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rps: cleanups
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struct softnet_data holds many queues, so consistent use "sd" name
instead of "queue" is better.

Adds a rps_ipi_queued() helper to cleanup enqueue_to_backlog()

Adds a _and_irq_disable suffix to net_rps_action() name, as David
suggested.

incr_input_queue_head() becomes input_queue_head_incr()

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Eric Dumazet authored and David S. Miller committed Apr 20, 2010
1 parent f5acb90 commit e36fa2f
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Showing 2 changed files with 82 additions and 71 deletions.
4 changes: 2 additions & 2 deletions include/linux/netdevice.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1401,10 +1401,10 @@ struct softnet_data {
struct napi_struct backlog;
};

static inline void incr_input_queue_head(struct softnet_data *queue)
static inline void input_queue_head_incr(struct softnet_data *sd)
{
#ifdef CONFIG_RPS
queue->input_queue_head++;
sd->input_queue_head++;
#endif
}

Expand Down
149 changes: 80 additions & 69 deletions net/core/dev.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -208,17 +208,17 @@ static inline struct hlist_head *dev_index_hash(struct net *net, int ifindex)
return &net->dev_index_head[ifindex & (NETDEV_HASHENTRIES - 1)];
}

static inline void rps_lock(struct softnet_data *queue)
static inline void rps_lock(struct softnet_data *sd)
{
#ifdef CONFIG_RPS
spin_lock(&queue->input_pkt_queue.lock);
spin_lock(&sd->input_pkt_queue.lock);
#endif
}

static inline void rps_unlock(struct softnet_data *queue)
static inline void rps_unlock(struct softnet_data *sd)
{
#ifdef CONFIG_RPS
spin_unlock(&queue->input_pkt_queue.lock);
spin_unlock(&sd->input_pkt_queue.lock);
#endif
}

Expand Down Expand Up @@ -2346,63 +2346,74 @@ static int get_rps_cpu(struct net_device *dev, struct sk_buff *skb,
}

/* Called from hardirq (IPI) context */
static void trigger_softirq(void *data)
static void rps_trigger_softirq(void *data)
{
struct softnet_data *queue = data;
__napi_schedule(&queue->backlog);
struct softnet_data *sd = data;

__napi_schedule(&sd->backlog);
__get_cpu_var(netdev_rx_stat).received_rps++;
}

#endif /* CONFIG_RPS */

/*
* Check if this softnet_data structure is another cpu one
* If yes, queue it to our IPI list and return 1
* If no, return 0
*/
static int rps_ipi_queued(struct softnet_data *sd)
{
#ifdef CONFIG_RPS
struct softnet_data *mysd = &__get_cpu_var(softnet_data);

if (sd != mysd) {
sd->rps_ipi_next = mysd->rps_ipi_list;
mysd->rps_ipi_list = sd;

__raise_softirq_irqoff(NET_RX_SOFTIRQ);
return 1;
}
#endif /* CONFIG_RPS */
return 0;
}

/*
* enqueue_to_backlog is called to queue an skb to a per CPU backlog
* queue (may be a remote CPU queue).
*/
static int enqueue_to_backlog(struct sk_buff *skb, int cpu,
unsigned int *qtail)
{
struct softnet_data *queue;
struct softnet_data *sd;
unsigned long flags;

queue = &per_cpu(softnet_data, cpu);
sd = &per_cpu(softnet_data, cpu);

local_irq_save(flags);
__get_cpu_var(netdev_rx_stat).total++;

rps_lock(queue);
if (queue->input_pkt_queue.qlen <= netdev_max_backlog) {
if (queue->input_pkt_queue.qlen) {
rps_lock(sd);
if (sd->input_pkt_queue.qlen <= netdev_max_backlog) {
if (sd->input_pkt_queue.qlen) {
enqueue:
__skb_queue_tail(&queue->input_pkt_queue, skb);
__skb_queue_tail(&sd->input_pkt_queue, skb);
#ifdef CONFIG_RPS
*qtail = queue->input_queue_head +
queue->input_pkt_queue.qlen;
*qtail = sd->input_queue_head + sd->input_pkt_queue.qlen;
#endif
rps_unlock(queue);
rps_unlock(sd);
local_irq_restore(flags);
return NET_RX_SUCCESS;
}

/* Schedule NAPI for backlog device */
if (napi_schedule_prep(&queue->backlog)) {
#ifdef CONFIG_RPS
if (cpu != smp_processor_id()) {
struct softnet_data *myqueue;

myqueue = &__get_cpu_var(softnet_data);
queue->rps_ipi_next = myqueue->rps_ipi_list;
myqueue->rps_ipi_list = queue;

__raise_softirq_irqoff(NET_RX_SOFTIRQ);
goto enqueue;
}
#endif
__napi_schedule(&queue->backlog);
if (napi_schedule_prep(&sd->backlog)) {
if (!rps_ipi_queued(sd))
__napi_schedule(&sd->backlog);
}
goto enqueue;
}

rps_unlock(queue);
rps_unlock(sd);

