Currently, we use kcalloc to allocate rx/tx queues for a net device which could
be easily lead to a high order memory allocation request when initializing a
multiqueue net device. We can simply avoid this by switching to use flex array
which always allocate at order zero.
Signed-off-by: Jason Wang <jasow...@redhat.com>
---
include/linux/netdevice.h | 13 ++++++----
net/core/dev.c | 57 ++++++++++++++++++++++++++++++++------------
net/core/net-sysfs.c | 15 +++++++----
3 files changed, 58 insertions(+), 27 deletions(-)
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 09b4188..c0b5d04 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -32,6 +32,7 @@
#include <linux/atomic.h>
#include <asm/cache.h>
#include <asm/byteorder.h>
+#include <linux/flex_array.h>
#include <linux/percpu.h>
#include <linux/rculist.h>
@@ -1230,7 +1231,7 @@ struct net_device {
#ifdef CONFIG_RPS
- struct netdev_rx_queue *_rx;
+ struct flex_array *_rx;
/* Number of RX queues allocated at register_netdev() time */
unsigned int num_rx_queues;
@@ -1250,7 +1251,7 @@ struct net_device {
/*
* Cache lines mostly used on transmit path
*/
- struct netdev_queue *_tx ____cacheline_aligned_in_smp;
+ struct flex_array *_tx ____cacheline_aligned_in_smp;
/* Number of TX queues allocated at alloc_netdev_mq() time */
unsigned int num_tx_queues;
@@ -1434,7 +1435,7 @@ static inline
struct netdev_queue *netdev_get_tx_queue(const struct net_device *dev,
unsigned int index)
{
- return &dev->_tx[index];
+ return flex_array_get(dev->_tx, index);
}
static inline void netdev_for_each_tx_queue(struct net_device *dev,
@@ -1445,8 +1446,10 @@ static inline void netdev_for_each_tx_queue(struct
net_device *dev,
{
unsigned int i;
- for (i = 0; i < dev->num_tx_queues; i++)
- f(dev, &dev->_tx[i], arg);
+ for (i = 0; i < dev->num_tx_queues; i++) {
+ struct netdev_queue *txq = flex_array_get(dev->_tx, i);
+ f(dev, txq, arg);
+ }
}
extern struct netdev_queue *netdev_pick_tx(struct net_device *dev,
diff --git a/net/core/dev.c b/net/core/dev.c
index fa007db..3a4ecb1 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -130,6 +130,7 @@
#include <linux/cpu_rmap.h>
#include <linux/static_key.h>
#include <linux/hashtable.h>
+#include <linux/flex_array.h>
#include "net-sysfs.h"
@@ -2902,7 +2903,7 @@ set_rps_cpu(struct net_device *dev, struct sk_buff *skb,
if (rxq_index == skb_get_rx_queue(skb))
goto out;
- rxqueue = dev->_rx + rxq_index;
+ rxqueue = flex_array_get(dev->_rx, rxq_index);
flow_table = rcu_dereference(rxqueue->rps_flow_table);
if (!flow_table)
goto out;
@@ -2950,9 +2951,9 @@ static int get_rps_cpu(struct net_device *dev, struct
sk_buff *skb,
dev->name, index, dev->real_num_rx_queues);
goto done;
}
- rxqueue = dev->_rx + index;
+ rxqueue = flex_array_get(dev->_rx, index);
} else
- rxqueue = dev->_rx;
+ rxqueue = flex_array_get(dev->_rx, 0);
map = rcu_dereference(rxqueue->rps_map);
if (map) {
@@ -3038,7 +3039,7 @@ done:
bool rps_may_expire_flow(struct net_device *dev, u16 rxq_index,
u32 flow_id, u16 filter_id)
{
- struct netdev_rx_queue *rxqueue = dev->_rx + rxq_index;
+ struct netdev_rx_queue *rxqueue = flex_array_get(dev->_rx, rxq_index);
struct rps_dev_flow_table *flow_table;
struct rps_dev_flow *rflow;
bool expire = true;
@@ -5223,18 +5224,31 @@ EXPORT_SYMBOL(netif_stacked_transfer_operstate);
static int netif_alloc_rx_queues(struct net_device *dev)
{
unsigned int i, count = dev->num_rx_queues;
- struct netdev_rx_queue *rx;
+ struct flex_array *rx;
+ int err;
BUG_ON(count < 1);
- rx = kcalloc(count, sizeof(struct netdev_rx_queue), GFP_KERNEL);
- if (!rx)
