[NET]: Remove obsolete netif_rx congestion sensing mechanism.

Remove the congestion sensing mechanism from netif_rx, and always
return either full or empty.  Almost no driver checks the return value
from netif_rx, and those that do only use it for debug messages.

The original design of netif_rx was to do flow control based on the
receive queue, but NAPI has supplanted this and no driver uses the
feedback.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 1 insertions, 125 deletions

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index c2e15e381a58..718ad579c65c 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -558,8 +558,6 @@ static inline int unregister_gifconf(unsigned int family)
 struct softnet_data
 {
         int                     throttle;
-        int                     cng_level;
-        int                     avg_blog;
         struct sk_buff_head     input_pkt_queue;
         struct list_head        poll_list;
         struct net_device       *output_queue;
diff --git a/net/core/dev.c b/net/core/dev.c
index 4f1ae2efe872..3156df699f01 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -115,18 +115,6 @@
 #endif  /* CONFIG_NET_RADIO */
 #include <asm/current.h>
 
-/* This define, if set, will randomly drop a packet when congestion
- * is more than moderate.  It helps fairness in the multi-interface
- * case when one of them is a hog, but it kills performance for the
- * single interface case so it is off now by default.
- */
-#undef RAND_LIE
-
-/* Setting this will sample the queue lengths and thus congestion
- * via a timer instead of as each packet is received.
- */
-#undef OFFLINE_SAMPLE
-
 /*
  *      The list of packet types we will receive (as opposed to discard)
  *      and the routines to invoke.
@@ -159,11 +147,6 @@ static DEFINE_SPINLOCK(ptype_lock);
 static struct list_head ptype_base[16]; /* 16 way hashed list */
 static struct list_head ptype_all;              /* Taps */
 
-#ifdef OFFLINE_SAMPLE
-static void sample_queue(unsigned long dummy);
-static struct timer_list samp_timer = TIMER_INITIALIZER(sample_queue, 0, 0);
-#endif
-
 /*
  * The @dev_base list is protected by @dev_base_lock and the rtln
  * semaphore.
@@ -1365,69 +1348,10 @@ out:
 
 int netdev_max_backlog = 300;
 int weight_p = 64;            /* old backlog weight */
-/* These numbers are selected based on intuition and some
- * experimentatiom, if you have more scientific way of doing this
- * please go ahead and fix things.
- */
-int no_cong_thresh = 10;
-int no_cong = 20;
-int lo_cong = 100;
-int mod_cong = 290;
 
 DEFINE_PER_CPU(struct netif_rx_stats, netdev_rx_stat) = { 0, };
 
 
-static void get_sample_stats(int cpu)
-{
-#ifdef RAND_LIE
-        unsigned long rd;
-        int rq;
-#endif
-        struct softnet_data *sd = &per_cpu(softnet_data, cpu);
-        int blog = sd->input_pkt_queue.qlen;
-        int avg_blog = sd->avg_blog;
-
-        avg_blog = (avg_blog >> 1) + (blog >> 1);
-
-        if (avg_blog > mod_cong) {
-                /* Above moderate congestion levels. */
-                sd->cng_level = NET_RX_CN_HIGH;
-#ifdef RAND_LIE
-                rd = net_random();
-                rq = rd % netdev_max_backlog;
-                if (rq < avg_blog) /* unlucky bastard */
-                        sd->cng_level = NET_RX_DROP;
-#endif
-        } else if (avg_blog > lo_cong) {
-                sd->cng_level = NET_RX_CN_MOD;
-#ifdef RAND_LIE
-                rd = net_random();
-                rq = rd % netdev_max_backlog;
-                        if (rq < avg_blog) /* unlucky bastard */
-                                sd->cng_level = NET_RX_CN_HIGH;
-#endif
-        } else if (avg_blog > no_cong)
-                sd->cng_level = NET_RX_CN_LOW;
-        else  /* no congestion */
-                sd->cng_level = NET_RX_SUCCESS;
-
-        sd->avg_blog = avg_blog;
-}
-
-#ifdef OFFLINE_SAMPLE
-static void sample_queue(unsigned long dummy)
-{
-/* 10 ms 0r 1ms -- i don't care -- JHS */
-        int next_tick = 1;
-        int cpu = smp_processor_id();
-
-        get_sample_stats(cpu);
-        next_tick += jiffies;
-        mod_timer(&samp_timer, next_tick);
-}
-#endif
-
-
 /**
  *      netif_rx        -       post buffer to the network code
  *      @skb: buffer to post
@@ -1476,11 +1400,8 @@ int netif_rx(struct sk_buff *skb)
 enqueue:
                         dev_hold(skb->dev);
                         __skb_queue_tail(&queue->input_pkt_queue, skb);
-#ifndef OFFLINE_SAMPLE
-                        get_sample_stats(this_cpu);
-#endif
                         local_irq_restore(flags);
-                        return queue->cng_level;
+                        return NET_RX_SUCCESS;
                 }
 
