientjes X-X-Sender: rientjes@chino.kir.corp.google.com To: "Zhang, Yanmin" cc: Jack Steiner , alex.shi@intel.com, LKML , Ingo Molnar , Andi Kleen Subject: Re: [PATCH] Fix early panic issue on machines with memless node In-Reply-To: <1241493327.27664.17.camel@ymzhang> Message-ID: References: <1241493327.27664.17.camel@ymzhang> User-Agent: Alpine 2.00 (DEB 1167 2008-08-23) MIME-Version: 1.0 Content-Type: MULTIPART/MIXED; BOUNDARY="497827084-1046729195-1241494359=:29856" X-System-Of-Record: true Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This message is in MIME format. The first part should be readable text, while the remaining parts are likely unreadable without MIME-aware tools. --497827084-1046729195-1241494359=:29856 Content-Type: TEXT/PLAIN; charset=UTF-8 Content-Transfer-Encoding: 8BIT 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 --- 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; --497827084-1046729195-1241494359=:29856--