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Commit 811d8d6f authored by Tejun Heo's avatar Tejun Heo
Browse files

netprio_cgroup: allow nesting and inherit config on cgroup creation 



Inherit netprio configuration from ->css_online(), allow nesting and
remove .broken_hierarchy marking.  This makes netprio_cgroup's
behavior match netcls_cgroup's.

Note that this patch changes userland-visible behavior.  Nesting is
allowed and the first level cgroups below the root cgroup behave
differently - they inherit priorities from the root cgroup on creation
instead of starting with 0.  This is unfortunate but not doing so is
much crazier.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Tested-and-Acked-by: default avatarDaniel Wagner <daniel.wagner@bmw-carit.de>
Acked-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 666b0ebe

Documentation/cgroups/net_prio.txt

+2 −0
Original line number Diff line number Diff line
@@ -51,3 +51,5 @@ One usage for the net_prio cgroup is with mqprio qdisc allowing application 
traffic to be steered to hardware/driver based traffic classes. These mappings

can then be managed by administrators or other networking protocols such as

DCBX.



A new net_prio cgroup inherits the parent's configuration.

net/core/netprio_cgroup.c

+24 −18
Original line number Diff line number Diff line
@@ -136,9 +136,6 @@ static struct cgroup_subsys_state *cgrp_css_alloc(struct cgroup *cgrp) 
{

	struct cgroup_netprio_state *cs;



	if (cgrp->parent && cgrp->parent->id)

		return ERR_PTR(-EINVAL);



	cs = kzalloc(sizeof(*cs), GFP_KERNEL);

	if (!cs)

		return ERR_PTR(-ENOMEM);
@@ -146,16 +143,34 @@ static struct cgroup_subsys_state *cgrp_css_alloc(struct cgroup *cgrp) 
	return &cs->css;

}



static void cgrp_css_free(struct cgroup *cgrp)

static int cgrp_css_online(struct cgroup *cgrp)

{

	struct cgroup_netprio_state *cs = cgrp_netprio_state(cgrp);

	struct cgroup *parent = cgrp->parent;

	struct net_device *dev;

	int ret = 0;



	if (!parent)

		return 0;



	rtnl_lock();

	for_each_netdev(&init_net, dev)

		WARN_ON_ONCE(netprio_set_prio(cgrp, dev, 0));

	/*

	 * Inherit prios from the parent.  As all prios are set during

	 * onlining, there is no need to clear them on offline.

	 */

	for_each_netdev(&init_net, dev) {

		u32 prio = netprio_prio(parent, dev);



		ret = netprio_set_prio(cgrp, dev, prio);

		if (ret)

			break;

	}

	rtnl_unlock();

	kfree(cs);

	return ret;

}



static void cgrp_css_free(struct cgroup *cgrp)

{

	kfree(cgrp_netprio_state(cgrp));

}



static u64 read_prioidx(struct cgroup *cgrp, struct cftype *cft)
@@ -237,21 +252,12 @@ static struct cftype ss_files[] = { 
struct cgroup_subsys net_prio_subsys = {

	.name		= "net_prio",

	.css_alloc	= cgrp_css_alloc,

	.css_online	= cgrp_css_online,

	.css_free	= cgrp_css_free,

	.attach		= net_prio_attach,

	.subsys_id	= net_prio_subsys_id,

	.base_cftypes	= ss_files,

	.module		= THIS_MODULE,



	/*

	 * net_prio has artificial limit on the number of cgroups and

	 * disallows nesting making it impossible to co-mount it with other

	 * hierarchical subsystems.  Remove the artificially low PRIOIDX_SZ

	 * limit and properly nest configuration such that children follow

	 * their parents' configurations by default and are allowed to

	 * override and remove the following.

	 */

	.broken_hierarchy = true,

};



static int netprio_device_event(struct notifier_block *unused,