[PATCH] mm/memcontrol: Add the drop_cache interface for cgroup v2
From: <hidden>
Date: 2020-09-21 08:03:42
Also in:
bpf, cgroups, linux-doc, linux-mm, lkml
Subsystem:
control group (cgroup), control group - memory resource controller (memcg), documentation, memory management, the rest · Maintainers:
Tejun Heo, Johannes Weiner, Michal Koutný, Michal Hocko, Roman Gushchin, Shakeel Butt, Jonathan Corbet, Andrew Morton, Linus Torvalds
From: Chunxin Zang <redacted> In the cgroup v1, we have 'force_mepty' interface. This is very useful for userspace to actively release memory. But the cgroup v2 does not. This patch reuse cgroup v1's function, but have a new name for the interface. Because I think 'drop_cache' may be is easier to understand :) Signed-off-by: Chunxin Zang <redacted> --- Documentation/admin-guide/cgroup-v2.rst | 11 +++++++++++ mm/memcontrol.c | 5 +++++ 2 files changed, 16 insertions(+)
diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst
index ce3e05e41724..fbff959c8116 100644
--- a/Documentation/admin-guide/cgroup-v2.rst
+++ b/Documentation/admin-guide/cgroup-v2.rst@@ -1181,6 +1181,17 @@ PAGE_SIZE multiple when read back. high limit is used and monitored properly, this limit's utility is limited to providing the final safety net. + memory.drop_cache + A write-only single value file which exists on non-root + cgroups. + + Provide a mechanism for users to actively trigger memory + reclaim. The cgroup will be reclaimed and as many pages + reclaimed as possible. + + It will broke low boundary. Because it tries to reclaim the + memory many times, until the memory drops to a certain level. + memory.oom.group A read-write single value file which exists on non-root cgroups. The default value is "0".
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 0b38b6ad547d..98646484efff 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c@@ -6226,6 +6226,11 @@ static struct cftype memory_files[] = { .write = memory_max_write, }, { + .name = "drop_cache", + .flags = CFTYPE_NOT_ON_ROOT, + .write = mem_cgroup_force_empty_write, + }, + { .name = "events", .flags = CFTYPE_NOT_ON_ROOT, .file_offset = offsetof(struct mem_cgroup, events_file),
--
2.11.0