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Message-Id: <1353093624-22608-8-git-send-email-tj@kernel.org>
Date: Fri, 16 Nov 2012 11:20:23 -0800
From: Tejun Heo <tj@...nel.org>
To: daniel.wagner@...-carit.de, srivatsa.bhat@...ux.vnet.ibm.com,
john.r.fastabend@...el.com, nhorman@...driver.com
Cc: lizefan@...wei.com, containers@...ts.linux-foundation.org,
cgroups@...r.kernel.org, linux-kernel@...r.kernel.org,
Tejun Heo <tj@...nel.org>
Subject: [PATCH 7/8] netprio_cgroup: keep track of whether prio is set or not
netprio_cgroup keeps prio config per cgroup-netdev pair and doesn't
distinguish between unconfigured and explicit 0 priority. To
implement hierarchy support, it's necessary to know whether a given
pair has explicit configuration or not.
This patch adds netprio_map->aux[] which is indexed by cgroup->id and
currently only contains one bool - is_local. netprio[_set]_prio() is
updated to handle @is_local. is_local is set iff the pair has
explicit config. write_priomap() now clears is_local if a negative
value is written and sets on positive. With cgrp_css_free() also
updated to clear it, is_local is set for a cgroup-netdev pair iff the
pair is online and a positive prio has been configured via
"net_prio.ifpriomap".
is_local is visible to userland via cgroup file "net_prio.is_local".
This currently doesn't change any behavior. It will be used to
implement hierarchy support.
Signed-off-by: Tejun Heo <tj@...nel.org>
---
include/net/netprio_cgroup.h | 10 +++++
net/core/netprio_cgroup.c | 94 ++++++++++++++++++++++++++++++++++----------
2 files changed, 83 insertions(+), 21 deletions(-)
diff --git a/include/net/netprio_cgroup.h b/include/net/netprio_cgroup.h
index 1d04b6f..bd3daf8 100644
--- a/include/net/netprio_cgroup.h
+++ b/include/net/netprio_cgroup.h
@@ -19,8 +19,18 @@
#if IS_ENABLED(CONFIG_NETPRIO_CGROUP)
+
+/*
+ * Auxliary per-cgroup-netdev configuration. Kept separate from priomap[]
+ * so that priomap[] has better spatial locality.
+ */
+struct netprio_aux {
+ bool is_local:1; /* cgroup has priority configured */
+};
+
struct netprio_map {
struct rcu_head rcu;
+ struct netprio_aux *aux; /* auxiliary config array */
u32 priomap_len;
u32 priomap[];
};
diff --git a/net/core/netprio_cgroup.c b/net/core/netprio_cgroup.c
index b2af0d0..e7a5b03 100644
--- a/net/core/netprio_cgroup.c
+++ b/net/core/netprio_cgroup.c
@@ -35,6 +35,14 @@ static inline struct cgroup_netprio_state *cgrp_netprio_state(struct cgroup *cgr
struct cgroup_netprio_state, css);
}
+static void free_netprio_map(struct netprio_map *map)
+{
+ if (map) {
+ kfree(map->aux);
+ kfree_rcu(map, rcu);
+ }
+}
+
/*
* Extend @dev->priomap so that it's large enough to accomodate
* @target_idx. @dev->priomap.priomap_len > @target_idx after successful
@@ -69,38 +77,55 @@ static int extend_netdev_table(struct net_device *dev, u32 target_idx)
/* allocate & copy */
new = kzalloc(new_sz, GFP_KERNEL);
- if (!new) {
- pr_warn("Unable to alloc new priomap!\n");
- return -ENOMEM;
- }
+ if (!new)
+ goto enomem;
+
+ new->aux = kzalloc(new_len * sizeof(new->aux[0]), GFP_KERNEL);
+ if (!new->aux)
+ goto enomem;
- if (old)
+ if (old) {
memcpy(new->priomap, old->priomap,
old->priomap_len * sizeof(old->priomap[0]));
+ memcpy(new->aux, old->aux,
+ old->priomap_len * sizeof(old->aux[0]));
+ }
new->priomap_len = new_len;
/* install the new priomap */
rcu_assign_pointer(dev->priomap, new);
- if (old)
- kfree_rcu(old, rcu);
+ free_netprio_map(old);
return 0;
+
+enomem:
+ free_netprio_map(new);
+ pr_warn("Unable to alloc new priomap!\n");
+ return -ENOMEM;
}
/**
* netprio_prio - return the effective netprio of a cgroup-net_device pair
* @cgrp: cgroup part of the target pair
* @dev: net_device part of the target pair
+ * @is_local_p: optional out param, %true if @cgrp-@dev has local config
*
* Should be called under RCU read or rtnl lock.
