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-rw-r--r--target/linux/generic/pending-4.19/690-net-add-support-for-threaded-NAPI-polling.patch339
1 files changed, 0 insertions, 339 deletions
diff --git a/target/linux/generic/pending-4.19/690-net-add-support-for-threaded-NAPI-polling.patch b/target/linux/generic/pending-4.19/690-net-add-support-for-threaded-NAPI-polling.patch
deleted file mode 100644
index b5c701c80b..0000000000
--- a/target/linux/generic/pending-4.19/690-net-add-support-for-threaded-NAPI-polling.patch
+++ /dev/null
@@ -1,339 +0,0 @@
-From: Felix Fietkau <nbd@nbd.name>
-Date: Sun, 26 Jul 2020 14:03:21 +0200
-Subject: [PATCH] net: add support for threaded NAPI polling
-
-For some drivers (especially 802.11 drivers), doing a lot of work in the NAPI
-poll function does not perform well. Since NAPI poll is bound to the CPU it
-was scheduled from, we can easily end up with a few very busy CPUs spending
-most of their time in softirq/ksoftirqd and some idle ones.
-
-Introduce threaded NAPI for such drivers based on a workqueue. The API is the
-same except for using netif_threaded_napi_add instead of netif_napi_add.
-
-In my tests with mt76 on MT7621 using threaded NAPI + a thread for tx scheduling
-improves LAN->WLAN bridging throughput by 10-50%. Throughput without threaded
-NAPI is wildly inconsistent, depending on the CPU that runs the tx scheduling
-thread.
-
-With threaded NAPI it seems stable and consistent (and higher than the best
-results I got without it).
-
-Based on a patch by Hillf Danton
-
-Cc: Hillf Danton <hdanton@sina.com>
-Signed-off-by: Felix Fietkau <nbd@nbd.name>
----
-
---- a/include/linux/netdevice.h
-+++ b/include/linux/netdevice.h
-@@ -339,6 +339,7 @@ struct napi_struct {
- struct list_head dev_list;
- struct hlist_node napi_hash_node;
- unsigned int napi_id;
-+ struct work_struct work;
- };
-
- enum {
-@@ -349,6 +350,7 @@ enum {
- NAPI_STATE_HASHED, /* In NAPI hash (busy polling possible) */
- NAPI_STATE_NO_BUSY_POLL,/* Do not add in napi_hash, no busy polling */
- NAPI_STATE_IN_BUSY_POLL,/* sk_busy_loop() owns this NAPI */
-+ NAPI_STATE_THREADED, /* Use threaded NAPI */
- };
-
- enum {
-@@ -359,6 +361,7 @@ enum {
- NAPIF_STATE_HASHED = BIT(NAPI_STATE_HASHED),
- NAPIF_STATE_NO_BUSY_POLL = BIT(NAPI_STATE_NO_BUSY_POLL),
- NAPIF_STATE_IN_BUSY_POLL = BIT(NAPI_STATE_IN_BUSY_POLL),
-+ NAPIF_STATE_THREADED = BIT(NAPI_STATE_THREADED),
- };
-
- enum gro_result {
-@@ -2230,6 +2233,26 @@ void netif_napi_add(struct net_device *d
- int (*poll)(struct napi_struct *, int), int weight);
-
- /**
-+ * netif_threaded_napi_add - initialize a NAPI context
-+ * @dev: network device
-+ * @napi: NAPI context
-+ * @poll: polling function
-+ * @weight: default weight
-+ *
-+ * This variant of netif_napi_add() should be used from drivers using NAPI
-+ * with CPU intensive poll functions.
