mm/memcg: move cgroup high memory limit setting into struct page_counter

High memory limit is currently recorded directly in struct mem_cgroup.
We are about to add a high limit for swap, move the field to struct
page_counter and add some helpers.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Chris Down <chris@chrisdown.name>
Cc: Hugh Dickins <hughd@google.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Link: http://lkml.kernel.org/r/20200527195846.102707-4-kuba@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 8 insertions, 0 deletions

diff --git a/include/linux/page_counter.h b/include/linux/page_counter.h
index bab7e57f659b..85bd413e784e 100644
--- a/include/linux/page_counter.h
+++ b/include/linux/page_counter.h
@@ -10,6 +10,7 @@ struct page_counter {
 	atomic_long_t usage;
 	unsigned long min;
 	unsigned long low;
+	unsigned long high;
 	unsigned long max;
 	struct page_counter *parent;
 
@@ -55,6 +56,13 @@ bool page_counter_try_charge(struct page_counter *counter,
 void page_counter_uncharge(struct page_counter *counter, unsigned long nr_pages);
 void page_counter_set_min(struct page_counter *counter, unsigned long nr_pages);
 void page_counter_set_low(struct page_counter *counter, unsigned long nr_pages);
+
+static inline void page_counter_set_high(struct page_counter *counter,
+					 unsigned long nr_pages)
+{
+	WRITE_ONCE(counter->high, nr_pages);
+}
+
 int page_counter_set_max(struct page_counter *counter, unsigned long nr_pages);
 int page_counter_memparse(const char *buf, const char *max,
 			  unsigned long *nr_pages);