__get_cpu_var(netdev_rx_stat).dropped++;
local_irq_restore(flags);
Expand Down Expand Up @@ -2903,17 +2914,17 @@ EXPORT_SYMBOL(netif_receive_skb);
static void flush_backlog(void *arg)
{
struct net_device *dev = arg;
struct softnet_data *queue = &__get_cpu_var(softnet_data);
struct softnet_data *sd = &__get_cpu_var(softnet_data);
struct sk_buff *skb, *tmp;

rps_lock(queue);
skb_queue_walk_safe(&queue->input_pkt_queue, skb, tmp)
rps_lock(sd);
skb_queue_walk_safe(&sd->input_pkt_queue, skb, tmp)
if (skb->dev == dev) {
__skb_unlink(skb, &queue->input_pkt_queue);
__skb_unlink(skb, &sd->input_pkt_queue);
kfree_skb(skb);
incr_input_queue_head(queue);
input_queue_head_incr(sd);
}
rps_unlock(queue);
rps_unlock(sd);
}

static int napi_gro_complete(struct sk_buff *skb)
Expand Down Expand Up @@ -3219,23 +3230,23 @@ EXPORT_SYMBOL(napi_gro_frags);
static int process_backlog(struct napi_struct *napi, int quota)
{
int work = 0;
struct softnet_data *queue = &__get_cpu_var(softnet_data);
struct softnet_data *sd = &__get_cpu_var(softnet_data);

napi->weight = weight_p;
do {
struct sk_buff *skb;

local_irq_disable();
rps_lock(queue);
skb = __skb_dequeue(&queue->input_pkt_queue);
rps_lock(sd);
skb = __skb_dequeue(&sd->input_pkt_queue);
if (!skb) {
__napi_complete(napi);
rps_unlock(queue);
rps_unlock(sd);
local_irq_enable();
break;
}
incr_input_queue_head(queue);
rps_unlock(queue);
input_queue_head_incr(sd);
rps_unlock(sd);
local_irq_enable();

__netif_receive_skb(skb);
Expand Down Expand Up @@ -3331,24 +3342,25 @@ EXPORT_SYMBOL(netif_napi_del);
* net_rps_action sends any pending IPI's for rps.
* Note: called with local irq disabled, but exits with local irq enabled.
*/
static void net_rps_action(void)
static void net_rps_action_and_irq_disable(void)
{
#ifdef CONFIG_RPS
struct softnet_data *locqueue = &__get_cpu_var(softnet_data);
struct softnet_data *remqueue = locqueue->rps_ipi_list;
struct softnet_data *sd = &__get_cpu_var(softnet_data);
struct softnet_data *remsd = sd->rps_ipi_list;

if (remqueue) {
locqueue->rps_ipi_list = NULL;
if (remsd) {
sd->rps_ipi_list = NULL;

local_irq_enable();

/* Send pending IPI's to kick RPS processing on remote cpus. */
while (remqueue) {
struct softnet_data *next = remqueue->rps_ipi_next;
if (cpu_online(remqueue->cpu))
__smp_call_function_single(remqueue->cpu,
&remqueue->csd, 0);
remqueue = next;
while (remsd) {
struct softnet_data *next = remsd->rps_ipi_next;

if (cpu_online(remsd->cpu))
__smp_call_function_single(remsd->cpu,
&remsd->csd, 0);
remsd = next;
}
} else
#endif
Expand Down Expand Up @@ -3423,7 +3435,7 @@ static void net_rx_action(struct softirq_action *h)
netpoll_poll_unlock(have);
}
out:
net_rps_action();
net_rps_action_and_irq_disable();

#ifdef CONFIG_NET_DMA
/*
Expand Down Expand Up @@ -5595,7 +5607,7 @@ static int dev_cpu_callback(struct notifier_block *nfb,
/* Process offline CPU's input_pkt_queue */
while ((skb = __skb_dequeue(&oldsd->input_pkt_queue))) {
netif_rx(skb);
incr_input_queue_head(oldsd);
input_queue_head_incr(oldsd);
}

return NOTIFY_OK;
Expand Down Expand Up @@ -5812,24 +5824,23 @@ static int __init net_dev_init(void)
*/

for_each_possible_cpu(i) {
struct softnet_data *queue;
struct softnet_data *sd = &per_cpu(softnet_data, i);

queue = &per_cpu(softnet_data, i);
skb_queue_head_init(&queue->input_pkt_queue);
queue->completion_queue = NULL;
INIT_LIST_HEAD(&queue->poll_list);
skb_queue_head_init(&sd->input_pkt_queue);
sd->completion_queue = NULL;
INIT_LIST_HEAD(&sd->poll_list);

#ifdef CONFIG_RPS
queue->csd.func = trigger_softirq;
queue->csd.info = queue;
queue->csd.flags = 0;
queue->cpu = i;
sd->csd.func = rps_trigger_softirq;
sd->csd.info = sd;
sd->csd.flags = 0;
sd->cpu = i;
#endif

queue->backlog.poll = process_backlog;
queue->backlog.weight = weight_p;
queue->backlog.gro_list = NULL;
queue->backlog.gro_count = 0;
sd->backlog.poll = process_backlog;
sd->backlog.weight = weight_p;
sd->backlog.gro_list = NULL;
sd->backlog.gro_count = 0;
}

dev_boot_phase = 0;
Expand Down

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