On Wed 13-10-21 18:40:26, Aneesh Kumar K.V wrote: > On 10/13/21 18:37, Michal Hocko wrote: > > On Wed 13-10-21 18:28:40, Aneesh Kumar K.V wrote: > > > On 10/13/21 18:20, Michal Hocko wrote: > > [...] > > > > I am still not sure the semantic makes sense though. Why should > > > > the lowest node in the nodemask have any special meaning? What if it is > > > > a node with a higher number that somebody preferes to start with? > > > > > > > > > > That is true. I haven't been able to find an easy way to specify the > > > preferred node other than expressing it as first node in the node mask. Yes, > > > it limits the usage of the policy. Any alternate suggestion? > > > > set_mempolicy is indeed not very suitable for something you are looking > > for. Could you be more specific why the initial node is so important? > > Is this because you want to allocate from a cpu less node first before > > falling back to others? > > > > One of the reason is that the thread that is faulting in pages first is not > the one that is going to operate on this page long term. Application wants > to hint the allocation node for the same reason they use MPOL_PREFERRED now. Why cannot you move the faulting thread to a numa node of the preference during the faulting and them move it out if that is really necessary? -- Michal Hocko SUSE Labs
