mlxsw: spectrum_router: Share nexthop counters in resilient groups

For resilient groups, we can reuse the same counter for all the buckets
that share the same nexthop. Keep a reference count per counter, and keep
all these counters in a per-next hop group xarray, which serves as a
NHID->counter cache. If a counter is already present for a given NHID, just
take a reference and use the same counter.

Signed-off-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://lore.kernel.org/r/cdd00084533fc83ac5917562f54642f008205bf3.1709901020.git.petrm@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
index 93ead5ccf864c7ca806a4aad21a672c3860e52fe..40ba314fbc72acf7e4e64413e655f07f23bdda43 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
@@ -19,6 +19,7 @@
 #include <linux/net_namespace.h>
 #include <linux/mutex.h>
 #include <linux/genalloc.h>
+#include <linux/xarray.h>
 #include <net/netevent.h>
 #include <net/neighbour.h>
 #include <net/arp.h>
@@ -3111,6 +3112,7 @@ struct mlxsw_sp_nexthop_group_info {
           is_resilient:1,
           hw_stats:1;
        struct list_head list; /* member in nh_res_grp_list */
+       struct xarray nexthop_counters;
        struct mlxsw_sp_nexthop nexthops[] __counted_by(count);
 };
 
@@ -3156,6 +3158,7 @@ struct mlxsw_sp_nexthop_group {
 
 struct mlxsw_sp_nexthop_counter {
        unsigned int counter_index;
+       refcount_t ref_count;
 };
 
 static struct mlxsw_sp_nexthop_counter *
@@ -3172,6 +3175,7 @@ mlxsw_sp_nexthop_counter_alloc(struct mlxsw_sp *mlxsw_sp)
        if (err)
                goto err_counter_alloc;
 
+       refcount_set(&nhct->ref_count, 1);
        return nhct;
 
 err_counter_alloc:
@@ -3187,6 +3191,56 @@ mlxsw_sp_nexthop_counter_free(struct mlxsw_sp *mlxsw_sp,
        kfree(nhct);
 }
 
+static struct mlxsw_sp_nexthop_counter *
+mlxsw_sp_nexthop_sh_counter_get(struct mlxsw_sp *mlxsw_sp,
+                               struct mlxsw_sp_nexthop *nh)
+{
+       struct mlxsw_sp_nexthop_group *nh_grp = nh->nhgi->nh_grp;
+       struct mlxsw_sp_nexthop_counter *nhct;
+       void *ptr;
+       int err;
+
+       nhct = xa_load(&nh_grp->nhgi->nexthop_counters, nh->id);
+       if (nhct) {
+               refcount_inc(&nhct->ref_count);
+               return nhct;
+       }
+
+       nhct = mlxsw_sp_nexthop_counter_alloc(mlxsw_sp);
+       if (IS_ERR(nhct))
+               return nhct;
+
+       ptr = xa_store(&nh_grp->nhgi->nexthop_counters, nh->id, nhct,
+                      GFP_KERNEL);
+       if (IS_ERR(ptr)) {
+               err = PTR_ERR(ptr);
+               goto err_store;
+       }
+
+       return nhct;
+
+err_store:
+       mlxsw_sp_nexthop_counter_free(mlxsw_sp, nhct);
+       return ERR_PTR(err);
+}
+
+static void mlxsw_sp_nexthop_sh_counter_put(struct mlxsw_sp *mlxsw_sp,
+                                           struct mlxsw_sp_nexthop *nh)
+{
+       struct mlxsw_sp_nexthop_group *nh_grp = nh->nhgi->nh_grp;
+       struct mlxsw_sp_nexthop_counter *nhct;
+
+       nhct = xa_load(&nh_grp->nhgi->nexthop_counters, nh->id);
+       if (WARN_ON(!nhct))
+               return;
+
+       if (!refcount_dec_and_test(&nhct->ref_count))
+               return;
+
+       xa_erase(&nh_grp->nhgi->nexthop_counters, nh->id);
+       mlxsw_sp_nexthop_counter_free(mlxsw_sp, nhct);
+}
+
 int mlxsw_sp_nexthop_counter_enable(struct mlxsw_sp *mlxsw_sp,
                                    struct mlxsw_sp_nexthop *nh)
 {
@@ -3203,7 +3257,10 @@ int mlxsw_sp_nexthop_counter_enable(struct mlxsw_sp *mlxsw_sp,
        if (!(nh->nhgi->hw_stats || dpipe_stats))
                return 0;
 
-       nhct = mlxsw_sp_nexthop_counter_alloc(mlxsw_sp);
+       if (nh->id)
+               nhct = mlxsw_sp_nexthop_sh_counter_get(mlxsw_sp, nh);
+       else
+               nhct = mlxsw_sp_nexthop_counter_alloc(mlxsw_sp);
        if (IS_ERR(nhct))
                return PTR_ERR(nhct);
 
@@ -3216,7 +3273,11 @@ void mlxsw_sp_nexthop_counter_disable(struct mlxsw_sp *mlxsw_sp,
 {
        if (!nh->counter)
                return;
-       mlxsw_sp_nexthop_counter_free(mlxsw_sp, nh->counter);
+
+       if (nh->id)
+               mlxsw_sp_nexthop_sh_counter_put(mlxsw_sp, nh);
+       else
+               mlxsw_sp_nexthop_counter_free(mlxsw_sp, nh->counter);
        nh->counter = NULL;
 }
 
@@ -5145,6 +5206,9 @@ mlxsw_sp_nexthop_obj_group_info_init(struct mlxsw_sp *mlxsw_sp,
        nhgi->is_resilient = is_resilient;
        nhgi->count = nhs;
        nhgi->hw_stats = hw_stats;
+
+       xa_init_flags(&nhgi->nexthop_counters, XA_FLAGS_ALLOC1);
+
        for (i = 0; i < nhgi->count; i++) {
                struct nh_notifier_single_info *nh_obj;
                int weight;
@@ -5227,6 +5291,8 @@ mlxsw_sp_nexthop_obj_group_info_fini(struct mlxsw_sp *mlxsw_sp,
        }
        mlxsw_sp_nexthop_group_refresh(mlxsw_sp, nh_grp);
        WARN_ON_ONCE(nhgi->adj_index_valid);
+       WARN_ON(!xa_empty(&nhgi->nexthop_counters));
+       xa_destroy(&nhgi->nexthop_counters);
        kfree(nhgi);
 }