[PATCH net-next 0/4] sfc: ARFS expiry improvements

[PATCH net-next 0/4] sfc: ARFS expiry improvements

[Edward Cree]

A series of changes to how we check filters for expiry, manage how much
 of that work to do & when, etc.
Prompted by some pathological behaviour under heavy load, which was
Reported-By: David Ahern <dahern@digitalocean.com>

Edward Cree (4):
  sfc: change ARFS expiry mechanism
  sfc: suppress MCDI errors from ARFS
  sfc: add statistics for ARFS
  sfc: do ARFS expiry work occasionally even without NAPI poll

 drivers/net/ethernet/sfc/ef10.c       |  8 +++-
 drivers/net/ethernet/sfc/efx.c        | 14 +++---
 drivers/net/ethernet/sfc/efx.h        | 19 +++++---
 drivers/net/ethernet/sfc/ethtool.c    |  6 +++
 drivers/net/ethernet/sfc/net_driver.h | 20 +++++---
 drivers/net/ethernet/sfc/rx.c         | 68 +++++++++++++++++++--------
 6 files changed, 94 insertions(+), 41 deletions(-)

[PATCH net-next 1/4] sfc: change ARFS expiry mechanism

[Edward Cree]

The old rfs_filters_added method for determining the quota could potentially
 allow the NIC to become filled with old filters, which never get tested for
 expiry.  Instead, explicitly make expiry check work depend on the number of
 filters installed, and don't count checking slots without filters in as
 doing work.  This guarantees that each filter will be checked for expiry at
 least once every thirty seconds (assuming the channel to which it belongs is
 NAPI polling actively) regardless of fill level.

Signed-off-by: Edward Cree <ecree@solarflare.com>
---
 drivers/net/ethernet/sfc/efx.c        |  8 +++--
 drivers/net/ethernet/sfc/efx.h        |  9 +++---
 drivers/net/ethernet/sfc/net_driver.h | 14 ++++----
 drivers/net/ethernet/sfc/rx.c         | 46 ++++++++++++++++-----------
 4 files changed, 45 insertions(+), 32 deletions(-)

diff --git a/drivers/net/ethernet/sfc/efx.c b/drivers/net/ethernet/sfc/efx.c
index 0fa9972027db..38d186b949be 100644
--- a/drivers/net/ethernet/sfc/efx.c
+++ b/drivers/net/ethernet/sfc/efx.c
@@ -1969,6 +1969,8 @@ static int efx_probe_filters(struct efx_nic *efx)
 				     ++i)
 					channel->rps_flow_id[i] =
 						RPS_FLOW_ID_INVALID;
+			channel->rfs_expire_index = 0;
+			channel->rfs_filter_count = 0;
 		}
 
 		if (!success) {
@@ -1978,8 +1980,6 @@ static int efx_probe_filters(struct efx_nic *efx)
 			rc = -ENOMEM;
 			goto out_unlock;
 		}
-
-		efx->rps_expire_index = efx->rps_expire_channel = 0;
 	}
 #endif
 out_unlock:
@@ -1993,8 +1993,10 @@ static void efx_remove_filters(struct efx_nic *efx)
 #ifdef CONFIG_RFS_ACCEL
 	struct efx_channel *channel;
 
-	efx_for_each_channel(channel, efx)
+	efx_for_each_channel(channel, efx) {
+		flush_work(&channel->filter_work);
 		kfree(channel->rps_flow_id);
+	}
 #endif
 	down_write(&efx->filter_sem);
 	efx->type->filter_table_remove(efx);
diff --git a/drivers/net/ethernet/sfc/efx.h b/drivers/net/ethernet/sfc/efx.h
index 45c7ae4114ec..e58c2b6d64d9 100644
--- a/drivers/net/ethernet/sfc/efx.h
+++ b/drivers/net/ethernet/sfc/efx.h
@@ -166,15 +166,16 @@ static inline s32 efx_filter_get_rx_ids(struct efx_nic *efx,
 #ifdef CONFIG_RFS_ACCEL
 int efx_filter_rfs(struct net_device *net_dev, const struct sk_buff *skb,
 		   u16 rxq_index, u32 flow_id);
-bool __efx_filter_rfs_expire(struct efx_nic *efx, unsigned quota);
+bool __efx_filter_rfs_expire(struct efx_channel *channel, unsigned int quota);
 static inline void efx_filter_rfs_expire(struct work_struct *data)
 {
 	struct efx_channel *channel = container_of(data, struct efx_channel,
 						   filter_work);
+	unsigned int time = jiffies - channel->rfs_last_expiry, quota;
 