                 if (queue->throttle)
@@ -3300,8 +3221,6 @@ static int __init net_dev_init(void)
                 queue = &per_cpu(softnet_data, i);
                 skb_queue_head_init(&queue->input_pkt_queue);
                 queue->throttle = 0;
-                queue->cng_level = 0;
-                queue->avg_blog = 10; /* arbitrary non-zero */
                 queue->completion_queue = NULL;
                 INIT_LIST_HEAD(&queue->poll_list);
                 set_bit(__LINK_STATE_START, &queue->backlog_dev.state);
@@ -3310,11 +3229,6 @@ static int __init net_dev_init(void)
                 atomic_set(&queue->backlog_dev.refcnt, 1);
         }
 
-#ifdef OFFLINE_SAMPLE
-        samp_timer.expires = jiffies + (10 * HZ);
-        add_timer(&samp_timer);
-#endif
-
         dev_boot_phase = 0;
 
         open_softirq(NET_TX_SOFTIRQ, net_tx_action, NULL);
diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c
index 76e9987474ca..fff63643a35c 100644
--- a/net/core/sysctl_net_core.c
+++ b/net/core/sysctl_net_core.c
@@ -14,10 +14,6 @@
 
 extern int netdev_max_backlog;
 extern int weight_p;
-extern int no_cong_thresh;
-extern int no_cong;
-extern int lo_cong;
-extern int mod_cong;
 extern int net_msg_cost;
 extern int net_msg_burst;
 
@@ -85,38 +81,6 @@ ctl_table core_table[] = {
                 .proc_handler   = &proc_dointvec
         },
         {
-                .ctl_name       = NET_CORE_NO_CONG_THRESH,
-                .procname       = "no_cong_thresh",
-                .data           = &no_cong_thresh,
-                .maxlen         = sizeof(int),
-                .mode           = 0644,
-                .proc_handler   = &proc_dointvec
-        },
-        {
-                .ctl_name       = NET_CORE_NO_CONG,
-                .procname       = "no_cong",
-                .data           = &no_cong,
-                .maxlen         = sizeof(int),
-                .mode           = 0644,
-                .proc_handler   = &proc_dointvec
-        },
-        {
-                .ctl_name       = NET_CORE_LO_CONG,
-                .procname       = "lo_cong",
-                .data           = &lo_cong,
-                .maxlen         = sizeof(int),
-                .mode           = 0644,
-                .proc_handler   = &proc_dointvec
-        },
-        {
-                .ctl_name       = NET_CORE_MOD_CONG,
-                .procname       = "mod_cong",
-                .data           = &mod_cong,
-                .maxlen         = sizeof(int),
-                .mode           = 0644,
-                .proc_handler   = &proc_dointvec
-        },
-        {
                 .ctl_name       = NET_CORE_MSG_COST,
                 .procname       = "message_cost",
                 .data           = &net_msg_cost,