On Thu, Feb 20, 2020 at 8:52 AM Dan Schatzberg <schatzberg.dan@xxxxxxxxx> wrote: > > memalloc_use_memcg() worked for kernel allocations but was silently > ignored for user pages. > > This patch establishes a precedence order for who gets charged: > > 1. If there is a memcg associated with the page already, that memcg is > charged. This happens during swapin. > > 2. If an explicit mm is passed, mm->memcg is charged. This happens > during page faults, which can be triggered in remote VMs (eg gup). > > 3. Otherwise consult the current process context. If it has configured > a current->active_memcg, use that. Otherwise, current->mm->memcg. > > Previously, if a NULL mm was passed to mem_cgroup_try_charge (case 3) it > would always charge the root cgroup. Now it looks up the current > active_memcg first (falling back to charging the root cgroup if not > set). > > Signed-off-by: Dan Schatzberg <schatzberg.dan@xxxxxxxxx> > Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx> > Acked-by: Tejun Heo <tj@xxxxxxxxxx> Reviewed-by: Shakeel Butt <shakeelb@xxxxxxxxxx>