-	if (channel->rfs_filters_added >= 60 &&
-	    __efx_filter_rfs_expire(channel->efx, 100))
-		channel->rfs_filters_added -= 60;
+	quota = channel->rfs_filter_count * time / (30 * HZ);
+	if (quota > 20 && __efx_filter_rfs_expire(channel, min(channel->rfs_filter_count, quota)))
+		channel->rfs_last_expiry += time;
 }
 #define efx_filter_rfs_enabled() 1
 #else
diff --git a/drivers/net/ethernet/sfc/net_driver.h b/drivers/net/ethernet/sfc/net_driver.h
index 04e49eac7327..5b1b882f6c67 100644
--- a/drivers/net/ethernet/sfc/net_driver.h
+++ b/drivers/net/ethernet/sfc/net_driver.h
@@ -439,6 +439,11 @@ enum efx_sync_events_state {
  * @event_test_cpu: Last CPU to handle interrupt or test event for this channel
  * @irq_count: Number of IRQs since last adaptive moderation decision
  * @irq_mod_score: IRQ moderation score
+ * @rfs_filter_count: number of accelerated RFS filters currently in place;
+ *	equals the count of @rps_flow_id slots filled
+ * @rfs_last_expiry: value of jiffies last time some accelerated RFS filters
+ *	were checked for expiry
+ * @rfs_expire_index: next accelerated RFS filter ID to check for expiry
  * @filter_work: Work item for efx_filter_rfs_expire()
  * @rps_flow_id: Flow IDs of filters allocated for accelerated RFS,
  *      indexed by filter ID
@@ -489,7 +494,9 @@ struct efx_channel {
 	unsigned int irq_count;
 	unsigned int irq_mod_score;
 #ifdef CONFIG_RFS_ACCEL
-	unsigned int rfs_filters_added;
+	unsigned int rfs_filter_count;
+	unsigned int rfs_last_expiry;
+	unsigned int rfs_expire_index;
 	struct work_struct filter_work;
 #define RPS_FLOW_ID_INVALID 0xFFFFFFFF
 	u32 *rps_flow_id;
@@ -923,9 +930,6 @@ struct efx_async_filter_insertion {
  * @filter_sem: Filter table rw_semaphore, protects existence of @filter_state
  * @filter_state: Architecture-dependent filter table state
  * @rps_mutex: Protects RPS state of all channels
- * @rps_expire_channel: Next channel to check for expiry
- * @rps_expire_index: Next index to check for expiry in
- *	@rps_expire_channel's @rps_flow_id
  * @rps_slot_map: bitmap of in-flight entries in @rps_slot
  * @rps_slot: array of ARFS insertion requests for efx_filter_rfs_work()
  * @rps_hash_lock: Protects ARFS filter mapping state (@rps_hash_table and
@@ -1096,8 +1100,6 @@ struct efx_nic {
 	void *filter_state;
 #ifdef CONFIG_RFS_ACCEL
 	struct mutex rps_mutex;
-	unsigned int rps_expire_channel;
-	unsigned int rps_expire_index;
 	unsigned long rps_slot_map;
 	struct efx_async_filter_insertion rps_slot[EFX_RPS_MAX_IN_FLIGHT];
 	spinlock_t rps_hash_lock;
diff --git a/drivers/net/ethernet/sfc/rx.c b/drivers/net/ethernet/sfc/rx.c
index bec261905530..bbf2393f7599 100644
--- a/drivers/net/ethernet/sfc/rx.c
+++ b/drivers/net/ethernet/sfc/rx.c
@@ -988,6 +988,7 @@ static void efx_filter_rfs_work(struct work_struct *data)
 
