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-rw-r--r--Documentation/admin-guide/cgroup-v2.rst16
-rw-r--r--include/linux/memcontrol.h5
-rw-r--r--mm/memcontrol.c24
3 files changed, 44 insertions, 1 deletions
diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst
index 74cdeaed9f7a..b0dda10b9382 100644
--- a/Documentation/admin-guide/cgroup-v2.rst
+++ b/Documentation/admin-guide/cgroup-v2.rst
@@ -1199,6 +1199,22 @@ PAGE_SIZE multiple when read back.
Swap usage hard limit. If a cgroup's swap usage reaches this
limit, anonymous memory of the cgroup will not be swapped out.
+ memory.swap.events
+ A read-only flat-keyed file which exists on non-root cgroups.
+ The following entries are defined. Unless specified
+ otherwise, a value change in this file generates a file
+ modified event.
+
+ max
+ The number of times the cgroup's swap usage was about
+ to go over the max boundary and swap allocation
+ failed.
+
+ fail
+ The number of times swap allocation failed either
+ because of running out of swap system-wide or max
+ limit.
+
Usage Guidelines
~~~~~~~~~~~~~~~~
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index d99b71bc2c66..517096c3cc99 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -53,6 +53,8 @@ enum memcg_memory_event {
MEMCG_HIGH,
MEMCG_MAX,
MEMCG_OOM,
+ MEMCG_SWAP_MAX,
+ MEMCG_SWAP_FAIL,
MEMCG_NR_MEMORY_EVENTS,
};
@@ -208,6 +210,9 @@ struct mem_cgroup {
atomic_long_t memory_events[MEMCG_NR_MEMORY_EVENTS];
struct cgroup_file events_file;
+ /* handle for "memory.swap.events" */
+ struct cgroup_file swap_events_file;
+
/* protect arrays of thresholds */
struct mutex thresholds_lock;
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index e8166521a474..d86665cf4a49 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -6012,13 +6012,17 @@ int mem_cgroup_try_charge_swap(struct page *page, swp_entry_t entry)
if (!memcg)
return 0;
- if (!entry.val)
+ if (!entry.val) {
+ memcg_memory_event(memcg, MEMCG_SWAP_FAIL);
return 0;
+ }
memcg = mem_cgroup_id_get_online(memcg);
if (!mem_cgroup_is_root(memcg) &&
!page_counter_try_charge(&memcg->swap, nr_pages, &counter)) {
+ memcg_memory_event(memcg, MEMCG_SWAP_MAX);
+ memcg_memory_event(memcg, MEMCG_SWAP_FAIL);
mem_cgroup_id_put(memcg);
return -ENOMEM;
}
@@ -6156,6 +6160,18 @@ static ssize_t swap_max_write(struct kernfs_open_file *of,
return nbytes;
}
+static int swap_events_show(struct seq_file *m, void *v)
+{
+ struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
+
+ seq_printf(m, "max %lu\n",
+ atomic_long_read(&memcg->memory_events[MEMCG_SWAP_MAX]));
+ seq_printf(m, "fail %lu\n",
+ atomic_long_read(&memcg->memory_events[MEMCG_SWAP_FAIL]));
+
+ return 0;
+}
+
static struct cftype swap_files[] = {
{
.name = "swap.current",
@@ -6168,6 +6184,12 @@ static struct cftype swap_files[] = {
.seq_show = swap_max_show,
.write = swap_max_write,
},
+ {
+ .name = "swap.events",
+ .flags = CFTYPE_NOT_ON_ROOT,
+ .file_offset = offsetof(struct mem_cgroup, swap_events_file),
+ .seq_show = swap_events_show,
+ },
{ } /* terminate */
};