Patch "mm: memcontrol: reclaim when shrinking memory.high below usage" has been added to the 4.5-stable tree

This is a note to let you know that I've just added the patch titled

mm: memcontrol: reclaim when shrinking memory.high below usage

to the 4.5-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
mm-memcontrol-reclaim-when-shrinking-memory.high-below-usage.patch
and it can be found in the queue-4.5 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Johannes Weiner <[email protected]>
Date: Thu, 17 Mar 2016 14:20:25 -0700
Subject: mm: memcontrol: reclaim when shrinking memory.high below usage

From: Johannes Weiner <[email protected]>

commit 588083bb37a3cea8533c392370a554417c8f29cb upstream.

When setting memory.high below usage, nothing happens until the next charge comes along, and then it will only reclaim its own charge and not the now potentially huge excess of the new memory.high. This can cause groups to stay in excess of their memory.high indefinitely.

To fix that, when shrinking memory.high, kick off a reclaim cycle that goes after the delta.

---
 mm/memcontrol.c |    6 ++++++
 1 file changed, 6 insertions(+)

@@ -5051,6 +5051,7 @@ static ssize_t memory_high_write(struct
 				 char *buf, size_t nbytes, loff_t off)
 {
 	struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
+	unsigned long nr_pages;
 	unsigned long high;
 	int err;
 

@@ -5061,6 +5062,11 @@ static ssize_t memory_high_write(struct
 
 	memcg->high = high;
 
+	nr_pages = page_counter_read(&memcg->memory);
+	if (nr_pages > high)
+		try_to_free_mem_cgroup_pages(memcg, nr_pages - high,
+					     GFP_KERNEL, true);
+
 	memcg_wb_domain_size_changed(memcg);
 	return nbytes;
 }

Patches currently in stable-queue which might be from [email protected] are

queue-4.5/mm-memcontrol-reclaim-when-shrinking-memory.high-below-usage.patch queue-4.5/mm-memcontrol-reclaim-and-oom-kill-when-shrinking-memory.max-below-usage.patch