 	rc = efx->type->filter_insert(efx, &req->spec, true);
 	if (rc >= 0)
+		/* Discard 'priority' part of EF10+ filter ID (mcdi_filters) */
 		rc %= efx->type->max_rx_ip_filters;
 	if (efx->rps_hash_table) {
 		spin_lock_bh(&efx->rps_hash_lock);
@@ -1012,8 +1013,9 @@ static void efx_filter_rfs_work(struct work_struct *data)
 		 * later.
 		 */
 		mutex_lock(&efx->rps_mutex);
+		if (channel->rps_flow_id[rc] == RPS_FLOW_ID_INVALID)
+			channel->rfs_filter_count++;
 		channel->rps_flow_id[rc] = req->flow_id;
-		++channel->rfs_filters_added;
 		mutex_unlock(&efx->rps_mutex);
 
 		if (req->spec.ether_type == htons(ETH_P_IP))
@@ -1139,38 +1141,44 @@ int efx_filter_rfs(struct net_device *net_dev, const struct sk_buff *skb,
 	return rc;
 }
 
-bool __efx_filter_rfs_expire(struct efx_nic *efx, unsigned int quota)
+bool __efx_filter_rfs_expire(struct efx_channel *channel, unsigned int quota)
 {
 	bool (*expire_one)(struct efx_nic *efx, u32 flow_id, unsigned int index);
-	unsigned int channel_idx, index, size;
+	struct efx_nic *efx = channel->efx;
+	unsigned int index, size, start;
 	u32 flow_id;
 
 	if (!mutex_trylock(&efx->rps_mutex))
 		return false;
 	expire_one = efx->type->filter_rfs_expire_one;
-	channel_idx = efx->rps_expire_channel;
-	index = efx->rps_expire_index;
+	index = channel->rfs_expire_index;
+	start = index;
 	size = efx->type->max_rx_ip_filters;
-	while (quota--) {
-		struct efx_channel *channel = efx_get_channel(efx, channel_idx);
+	while (quota) {
 		flow_id = channel->rps_flow_id[index];
 
-		if (flow_id != RPS_FLOW_ID_INVALID &&
-		    expire_one(efx, flow_id, index)) {
-			netif_info(efx, rx_status, efx->net_dev,
-				   "expired filter %d [queue %u flow %u]\n",
-				   index, channel_idx, flow_id);
-			channel->rps_flow_id[index] = RPS_FLOW_ID_INVALID;
+		if (flow_id != RPS_FLOW_ID_INVALID) {
+			quota--;
+			if (expire_one(efx, flow_id, index)) {
+				netif_info(efx, rx_status, efx->net_dev,
+					   "expired filter %d [channel %u flow %u]\n",
+					   index, channel->channel, flow_id);
+				channel->rps_flow_id[index] = RPS_FLOW_ID_INVALID;
+				channel->rfs_filter_count--;
+			}
 		}
-		if (++index == size) {
-			if (++channel_idx == efx->n_channels)
-				channel_idx = 0;
+		if (++index == size)
 			index = 0;
-		}
+		/* If we were called with a quota that exceeds the total number
+		 * of filters in the table (which should never happen), ensure
+		 * that we don't loop forever - stop when we've examined every
+		 * row of the table.
+		 */
+		if (WARN_ON(index == start && quota))
+			break;
 	}
-	efx->rps_expire_channel = channel_idx;
-	efx->rps_expire_index = index;
 
+	channel->rfs_expire_index = index;
 	mutex_unlock(&efx->rps_mutex);
 	return true;
 }

[PATCH net-next 2/4] sfc: suppress MCDI errors from ARFS

[Edward Cree]

In high connection count usage, the NIC's filter table may be filled with
 sufficiently many ARFS filters that further insertions fail.  As this
 does not represent a correctness issue, do not log the resulting MCDI
 errors.  Add a debug-level message under the (by default disabled)
 rx_status category instead; and take the opportunity to do a little extra
 expiry work.

