Commit 7b4ac12c authored by Sebastian Andrzej Siewior's avatar Sebastian Andrzej Siewior Committed by Paolo Abeni
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openvswitch: Allocate struct ovs_pcpu_storage dynamically 



PERCPU_MODULE_RESERVE defines the maximum size that can by used for the
per-CPU data size used by modules. This is 8KiB.

Commit 035fcdc4 ("openvswitch: Merge three per-CPU structures into
one") restructured the per-CPU memory allocation for the module and
moved the separate alloc_percpu() invocations at module init time to a
static per-CPU variable which is allocated by the module loader.

The size of the per-CPU data section for openvswitch is 6488 bytes which
is ~80% of the available per-CPU memory. Together with a few other
modules it is easy to exhaust the available 8KiB of memory.

Allocate ovs_pcpu_storage dynamically at module init time.

Reported-by: default avatarGal Pressman <gal@nvidia.com>
Closes: https://lore.kernel.org/all/c401e017-f8db-4f57-a1cd-89beb979a277@nvidia.com


Fixes: 035fcdc4 ("openvswitch: Merge three per-CPU structures into one")
Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: default avatarAaron Conole <aconole@redhat.com>
Link: https://patch.msgid.link/20250613123629.-XSoQTCu@linutronix.de


Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
parent 1224b218

net/openvswitch/actions.c

+10 −13
Original line number Diff line number Diff line
@@ -39,16 +39,14 @@ 
#include "flow_netlink.h"

#include "openvswitch_trace.h"



DEFINE_PER_CPU(struct ovs_pcpu_storage, ovs_pcpu_storage) = {

	.bh_lock = INIT_LOCAL_LOCK(bh_lock),

};

struct ovs_pcpu_storage __percpu *ovs_pcpu_storage;



/* Make a clone of the 'key', using the pre-allocated percpu 'flow_keys'

 * space. Return NULL if out of key spaces.

 */

static struct sw_flow_key *clone_key(const struct sw_flow_key *key_)

{

	struct ovs_pcpu_storage *ovs_pcpu = this_cpu_ptr(&ovs_pcpu_storage);

	struct ovs_pcpu_storage *ovs_pcpu = this_cpu_ptr(ovs_pcpu_storage);

	struct action_flow_keys *keys = &ovs_pcpu->flow_keys;

	int level = ovs_pcpu->exec_level;

	struct sw_flow_key *key = NULL;
@@ -94,7 +92,7 @@ static struct deferred_action *add_deferred_actions(struct sk_buff *skb, 
				    const struct nlattr *actions,

				    const int actions_len)

{

	struct action_fifo *fifo = this_cpu_ptr(&ovs_pcpu_storage.action_fifos);

	struct action_fifo *fifo = this_cpu_ptr(&ovs_pcpu_storage->action_fifos);

	struct deferred_action *da;



	da = action_fifo_put(fifo);
@@ -755,7 +753,7 @@ static int set_sctp(struct sk_buff *skb, struct sw_flow_key *flow_key, 
static int ovs_vport_output(struct net *net, struct sock *sk,

			    struct sk_buff *skb)

{

	struct ovs_frag_data *data = this_cpu_ptr(&ovs_pcpu_storage.frag_data);

	struct ovs_frag_data *data = this_cpu_ptr(&ovs_pcpu_storage->frag_data);

	struct vport *vport = data->vport;



	if (skb_cow_head(skb, data->l2_len) < 0) {
@@ -807,7 +805,7 @@ static void prepare_frag(struct vport *vport, struct sk_buff *skb, 
	unsigned int hlen = skb_network_offset(skb);

	struct ovs_frag_data *data;



	data = this_cpu_ptr(&ovs_pcpu_storage.frag_data);

	data = this_cpu_ptr(&ovs_pcpu_storage->frag_data);

	data->dst = skb->_skb_refdst;

	data->vport = vport;

	data->cb = *OVS_CB(skb);
@@ -1566,16 +1564,15 @@ static int clone_execute(struct datapath *dp, struct sk_buff *skb, 
	clone = clone_flow_key ? clone_key(key) : key;

	if (clone) {

		int err = 0;



		if (actions) { /* Sample action */

			if (clone_flow_key)

				__this_cpu_inc(ovs_pcpu_storage.exec_level);

				__this_cpu_inc(ovs_pcpu_storage->exec_level);



			err = do_execute_actions(dp, skb, clone,

						 actions, len);



			if (clone_flow_key)

				__this_cpu_dec(ovs_pcpu_storage.exec_level);

				__this_cpu_dec(ovs_pcpu_storage->exec_level);

		} else { /* Recirc action */

			clone->recirc_id = recirc_id;

			ovs_dp_process_packet(skb, clone);
@@ -1611,7 +1608,7 @@ static int clone_execute(struct datapath *dp, struct sk_buff *skb, 


static void process_deferred_actions(struct datapath *dp)

{

	struct action_fifo *fifo = this_cpu_ptr(&ovs_pcpu_storage.action_fifos);

	struct action_fifo *fifo = this_cpu_ptr(&ovs_pcpu_storage->action_fifos);



	/* Do not touch the FIFO in case there is no deferred actions. */

	if (action_fifo_is_empty(fifo))
@@ -1642,7 +1639,7 @@ int ovs_execute_actions(struct datapath *dp, struct sk_buff *skb, 
{

	int err, level;



	level = __this_cpu_inc_return(ovs_pcpu_storage.exec_level);

	level = __this_cpu_inc_return(ovs_pcpu_storage->exec_level);

	if (unlikely(level > OVS_RECURSION_LIMIT)) {

		net_crit_ratelimited("ovs: recursion limit reached on datapath %s, probable configuration error\n",

				     ovs_dp_name(dp));
@@ -1659,6 +1656,6 @@ int ovs_execute_actions(struct datapath *dp, struct sk_buff *skb, 
		process_deferred_actions(dp);



out:

