On Fri, Oct 25, 2024 at 12:36:28PM -0700, Christoph Lameter (Ampere) wrote: > > Sorry saw this after the other email. > > On Fri, 25 Oct 2024, Peter Zijlstra wrote: > > > > Could we follow NUMA policies like with other metadata allocations during > > > systen call processing? > > > > I had a quick look at this, and since the mempolicy stuff is per vma, > > and we don't have the vma, this is going to be terribly expensive -- > > mmap_lock and all that. > > There is a memory policy for the task as a whole that is used for slab > allocations and allocations that are not vma bound in current->mempolicy. > Use that. > You can get a node number following the current task mempolicy by calling > mempolicy_slab_node() and keep using that node for the future. I'll look into the per task thing, which I'm hoping means per-process. We need something that is mm wide consistent. But since futexes play in the address space, I was really rather thinking we ought to use the vma policy.