Since there are now multiple workitems able to call __efx_filter_rfs_expire
 on a given channel, it is possible for them to race and thus pass quotas
 which, combined, exceed rfs_filter_count.  Thus, don't WARN_ON if we loop
 all the way around the table with quota left over.

Signed-off-by: Edward Cree <ecree@solarflare.com>
---
 drivers/net/ethernet/sfc/ef10.c |  8 ++++++--
 drivers/net/ethernet/sfc/rx.c   | 28 ++++++++++++++++++++++++----
 2 files changed, 30 insertions(+), 6 deletions(-)

diff --git a/drivers/net/ethernet/sfc/ef10.c b/drivers/net/ethernet/sfc/ef10.c
index ad68eb0cb8fd..4d9bbccc6f89 100644
--- a/drivers/net/ethernet/sfc/ef10.c
+++ b/drivers/net/ethernet/sfc/ef10.c
@@ -4202,11 +4202,15 @@ static int efx_ef10_filter_push(struct efx_nic *efx,
 {
 	MCDI_DECLARE_BUF(inbuf, MC_CMD_FILTER_OP_EXT_IN_LEN);
 	MCDI_DECLARE_BUF(outbuf, MC_CMD_FILTER_OP_EXT_OUT_LEN);
+	size_t outlen;
 	int rc;
 
 	efx_ef10_filter_push_prep(efx, spec, inbuf, *handle, ctx, replacing);
-	rc = efx_mcdi_rpc(efx, MC_CMD_FILTER_OP, inbuf, sizeof(inbuf),
-			  outbuf, sizeof(outbuf), NULL);
+	rc = efx_mcdi_rpc_quiet(efx, MC_CMD_FILTER_OP, inbuf, sizeof(inbuf),
+				outbuf, sizeof(outbuf), &outlen);
+	if (rc && spec->priority != EFX_FILTER_PRI_HINT)
+		efx_mcdi_display_error(efx, MC_CMD_FILTER_OP, sizeof(inbuf),
+				       outbuf, outlen, rc);
 	if (rc == 0)
 		*handle = MCDI_QWORD(outbuf, FILTER_OP_OUT_HANDLE);
 	if (rc == -ENOSPC)
diff --git a/drivers/net/ethernet/sfc/rx.c b/drivers/net/ethernet/sfc/rx.c
index bbf2393f7599..252a5f10596d 100644
--- a/drivers/net/ethernet/sfc/rx.c
+++ b/drivers/net/ethernet/sfc/rx.c
@@ -1032,6 +1032,26 @@ static void efx_filter_rfs_work(struct work_struct *data)
 				   req->spec.rem_host, ntohs(req->spec.rem_port),
 				   req->spec.loc_host, ntohs(req->spec.loc_port),
 				   req->rxq_index, req->flow_id, rc, arfs_id);
+	} else {
+		if (req->spec.ether_type == htons(ETH_P_IP))
+			netif_dbg(efx, rx_status, efx->net_dev,
+				  "failed to steer %s %pI4:%u:%pI4:%u to queue %u [flow %u rc %d id %u]\n",
+				  (req->spec.ip_proto == IPPROTO_TCP) ? "TCP" : "UDP",
+				  req->spec.rem_host, ntohs(req->spec.rem_port),
+				  req->spec.loc_host, ntohs(req->spec.loc_port),
+				  req->rxq_index, req->flow_id, rc, arfs_id);
+		else
+			netif_dbg(efx, rx_status, efx->net_dev,
+				  "failed to steer %s [%pI6]:%u:[%pI6]:%u to queue %u [flow %u rc %d id %u]\n",
+				  (req->spec.ip_proto == IPPROTO_TCP) ? "TCP" : "UDP",
+				  req->spec.rem_host, ntohs(req->spec.rem_port),
+				  req->spec.loc_host, ntohs(req->spec.loc_port),
+				  req->rxq_index, req->flow_id, rc, arfs_id);
+		/* We're overloading the NIC's filter tables, so let's do a
+		 * chunk of extra expiry work.
+		 */
+		__efx_filter_rfs_expire(channel, min(channel->rfs_filter_count,
+						     100u));
 	}
 
