From: "Michal Koutný" <mkoutny@suse.com>
To: cgroups@vger.kernel.org, linux-doc@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org
Cc: Tejun Heo <tj@kernel.org>, Zefan Li <lizefan.x@bytedance.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Jonathan Corbet <corbet@lwn.net>, Shuah Khan <shuah@kernel.org>,
Muhammad Usama Anjum <usama.anjum@collabora.com>
Subject: [PATCH v4 3/6] cgroup/pids: Make event counters hierarchical
Date: Tue, 16 Apr 2024 16:20:11 +0200 [thread overview]
Message-ID: <20240416142014.27630-4-mkoutny@suse.com> (raw)
In-Reply-To: <20240416142014.27630-1-mkoutny@suse.com>
The pids.events file should honor the hierarchy, so make the events
propagate from their origin up to the root on the unified hierarchy. The
legacy behavior remains non-hierarchical.
Signed-off-by: Michal Koutný <mkoutny@suse.com>
---
Documentation/admin-guide/cgroup-v2.rst | 2 +-
kernel/cgroup/pids.c | 46 ++++++++++++++++---------
2 files changed, 31 insertions(+), 17 deletions(-)
diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst
index 108b03dfb26a..aa97e9f91c51 100644
--- a/Documentation/admin-guide/cgroup-v2.rst
+++ b/Documentation/admin-guide/cgroup-v2.rst
@@ -241,7 +241,7 @@ cgroup v2 currently supports the following mount options.
pid_localevents
Represent fork failures inside cgroup's pids.events:max (not its limit
- being hit).
+ being hit) and exclude subtree events from pids.events.
Organizing Processes and Threads
diff --git a/kernel/cgroup/pids.c b/kernel/cgroup/pids.c
index ea1fc6b37c0d..4ad28109c1c8 100644
--- a/kernel/cgroup/pids.c
+++ b/kernel/cgroup/pids.c
@@ -238,6 +238,34 @@ static void pids_cancel_attach(struct cgroup_taskset *tset)
}
}
+static void pids_event(struct pids_cgroup *pids_forking,
+ struct pids_cgroup *pids_over_limit)
+{
+ struct pids_cgroup *p = pids_forking;
+ bool limit = false;
+
+ for (; parent_pids(p); p = parent_pids(p)) {
+ /* Only log the first time limit is hit. */
+ if (atomic64_inc_return(&p->events[PIDCG_FORKFAIL]) == 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_file);
+
+ if (!cgroup_subsys_on_dfl(pids_cgrp_subsys) ||
+ cgrp_dfl_root.flags & CGRP_ROOT_PIDS_LOCAL_EVENTS)
+ break;
+
+ if (p == pids_over_limit)
+ limit = true;
+ if (limit)
+ atomic64_inc(&p->events[PIDCG_MAX]);
+
+ cgroup_file_notify(&p->events_file);
+ }
+}
+
/*
* task_css_check(true) in pids_can_fork() and pids_cancel_fork() relies
* on cgroup_threadgroup_change_begin() held by the copy_process().
@@ -254,23 +282,9 @@ static int pids_can_fork(struct task_struct *task, struct css_set *cset)
css = task_css_check(current, pids_cgrp_id, true);
pids = css_pids(css);
err = pids_try_charge(pids, 1, &pids_over_limit);
- if (err) {
- /* compatibility on v1 where events were notified in leaves. */
- if (!cgroup_subsys_on_dfl(pids_cgrp_subsys))
- pids_over_limit = pids;
-
- /* Only log the first time limit is hit. */
- if (atomic64_inc_return(&pids->events[PIDCG_FORKFAIL]) == 1) {
- pr_info("cgroup: fork rejected by pids controller in ");
- pr_cont_cgroup_path(pids->css.cgroup);
- pr_cont("\n");
- }
- atomic64_inc(&pids_over_limit->events[PIDCG_MAX]);
+ if (err)
+ pids_event(pids, pids_over_limit);
- cgroup_file_notify(&pids->events_file);
- if (pids_over_limit != pids)
- cgroup_file_notify(&pids_over_limit->events_file);
- }
return err;
}
--
2.44.0
next prev parent reply other threads:[~2024-04-16 14:20 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-16 14:20 [PATCH v4 0/6] pids controller events rework Michal Koutný
2024-04-16 14:20 ` [PATCH v4 1/6] cgroup/pids: Remove superfluous zeroing Michal Koutný
2024-04-16 19:23 ` Tejun Heo
2024-04-16 14:20 ` [PATCH v4 2/6] cgroup/pids: Separate semantics of pids.events related to pids.max Michal Koutný
2024-04-16 19:27 ` Tejun Heo
2024-04-16 14:20 ` Michal Koutný [this message]
2024-04-16 14:20 ` [PATCH v4 4/6] cgroup/pids: Add pids.events.local Michal Koutný
2024-04-16 19:31 ` Tejun Heo
2024-04-16 14:20 ` [PATCH v4 5/6] selftests: cgroup: Lexicographic order in Makefile Michal Koutný
2024-04-16 14:20 ` [PATCH v4 6/6] selftests: cgroup: Add basic tests for pids controller Michal Koutný
2024-04-16 19:32 ` [PATCH v4 0/6] pids controller events rework Tejun Heo
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