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Merge branch 'for-4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup

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Pull cgroup updates from Tejun Heo:
 "Nothing too exciting.

   - updates to the pids controller so that pid limit breaches can be
     noticed and monitored from userland.

   - cleanups and non-critical bug fixes"

* 'for-4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  cgroup: remove duplicated include from cgroup.c
  cgroup: Use lld instead of ld when printing pids controller events_limit
  cgroup: Add pids controller event when fork fails because of pid limit
  cgroup: allow NULL return from ss->css_alloc()
  cgroup: remove unnecessary 0 check from css_from_id()
  cgroup: fix idr leak for the first cgroup root
This commit is contained in:
Linus Torvalds 2016-07-26 14:34:17 -07:00
commit b55b048718
2 changed files with 37 additions and 10 deletions
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13
kernel/cgroup.c
View File

@ -61,7 +61,6 @@
#include <linux/cpuset.h>
#include <linux/proc_ns.h>
#include <linux/nsproxy.h>
#include <linux/proc_ns.h>
#include <net/sock.h>
/*
@ -1160,18 +1159,12 @@ static void cgroup_exit_root_id(struct cgroup_root *root)
{
lockdep_assert_held(&cgroup_mutex);
if (root->hierarchy_id) {
idr_remove(&cgroup_hierarchy_idr, root->hierarchy_id);
root->hierarchy_id = 0;
}
idr_remove(&cgroup_hierarchy_idr, root->hierarchy_id);
}
static void cgroup_free_root(struct cgroup_root *root)
{
if (root) {
/* hierarchy ID should already have been released */
WARN_ON_ONCE(root->hierarchy_id);
idr_destroy(&root->cgroup_idr);
kfree(root);
}
@ -5146,6 +5139,8 @@ static struct cgroup_subsys_state *css_create(struct cgroup *cgrp,
lockdep_assert_held(&cgroup_mutex);
css = ss->css_alloc(parent_css);
if (!css)
css = ERR_PTR(-ENOMEM);
if (IS_ERR(css))
return css;
@ -6172,7 +6167,7 @@ struct cgroup_subsys_state *css_tryget_online_from_dir(struct dentry *dentry,
struct cgroup_subsys_state *css_from_id(int id, struct cgroup_subsys *ss)
{
WARN_ON_ONCE(!rcu_read_lock_held());
return id > 0 ? idr_find(&ss->css_idr, id) : NULL;
return idr_find(&ss->css_idr, id);
}
/**

34
kernel/cgroup_pids.c
View File

@ -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 %lld\n", (s64)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 */
};