 	/* Release references */
@@ -1170,11 +1190,11 @@ bool __efx_filter_rfs_expire(struct efx_channel *channel, unsigned int quota)
 		if (++index == size)
 			index = 0;
 		/* If we were called with a quota that exceeds the total number
-		 * of filters in the table (which should never happen), ensure
-		 * that we don't loop forever - stop when we've examined every
-		 * row of the table.
+		 * of filters in the table (which shouldn't happen, but could
+		 * if two callers race), ensure that we don't loop forever -
+		 * stop when we've examined every row of the table.
 		 */
-		if (WARN_ON(index == start && quota))
+		if (index == start)
 			break;
 	}
 

[PATCH net-next 3/4] sfc: add statistics for ARFS

[Edward Cree]

Report the number of successful and failed insertions, and also the
 current count of filters, to aid in tuning e.g. rps_flow_cnt.

Signed-off-by: Edward Cree <ecree@solarflare.com>
---
 drivers/net/ethernet/sfc/ethtool.c    | 6 ++++++
 drivers/net/ethernet/sfc/net_driver.h | 4 ++++
 drivers/net/ethernet/sfc/rx.c         | 2 ++
 3 files changed, 12 insertions(+)

diff --git a/drivers/net/ethernet/sfc/ethtool.c b/drivers/net/ethernet/sfc/ethtool.c
index 8db593fb9699..6a9347cd67f3 100644
--- a/drivers/net/ethernet/sfc/ethtool.c
+++ b/drivers/net/ethernet/sfc/ethtool.c
@@ -56,6 +56,9 @@ static u64 efx_get_atomic_stat(void *field)
 #define EFX_ETHTOOL_UINT_CHANNEL_STAT(field)			\
 	EFX_ETHTOOL_STAT(field, channel, n_##field,		\
 			 unsigned int, efx_get_uint_stat)
+#define EFX_ETHTOOL_UINT_CHANNEL_STAT_NO_N(field)		\
+	EFX_ETHTOOL_STAT(field, channel, field,			\
+			 unsigned int, efx_get_uint_stat)
 
 #define EFX_ETHTOOL_UINT_TXQ_STAT(field)			\
 	EFX_ETHTOOL_STAT(tx_##field, tx_queue, field,		\
@@ -87,6 +90,9 @@ static const struct efx_sw_stat_desc efx_sw_stat_desc[] = {
 	EFX_ETHTOOL_UINT_CHANNEL_STAT(rx_xdp_bad_drops),
 	EFX_ETHTOOL_UINT_CHANNEL_STAT(rx_xdp_tx),
 	EFX_ETHTOOL_UINT_CHANNEL_STAT(rx_xdp_redirect),
+	EFX_ETHTOOL_UINT_CHANNEL_STAT_NO_N(rfs_filter_count),
+	EFX_ETHTOOL_UINT_CHANNEL_STAT(rfs_succeeded),
+	EFX_ETHTOOL_UINT_CHANNEL_STAT(rfs_failed),
 };
 
