[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>

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index c2e15e3..718ad57 100644 (file)
--- 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 4f1ae2e..3156df6 100644 (file)
--- 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 76e9987..fff6364 100644 (file)
--- 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,