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 <mho...@kernel.org> > > > 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.leiz...@huawei.com> > > > > Acked-by: Michal Hocko <mho...@suse.com> > > 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? -- Michal Hocko SUSE Labs
