nfp: abm: restructure Qdisc handling

In preparation of handling more Qdisc types switch to a different
offload strategy.  We have now recreated the Qdisc hierarchy in
the driver.  Every time the hierarchy changes parse it, and update
the configuration of the HW accordingly.

While at it drop the support of pretending that we can instantiate
a single queue on a multi-queue device in HW/FW.  MQ is now required,
and each queue will have its own instance of RED.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: John Hurley <john.hurley@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/netronome/nfp/abm/ctrl.c

@@ -50,27 +50,6 @@ nfp_abm_ctrl_stat(struct nfp_abm_link *alink, const struct nfp_rtsym *sym,
 	return 0;
 }
 
-static int
-nfp_abm_ctrl_stat_all(struct nfp_abm_link *alink, const struct nfp_rtsym *sym,
-		      unsigned int stride, unsigned int offset, bool is_u64,
-		      u64 *res)
-{
-	u64 val, sum = 0;
-	unsigned int i;
-	int err;
-
-	for (i = 0; i < alink->vnic->max_rx_rings; i++) {
-		err = nfp_abm_ctrl_stat(alink, sym, stride, offset, i,
-					is_u64, &val);
-		if (err)
-			return err;
-		sum += val;
-	}
-
-	*res = sum;
-	return 0;
-}
-
 int __nfp_abm_ctrl_set_q_lvl(struct nfp_abm *abm, unsigned int id, u32 val)
 {
 	struct nfp_cpp *cpp = abm->app->cpp;
@@ -155,42 +134,6 @@ int nfp_abm_ctrl_read_q_stats(struct nfp_abm_link *alink, unsigned int i,
 				 i, true, &stats->overlimits);
 }
 
-int nfp_abm_ctrl_read_stats(struct nfp_abm_link *alink,
-			    struct nfp_alink_stats *stats)
-{
-	u64 pkts = 0, bytes = 0;
-	int i, err;
-
-	for (i = 0; i < alink->vnic->max_rx_rings; i++) {
-		pkts += nn_readq(alink->vnic, NFP_NET_CFG_RXR_STATS(i));
-		bytes += nn_readq(alink->vnic, NFP_NET_CFG_RXR_STATS(i) + 8);
-	}
-	stats->tx_pkts = pkts;
-	stats->tx_bytes = bytes;
-
-	err = nfp_abm_ctrl_stat_all(alink, alink->abm->q_lvls,
-				    NFP_QLVL_STRIDE, NFP_QLVL_BLOG_BYTES,
-				    false, &stats->backlog_bytes);
-	if (err)
-		return err;
-
-	err = nfp_abm_ctrl_stat_all(alink, alink->abm->q_lvls,
-				    NFP_QLVL_STRIDE, NFP_QLVL_BLOG_PKTS,
-				    false, &stats->backlog_pkts);
-	if (err)
-		return err;
-
-	err = nfp_abm_ctrl_stat_all(alink, alink->abm->qm_stats,
-				    NFP_QMSTAT_STRIDE, NFP_QMSTAT_DROP,
-				    true, &stats->drops);
-	if (err)
-		return err;
-
-	return nfp_abm_ctrl_stat_all(alink, alink->abm->qm_stats,
-				     NFP_QMSTAT_STRIDE, NFP_QMSTAT_ECN,
-				     true, &stats->overlimits);
-}
-
 int nfp_abm_ctrl_read_q_xstats(struct nfp_abm_link *alink, unsigned int i,
 			       struct nfp_alink_xstats *xstats)
 {
@@ -207,22 +150,6 @@ int nfp_abm_ctrl_read_q_xstats(struct nfp_abm_link *alink, unsigned int i,
 				 i, true, &xstats->ecn_marked);
 }
 
