From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail191.messagelabs.com (mail191.messagelabs.com [216.82.242.19]) by kanga.kvack.org (Postfix) with SMTP id EE5826B01D1 for ; Tue, 18 May 2010 02:17:45 -0400 (EDT) From: minskey guo Subject: [PATCH] online CPU before memory failed in pcpu_alloc_pages() Date: Tue, 18 May 2010 14:17:22 +0800 Message-Id: <1274163442-7081-1-git-send-email-chaohong_guo@linux.intel.com> Sender: owner-linux-mm@kvack.org To: akpm@linux-foundation.org, linux-mm@kvack.org Cc: prarit@redhat.com, andi.kleen@intel.com, linux-kernel@vger.kernel.org, minskey guo List-ID: From: minskey guo The operation of "enable CPU to online before memory within a node" fails in some case according to Prarit. The warnings as follows: Pid: 7440, comm: bash Not tainted 2.6.32 #2 Call Trace: [] pcpu_alloc+0xa05/0xa70 [] __alloc_percpu+0x10/0x20 [] __create_workqueue_key+0x75/0x280 [] ? __build_all_zonelists+0x0/0x5d0 [] stop_machine_create+0x3a/0xb0 [] stop_machine+0x27/0x60 [] build_all_zonelists+0xd0/0x2b0 [] cpu_up+0xb3/0xe3 [] store_online+0x70/0xa0 [] sysdev_store+0x20/0x30 [] sysfs_write_file+0xe5/0x170 [] vfs_write+0xb8/0x1a0 [] ? audit_syscall_entry+0x252/0x280 [] sys_write+0x51/0x90 [] system_call_fastpath+0x16/0x1b Built 4 zonelists in Zone order, mobility grouping on. Total pages: 12331603 PERCPU: allocation failed, size=128 align=64, failed to populate With "enable CPU to online before memory" patch, when the 1st CPU of an offlined node is being onlined, we build zonelists for that node. If per-cpu area needs to be extended during zonelists building period, alloc_pages_node() will be called. The routine alloc_pages_node() fails on the node in-onlining because the node doesn't have zonelists created yet. To fix this issue, we try to alloc memory from current node. Signed-off-by: minskey guo --- mm/percpu.c | 18 +++++++++++++++++- 1 files changed, 17 insertions(+), 1 deletions(-) diff --git a/mm/percpu.c b/mm/percpu.c index 6e09741..fabdb10 100644 --- a/mm/percpu.c +++ b/mm/percpu.c @@ -714,13 +714,29 @@ static int pcpu_alloc_pages(struct pcpu_chunk *chunk, { const gfp_t gfp = GFP_KERNEL | __GFP_HIGHMEM | __GFP_COLD; unsigned int cpu; + int nid; int i; for_each_possible_cpu(cpu) { for (i = page_start; i < page_end; i++) { struct page **pagep = &pages[pcpu_page_idx(cpu, i)]; - *pagep = alloc_pages_node(cpu_to_node(cpu), gfp, 0); + nid = cpu_to_node(cpu); + + /* + * It is allowable to online a CPU within a NUMA + * node which doesn't have onlined local memory. + * In this case, we need to create zonelists for + * that node when cpu is being onlined. If per-cpu + * area needs to be extended at the exact time when + * zonelists of that node is being created, we alloc + * memory from current node. + */ + if ((nid == -1) || + !(node_zonelist(nid, GFP_KERNEL)->_zonerefs->zone)) + nid = numa_node_id(); + + *pagep = alloc_pages_node(nid, gfp, 0); if (!*pagep) { pcpu_free_pages(chunk, pages, populated, page_start, page_end); -- 1.7.0.4 -- 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: email@kvack.org