 #define EFX_ETHTOOL_SW_STAT_COUNT ARRAY_SIZE(efx_sw_stat_desc)
diff --git a/drivers/net/ethernet/sfc/net_driver.h b/drivers/net/ethernet/sfc/net_driver.h
index 5b1b882f6c67..ccd480e699d3 100644
--- a/drivers/net/ethernet/sfc/net_driver.h
+++ b/drivers/net/ethernet/sfc/net_driver.h
@@ -444,6 +444,8 @@ enum efx_sync_events_state {
  * @rfs_last_expiry: value of jiffies last time some accelerated RFS filters
  *	were checked for expiry
  * @rfs_expire_index: next accelerated RFS filter ID to check for expiry
+ * @n_rfs_succeeded: number of successful accelerated RFS filter insertions
+ * @n_rfs_failed; number of failed accelerated RFS filter insertions
  * @filter_work: Work item for efx_filter_rfs_expire()
  * @rps_flow_id: Flow IDs of filters allocated for accelerated RFS,
  *      indexed by filter ID
@@ -497,6 +499,8 @@ struct efx_channel {
 	unsigned int rfs_filter_count;
 	unsigned int rfs_last_expiry;
 	unsigned int rfs_expire_index;
+	unsigned int n_rfs_succeeded;
+	unsigned int n_rfs_failed;
 	struct work_struct filter_work;
 #define RPS_FLOW_ID_INVALID 0xFFFFFFFF
 	u32 *rps_flow_id;
diff --git a/drivers/net/ethernet/sfc/rx.c b/drivers/net/ethernet/sfc/rx.c
index 252a5f10596d..ef52b24ad9e7 100644
--- a/drivers/net/ethernet/sfc/rx.c
+++ b/drivers/net/ethernet/sfc/rx.c
@@ -1032,6 +1032,7 @@ static void efx_filter_rfs_work(struct work_struct *data)
 				   req->spec.rem_host, ntohs(req->spec.rem_port),
 				   req->spec.loc_host, ntohs(req->spec.loc_port),
 				   req->rxq_index, req->flow_id, rc, arfs_id);
+		channel->n_rfs_succeeded++;
 	} else {
 		if (req->spec.ether_type == htons(ETH_P_IP))
 			netif_dbg(efx, rx_status, efx->net_dev,
@@ -1047,6 +1048,7 @@ static void efx_filter_rfs_work(struct work_struct *data)
 				  req->spec.rem_host, ntohs(req->spec.rem_port),
 				  req->spec.loc_host, ntohs(req->spec.loc_port),
 				  req->rxq_index, req->flow_id, rc, arfs_id);
+		channel->n_rfs_failed++;
 		/* We're overloading the NIC's filter tables, so let's do a
 		 * chunk of extra expiry work.
 		 */

[PATCH net-next 4/4] sfc: do ARFS expiry work occasionally even without NAPI poll

[Edward Cree]

If there's no traffic on a channel, its ARFS expiry work will never get
 scheduled by efx_poll() as that isn't being run.
So make efx_filter_rfs_expire() reschedule itself to run after 30 seconds.

Signed-off-by: Edward Cree <ecree@solarflare.com>
---
 drivers/net/ethernet/sfc/efx.c        |  8 ++++----
 drivers/net/ethernet/sfc/efx.h        | 10 +++++++---
 drivers/net/ethernet/sfc/net_driver.h |  2 +-
 3 files changed, 12 insertions(+), 8 deletions(-)

diff --git a/drivers/net/ethernet/sfc/efx.c b/drivers/net/ethernet/sfc/efx.c
index 38d186b949be..992c773620ec 100644
--- a/drivers/net/ethernet/sfc/efx.c
+++ b/drivers/net/ethernet/sfc/efx.c
@@ -355,7 +355,7 @@ static int efx_poll(struct napi_struct *napi, int budget)
 
 #ifdef CONFIG_RFS_ACCEL
 		/* Perhaps expire some ARFS filters */
-		schedule_work(&channel->filter_work);
+		mod_delayed_work(system_wq, &channel->filter_work, 0);
 #endif
 
 		/* There is no race here; although napi_disable() will
@@ -487,7 +487,7 @@ efx_alloc_channel(struct efx_nic *efx, int i, struct efx_channel *old_channel)
 	}
 
 #ifdef CONFIG_RFS_ACCEL
-	INIT_WORK(&channel->filter_work, efx_filter_rfs_expire);
+	INIT_DELAYED_WORK(&channel->filter_work, efx_filter_rfs_expire);
 #endif
 
 	rx_queue = &channel->rx_queue;
@@ -533,7 +533,7 @@ efx_copy_channel(const struct efx_channel *old_channel)
 	memset(&rx_queue->rxd, 0, sizeof(rx_queue->rxd));
 	timer_setup(&rx_queue->slow_fill, efx_rx_slow_fill, 0);
 #ifdef CONFIG_RFS_ACCEL
-	INIT_WORK(&channel->filter_work, efx_filter_rfs_expire);
+	INIT_DELAYED_WORK(&channel->filter_work, efx_filter_rfs_expire);
 #endif
 
 	return channel;
@@ -1994,7 +1994,7 @@ static void efx_remove_filters(struct efx_nic *efx)
 	struct efx_channel *channel;
 
