From: Yinghai Lu Date: Fri, 4 Mar 2011 13:49:28 +0000 (+0100) Subject: x86-64, NUMA: Fix numa_emulation code with node0 without RAM X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=51b361b4009f4e19ae68d2bcbb35e254e91b6054;p=deliverable%2Flinux.git x86-64, NUMA: Fix numa_emulation code with node0 without RAM On one system that does not have RAM on node0. When numa_emulation is compiled in, and 1. boot system without numa=fake... 2. or boot system with numa=fake=128 to make emulation fail will get: [ 0.092026] ------------[ cut here ]------------ [ 0.096005] kernel BUG at arch/x86/mm/numa_emulation.c:439! [ 0.096005] invalid opcode: 0000 [#1] SMP [ 0.096005] last sysfs file: [ 0.096005] CPU 0 [ 0.096005] Modules linked in: [ 0.096005] [ 0.096005] Pid: 0, comm: swapper Not tainted 2.6.38-rc6-tip-yh-03869-gcb0491d-dirty #684 Sun Microsystems Sun Fire X4240/Sun Fire X4240 [ 0.096005] RIP: 0010:[] [] numa_add_cpu+0x56/0xcf [ 0.096005] RSP: 0000:ffffffff82437ed8 EFLAGS: 00010246 ... [ 0.096005] Call Trace: [ 0.096005] [] identify_cpu+0x2d7/0x2df [ 0.096005] [] identify_boot_cpu+0x10/0x30 [ 0.096005] [] check_bugs+0x9/0x2d [ 0.096005] [] start_kernel+0x3d7/0x3f1 [ 0.096005] [] x86_64_start_reservations+0x9c/0xa0 [ 0.096005] [] x86_64_start_kernel+0x1dd/0x1e8 [ 0.096005] Code: 74 06 48 8d 04 90 eb 0f 48 c7 c0 30 d9 00 00 48 03 04 d5 90 0f 60 82 8b 00 83 f8 ff 74 0d 0f a3 05 8b 7e 92 00 19 d2 85 d2 75 02 <0f> 0b 48 98 be 00 01 00 00 48 c7 c7 e0 44 60 82 44 8b 2c 85 e0 [ 0.096005] RIP [] numa_add_cpu+0x56/0xcf [ 0.096005] RSP [ 0.096026] ---[ end trace a7919e7f17c0a725 ]--- We need to use early_cpu_to_node() directly, because numa_cpu_node() will return node0 that is not onlined. Signed-off-by: Yinghai Lu Signed-off-by: Tejun Heo --- diff --git a/arch/x86/mm/numa_emulation.c b/arch/x86/mm/numa_emulation.c index aeecea93820f..75b31dc0f329 100644 --- a/arch/x86/mm/numa_emulation.c +++ b/arch/x86/mm/numa_emulation.c @@ -417,9 +417,7 @@ void __cpuinit numa_add_cpu(int cpu) { int physnid, nid; - nid = numa_cpu_node(cpu); - if (nid == NUMA_NO_NODE) - nid = early_cpu_to_node(cpu); + nid = early_cpu_to_node(cpu); BUG_ON(nid == NUMA_NO_NODE || !node_online(nid)); physnid = emu_nid_to_phys[nid];