Hierarchical counting of events is not practical for watching when a
particular pids.max is being hit. Therefore introduce .local flavor of
events file (akin to memory controller) that collects only events
relevant to given cgroup.
Signed-off-by: Michal Koutný <[email protected]>
---
kernel/cgroup/pids.c | 41 +++++++++++++++++++++++++++++++++--------
1 file changed, 33 insertions(+), 8 deletions(-)
diff --git a/kernel/cgroup/pids.c b/kernel/cgroup/pids.c
index 76c0a97e42da..f5f81274658e 100644
--- a/kernel/cgroup/pids.c
+++ b/kernel/cgroup/pids.c
@@ -57,10 +57,12 @@ struct pids_cgroup {
atomic64_t limit;
int64_t watermark;
- /* Handle for "pids.events" */
+ /* Handles for pids.events[.local] */
struct cgroup_file events_file;
+ struct cgroup_file events_local_file;
atomic64_t events[NR_PIDCG_EVENTS];
+ atomic64_t events_local[NR_PIDCG_EVENTS];
};
static struct pids_cgroup *css_pids(struct cgroup_subsys_state *css)
@@ -245,11 +247,12 @@ static void pids_event(struct pids_cgroup *pids_forking,
bool limit = false;
/* Only log the first time limit is hit. */
- if (atomic64_inc_return(&p->events[PIDCG_MAX_IMPOSED]) == 1) {
+ if (atomic64_inc_return(&p->events_local[PIDCG_MAX_IMPOSED]) == 1) {
pr_info("cgroup: fork rejected by pids controller in ");
pr_cont_cgroup_path(p->css.cgroup);
pr_cont("\n");
}
+ cgroup_file_notify(&p->events_local_file);
/* Events are only notified in pids_forking on v1 */
if (!cgroup_subsys_on_dfl(pids_cgrp_subsys))
return;
@@ -257,8 +260,11 @@ static void pids_event(struct pids_cgroup *pids_forking,
for (; parent_pids(p); p = parent_pids(p)) {
atomic64_inc(&p->events[PIDCG_MAX_IMPOSED]);
- if (p == pids_over_limit)
+ if (p == pids_over_limit) {
limit = true;
+ atomic64_inc(&p->events_local[PIDCG_MAX]);
+ cgroup_file_notify(&p->events_local_file);
+ }
if (limit)
atomic64_inc(&p->events[PIDCG_MAX]);
@@ -368,12 +374,25 @@ static s64 pids_peak_read(struct cgroup_subsys_state *css,
return READ_ONCE(pids->watermark);
}
-static int pids_events_show(struct seq_file *sf, void *v)
+static int __pids_events_show(struct seq_file *sf, bool local)
{
struct pids_cgroup *pids = css_pids(seq_css(sf));
+ atomic64_t *events = local ? pids->events_local : pids->events;
+
+ seq_printf(sf, "max %lld\n", (s64)atomic64_read(&events[PIDCG_MAX]));
+ seq_printf(sf, "max.imposed %lld\n", (s64)atomic64_read(&events[PIDCG_MAX_IMPOSED]));
+ return 0;
+}
+
+static int pids_events_show(struct seq_file *sf, void *v)
+{
+ __pids_events_show(sf, false);
+ return 0;
+}
- seq_printf(sf, "max %lld\n", (s64)atomic64_read(&pids->events[PIDCG_MAX]));
- seq_printf(sf, "max.imposed %lld\n", (s64)atomic64_read(&pids->events[PIDCG_MAX_IMPOSED]));
+static int pids_events_local_show(struct seq_file *sf, void *v)
+{
+ __pids_events_show(sf, true);
return 0;
}
@@ -381,7 +400,7 @@ static int pids_events_show_legacy(struct seq_file *sf, void *v)
{
struct pids_cgroup *pids = css_pids(seq_css(sf));
- seq_printf(sf, "max%lld\n", (s64)atomic64_read(&pids->events[PIDCG_MAX_IMPOSED]));
+ seq_printf(sf, "max%lld\n", (s64)atomic64_read(&pids->events_local[PIDCG_MAX_IMPOSED]));
return 0;
}
@@ -408,6 +427,12 @@ static struct cftype pids_files[] = {
.file_offset = offsetof(struct pids_cgroup, events_file),
.flags = CFTYPE_NOT_ON_ROOT,
},
+ {
+ .name = "events.local",
+ .seq_show = pids_events_local_show,
+ .file_offset = offsetof(struct pids_cgroup, events_file),
+ .flags = CFTYPE_NOT_ON_ROOT,
+ },
{ } /* terminate */
};
@@ -426,7 +451,7 @@ static struct cftype pids_files_legacy[] = {
{
.name = "events",
.seq_show = pids_events_show_legacy,
- .file_offset = offsetof(struct pids_cgroup, events_file),
+ .file_offset = offsetof(struct pids_cgroup, events_local_file),
.flags = CFTYPE_NOT_ON_ROOT,
},
{ } /* terminate */
--
2.44.0