 	efx_for_each_channel(channel, efx) {
-		flush_work(&channel->filter_work);
+		cancel_delayed_work_sync(&channel->filter_work);
 		kfree(channel->rps_flow_id);
 	}
 #endif
diff --git a/drivers/net/ethernet/sfc/efx.h b/drivers/net/ethernet/sfc/efx.h
index e58c2b6d64d9..2dd8d5002315 100644
--- a/drivers/net/ethernet/sfc/efx.h
+++ b/drivers/net/ethernet/sfc/efx.h
@@ -169,13 +169,17 @@ int efx_filter_rfs(struct net_device *net_dev, const struct sk_buff *skb,
 bool __efx_filter_rfs_expire(struct efx_channel *channel, unsigned int quota);
 static inline void efx_filter_rfs_expire(struct work_struct *data)
 {
-	struct efx_channel *channel = container_of(data, struct efx_channel,
-						   filter_work);
-	unsigned int time = jiffies - channel->rfs_last_expiry, quota;
+	struct delayed_work *dwork = to_delayed_work(data);
+	struct efx_channel *channel;
+	unsigned int time, quota;
 
+	channel = container_of(dwork, struct efx_channel, filter_work);
+	time = jiffies - channel->rfs_last_expiry;
 	quota = channel->rfs_filter_count * time / (30 * HZ);
 	if (quota > 20 && __efx_filter_rfs_expire(channel, min(channel->rfs_filter_count, quota)))
 		channel->rfs_last_expiry += time;
+	/* Ensure we do more work eventually even if NAPI poll is not happening */
+	schedule_delayed_work(dwork, 30 * HZ);
 }
 #define efx_filter_rfs_enabled() 1
 #else
diff --git a/drivers/net/ethernet/sfc/net_driver.h b/drivers/net/ethernet/sfc/net_driver.h
index ccd480e699d3..1f88212be085 100644
--- a/drivers/net/ethernet/sfc/net_driver.h
+++ b/drivers/net/ethernet/sfc/net_driver.h
@@ -501,7 +501,7 @@ struct efx_channel {
 	unsigned int rfs_expire_index;
 	unsigned int n_rfs_succeeded;
 	unsigned int n_rfs_failed;
-	struct work_struct filter_work;
+	struct delayed_work filter_work;
 #define RPS_FLOW_ID_INVALID 0xFFFFFFFF
 	u32 *rps_flow_id;
 #endif

Re: [PATCH net-next 1/4] sfc: change ARFS expiry mechanism

[David Ahern]

On 11/22/19 10:57 AM, Edward Cree wrote:
> The old rfs_filters_added method for determining the quota could potentially
>  allow the NIC to become filled with old filters, which never get tested for
>  expiry.  Instead, explicitly make expiry check work depend on the number of
>  filters installed, and don't count checking slots without filters in as
>  doing work.  This guarantees that each filter will be checked for expiry at
>  least once every thirty seconds (assuming the channel to which it belongs is
>  NAPI polling actively) regardless of fill level.
> 
> Signed-off-by: Edward Cree <ecree@solarflare.com>
> ---
>  drivers/net/ethernet/sfc/efx.c        |  8 +++--
>  drivers/net/ethernet/sfc/efx.h        |  9 +++---
>  drivers/net/ethernet/sfc/net_driver.h | 14 ++++----
>  drivers/net/ethernet/sfc/rx.c         | 46 ++++++++++++++++-----------
>  4 files changed, 45 insertions(+), 32 deletions(-)
> 

Tested-By: David Ahern <dahern@digitalocean.com>

Re: [PATCH net-next 2/4] sfc: suppress MCDI errors from ARFS

[David Ahern]