-int nfp_abm_ctrl_read_xstats(struct nfp_abm_link *alink,
-			     struct nfp_alink_xstats *xstats)
-{
-	int err;
-
-	err = nfp_abm_ctrl_stat_all(alink, alink->abm->qm_stats,
-				    NFP_QMSTAT_STRIDE, NFP_QMSTAT_DROP,
-				    true, &xstats->pdrop);
-	if (err)
-		return err;
-
-	return nfp_abm_ctrl_stat_all(alink, alink->abm->qm_stats,
-				     NFP_QMSTAT_STRIDE, NFP_QMSTAT_ECN,
-				     true, &xstats->ecn_marked);
-}
-
 int nfp_abm_ctrl_qm_enable(struct nfp_abm *abm)
 {
 	return nfp_mbox_cmd(abm->app->pf, NFP_MBOX_PCIE_ABM_ENABLE,

drivers/net/ethernet/netronome/nfp/abm/main.c

@@ -7,6 +7,7 @@
 #include <linux/lockdep.h>
 #include <linux/netdevice.h>
 #include <linux/rcupdate.h>
+#include <linux/rtnetlink.h>
 #include <linux/slab.h>
 
 #include "../nfpcore/nfp.h"
@@ -310,22 +311,14 @@ nfp_abm_vnic_alloc(struct nfp_app *app, struct nfp_net *nn, unsigned int id)
 	alink->abm = abm;
 	alink->vnic = nn;
 	alink->id = id;
-	alink->parent = TC_H_ROOT;
 	alink->total_queues = alink->vnic->max_rx_rings;
-	alink->red_qdiscs = kvcalloc(alink->total_queues,
-				     sizeof(*alink->red_qdiscs),
-				     GFP_KERNEL);
-	if (!alink->red_qdiscs) {
-		err = -ENOMEM;
-		goto err_free_alink;
-	}
 
 	/* This is a multi-host app, make sure MAC/PHY is up, but don't
 	 * make the MAC/PHY state follow the state of any of the ports.
 	 */
 	err = nfp_eth_set_configured(app->cpp, eth_port->index, true);
 	if (err < 0)
-		goto err_free_qdiscs;
+		goto err_free_alink;
 
 	netif_keep_dst(nn->dp.netdev);
 
@@ -335,8 +328,6 @@ nfp_abm_vnic_alloc(struct nfp_app *app, struct nfp_net *nn, unsigned int id)
 
 	return 0;
 
-err_free_qdiscs:
-	kvfree(alink->red_qdiscs);
 err_free_alink:
 	kfree(alink);
 	return err;
@@ -348,7 +339,6 @@ static void nfp_abm_vnic_free(struct nfp_app *app, struct nfp_net *nn)
 
 	nfp_abm_kill_reprs(alink->abm, alink);
 	WARN(!radix_tree_empty(&alink->qdiscs), "left over qdiscs\n");
-	kvfree(alink->red_qdiscs);
 	kfree(alink);
 }
 

drivers/net/ethernet/netronome/nfp/abm/main.h

@@ -9,6 +9,11 @@
 #include <net/devlink.h>
 #include <net/pkt_cls.h>
 
+/* Dump of 64 PRIOs and 256 REDs seems to take 850us on Xeon v4 @ 2.20GHz;
+ * 2.5ms / 400Hz seems more than sufficient for stats resolution.
+ */
+#define NFP_ABM_STATS_REFRESH_IVAL	(2500 * 1000) /* ns */
+
 #define NFP_ABM_LVL_INFINITY		S32_MAX
 
 struct nfp_app;
@@ -91,9 +96,19 @@ enum nfp_qdisc_type {
  * @children:		pointers to children
  *
  * @params_ok:		parameters of this Qdisc are OK for offload
+ * @offload_mark:	offload refresh state - selected for offload
+ * @offloaded:		Qdisc is currently offloaded to the HW
+ *
+ * @mq:			MQ Qdisc specific parameters and state
+ * @mq.stats:		current stats of the MQ Qdisc
+ * @mq.prev_stats:	previously reported @mq.stats
  *
  * @red:		RED Qdisc specific parameters and state
  * @red.threshold:	ECN marking threshold
+ * @red.stats:		current stats of the RED Qdisc
+ * @red.prev_stats:	previously reported @red.stats
+ * @red.xstats:		extended stats for RED - current
+ * @red.prev_xstats:	extended stats for RED - previously reported
  */
 struct nfp_qdisc {
 	struct net_device *netdev;
@@ -105,27 +120,24 @@ struct nfp_qdisc {
 	struct nfp_qdisc **children;
 
