[PATCH rdma-next] RDMA/mlx5: Introduce ODP prefetch counter

[PATCH rdma-next] RDMA/mlx5: Introduce ODP prefetch counter

[Leon Romanovsky]

From: Maor Gottlieb <maorg@mellanox.com>

For debugging purpose it will be easier to understand if prefetch
works okay if it has its own counter. Introduce ODP prefetch counter
and count per MR the total number of prefetched pages.

In addition remove comment which is not relevant anymore and anyway
not in the correct place.

Signed-off-by: Maor Gottlieb <maorg@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
---
 drivers/infiniband/hw/mlx5/odp.c      | 19 ++++++++++---------
 drivers/infiniband/hw/mlx5/restrack.c |  3 +++
 include/rdma/ib_verbs.h               |  1 +
 3 files changed, 14 insertions(+), 9 deletions(-)

diff --git a/drivers/infiniband/hw/mlx5/odp.c b/drivers/infiniband/hw/mlx5/odp.c
index 7d2ec9ee5097..ee88b32d143d 100644
--- a/drivers/infiniband/hw/mlx5/odp.c
+++ b/drivers/infiniband/hw/mlx5/odp.c
@@ -913,11 +913,6 @@ static int pagefault_single_data_segment(struct mlx5_ib_dev *dev,
 		if (ret < 0)
 			goto srcu_unlock;
 
-		/*
-		 * When prefetching a page, page fault is generated
-		 * in order to bring the page to the main memory.
-		 * In the current flow, page faults are being counted.
-		 */
 		mlx5_update_odp_stats(mr, faults, ret);
 
 		npages += ret;
@@ -1755,12 +1750,17 @@ static void mlx5_ib_prefetch_mr_work(struct work_struct *w)
 	struct prefetch_mr_work *work =
 		container_of(w, struct prefetch_mr_work, work);
 	u32 bytes_mapped = 0;
+	int ret;
 	u32 i;
 
-	for (i = 0; i < work->num_sge; ++i)
-		pagefault_mr(work->frags[i].mr, work->frags[i].io_virt,
-			     work->frags[i].length, &bytes_mapped,
-			     work->pf_flags);
+	for (i = 0; i < work->num_sge; ++i) {
+		ret = pagefault_mr(work->frags[i].mr, work->frags[i].io_virt,
+				   work->frags[i].length, &bytes_mapped,
+				   work->pf_flags);
+		if (ret <= 0)
+			continue;
+		mlx5_update_odp_stats(work->frags[i].mr, prefetch, ret);
+	}
 
 	destroy_prefetch_work(work);
 }
@@ -1818,6 +1818,7 @@ static int mlx5_ib_prefetch_sg_list(struct ib_pd *pd,
 				   &bytes_mapped, pf_flags);
 		if (ret < 0)
 			goto out;
+		mlx5_update_odp_stats(mr, prefetch, ret);
 	}
 	ret = 0;
 
diff --git a/drivers/infiniband/hw/mlx5/restrack.c b/drivers/infiniband/hw/mlx5/restrack.c
index 224a63975822..32c6d0397946 100644
--- a/drivers/infiniband/hw/mlx5/restrack.c
+++ b/drivers/infiniband/hw/mlx5/restrack.c
@@ -99,6 +99,9 @@ int mlx5_ib_fill_stat_mr_entry(struct sk_buff *msg,
 		    msg, "page_invalidations",
 		    atomic64_read(&mr->odp_stats.invalidations)))
 		goto err_table;
+	if (rdma_nl_stat_hwcounter_entry(msg, "page_prefetch",
+					 atomic64_read(&mr->odp_stats.prefetch)))
+		goto err_table;
 
 	nla_nest_end(msg, table_attr);
 	return 0;
diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h
index 9b973b3b6f4c..1691c10f6e8a 100644
--- a/include/rdma/ib_verbs.h
+++ b/include/rdma/ib_verbs.h
@@ -2271,6 +2271,7 @@ struct rdma_netdev_alloc_params {
 struct ib_odp_counters {
 	atomic64_t faults;
 	atomic64_t invalidations;
+	atomic64_t prefetch;
 };
 
 struct ib_counters {
-- 
2.26.2

Re: [PATCH rdma-next] RDMA/mlx5: Introduce ODP prefetch counter

[Jason Gunthorpe]

On Sun, Jun 21, 2020 at 01:41:47PM +0300, Leon Romanovsky wrote:
> From: Maor Gottlieb <maorg@mellanox.com>
> 
> For debugging purpose it will be easier to understand if prefetch
> works okay if it has its own counter. Introduce ODP prefetch counter
> and count per MR the total number of prefetched pages.
> 
> In addition remove comment which is not relevant anymore and anyway
> not in the correct place.
> 
> Signed-off-by: Maor Gottlieb <maorg@mellanox.com>
> Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
> ---
>  drivers/infiniband/hw/mlx5/odp.c      | 19 ++++++++++---------
>  drivers/infiniband/hw/mlx5/restrack.c |  3 +++
>  include/rdma/ib_verbs.h               |  1 +
>  3 files changed, 14 insertions(+), 9 deletions(-)

Applied to for-next, thanks

Jason