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Date: Fri, 29 Jun 2012 17:16:23 -0700
From: Alexander Duyck <alexander.h.duyck@...el.com>
To: netdev@...r.kernel.org
Cc: davem@...emloft.net, jeffrey.t.kirsher@...el.com,
edumazet@...gle.com, bhutchings@...arflare.com,
therbert@...gle.com, alexander.duyck@...il.com
Subject: [RFC PATCH 02/10] net: Add functions netif_reset_xps_queue and
netif_set_xps_queue
This patch adds two functions, netif_reset_xps_queue and
netif_set_xps_queue. The main idea behind these to functions is to provide
a mechanism through which drivers can update their defaults in regards to
XPS.
Currently no such mechanism exists and as a result we cannot use XPS for
things such as ATR which would require a basic configuration to start in
which the Tx queues are mapped to CPUs via a 1:1 mapping. With this change
I am making it possible for drivers such as ixgbe to be able to use the XPS
feature by controlling the default configuration.
Signed-off-by: Alexander Duyck <alexander.h.duyck@...el.com>
---
include/linux/netdevice.h | 13 ++++
net/core/dev.c | 155 +++++++++++++++++++++++++++++++++++++++++++++
net/core/net-sysfs.c | 148 +------------------------------------------
3 files changed, 173 insertions(+), 143 deletions(-)
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 3329d70..e9e74b7 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -2072,6 +2072,19 @@ static inline void netif_wake_subqueue(struct net_device *dev, u16 queue_index)
__netif_schedule(txq->qdisc);
}
+#ifdef CONFIG_XPS
+extern void netif_reset_xps_queue(struct net_device *dev, u16 index);
+extern int netif_set_xps_queue(struct net_device *dev, struct cpumask *mask,
+ u16 index);
+#else
+static inline int netif_set_xps_queue(struct net_device *dev,
+ struct cpumask *mask,
+ u16 index)
+{
+ return 0;
+}
+#endif
+
/*
* Returns a Tx hash for the given packet when dev->real_num_tx_queues is used
* as a distribution range limit for the returned value.
diff --git a/net/core/dev.c b/net/core/dev.c
index b31a9ff..4c0981b 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -1728,6 +1728,161 @@ static void netif_setup_tc(struct net_device *dev, unsigned int txq)
}
}
+#ifdef CONFIG_XPS
+static DEFINE_MUTEX(xps_map_mutex);
+#define xmap_dereference(P) \
+ rcu_dereference_protected((P), lockdep_is_held(&xps_map_mutex))
+
+void netif_reset_xps_queue(struct net_device *dev, u16 index)
+{
+ struct xps_dev_maps *dev_maps;
+ struct xps_map *map;
+ int i, pos, nonempty = 0;
+
+ mutex_lock(&xps_map_mutex);
+ dev_maps = xmap_dereference(dev->xps_maps);
+
+ if (!dev_maps)
+ goto out_no_maps;
+
+ for_each_possible_cpu(i) {
+ map = xmap_dereference(dev_maps->cpu_map[i]);
+ if (!map)
+ continue;
+
+ for (pos = 0; pos < map->len; pos++)
+ if (map->queues[pos] == index)
+ break;
+
+ if (pos < map->len) {
+ if (map->len > 1) {
+ map->queues[pos] = map->queues[--map->len];
+ } else {
+ RCU_INIT_POINTER(dev_maps->cpu_map[i], NULL);
+ kfree_rcu(map, rcu);
+ map = NULL;
+ }
+ }
+ if (map)
+ nonempty = 1;
+ }
+
+ if (!nonempty) {
+ RCU_INIT_POINTER(dev->xps_maps, NULL);
+ kfree_rcu(dev_maps, rcu);
+ }
+
+out_no_maps:
+ mutex_unlock(&xps_map_mutex);
+}
+
+int netif_set_xps_queue(struct net_device *dev, struct cpumask *mask, u16 index)
+{
+ int i, cpu, pos, map_len, alloc_len, need_set;
+ struct xps_map *map, *new_map;
+ struct xps_dev_maps *dev_maps, *new_dev_maps;
+ int nonempty = 0;
+ int numa_node_id = -2;
+ int maps_sz = max_t(unsigned int, XPS_DEV_MAPS_SIZE, L1_CACHE_BYTES);
+
+ new_dev_maps = kzalloc(maps_sz, GFP_KERNEL);
+ if (!new_dev_maps)
+ return -ENOMEM;
+
+ mutex_lock(&xps_map_mutex);
+
+ dev_maps = xmap_dereference(dev->xps_maps);
+
+ for_each_possible_cpu(cpu) {
+ map = dev_maps ?
