From: Waiman Long <longman@redhat.com>
To: Andrew Morton <akpm@linux-foundation.org>,
Johannes Weiner <hannes@cmpxchg.org>,
Michal Hocko <mhocko@kernel.org>,
Vladimir Davydov <vdavydov.dev@gmail.com>,
Jonathan Corbet <corbet@lwn.net>,
Alexey Dobriyan <adobriyan@gmail.com>,
Ingo Molnar <mingo@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Juri Lelli <juri.lelli@redhat.com>,
Vincent Guittot <vincent.guittot@linaro.org>
Cc: linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org,
linux-fsdevel@vger.kernel.org, cgroups@vger.kernel.org,
linux-mm@kvack.org, Waiman Long <longman@redhat.com>
Subject: [RFC PATCH 6/8] memcg: Introduce additional memory control slowdown if needed
Date: Mon, 17 Aug 2020 10:08:29 -0400 [thread overview]
Message-ID: <20200817140831.30260-7-longman@redhat.com> (raw)
In-Reply-To: <20200817140831.30260-1-longman@redhat.com>
For fast cpus on slow disks, yielding the cpus repeatedly with
PR_MEMACT_SLOWDOWN may not be able to slow down memory allocation enough
for memory reclaim to catch up. In case a large memory block is mmap'ed
and the pages are faulted in one-by-one, the syscall delays won't be
activated during this process.
To be safe, an additional variable delay of 20-5000 us will be added
to __mem_cgroup_over_high_action() if the excess memory used is more
than 1/256 of the memory limit.
Signed-off-by: Waiman Long <longman@redhat.com>
---
mm/memcontrol.c | 22 ++++++++++++++++------
1 file changed, 16 insertions(+), 6 deletions(-)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 6488f8a10d66..bddf3e659469 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2643,11 +2643,10 @@ get_rss_counter(struct mm_struct *mm, int mm_bit, u16 flags, int rss_bit)
static bool __mem_cgroup_over_high_action(struct mem_cgroup *memcg, u8 action,
u16 flags)
{
- unsigned long mem = 0;
+ unsigned long mem = 0, limit = 0, excess = 0;
bool ret = false;
struct mm_struct *mm = get_task_mm(current);
u8 signal = READ_ONCE(current->memcg_over_high_signal);
- u32 limit;
if (!mm)
return true; /* No more check is needed */
@@ -2657,9 +2656,10 @@ static bool __mem_cgroup_over_high_action(struct mem_cgroup *memcg, u8 action,
if (memcg) {
mem = page_counter_read(&memcg->memory);
- limit = READ_ONCE(current->memcg_over_high_climit);
- if (mem <= memcg->memory.high + limit)
+ limit = READ_ONCE(current->memcg_over_high_climit) + memcg->memory.high;
+ if (mem <= limit)
goto out;
+ excess = mem - limit;
}
/*
@@ -2676,6 +2676,7 @@ static bool __mem_cgroup_over_high_action(struct mem_cgroup *memcg, u8 action,
limit = READ_ONCE(current->memcg_over_high_plimit);
if (mem <= limit)
goto out;
+ excess = mem - limit;
}
ret = true;
@@ -2685,10 +2686,19 @@ static bool __mem_cgroup_over_high_action(struct mem_cgroup *memcg, u8 action,
break;
case PR_MEMACT_SLOWDOWN:
/*
- * Slow down by yielding the cpu & adding delay to
- * memory allocation syscalls.
+ * Slow down by yielding the cpu & adding delay to memory
+ * allocation syscalls.
+ *
+ * An additional 20-5000 us of delay is added in case the
+ * excess memory is more than 1/256 of the limit.
*/
WRITE_ONCE(current->memcg_over_limit, true);
+ limit >>= 8;
+ if (limit && (excess > limit)) {
+ int delay = min(5000UL, excess/limit * 20UL);
+
+ udelay(delay);
+ }
set_tsk_need_resched(current);
set_preempt_need_resched();
break;
--
2.18.1
next prev parent reply other threads:[~2020-08-17 14:10 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-17 14:08 [RFC PATCH 0/8] memcg: Enable fine-grained per process memory control Waiman Long
2020-08-17 14:08 ` [RFC PATCH 1/8] memcg: Enable fine-grained control of over memory.high action Waiman Long
2020-08-17 14:30 ` Chris Down
2020-08-17 15:38 ` Waiman Long
2020-08-17 16:11 ` Chris Down
2020-08-17 16:44 ` Shakeel Butt
2020-08-17 16:56 ` Chris Down
2020-08-18 19:12 ` Waiman Long
2020-08-18 19:14 ` Waiman Long
2020-08-17 14:08 ` [RFC PATCH 2/8] memcg, mm: Return ENOMEM or delay if memcg_over_limit Waiman Long
2020-08-17 14:08 ` [RFC PATCH 3/8] memcg: Allow the use of task RSS memory as over-high action trigger Waiman Long
2020-08-17 14:08 ` [RFC PATCH 4/8] fs/proc: Support a new procfs memctl file Waiman Long
2020-08-17 14:08 ` [RFC PATCH 5/8] memcg: Allow direct per-task memory limit checking Waiman Long
2020-08-17 14:08 ` Waiman Long [this message]
2020-08-17 14:08 ` [RFC PATCH 7/8] memcg: Enable logging of memory control mitigation action Waiman Long
2020-08-17 14:08 ` [RFC PATCH 8/8] memcg: Add over-high action prctl() documentation Waiman Long
2020-08-17 15:26 ` [RFC PATCH 0/8] memcg: Enable fine-grained per process memory control Michal Hocko
2020-08-17 15:55 ` Waiman Long
2020-08-17 19:26 ` Michal Hocko
2020-08-18 19:20 ` Waiman Long
2020-08-18 9:14 ` peterz
2020-08-18 9:26 ` Michal Hocko
2020-08-18 9:59 ` peterz
2020-08-18 10:05 ` Michal Hocko
2020-08-18 10:18 ` peterz
2020-08-18 10:30 ` Michal Hocko
2020-08-18 10:36 ` peterz
2020-08-18 13:49 ` Johannes Weiner
2020-08-21 19:37 ` Peter Zijlstra
2020-08-24 16:58 ` Johannes Weiner
2020-09-07 11:47 ` Chris Down
2020-09-09 11:53 ` Michal Hocko
2020-08-18 10:17 ` Chris Down
2020-08-18 10:26 ` peterz
2020-08-18 10:35 ` Chris Down
2020-08-23 2:49 ` Waiman Long
2020-08-18 9:27 ` Chris Down
2020-08-18 10:04 ` peterz
2020-08-18 12:55 ` Matthew Wilcox
2020-08-20 6:11 ` Dave Chinner
2020-08-18 19:30 ` Waiman Long
2020-08-18 19:27 ` Waiman Long
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