netdev - [PATCH 1/1] net/rds: suppress page allocation failure error in recv buffer refill

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Date:   Fri,  2 Oct 2020 13:05:45 -0700
From:   Manjunath Patil <manjunath.b.patil@...cle.com>
To:     santosh.shilimkar@...cle.com
Cc:     netdev@...r.kernel.org, linux-rdma@...r.kernel.org,
        aruna.ramakrishna@...cle.com, rama.nichanamatlu@...cle.com,
        manjunath.b.patil@...cle.com
Subject: [PATCH 1/1] net/rds: suppress page allocation failure error in recv buffer refill

RDS/IB tries to refill the recv buffer in softirq context using
GFP_NOWAIT flag. However alloc failure is handled by queueing a work to
refill the recv buffer with GFP_KERNEL flag. This means failure to
allocate with GFP_NOWAIT isn't fatal. Do not print the PAF warnings if
softirq context fails to refill the recv buffer, instead print rate
limited warnings.

Signed-off-by: Manjunath Patil <manjunath.b.patil@...cle.com>
Reviewed-by: Aruna Ramakrishna <aruna.ramakrishna@...cle.com>
---
 net/rds/ib_recv.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/net/rds/ib_recv.c b/net/rds/ib_recv.c
index 694d411dc72f..b4ed421acc7b 100644
--- a/net/rds/ib_recv.c
+++ b/net/rds/ib_recv.c
@@ -310,8 +310,8 @@ static int rds_ib_recv_refill_one(struct rds_connection *conn,
 	struct rds_ib_connection *ic = conn->c_transport_data;
 	struct ib_sge *sge;
 	int ret = -ENOMEM;
-	gfp_t slab_mask = GFP_NOWAIT;
-	gfp_t page_mask = GFP_NOWAIT;
+	gfp_t slab_mask = gfp;
+	gfp_t page_mask = gfp;
 
 	if (gfp & __GFP_DIRECT_RECLAIM) {
 		slab_mask = GFP_KERNEL;
@@ -406,6 +406,9 @@ void rds_ib_recv_refill(struct rds_connection *conn, int prefill, gfp_t gfp)
 		recv = &ic->i_recvs[pos];
 		ret = rds_ib_recv_refill_one(conn, recv, gfp);
 		if (ret) {
+			pr_warn_ratelimited("RDS/IB: failed to refill recv buffer for <%pI6c,%pI6c,%d>, waking worker\n",
+					    &conn->c_laddr, &conn->c_faddr,
+					    conn->c_tos);
 			must_wake = true;
 			break;
 		}
@@ -1020,7 +1023,7 @@ void rds_ib_recv_cqe_handler(struct rds_ib_connection *ic,
 		rds_ib_stats_inc(s_ib_rx_ring_empty);
 
 	if (rds_ib_ring_low(&ic->i_recv_ring)) {
-		rds_ib_recv_refill(conn, 0, GFP_NOWAIT);
+		rds_ib_recv_refill(conn, 0, GFP_NOWAIT | __GFP_NOWARN);
 		rds_ib_stats_inc(s_ib_rx_refill_from_cq);
 	}
 }
-- 
2.27.0.112.g101b320