	__this_cpu_dec(ovs_pcpu_storage.exec_level);

	__this_cpu_dec(ovs_pcpu_storage->exec_level);

	return err;

}

net/openvswitch/datapath.c

+35 −7
Original line number Diff line number Diff line
@@ -244,7 +244,7 @@ void ovs_dp_detach_port(struct vport *p) 
/* Must be called with rcu_read_lock. */

void ovs_dp_process_packet(struct sk_buff *skb, struct sw_flow_key *key)

{

	struct ovs_pcpu_storage *ovs_pcpu = this_cpu_ptr(&ovs_pcpu_storage);

	struct ovs_pcpu_storage *ovs_pcpu = this_cpu_ptr(ovs_pcpu_storage);

	const struct vport *p = OVS_CB(skb)->input_vport;

	struct datapath *dp = p->dp;

	struct sw_flow *flow;
@@ -299,7 +299,7 @@ void ovs_dp_process_packet(struct sk_buff *skb, struct sw_flow_key *key) 
	 * avoided.

	 */

	if (IS_ENABLED(CONFIG_PREEMPT_RT) && ovs_pcpu->owner != current) {

		local_lock_nested_bh(&ovs_pcpu_storage.bh_lock);

		local_lock_nested_bh(&ovs_pcpu_storage->bh_lock);

		ovs_pcpu->owner = current;

		ovs_pcpu_locked = true;

	}
@@ -310,7 +310,7 @@ void ovs_dp_process_packet(struct sk_buff *skb, struct sw_flow_key *key) 
				    ovs_dp_name(dp), error);

	if (ovs_pcpu_locked) {

		ovs_pcpu->owner = NULL;

		local_unlock_nested_bh(&ovs_pcpu_storage.bh_lock);

		local_unlock_nested_bh(&ovs_pcpu_storage->bh_lock);

	}



	stats_counter = &stats->n_hit;
@@ -689,13 +689,13 @@ static int ovs_packet_cmd_execute(struct sk_buff *skb, struct genl_info *info) 
	sf_acts = rcu_dereference(flow->sf_acts);



	local_bh_disable();

	local_lock_nested_bh(&ovs_pcpu_storage.bh_lock);

	local_lock_nested_bh(&ovs_pcpu_storage->bh_lock);

	if (IS_ENABLED(CONFIG_PREEMPT_RT))

		this_cpu_write(ovs_pcpu_storage.owner, current);

		this_cpu_write(ovs_pcpu_storage->owner, current);

	err = ovs_execute_actions(dp, packet, sf_acts, &flow->key);

	if (IS_ENABLED(CONFIG_PREEMPT_RT))

		this_cpu_write(ovs_pcpu_storage.owner, NULL);

	local_unlock_nested_bh(&ovs_pcpu_storage.bh_lock);

		this_cpu_write(ovs_pcpu_storage->owner, NULL);

	local_unlock_nested_bh(&ovs_pcpu_storage->bh_lock);

	local_bh_enable();

	rcu_read_unlock();
@@ -2744,6 +2744,28 @@ static struct drop_reason_list drop_reason_list_ovs = { 
	.n_reasons = ARRAY_SIZE(ovs_drop_reasons),

};



static int __init ovs_alloc_percpu_storage(void)

{

	unsigned int cpu;



	ovs_pcpu_storage = alloc_percpu(*ovs_pcpu_storage);

	if (!ovs_pcpu_storage)

		return -ENOMEM;



	for_each_possible_cpu(cpu) {

		struct ovs_pcpu_storage *ovs_pcpu;



		ovs_pcpu = per_cpu_ptr(ovs_pcpu_storage, cpu);

		local_lock_init(&ovs_pcpu->bh_lock);

	}

	return 0;

}



static void ovs_free_percpu_storage(void)

{

	free_percpu(ovs_pcpu_storage);

}



static int __init dp_init(void)

{

	int err;
@@ -2753,6 +2775,10 @@ static int __init dp_init(void) 


	pr_info("Open vSwitch switching datapath\n");



	err = ovs_alloc_percpu_storage();

	if (err)

		goto error;



	err = ovs_internal_dev_rtnl_link_register();

	if (err)

		goto error;
@@ -2799,6 +2825,7 @@ static int __init dp_init(void) 
error_unreg_rtnl_link:

	ovs_internal_dev_rtnl_link_unregister();

error:

	ovs_free_percpu_storage();

	return err;

}
@@ -2813,6 +2840,7 @@ static void dp_cleanup(void) 
	ovs_vport_exit();

	ovs_flow_exit();

	ovs_internal_dev_rtnl_link_unregister();

	ovs_free_percpu_storage();

}



module_init(dp_init);

net/openvswitch/datapath.h

+2 −1
Original line number Diff line number Diff line
@@ -220,7 +220,8 @@ struct ovs_pcpu_storage { 
	struct task_struct *owner;

	local_lock_t bh_lock;

};

DECLARE_PER_CPU(struct ovs_pcpu_storage, ovs_pcpu_storage);



extern struct ovs_pcpu_storage __percpu *ovs_pcpu_storage;



/**

 * enum ovs_pkt_hash_types - hash info to include with a packet