+ xmap_dereference(dev_maps->cpu_map[cpu]) : NULL;
+ new_map = map;
+ if (map) {
+ for (pos = 0; pos < map->len; pos++)
+ if (map->queues[pos] == index)
+ break;
+ map_len = map->len;
+ alloc_len = map->alloc_len;
+ } else
+ pos = map_len = alloc_len = 0;
+
+ need_set = cpumask_test_cpu(cpu, mask) && cpu_online(cpu);
+#ifdef CONFIG_NUMA
+ if (need_set) {
+ if (numa_node_id == -2)
+ numa_node_id = cpu_to_node(cpu);
+ else if (numa_node_id != cpu_to_node(cpu))
+ numa_node_id = -1;
+ }
+#endif
+ if (need_set && pos >= map_len) {
+ /* Need to add queue to this CPU's map */
+ if (map_len >= alloc_len) {
+ alloc_len = alloc_len ?
+ 2 * alloc_len : XPS_MIN_MAP_ALLOC;
+ new_map = kzalloc_node(XPS_MAP_SIZE(alloc_len),
+ GFP_KERNEL,
+ cpu_to_node(cpu));
+ if (!new_map)
+ goto error;
+ new_map->alloc_len = alloc_len;
+ for (i = 0; i < map_len; i++)
+ new_map->queues[i] = map->queues[i];
+ new_map->len = map_len;
+ }
+ new_map->queues[new_map->len++] = index;
+ } else if (!need_set && pos < map_len) {
+ /* Need to remove queue from this CPU's map */
+ if (map_len > 1)
+ new_map->queues[pos] =
+ new_map->queues[--new_map->len];
+ else
+ new_map = NULL;
+ }
+ RCU_INIT_POINTER(new_dev_maps->cpu_map[cpu], new_map);
+ }
+
+ /* Cleanup old maps */
+ for_each_possible_cpu(cpu) {
+ map = dev_maps ?
+ xmap_dereference(dev_maps->cpu_map[cpu]) : NULL;
+ if (map && xmap_dereference(new_dev_maps->cpu_map[cpu]) != map)
+ kfree_rcu(map, rcu);
+ if (new_dev_maps->cpu_map[cpu])
+ nonempty = 1;
+ }
+
+ if (nonempty) {
+ rcu_assign_pointer(dev->xps_maps, new_dev_maps);
+ } else {
+ kfree(new_dev_maps);
+ RCU_INIT_POINTER(dev->xps_maps, NULL);
+ }
+
+ if (dev_maps)
+ kfree_rcu(dev_maps, rcu);
+
+ netdev_queue_numa_node_write(netdev_get_tx_queue(dev, index),
+ (numa_node_id >= 0) ? numa_node_id :
+ NUMA_NO_NODE);
+
+ mutex_unlock(&xps_map_mutex);
+
+ return 0;
+error:
+ mutex_unlock(&xps_map_mutex);
+
+ if (new_dev_maps)
+ for_each_possible_cpu(i)
+ kfree(rcu_dereference_protected(
+ new_dev_maps->cpu_map[i],
+ 1));
+ kfree(new_dev_maps);
+ return -ENOMEM;
+}
+EXPORT_SYMBOL(netif_set_xps_queue);
+
+#endif
/*
* Routine to help set real_num_tx_queues. To avoid skbs mapped to queues
* greater then real_num_tx_queues stale skbs on the qdisc must be flushed.
diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index 7260717..092d338 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -963,54 +963,14 @@ static ssize_t show_xps_map(struct netdev_queue *queue,
return len;
}
-static DEFINE_MUTEX(xps_map_mutex);
-#define xmap_dereference(P) \
- rcu_dereference_protected((P), lockdep_is_held(&xps_map_mutex))
-
static void xps_queue_release(struct netdev_queue *queue)
{
struct net_device *dev = queue->dev;
- struct xps_dev_maps *dev_maps;
- struct xps_map *map;
unsigned long index;
- int i, pos, nonempty = 0;
index = get_netdev_queue_index(queue);
- mutex_lock(&xps_map_mutex);
- dev_maps = xmap_dereference(dev->xps_maps);
-
- if (dev_maps) {
- for_each_possible_cpu(i) {
- map = xmap_dereference(dev_maps->cpu_map[i]);
- if (!map)
- continue;
-
- for (pos = 0; pos < map->len; pos++)
- if (map->queues[pos] == index)
- break;
-
- if (pos < map->len) {
- if (map->len > 1)
- map->queues[pos] =
- map->queues[--map->len];
- else {
- RCU_INIT_POINTER(dev_maps->cpu_map[i],
- NULL);
- kfree_rcu(map, rcu);
- map = NULL;
- }
- }
- if (map)
- nonempty = 1;
- }
-
- if (!nonempty) {
- RCU_INIT_POINTER(dev->xps_maps, NULL);
- kfree_rcu(dev_maps, rcu);
- }
- }
- mutex_unlock(&xps_map_mutex);
+ netif_reset_xps_queue(dev, index);
}
static ssize_t store_xps_map(struct netdev_queue *queue,
@@ -1018,13 +978,9 @@ static ssize_t store_xps_map(struct netdev_queue *queue,
const char *buf, size_t len)
{
struct net_device *dev = queue->dev;
- cpumask_var_t mask;
- int err, i, cpu, pos, map_len, alloc_len, need_set;
unsigned long index;
- struct xps_map *map, *new_map;
- struct xps_dev_maps *dev_maps, *new_dev_maps;
- int nonempty = 0;
- int numa_node_id = -2;
+ cpumask_var_t mask;
+ int err;
if (!capable(CAP_NET_ADMIN))
return -EPERM;
@@ -1040,105 +996,11 @@ static ssize_t store_xps_map(struct netdev_queue *queue,
return err;
}
- new_dev_maps = kzalloc(max_t(unsigned int,
- XPS_DEV_MAPS_SIZE, L1_CACHE_BYTES), GFP_KERNEL);
- if (!new_dev_maps) {
- free_cpumask_var(mask);
- return -ENOMEM;
- }
-
- mutex_lock(&xps_map_mutex);
-
- dev_maps = xmap_dereference(dev->xps_maps);
-
- for_each_possible_cpu(cpu) {
- map = dev_maps ?
- xmap_dereference(dev_maps->cpu_map[cpu]) : NULL;
- new_map = map;
- if (map) {
- for (pos = 0; pos < map->len; pos++)
- if (map->queues[pos] == index)
- break;
- map_len = map->len;
- alloc_len = map->alloc_len;
- } else
- pos = map_len = alloc_len = 0;
-
- need_set = cpumask_test_cpu(cpu, mask) && cpu_online(cpu);
-#ifdef CONFIG_NUMA
- if (need_set) {
- if (numa_node_id == -2)
- numa_node_id = cpu_to_node(cpu);
- else if (numa_node_id != cpu_to_node(cpu))
- numa_node_id = -1;
- }
-#endif
- if (need_set && pos >= map_len) {
- /* Need to add queue to this CPU's map */
- if (map_len >= alloc_len) {
- alloc_len = alloc_len ?
- 2 * alloc_len : XPS_MIN_MAP_ALLOC;
- new_map = kzalloc_node(XPS_MAP_SIZE(alloc_len),
- GFP_KERNEL,
- cpu_to_node(cpu));
- if (!new_map)
- goto error;
- new_map->alloc_len = alloc_len;
- for (i = 0; i < map_len; i++)
- new_map->queues[i] = map->queues[i];
- new_map->len = map_len;
- }
- new_map->queues[new_map->len++] = index;
- } else if (!need_set && pos < map_len) {
- /* Need to remove queue from this CPU's map */
- if (map_len > 1)
- new_map->queues[pos] =
- new_map->queues[--new_map->len];
- else
- new_map = NULL;
- }
- RCU_INIT_POINTER(new_dev_maps->cpu_map[cpu], new_map);
- }
-
- /* Cleanup old maps */
- for_each_possible_cpu(cpu) {
- map = dev_maps ?
- xmap_dereference(dev_maps->cpu_map[cpu]) : NULL;
- if (map && xmap_dereference(new_dev_maps->cpu_map[cpu]) != map)
- kfree_rcu(map, rcu);
- if (new_dev_maps->cpu_map[cpu])
- nonempty = 1;
- }
-
- if (nonempty) {
- rcu_assign_pointer(dev->xps_maps, new_dev_maps);
- } else {
- kfree(new_dev_maps);
- RCU_INIT_POINTER(dev->xps_maps, NULL);
- }
-
- if (dev_maps)
- kfree_rcu(dev_maps, rcu);
-
- netdev_queue_numa_node_write(queue, (numa_node_id >= 0) ? numa_node_id :
- NUMA_NO_NODE);
-
- mutex_unlock(&xps_map_mutex);
+ err = netif_set_xps_queue(dev, mask, index);
free_cpumask_var(mask);
- return len;
-error:
- mutex_unlock(&xps_map_mutex);
-
- if (new_dev_maps)
- for_each_possible_cpu(i)
- kfree(rcu_dereference_protected(
- new_dev_maps->cpu_map[i],
- 1));
- kfree(new_dev_maps);
- free_cpumask_var(mask);
- return -ENOMEM;
+ return err ? : len;
}
static struct netdev_queue_attribute xps_cpus_attribute =
--
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