+ rx = flex_array_alloc(sizeof(struct netdev_rx_queue), count,
+ GFP_KERNEL | __GFP_ZERO);
+ if (!rx) {
+ pr_err("netdev: Unable to allocate flex array for rx queues\n");
return -ENOMEM;
+ }
+
+ err = flex_array_prealloc(rx, 0, count, GFP_KERNEL | __GFP_ZERO);
+ if (err) {
+ pr_err("netdev, Unable to prealloc %u rx qeueus\n", count);
+ flex_array_free(rx);
+ return err;
+ }
dev->_rx = rx;
- for (i = 0; i < count; i++)
- rx[i].dev = dev;
+ for (i = 0; i < count; i++) {
+ struct netdev_rx_queue *rxq = flex_array_get(rx, i);
+ rxq->dev = dev;
+ }
return 0;
}
#endif
@@ -5256,13 +5270,24 @@ static void netdev_init_one_queue(struct net_device
*dev,
static int netif_alloc_netdev_queues(struct net_device *dev)
{
unsigned int count = dev->num_tx_queues;
- struct netdev_queue *tx;
+ struct flex_array *tx;
+ int err;
BUG_ON(count < 1);
- tx = kcalloc(count, sizeof(struct netdev_queue), GFP_KERNEL);
- if (!tx)
+ tx = flex_array_alloc(sizeof(struct netdev_queue), count,
+ GFP_KERNEL | __GFP_ZERO);
+ if (!tx) {
+ pr_err("netdev: Unable to allocate flex array for tx queues\n");
return -ENOMEM;
+ }
+
+ err = flex_array_prealloc(tx, 0, count, GFP_KERNEL | __GFP_ZERO);
+ if (err) {
+ pr_err("netdev, Unable to prealloc %u tx qeueus\n", count);
+ flex_array_free(tx);
+ return err;
+ }
dev->_tx = tx;
@@ -5811,9 +5836,9 @@ free_all:
free_pcpu:
free_percpu(dev->pcpu_refcnt);
- kfree(dev->_tx);
+ flex_array_free(dev->_tx);
#ifdef CONFIG_RPS
- kfree(dev->_rx);
+ flex_array_free(dev->_rx);
#endif
free_p:
@@ -5836,9 +5861,9 @@ void free_netdev(struct net_device *dev)
release_net(dev_net(dev));
- kfree(dev->_tx);
+ flex_array_free(dev->_tx);
#ifdef CONFIG_RPS
- kfree(dev->_rx);
+ flex_array_free(dev->_rx);
#endif
kfree(rcu_dereference_protected(dev->ingress_queue, 1));
diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index 981fed3..4328c3a 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -22,6 +22,7 @@
#include <linux/export.h>
#include <linux/jiffies.h>
#include <linux/pm_runtime.h>
+#include <linux/flex_array.h>
#include "net-sysfs.h"
@@ -717,7 +718,7 @@ static struct kobj_type rx_queue_ktype = {
static int rx_queue_add_kobject(struct net_device *net, int index)
{
- struct netdev_rx_queue *queue = net->_rx + index;
+ struct netdev_rx_queue *queue = flex_array_get(net->_rx, index);
struct kobject *kobj = &queue->kobj;
int error = 0;
@@ -751,8 +752,10 @@ net_rx_queue_update_kobjects(struct net_device *net, int
old_num, int new_num)
}
}
- while (--i >= new_num)
- kobject_put(&net->_rx[i].kobj);
+ while (--i >= new_num) {
+ struct netdev_rx_queue *rxq = flex_array_get(net->_rx, i);
+ kobject_put(&rxq->kobj);
+ }
return error;
#else
@@ -939,7 +942,7 @@ static inline unsigned int get_netdev_queue_index(struct
netdev_queue *queue)
int i;
for (i = 0; i < dev->num_tx_queues; i++)
- if (queue == &dev->_tx[i])
+ if (queue == (struct netdev_queue *)flex_array_get(dev->_tx, i))
break;
BUG_ON(i >= dev->num_tx_queues);
@@ -1051,7 +1054,7 @@ static struct kobj_type netdev_queue_ktype = {
static int netdev_queue_add_kobject(struct net_device *net, int index)
{
- struct netdev_queue *queue = net->_tx + index;
+ struct netdev_queue *queue = flex_array_get(net->_tx, index);
struct kobject *kobj = &queue->kobj;
int error = 0;
@@ -1093,7 +1096,7 @@ netdev_queue_update_kobjects(struct net_device *net, int
old_num, int new_num)
}
while (--i >= new_num) {
- struct netdev_queue *queue = net->_tx + i;
+ struct netdev_queue *queue = flex_array_get(net->_tx, i);
#ifdef CONFIG_BQL
sysfs_remove_group(&queue->kobj, &dql_group);
--
1.7.1
--
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