From: Jakub Kicinski <kuba@kernel.org>
To: akpm@linux-foundation.org
Cc: linux-mm@kvack.org, kernel-team@fb.com, tj@kernel.org,
hannes@cmpxchg.org, chris@chrisdown.name,
cgroups@vger.kernel.org, shakeelb@google.com, mhocko@kernel.org,
Jakub Kicinski <kuba@kernel.org>
Subject: [PATCH mm v2 1/3] mm: prepare for swap over-high accounting and penalty calculation
Date: Mon, 11 May 2020 15:55:14 -0700 [thread overview]
Message-ID: <20200511225516.2431921-2-kuba@kernel.org> (raw)
In-Reply-To: <20200511225516.2431921-1-kuba@kernel.org>
Slice the memory overage calculation logic a little bit so we can
reuse it to apply a similar penalty to the swap. The logic which
accesses the memory-specific fields (use and high values) has to
be taken out of calculate_high_delay().
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
mm/memcontrol.c | 62 ++++++++++++++++++++++++++++---------------------
1 file changed, 35 insertions(+), 27 deletions(-)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 05dcb72314b5..8a9b671c3249 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2321,41 +2321,48 @@ static void high_work_func(struct work_struct *work)
#define MEMCG_DELAY_PRECISION_SHIFT 20
#define MEMCG_DELAY_SCALING_SHIFT 14
-/*
- * 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.
- */
-static unsigned long calculate_high_delay(struct mem_cgroup *memcg,
- unsigned int nr_pages)
+static u64 calculate_overage(unsigned long usage, unsigned long high)
{
- unsigned long penalty_jiffies;
- u64 max_overage = 0;
-
- do {
- unsigned long usage, high;
- u64 overage;
+ u64 overage;
- usage = page_counter_read(&memcg->memory);
- high = READ_ONCE(memcg->high);
+ if (usage <= high)
+ return 0;
- if (usage <= high)
- continue;
+ /*
+ * Prevent division by 0 in overage calculation by acting as if
+ * it was a threshold of 1 page
+ */
+ high = max(high, 1UL);
- /*
- * 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;
+ return div64_u64(overage, high);
+}
- overage = usage - high;
- overage <<= MEMCG_DELAY_PRECISION_SHIFT;
- overage = div64_u64(overage, high);
+static u64 mem_find_max_overage(struct mem_cgroup *memcg)
+{
+ u64 overage, max_overage = 0;
- if (overage > max_overage)
- max_overage = overage;
+ do {
+ overage = calculate_overage(page_counter_read(&memcg->memory),
+ READ_ONCE(memcg->high));
+ max_overage = max(overage, max_overage);
} while ((memcg = parent_mem_cgroup(memcg)) &&
!mem_cgroup_is_root(memcg));
+ return max_overage;
+}
+
+/*
+ * 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.
+ */
+static unsigned long calculate_high_delay(struct mem_cgroup *memcg,
+ unsigned int nr_pages,
+ u64 max_overage)
+{
+ unsigned long penalty_jiffies;
+
if (!max_overage)
return 0;
@@ -2411,7 +2418,8 @@ void mem_cgroup_handle_over_high(void)
* 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);
+ penalty_jiffies = calculate_high_delay(memcg, nr_pages,
+ mem_find_max_overage(memcg));
/*
* Don't sleep if the amount of jiffies this memcg owes us is so low
--
2.25.4
next prev parent reply other threads:[~2020-05-11 22:55 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-11 22:55 [PATCH mm v2 0/3] memcg: Slow down swap allocation as the available space gets depleted Jakub Kicinski
2020-05-11 22:55 ` Jakub Kicinski [this message]
2020-05-12 7:08 ` [PATCH mm v2 1/3] mm: prepare for swap over-high accounting and penalty calculation Michal Hocko
2020-05-12 17:28 ` Jakub Kicinski
2020-05-13 8:06 ` Michal Hocko
2020-05-11 22:55 ` [PATCH mm v2 2/3] mm: move penalty delay clamping out of calculate_high_delay() Jakub Kicinski
2020-05-11 22:55 ` [PATCH mm v2 3/3] mm: automatically penalize tasks with high swap use Jakub Kicinski
2020-05-12 7:26 ` Michal Hocko
2020-05-12 17:55 ` Jakub Kicinski
2020-05-13 8:32 ` Michal Hocko
2020-05-13 18:36 ` Jakub Kicinski
2020-05-14 7:42 ` Michal Hocko
2020-05-14 20:21 ` Johannes Weiner
2020-05-15 7:14 ` Michal Hocko
2020-05-13 8:38 ` Michal Hocko
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