-+ * This will schedule polling from a high priority workqueue
-+ */
-+static inline void netif_threaded_napi_add(struct net_device *dev,
-+ struct napi_struct *napi,
-+ int (*poll)(struct napi_struct *, int),
-+ int weight)
-+{
-+ set_bit(NAPI_STATE_THREADED, &napi->state);
-+ netif_napi_add(dev, napi, poll, weight);
-+}
-+
-+/**
- * netif_tx_napi_add - initialize a NAPI context
- * @dev: network device
- * @napi: NAPI context
---- a/net/core/dev.c
-+++ b/net/core/dev.c
-@@ -160,6 +160,7 @@ static DEFINE_SPINLOCK(offload_lock);
- struct list_head ptype_base[PTYPE_HASH_SIZE] __read_mostly;
- struct list_head ptype_all __read_mostly; /* Taps */
- static struct list_head offload_base __read_mostly;
-+static struct workqueue_struct *napi_workq __read_mostly;
-
- static int netif_rx_internal(struct sk_buff *skb);
- static int call_netdevice_notifiers_info(unsigned long val,
-@@ -5891,6 +5892,11 @@ void __napi_schedule(struct napi_struct
- {
- unsigned long flags;
-
-+ if (test_bit(NAPI_STATE_THREADED, &n->state)) {
-+ queue_work(napi_workq, &n->work);
-+ return;
-+ }
-+
- local_irq_save(flags);
- ____napi_schedule(this_cpu_ptr(&softnet_data), n);
- local_irq_restore(flags);
-@@ -5938,6 +5944,11 @@ EXPORT_SYMBOL(napi_schedule_prep);
- */
- void __napi_schedule_irqoff(struct napi_struct *n)
- {
-+ if (test_bit(NAPI_STATE_THREADED, &n->state)) {
-+ queue_work(napi_workq, &n->work);
-+ return;
-+ }
-+
- ____napi_schedule(this_cpu_ptr(&softnet_data), n);
- }
- EXPORT_SYMBOL(__napi_schedule_irqoff);
-@@ -6186,6 +6197,82 @@ static void init_gro_hash(struct napi_st
- napi->gro_bitmask = 0;
- }
-
-+static int __napi_poll(struct napi_struct *n, bool *repoll)
-+{
-+ int work, weight;
-+
-+ weight = n->weight;
-+
-+ /* This NAPI_STATE_SCHED test is for avoiding a race
-+ * with netpoll's poll_napi(). Only the entity which
-+ * obtains the lock and sees NAPI_STATE_SCHED set will
-+ * actually make the ->poll() call. Therefore we avoid
-+ * accidentally calling ->poll() when NAPI is not scheduled.
-+ */
-+ work = 0;
-+ if (test_bit(NAPI_STATE_SCHED, &n->state)) {
-+ work = n->poll(n, weight);
-+ trace_napi_poll(n, work, weight);
-+ }
-+
-+ WARN_ON_ONCE(work > weight);
-+
-+ if (likely(work < weight))
-+ return work;
-+
-+ /* Drivers must not modify the NAPI state if they
-+ * consume the entire weight. In such cases this code
-+ * still "owns" the NAPI instance and therefore can
-+ * move the instance around on the list at-will.
-+ */
-+ if (unlikely(napi_disable_pending(n))) {
-+ napi_complete(n);
-+ return work;
-+ }
-+
-+ if (n->gro_bitmask) {
-+ /* flush too old packets
-+ * If HZ < 1000, flush all packets.
-+ */
-+ napi_gro_flush(n, HZ >= 1000);
-+ }
-+
-+ *repoll = true;
-+
-+ return work;
-+}
-+
-+static void napi_workfn(struct work_struct *work)
-+{
-+ struct napi_struct *n = container_of(work, struct napi_struct, work);
-+ void *have;
-+
-+ for (;;) {
-+ bool repoll = false;
-+
-+ local_bh_disable();
-+
-+ have = netpoll_poll_lock(n);
-+ __napi_poll(n, &repoll);
-+ netpoll_poll_unlock(have);
-+
-+ local_bh_enable();
-+
-+ if (!repoll)
-+ return;
-+
-+ if (!need_resched())
-+ continue;
-+
-+ /*
-+ * have to pay for the latency of task switch even if
-+ * napi is scheduled
-+ */
-+ queue_work(napi_workq, work);
-+ return;
-+ }
-+}
-+
- void netif_napi_add(struct net_device *dev, struct napi_struct *napi,
- int (*poll)(struct napi_struct *, int), int weight)
- {
-@@ -6204,6 +6291,7 @@ void netif_napi_add(struct net_device *d
- #ifdef CONFIG_NETPOLL
- napi->poll_owner = -1;
- #endif
-+ INIT_WORK(&napi->work, napi_workfn);
- set_bit(NAPI_STATE_SCHED, &napi->state);
- napi_hash_add(napi);
- }
-@@ -6242,6 +6330,7 @@ static void flush_gro_hash(struct napi_s
- void netif_napi_del(struct napi_struct *napi)
- {
- might_sleep();
-+ cancel_work_sync(&napi->work);
- if (napi_hash_del(napi))
- synchronize_net();
- list_del_init(&napi->dev_list);
-@@ -6254,48 +6343,18 @@ EXPORT_SYMBOL(netif_napi_del);
-
- static int napi_poll(struct napi_struct *n, struct list_head *repoll)
- {
-+ bool do_repoll = false;
- void *have;
-- int work, weight;
-+ int work;
-
- list_del_init(&n->poll_list);
-
- have = netpoll_poll_lock(n);
-
-- weight = n->weight;
--
-- /* This NAPI_STATE_SCHED test is for avoiding a race
-- * with netpoll's poll_napi(). Only the entity which
-- * obtains the lock and sees NAPI_STATE_SCHED set will
-- * actually make the ->poll() call. Therefore we avoid
-- * accidentally calling ->poll() when NAPI is not scheduled.
