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>> } >> >> +static struct mempolicy *kvm_gmem_get_folio_policy(struct gmem_inode *gi, >> + pgoff_t index) > > How about kvm_gmem_get_index_policy() instead, since the policy is keyed > by index? > >> +{ >> +#ifdef CONFIG_NUMA >> + struct mempolicy *mpol; >> + >> + mpol = mpol_shared_policy_lookup(&gi->policy, index); >> + return mpol ? mpol : get_task_policy(current); > > Should we be returning NULL if no shared policy was defined? > > By returning NULL, __filemap_get_folio_mpol() can handle the case where > cpuset_do_page_mem_spread(). > > If we always return current's task policy, what if the user wants to use > cpuset_do_page_mem_spread()? > I initially followed shmem's approach here. I agree that returning NULL maintains consistency with the current default behavior of cpuset_do_page_mem_spread(), regardless of CONFIG_NUMA. I'm curious what could be the practical implications of cpuset_do_page_mem_spread() v/s get_task_policy() as the fallback? Which is more appropriate for guest_memfd when no policy is explicitly set via mbind()?