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-rw-r--r--mm/page_counter.c8
1 files changed, 5 insertions, 3 deletions
diff --git a/mm/page_counter.c b/mm/page_counter.c
index 75d53f15f040..509143f232d8 100644
--- a/mm/page_counter.c
+++ b/mm/page_counter.c
@@ -17,6 +17,7 @@ static void propagate_protected_usage(struct page_counter *c,
unsigned long usage)
{
unsigned long protected, old_protected;
+ unsigned long low;
long delta;
if (!c->parent)
@@ -30,8 +31,9 @@ static void propagate_protected_usage(struct page_counter *c,
atomic_long_add(delta, &c->parent->children_min_usage);
}
- if (c->low || atomic_long_read(&c->low_usage)) {
- protected = min(usage, c->low);
+ low = READ_ONCE(c->low);
+ if (low || atomic_long_read(&c->low_usage)) {
+ protected = min(usage, low);
old_protected = atomic_long_xchg(&c->low_usage, protected);
delta = protected - old_protected;
if (delta)
@@ -222,7 +224,7 @@ void page_counter_set_low(struct page_counter *counter, unsigned long nr_pages)
{
struct page_counter *c;
- counter->low = nr_pages;
+ WRITE_ONCE(counter->low, nr_pages);
for (c = counter; c; c = c->parent)
propagate_protected_usage(c, atomic_long_read(&c->usage));