On 11/22/19 10:57 AM, Edward Cree wrote:
> In high connection count usage, the NIC's filter table may be filled with
>  sufficiently many ARFS filters that further insertions fail.  As this
>  does not represent a correctness issue, do not log the resulting MCDI
>  errors.  Add a debug-level message under the (by default disabled)
>  rx_status category instead; and take the opportunity to do a little extra
>  expiry work.
> 
> Since there are now multiple workitems able to call __efx_filter_rfs_expire
>  on a given channel, it is possible for them to race and thus pass quotas
>  which, combined, exceed rfs_filter_count.  Thus, don't WARN_ON if we loop
>  all the way around the table with quota left over.
> 
> Signed-off-by: Edward Cree <ecree@solarflare.com>
> ---
>  drivers/net/ethernet/sfc/ef10.c |  8 ++++++--
>  drivers/net/ethernet/sfc/rx.c   | 28 ++++++++++++++++++++++++----
>  2 files changed, 30 insertions(+), 6 deletions(-)
> 

Tested-By: David Ahern <dahern@digitalocean.com>

Re: [PATCH net-next 0/4] sfc: ARFS expiry improvements

[Jakub Kicinski]

On Fri, 22 Nov 2019 17:54:27 +0000, Edward Cree wrote:
> A series of changes to how we check filters for expiry, manage how much
>  of that work to do & when, etc.
> Prompted by some pathological behaviour under heavy load, which was
> Reported-By: David Ahern <dahern@digitalocean.com>

I guess that counts as a reported tag? Lemme make the By lower case,
then ;)

I'm not 100% happy on board with the abuse of statistics to show the
current count, now that we have devlink APIs to dump tables and capture
their occupancy.

Applied, thank you!

[PATCH net-next] sfc: fix build without CONFIG_RFS_ACCEL

[Jakub Kicinski]

The rfs members of struct efx_channel are under CONFIG_RFS_ACCEL.
Ethtool stats which access those need to be as well.

Reported-by: kbuild test robot <lkp@intel.com>
Fixes: ca70bd423f10 ("sfc: add statistics for ARFS")
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
---
 drivers/net/ethernet/sfc/ethtool.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/net/ethernet/sfc/ethtool.c b/drivers/net/ethernet/sfc/ethtool.c
index 6a9347cd67f3..b31032da4bcb 100644
--- a/drivers/net/ethernet/sfc/ethtool.c
+++ b/drivers/net/ethernet/sfc/ethtool.c
@@ -90,9 +90,11 @@ static const struct efx_sw_stat_desc efx_sw_stat_desc[] = {
 	EFX_ETHTOOL_UINT_CHANNEL_STAT(rx_xdp_bad_drops),
 	EFX_ETHTOOL_UINT_CHANNEL_STAT(rx_xdp_tx),
 	EFX_ETHTOOL_UINT_CHANNEL_STAT(rx_xdp_redirect),
+#ifdef CONFIG_RFS_ACCEL
 	EFX_ETHTOOL_UINT_CHANNEL_STAT_NO_N(rfs_filter_count),
 	EFX_ETHTOOL_UINT_CHANNEL_STAT(rfs_succeeded),
 	EFX_ETHTOOL_UINT_CHANNEL_STAT(rfs_failed),
+#endif
 };
 
 #define EFX_ETHTOOL_SW_STAT_COUNT ARRAY_SIZE(efx_sw_stat_desc)
-- 
2.23.0

Re: [PATCH net-next] sfc: fix build without CONFIG_RFS_ACCEL

[Jakub Kicinski]

On Sat, 23 Nov 2019 09:45:42 -0800, Jakub Kicinski wrote:
> The rfs members of struct efx_channel are under CONFIG_RFS_ACCEL.
> Ethtool stats which access those need to be as well.
> 
> Reported-by: kbuild test robot <lkp@intel.com>
> Fixes: ca70bd423f10 ("sfc: add statistics for ARFS")
> Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>

Applied.

Re: [PATCH net-next] sfc: fix build without CONFIG_RFS_ACCEL

[Edward Cree]

On 23/11/2019 17:45, Jakub Kicinski wrote:
> The rfs members of struct efx_channel are under CONFIG_RFS_ACCEL.
> Ethtool stats which access those need to be as well.
>
> Reported-by: kbuild test robot <lkp@intel.com>
> Fixes: ca70bd423f10 ("sfc: add statistics for ARFS")
> Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Thanks for catching this, mea culpa for not testing that case.
-Ed