From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001 From: André Fabian Silva Delgado Date: Wed, 5 Aug 2015 17:04:01 -0300 Subject: Initial import --- net/core/netprio_cgroup.c | 288 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 288 insertions(+) create mode 100644 net/core/netprio_cgroup.c (limited to 'net/core/netprio_cgroup.c') diff --git a/net/core/netprio_cgroup.c b/net/core/netprio_cgroup.c new file mode 100644 index 000000000..cbd0a199b --- /dev/null +++ b/net/core/netprio_cgroup.c @@ -0,0 +1,288 @@ +/* + * net/core/netprio_cgroup.c Priority Control Group + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + * + * Authors: Neil Horman + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include + +#define PRIOMAP_MIN_SZ 128 + +/* + * Extend @dev->priomap so that it's large enough to accommodate + * @target_idx. @dev->priomap.priomap_len > @target_idx after successful + * return. Must be called under rtnl lock. + */ +static int extend_netdev_table(struct net_device *dev, u32 target_idx) +{ + struct netprio_map *old, *new; + size_t new_sz, new_len; + + /* is the existing priomap large enough? */ + old = rtnl_dereference(dev->priomap); + if (old && old->priomap_len > target_idx) + return 0; + + /* + * Determine the new size. Let's keep it power-of-two. We start + * from PRIOMAP_MIN_SZ and double it until it's large enough to + * accommodate @target_idx. + */ + new_sz = PRIOMAP_MIN_SZ; + while (true) { + new_len = (new_sz - offsetof(struct netprio_map, priomap)) / + sizeof(new->priomap[0]); + if (new_len > target_idx) + break; + new_sz *= 2; + /* overflowed? */ + if (WARN_ON(new_sz < PRIOMAP_MIN_SZ)) + return -ENOSPC; + } + + /* allocate & copy */ + new = kzalloc(new_sz, GFP_KERNEL); + if (!new) + return -ENOMEM; + + if (old) + memcpy(new->priomap, old->priomap, + old->priomap_len * sizeof(old->priomap[0])); + + new->priomap_len = new_len; + + /* install the new priomap */ + rcu_assign_pointer(dev->priomap, new); + if (old) + kfree_rcu(old, rcu); + return 0; +} + +/** + * netprio_prio - return the effective netprio of a cgroup-net_device pair + * @css: css part of the target pair + * @dev: net_device part of the target pair + * + * Should be called under RCU read or rtnl lock. + */ +static u32 netprio_prio(struct cgroup_subsys_state *css, struct net_device *dev) +{ + struct netprio_map *map = rcu_dereference_rtnl(dev->priomap); + int id = css->cgroup->id; + + if (map && id < map->priomap_len) + return map->priomap[id]; + return 0; +} + +/** + * netprio_set_prio - set netprio on a cgroup-net_device pair + * @css: css part of the target pair + * @dev: net_device part of the target pair + * @prio: prio to set + * + * Set netprio to @prio on @css-@dev pair. Should be called under rtnl + * lock and may fail under memory pressure for non-zero @prio. + */ +static int netprio_set_prio(struct cgroup_subsys_state *css, + struct net_device *dev, u32 prio) +{ + struct netprio_map *map; + int id = css->cgroup->id; + int ret; + + /* avoid extending priomap for zero writes */ + map = rtnl_dereference(dev->priomap); + if (!prio && (!map || map->priomap_len <= id)) + return 0; + + ret = extend_netdev_table(dev, id); + if (ret) + return ret; + + map = rtnl_dereference(dev->priomap); + map->priomap[id] = prio; + return 0; +} + +static struct cgroup_subsys_state * +cgrp_css_alloc(struct cgroup_subsys_state *parent_css) +{ + struct cgroup_subsys_state *css; + + css = kzalloc(sizeof(*css), GFP_KERNEL); + if (!css) + return ERR_PTR(-ENOMEM); + + return css; +} + +static int cgrp_css_online(struct cgroup_subsys_state *css) +{ + struct cgroup_subsys_state *parent_css = css->parent; + struct net_device *dev; + int ret = 0; + + if (!parent_css) + return 0; + + rtnl_lock(); + /* + * 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_css, dev); + + ret = netprio_set_prio(css, dev, prio); + if (ret) + break; + } + rtnl_unlock(); + return ret; +} + +static void cgrp_css_free(struct cgroup_subsys_state *css) +{ + kfree(css); +} + +static u64 read_prioidx(struct cgroup_subsys_state *css, struct cftype *cft) +{ + return css->cgroup->id; +} + +static int read_priomap(struct seq_file *sf, void *v) +{ + struct net_device *dev; + + rcu_read_lock(); + for_each_netdev_rcu(&init_net, dev) + seq_printf(sf, "%s %u\n", dev->name, + netprio_prio(seq_css(sf), dev)); + rcu_read_unlock(); + return 0; +} + +static ssize_t write_priomap(struct kernfs_open_file *of, + char *buf, size_t nbytes, loff_t off) +{ + char devname[IFNAMSIZ + 1]; + struct net_device *dev; + u32 prio; + int ret; + + if (sscanf(buf, "%"__stringify(IFNAMSIZ)"s %u", devname, &prio) != 2) + return -EINVAL; + + dev = dev_get_by_name(&init_net, devname); + if (!dev) + return -ENODEV; + + rtnl_lock(); + + ret = netprio_set_prio(of_css(of), dev, prio); + + rtnl_unlock(); + dev_put(dev); + return ret ?: nbytes; +} + +static int update_netprio(const void *v, struct file *file, unsigned n) +{ + int err; + struct socket *sock = sock_from_file(file, &err); + if (sock) + sock->sk->sk_cgrp_prioidx = (u32)(unsigned long)v; + return 0; +} + +static void net_prio_attach(struct cgroup_subsys_state *css, + struct cgroup_taskset *tset) +{ + struct task_struct *p; + void *v = (void *)(unsigned long)css->cgroup->id; + + cgroup_taskset_for_each(p, tset) { + task_lock(p); + iterate_fd(p->files, 0, update_netprio, v); + task_unlock(p); + } +} + +static struct cftype ss_files[] = { + { + .name = "prioidx", + .read_u64 = read_prioidx, + }, + { + .name = "ifpriomap", + .seq_show = read_priomap, + .write = write_priomap, + }, + { } /* terminate */ +}; + +struct cgroup_subsys net_prio_cgrp_subsys = { + .css_alloc = cgrp_css_alloc, + .css_online = cgrp_css_online, + .css_free = cgrp_css_free, + .attach = net_prio_attach, + .legacy_cftypes = ss_files, +}; + +static int netprio_device_event(struct notifier_block *unused, + unsigned long event, void *ptr) +{ + struct net_device *dev = netdev_notifier_info_to_dev(ptr); + struct netprio_map *old; + + /* + * Note this is called with rtnl_lock held so we have update side + * protection on our rcu assignments + */ + + switch (event) { + case NETDEV_UNREGISTER: + old = rtnl_dereference(dev->priomap); + RCU_INIT_POINTER(dev->priomap, NULL); + if (old) + kfree_rcu(old, rcu); + break; + } + return NOTIFY_DONE; +} + +static struct notifier_block netprio_device_notifier = { + .notifier_call = netprio_device_event +}; + +static int __init init_cgroup_netprio(void) +{ + register_netdevice_notifier(&netprio_device_notifier); + return 0; +} + +subsys_initcall(init_cgroup_netprio); +MODULE_LICENSE("GPL v2"); -- cgit v1.2.3-54-g00ecf