Commit b55b0487 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

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

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
parents bbce2ad2 55094f57

kernel/cgroup.c

+4 −9
Original line number Diff line number Diff line
@@ -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;

	}

}



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);

}



/**

kernel/cgroup_pids.c

+33 −1
Original line number Diff line number Diff line
@@ -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 */

};

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