-- */
-- work = 0;
-- if (test_bit(NAPI_STATE_SCHED, &n->state)) {
-- work = n->poll(n, weight);
-- trace_napi_poll(n, work, weight);
-- }
--
-- WARN_ON_ONCE(work > weight);
--
-- if (likely(work < weight))
-- goto out_unlock;
-+ work = __napi_poll(n, &do_repoll);
-
-- /* Drivers must not modify the NAPI state if they
-- * consume the entire weight. In such cases this code
-- * still "owns" the NAPI instance and therefore can
-- * move the instance around on the list at-will.
-- */
-- if (unlikely(napi_disable_pending(n))) {
-- napi_complete(n);
-+ if (!do_repoll)
- goto out_unlock;
-- }
--
-- if (n->gro_bitmask) {
-- /* flush too old packets
-- * If HZ < 1000, flush all packets.
-- */
-- napi_gro_flush(n, HZ >= 1000);
-- }
-
- /* Some drivers may have called napi_schedule
- * prior to exhausting their budget.
-@@ -9895,6 +9954,10 @@ static int __init net_dev_init(void)
- sd->backlog.weight = weight_p;
- }
-
-+ napi_workq = alloc_workqueue("napi_workq", WQ_UNBOUND | WQ_HIGHPRI,
-+ WQ_UNBOUND_MAX_ACTIVE | WQ_SYSFS);
-+ BUG_ON(!napi_workq);
-+
- dev_boot_phase = 0;
-
- /* The loopback device is special if any other network devices
---- a/net/core/net-sysfs.c
-+++ b/net/core/net-sysfs.c
-@@ -447,6 +447,52 @@ static ssize_t proto_down_store(struct d
- }
- NETDEVICE_SHOW_RW(proto_down, fmt_dec);
-
-+static int change_napi_threaded(struct net_device *dev, unsigned long val)
-+{
-+ struct napi_struct *napi;
-+
-+ if (list_empty(&dev->napi_list))
-+ return -EOPNOTSUPP;
-+
-+ list_for_each_entry(napi, &dev->napi_list, dev_list) {
-+ if (val)
-+ set_bit(NAPI_STATE_THREADED, &napi->state);
-+ else
-+ clear_bit(NAPI_STATE_THREADED, &napi->state);
-+ }
-+
-+ return 0;
-+}
-+
-+static ssize_t napi_threaded_store(struct device *dev,
-+ struct device_attribute *attr,
-+ const char *buf, size_t len)
-+{
-+ return netdev_store(dev, attr, buf, len, change_napi_threaded);
-+}
-+
-+static ssize_t napi_threaded_show(struct device *dev,
-+ struct device_attribute *attr,
-+ char *buf)
-+{
-+ struct net_device *netdev = to_net_dev(dev);
-+ struct napi_struct *napi;
-+ bool enabled = false;
-+
-+ if (!rtnl_trylock())
-+ return restart_syscall();
-+
-+ list_for_each_entry(napi, &netdev->napi_list, dev_list) {
-+ if (test_bit(NAPI_STATE_THREADED, &napi->state))
-+ enabled = true;
-+ }
-+
-+ rtnl_unlock();
-+
-+ return sprintf(buf, fmt_dec, enabled);
-+}
-+static DEVICE_ATTR_RW(napi_threaded);
-+
- static ssize_t phys_port_id_show(struct device *dev,
- struct device_attribute *attr, char *buf)
- {
-@@ -542,6 +588,7 @@ static struct attribute *net_class_attrs
- &dev_attr_flags.attr,
- &dev_attr_tx_queue_len.attr,
- &dev_attr_gro_flush_timeout.attr,
-+ &dev_attr_napi_threaded.attr,
- &dev_attr_phys_port_id.attr,
- &dev_attr_phys_port_name.attr,
- &dev_attr_phys_switch_id.attr,
generated by cgit v1.2.3 (git 2.25.1) at 2024-07-02 17:38:31 +0000