On 2016/8/19 12:11, Ganapatrao Kulkarni wrote: > On Fri, Aug 19, 2016 at 9:30 AM, Ganapatrao Kulkarni > <gpkulka...@gmail.com> wrote: >> On Fri, Aug 19, 2016 at 7:28 AM, zhong jiang <zhongji...@huawei.com> wrote: >>> On 2016/8/19 1:45, Ganapatrao Kulkarni wrote: >>>> On Thu, Aug 18, 2016 at 9:34 PM, Catalin Marinas >>>> <catalin.mari...@arm.com> wrote: >>>>> On Thu, Aug 18, 2016 at 09:09:26PM +0800, zhongjiang wrote: >>>>>> At present, boot cpu will bound to a node from device tree when node_off >>>>>> enable. >>>>>> if the node is not initialization, it will lead to a following problem. >>>>>> >>>>>> next_zones_zonelist+0x18/0x80 >>>>>> __build_all_zonelists+0x1e0/0x288 >>>>>> build_all_zonelists_init+0x10/0x1c >>>>>> build_all_zonelists+0x114/0x128 >>>>>> start_kernel+0x1a0/0x414 >>>>> I think this "problem" is missing a lot of information. Is this supposed >>>>> to be a kernel panic? >>>>> >>>>>> The patch fix it by fallback to node 0. therefore, the cpu will bound to >>>>>> the node >>>>>> correctly. >>>>>> >>>>>> Signed-off-by: zhongjiang <zhongji...@huawei.com> >>>>>> --- >>>>>> arch/arm64/mm/numa.c | 2 +- >>>>>> 1 file changed, 1 insertion(+), 1 deletion(-) >>>>>> >>>>>> diff --git a/arch/arm64/mm/numa.c b/arch/arm64/mm/numa.c >>>>>> index 4dcd7d6..1f8f5da 100644 >>>>>> --- a/arch/arm64/mm/numa.c >>>>>> +++ b/arch/arm64/mm/numa.c >>>>>> @@ -119,7 +119,7 @@ void numa_store_cpu_info(unsigned int cpu) >>>>>> void __init early_map_cpu_to_node(unsigned int cpu, int nid) >>>>>> { >>>>>> /* fallback to node 0 */ >>>>>> - if (nid < 0 || nid >= MAX_NUMNODES) >>>>>> + if (nid < 0 || nid >= MAX_NUMNODES || numa_off) >>>> i did not understood how this line change fixes the issue that you >>>> have mentioned (i too not understood fully the issue description) >>>> this array used while mapping node id when secondary cores comes up >>>> when numa_off is set the cpu_to_node_map[cpu] is not used and set to >>>> node0 always( refer function numa_store_cpu_info).. >>>> please provide more details to understand the issue you are facing. >>>> /* >>>> * Set the cpu to node and mem mapping >>>> */ >>>> void numa_store_cpu_info(unsigned int cpu) >>>> { >>>> map_cpu_to_node(cpu, numa_off ? 0 : cpu_to_node_map[cpu]); >>>> } >>>> >>>> thanks >>>> Ganapat >>> The issue comes up when we test the kdump. it will leads to kernel crash. >>> when I debug the issue, I find boot cpu actually bound to the node1. while >>> node1 is not real existence when numa_off enable. >> boot cpu is default mapped to node0 >> are you running with any other patches? > if you added any patch to change this code > /* init boot processor */ > cpu_to_node_map[0] = 0; > map_cpu_to_node(0, 0); > > then adding code to take-care numa_off here might solve your issue. but in of_smp_init_cpus, boot cpu will call early_map_cpu_to_node[] to get the relation node. and the node is from devicetree.
you points to the code will be covered with another node. therefore, it is possible that cpu_to_node[cpu] will leads to the incorrect results. therefore, The crash will come up. >>> __build_all_zonelists will call the cpu_to_node[cpu], but orresponding >>> relation >>> will be obtained from the devicetree. therefore, the issue will come up. >> when numa_off, all cpus are mapped to node0( refer >> numa_store_cpu_info) and device tree mapping is ignored. >>> The corresponding message is as follows when kdump start. it is obvious >>> that mem >>> range points to the node1 in the devicetree. >>> >>> Early memory node ranges >>> node 0: [mem 0x0000005fe0000000-0x0000005fffffffff] >>> Initmem setup node 0 [mem 0x0000005fe0000000-0x0000005fffffffff] >>> >>> Unable to handle kernel paging request at virtual address 00001690 >>> pgd = ffff800001226000 >>> [00001690] *pgd=0000000000000000 >>> Internal error: Oops: 96000004 [#1] SMP >>> Modules linked in: >>> CPU: 0 PID: 0 Comm: swapper Not tainted 4.1.27-vhulk3.6.5.aarch64 #1 >>> Hardware name: Hisilicon Hi1612 Development Board (DT) >>> task: ffff80000102b730 ti: ffff800001018000 task.ti: ffff800001018000 >>> PC is at next_zones_zonelist+0x18/0x80 >>> LR is at __build_all_zonelists+0x1e0/0x288 >>> next_zones_zonelist+0x18/0x80 >>> __build_all_zonelists+0x1e0/0x288 >>> build_all_zonelists_init+0x10/0x1c >>> build_all_zonelists+0x114/0x128 >>> start_kernel+0x1a0/0x414 >>>>>> nid = 0; >>>>>> >>>>>> cpu_to_node_map[cpu] = nid; >>>>> The patch looks fine (slight inconsistence from the map_cpu_to_node() >>>>> callers but I guess we don't want to expose numa_off outside this file). >>>>> I would however like to see an Ack from Ganapat (cc'ed). >>>>> >>>>> -- >>>>> Catalin >>>>> >>>>> _______________________________________________ >>>>> linux-arm-kernel mailing list >>>>> linux-arm-ker...@lists.infradead.org >>>>> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel >>>> . >>>> >>> > . >