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-rw-r--r--kernel/cgroup_pids.c34
1 files changed, 33 insertions, 1 deletions
diff --git a/kernel/cgroup_pids.c b/kernel/cgroup_pids.c
index 303097b37429..9740ea6762de 100644
--- a/kernel/cgroup_pids.c
+++ b/kernel/cgroup_pids.c
@@ -49,6 +49,12 @@ struct pids_cgroup {
*/
atomic64_t counter;
int64_t limit;
+
+ /* Handle for "pids.events" */
+ struct cgroup_file events_file;
+
+ /* Number of times fork failed because limit was hit. */
+ atomic64_t events_limit;
};
static struct pids_cgroup *css_pids(struct cgroup_subsys_state *css)
@@ -72,6 +78,7 @@ pids_css_alloc(struct cgroup_subsys_state *parent)
pids->limit = PIDS_MAX;
atomic64_set(&pids->counter, 0);
+ atomic64_set(&pids->events_limit, 0);
return &pids->css;
}
@@ -213,10 +220,21 @@ static int pids_can_fork(struct task_struct *task)
{
struct cgroup_subsys_state *css;
struct pids_cgroup *pids;
+ int err;
css = task_css_check(current, pids_cgrp_id, true);
pids = css_pids(css);
- return pids_try_charge(pids, 1);
+ err = pids_try_charge(pids, 1);
+ if (err) {
+ /* Only log the first time events_limit is incremented. */
+ if (atomic64_inc_return(&pids->events_limit) == 1) {
+ pr_info("cgroup: fork rejected by pids controller in ");
+ pr_cont_cgroup_path(task_cgroup(current, pids_cgrp_id));
+ pr_cont("\n");
+ }
+ cgroup_file_notify(&pids->events_file);
+ }
+ return err;
}
static void pids_cancel_fork(struct task_struct *task)
@@ -288,6 +306,14 @@ static s64 pids_current_read(struct cgroup_subsys_state *css,
return atomic64_read(&pids->counter);
}
+static int pids_events_show(struct seq_file *sf, void *v)
+{
+ struct pids_cgroup *pids = css_pids(seq_css(sf));
+
+ seq_printf(sf, "max %ld\n", atomic64_read(&pids->events_limit));
+ return 0;
+}
+
static struct cftype pids_files[] = {
{
.name = "max",
@@ -300,6 +326,12 @@ static struct cftype pids_files[] = {
.read_s64 = pids_current_read,
.flags = CFTYPE_NOT_ON_ROOT,
},
+ {
+ .name = "events",
+ .seq_show = pids_events_show,
+ .file_offset = offsetof(struct pids_cgroup, events_file),
+ .flags = CFTYPE_NOT_ON_ROOT,
+ },
{ } /* terminate */
};