On 2017/8/28 21:13, Michal Hocko wrote: > On Fri 25-08-17 18:34:33, Will Deacon wrote: >> On Thu, Aug 24, 2017 at 10:32:26AM +0200, Michal Hocko wrote: >>> It seems this has slipped through cracks. Let's CC arm64 guys >>> >>> On Tue 20-06-17 20:43:28, Zhen Lei wrote: >>>> When I executed numactl -H(which read /sys/devices/system/node/nodeX/cpumap >>>> and display cpumask_of_node for each node), but I got different result on >>>> X86 and arm64. For each numa node, the former only displayed online CPUs, >>>> and the latter displayed all possible CPUs. Unfortunately, both Linux >>>> documentation and numactl manual have not described it clear. >>>> >>>> I sent a mail to ask for help, and Michal Hocko <mhocko@xxxxxxxxxx> replied >>>> that he preferred to print online cpus because it doesn't really make much >>>> sense to bind anything on offline nodes. >>> >>> Yes printing offline CPUs is just confusing and more so when the >>> behavior is not consistent over architectures. I believe that x86 >>> behavior is the more appropriate one because it is more logical to dump >>> the NUMA topology and use it for affinity setting than adding one >>> additional step to check the cpu state to achieve the same. >>> >>> It is true that the online/offline state might change at any time so the >>> above might be tricky on its own but if we should at least make the >>> behavior consistent. >>> >>>> Signed-off-by: Zhen Lei <thunder.leizhen@xxxxxxxxxx> >>> >>> Acked-by: Michal Hocko <mhocko@xxxxxxxx> >> >> The concept looks find to me, but shouldn't we use cpumask_var_t and >> alloc/free_cpumask_var? > > This will be safer but both callers of node_read_cpumap are shallow > stack so I am not sure a stack is a limiting factor here. > > Zhen Lei, would you care to update that part please? > Sure, I will send v2 immediately. I'm so sorry that missed this email until someone told me. -- Thanks! BestRegards -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
