memcg: convert threshold to bytes

memcg: convert threshold to bytes

page_counter_memparse() returns pages for the threshold, while
mem_cgroup_usage() returns bytes for memory usage.  Convert the
threshold to bytes.

Fixes: 3e32cb2e0a12b6915 ("memcg: rename cgroup_event to mem_cgroup_event").
Signed-off-by: Shaohua Li <[email protected]>
Cc: Johannes Weiner <[email protected]>
Acked-by: Michal Hocko <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>