 	bool params_ok;
+	bool offload_mark;
+	bool offloaded;
 
 	union {
+		/* NFP_QDISC_MQ */
+		struct {
+			struct nfp_alink_stats stats;
+			struct nfp_alink_stats prev_stats;
+		} mq;
 		/* TC_SETUP_QDISC_RED */
 		struct {
 			u32 threshold;
-		} red;
-	};
-};
-
-/**
- * struct nfp_red_qdisc - representation of single RED Qdisc
- * @handle:	handle of currently offloaded RED Qdisc
- * @threshold:	marking threshold of this Qdisc
- * @stats:	statistics from last refresh
- * @xstats:	base of extended statistics
- */
-struct nfp_red_qdisc {
-	u32 handle;
-	u32 threshold;
 			struct nfp_alink_stats stats;
+			struct nfp_alink_stats prev_stats;
 			struct nfp_alink_xstats xstats;
+			struct nfp_alink_xstats prev_xstats;
+		} red;
+	};
 };
 
 /**
@@ -135,9 +147,9 @@ struct nfp_red_qdisc {
  * @id:		id of the data vNIC
  * @queue_base:	id of base to host queue within PCIe (not QC idx)
  * @total_queues:	number of PF queues
- * @parent:	handle of expected parent, i.e. handle of MQ, or TC_H_ROOT
- * @num_qdiscs:	number of currently used qdiscs
- * @red_qdiscs:	array of qdiscs
+ *
+ * @last_stats_update:	ktime of last stats update
+ *
  * @root_qdisc:	pointer to the current root of the Qdisc hierarchy
  * @qdiscs:	all qdiscs recorded by major part of the handle
  */
@@ -147,13 +159,14 @@ struct nfp_abm_link {
 	unsigned int id;
 	unsigned int queue_base;
 	unsigned int total_queues;
-	u32 parent;
-	unsigned int num_qdiscs;
-	struct nfp_red_qdisc *red_qdiscs;
+
+	u64 last_stats_update;
+
 	struct nfp_qdisc *root_qdisc;
 	struct radix_tree_root qdiscs;
 };
 
+void nfp_abm_qdisc_offload_update(struct nfp_abm_link *alink);
 int nfp_abm_setup_root(struct net_device *netdev, struct nfp_abm_link *alink,
 		       struct tc_root_qopt_offload *opt);
 int nfp_abm_setup_tc_red(struct net_device *netdev, struct nfp_abm_link *alink,
@@ -166,12 +179,8 @@ int nfp_abm_ctrl_find_addrs(struct nfp_abm *abm);
 int __nfp_abm_ctrl_set_q_lvl(struct nfp_abm *abm, unsigned int id, u32 val);
 int nfp_abm_ctrl_set_q_lvl(struct nfp_abm_link *alink, unsigned int queue,
 			   u32 val);
-int nfp_abm_ctrl_read_stats(struct nfp_abm_link *alink,
-			    struct nfp_alink_stats *stats);
 int nfp_abm_ctrl_read_q_stats(struct nfp_abm_link *alink, unsigned int i,
 			      struct nfp_alink_stats *stats);
-int nfp_abm_ctrl_read_xstats(struct nfp_abm_link *alink,
-			     struct nfp_alink_xstats *xstats);
 int nfp_abm_ctrl_read_q_xstats(struct nfp_abm_link *alink, unsigned int i,
 			       struct nfp_alink_xstats *xstats);
 u64 nfp_abm_ctrl_stat_non_sto(struct nfp_abm_link *alink, unsigned int i);