*/
-static u32 netprio_prio(struct cgroup *cgrp, struct net_device *dev)
+static u32 netprio_prio(struct cgroup *cgrp, struct net_device *dev,
+ bool *is_local_p)
{
struct netprio_map *map = rcu_dereference_rtnl(dev->priomap);
+ bool is_local = false;
+ u32 prio = 0;
- if (map && cgrp->id < map->priomap_len)
- return map->priomap[cgrp->id];
- return 0;
+ if (map && cgrp->id < map->priomap_len) {
+ is_local = map->aux[cgrp->id].is_local;
+ prio = map->priomap[cgrp->id];
+ }
+ if (is_local_p)
+ *is_local_p = is_local;
+ return prio;
}
/**
@@ -108,19 +133,20 @@ static u32 netprio_prio(struct cgroup *cgrp, struct net_device *dev)
* @cgrp: cgroup part of the target pair
* @dev: net_device part of the target pair
* @prio: prio to set
+ * @is_local: indicates whether @prio is @cgrp's local prio configuration
*
* Set netprio to @prio on @cgrp-@dev pair. Should be called under rtnl
- * lock and may fail under memory pressure for non-zero @prio.
+ * lock and may fail under memory pressure if (@prio || @is_local).
*/
static int netprio_set_prio(struct cgroup *cgrp, struct net_device *dev,
- u32 prio)
+ u32 prio, bool is_local)
{
struct netprio_map *map;
int ret;
- /* avoid extending priomap for zero writes */
+ /* avoid extending priomap for clearing zero writes */
map = rtnl_dereference(dev->priomap);
- if (!prio && (!map || map->priomap_len <= cgrp->id))
+ if (!is_local && !prio && (!map || map->priomap_len <= cgrp->id))
return 0;
ret = extend_netdev_table(dev, cgrp->id);
@@ -128,6 +154,7 @@ static int netprio_set_prio(struct cgroup *cgrp, struct net_device *dev,
return ret;
map = rtnl_dereference(dev->priomap);
+ map->aux[cgrp->id].is_local = is_local;
map->priomap[cgrp->id] = prio;
return 0;
}
@@ -153,7 +180,7 @@ static void cgrp_css_free(struct cgroup *cgrp)
rtnl_lock();
for_each_netdev(&init_net, dev)
- WARN_ON_ONCE(netprio_set_prio(cgrp, dev, 0));
+ WARN_ON_ONCE(netprio_set_prio(cgrp, dev, 0, false));
rtnl_unlock();
kfree(cs);
}
@@ -170,7 +197,7 @@ static int read_priomap(struct cgroup *cont, struct cftype *cft,
rcu_read_lock();
for_each_netdev_rcu(&init_net, dev)
- cb->fill(cb, dev->name, netprio_prio(cont, dev));
+ cb->fill(cb, dev->name, netprio_prio(cont, dev, NULL));
rcu_read_unlock();
return 0;
}
@@ -180,25 +207,46 @@ static int write_priomap(struct cgroup *cgrp, struct cftype *cft,
{
char devname[IFNAMSIZ + 1];
struct net_device *dev;
+ s64 v;
u32 prio;
+ bool is_local;
int ret;
- if (sscanf(buffer, "%"__stringify(IFNAMSIZ)"s %u", devname, &prio) != 2)
+ if (sscanf(buffer, "%"__stringify(IFNAMSIZ)"s %lld", devname, &v) != 2)
return -EINVAL;
+ prio = clamp_val(v, 0, UINT_MAX);
+ is_local = v >= 0;
+
dev = dev_get_by_name(&init_net, devname);
if (!dev)
return -ENODEV;
rtnl_lock();
- ret = netprio_set_prio(cgrp, dev, prio);
+ ret = netprio_set_prio(cgrp, dev, prio, is_local);
rtnl_unlock();
dev_put(dev);
return ret;
}
+static int netprio_read_is_local(struct cgroup *cont, struct cftype *cft,
+ struct seq_file *m)
+{
+ struct net_device *dev;
+
+ rtnl_lock();
+ for_each_netdev(&init_net, dev) {
+ bool is_local;
+
+ netprio_prio(cont, dev, &is_local);
+ seq_printf(m, "%s %d\n", dev->name, is_local);
+ }
+ rtnl_unlock();
+ return 0;
+}
+
static int update_netprio(const void *v, struct file *file, unsigned n)
{
int err;
@@ -231,6 +279,10 @@ static struct cftype ss_files[] = {
.read_map = read_priomap,
.write_string = write_priomap,
},
+ {
+ .name = "is_local",
+ .read_seq_string = netprio_read_is_local,
+ },
{ } /* terminate */
};
@@ -270,7 +322,7 @@ static int netprio_device_event(struct notifier_block *unused,
old = rtnl_dereference(dev->priomap);
RCU_INIT_POINTER(dev->priomap, NULL);
if (old)
- kfree_rcu(old, rcu);
+ free_netprio_map(old);
break;
}
return NOTIFY_DONE;
@@ -308,7 +360,7 @@ static void __exit exit_cgroup_netprio(void)
old = rtnl_dereference(dev->priomap);
RCU_INIT_POINTER(dev->priomap, NULL);
if (old)
- kfree_rcu(old, rcu);
+ free_netprio_map(old);
}
rtnl_unlock();
}
--
1.7.11.7
--
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