On 2/3/20 3:22 PM, Mina Almasry wrote: > Normally the pointer to the cgroup to uncharge hangs off the struct > page, and gets queried when it's time to free the page. With > hugetlb_cgroup reservations, this is not possible. Because it's possible > for a page to be reserved by one task and actually faulted in by another > task. > > The best place to put the hugetlb_cgroup pointer to uncharge for > reservations is in the resv_map. But, because the resv_map has different > semantics for private and shared mappings, the code patch to > charge/uncharge shared and private mappings is different. This patch > implements charging and uncharging for private mappings. > > For private mappings, the counter to uncharge is in > resv_map->reservation_counter. On initializing the resv_map this is set > to NULL. On reservation of a region in private mapping, the tasks > hugetlb_cgroup is charged and the hugetlb_cgroup is placed is > resv_map->reservation_counter. > > On hugetlb_vm_op_close, we uncharge resv_map->reservation_counter. > > Signed-off-by: Mina Almasry <almasrymina@xxxxxxxxxx> > Reviewed-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx> > Acked-by: David Rientjes <rientjes@xxxxxxxxxx> > > --- > > Changes in v11: > - Refactored hugetlb_cgroup_uncharge_conuter a bit to eliminate > unnecessary #ifdefs. > - Added resv_map_set_hugetlb_cgroup_uncharge_info() to eliminate #ifdefs > in the middle of hugetlb logic. Thanks. Code looks better without the #ifdefs. You can keep my Reviewed-by: -- Mike Kravetz
