sfc: change ARFS expiry mechanism

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>
Tested-by: David Ahern <dahern@digitalocean.com>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>

1 files changed, 8 insertions, 6 deletions

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;