On 1/14/20 5:26 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> -- Mike Kravetz
