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-rw-r--r--mm/memcontrol.c93
1 files changed, 58 insertions, 35 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 6d276e1a3321..7a4bd8b9adc2 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2297,28 +2297,41 @@ static void high_work_func(struct work_struct *work)
#define MEMCG_DELAY_SCALING_SHIFT 14
/*
- * Scheduled by try_charge() to be executed from the userland return path
- * and reclaims memory over the high limit.
+ * Get the number of jiffies that we should penalise a mischievous cgroup which
+ * is exceeding its memory.high by checking both it and its ancestors.
*/
-void mem_cgroup_handle_over_high(void)
+static unsigned long calculate_high_delay(struct mem_cgroup *memcg,
+ unsigned int nr_pages)
{
- unsigned long usage, high, clamped_high;
- unsigned long pflags;
- unsigned long penalty_jiffies, overage;
- unsigned int nr_pages = current->memcg_nr_pages_over_high;
- struct mem_cgroup *memcg;
+ unsigned long penalty_jiffies;
+ u64 max_overage = 0;
- if (likely(!nr_pages))
- return;
+ do {
+ unsigned long usage, high;
+ u64 overage;
- memcg = get_mem_cgroup_from_mm(current->mm);
- reclaim_high(memcg, nr_pages, GFP_KERNEL);
- current->memcg_nr_pages_over_high = 0;
+ usage = page_counter_read(&memcg->memory);
+ high = READ_ONCE(memcg->high);
+
+ /*
+ * Prevent division by 0 in overage calculation by acting as if
+ * it was a threshold of 1 page
+ */
+ high = max(high, 1UL);
+
+ overage = usage - high;
+ overage <<= MEMCG_DELAY_PRECISION_SHIFT;
+ overage = div64_u64(overage, high);
+
+ if (overage > max_overage)
+ max_overage = overage;
+ } while ((memcg = parent_mem_cgroup(memcg)) &&
+ !mem_cgroup_is_root(memcg));
+
+ if (!max_overage)
+ return 0;
/*
- * memory.high is breached and reclaim is unable to keep up. Throttle
- * allocators proactively to slow down excessive growth.
- *
* We use overage compared to memory.high to calculate the number of
* jiffies to sleep (penalty_jiffies). Ideally this value should be
* fairly lenient on small overages, and increasingly harsh when the
@@ -2326,24 +2339,9 @@ void mem_cgroup_handle_over_high(void)
* its crazy behaviour, so we exponentially increase the delay based on
* overage amount.
*/
-
- usage = page_counter_read(&memcg->memory);
- high = READ_ONCE(memcg->high);
-
- if (usage <= high)
- goto out;
-
- /*
- * Prevent division by 0 in overage calculation by acting as if it was a
- * threshold of 1 page
- */
- clamped_high = max(high, 1UL);
-
- overage = div64_u64((u64)(usage - high) << MEMCG_DELAY_PRECISION_SHIFT,
- clamped_high);
-
- penalty_jiffies = ((u64)overage * overage * HZ)
- >> (MEMCG_DELAY_PRECISION_SHIFT + MEMCG_DELAY_SCALING_SHIFT);
+ penalty_jiffies = max_overage * max_overage * HZ;
+ penalty_jiffies >>= MEMCG_DELAY_PRECISION_SHIFT;
+ penalty_jiffies >>= MEMCG_DELAY_SCALING_SHIFT;
/*
* Factor in the task's own contribution to the overage, such that four
@@ -2360,7 +2358,32 @@ void mem_cgroup_handle_over_high(void)
* application moving forwards and also permit diagnostics, albeit
* extremely slowly.
*/
- penalty_jiffies = min(penalty_jiffies, MEMCG_MAX_HIGH_DELAY_JIFFIES);
+ return min(penalty_jiffies, MEMCG_MAX_HIGH_DELAY_JIFFIES);
+}
+
+/*
+ * Scheduled by try_charge() to be executed from the userland return path
+ * and reclaims memory over the high limit.
+ */
+void mem_cgroup_handle_over_high(void)
+{
+ unsigned long penalty_jiffies;
+ unsigned long pflags;
+ unsigned int nr_pages = current->memcg_nr_pages_over_high;
+ struct mem_cgroup *memcg;
+
+ if (likely(!nr_pages))
+ return;
+
+ memcg = get_mem_cgroup_from_mm(current->mm);
+ reclaim_high(memcg, nr_pages, GFP_KERNEL);
+ current->memcg_nr_pages_over_high = 0;
+
+ /*
+ * memory.high is breached and reclaim is unable to keep up. Throttle
+ * allocators proactively to slow down excessive growth.
+ */
+ penalty_jiffies = calculate_high_delay(memcg, nr_pages);
/*
* Don't sleep if the amount of jiffies this memcg owes us is so low