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

[Manjunath Patil <manjunath.b.patil@oracle.com>]

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 a one
line warning once a day.

Signed-off-by: Manjunath Patil <manjunath.b.patil@oracle.com>
Reviewed-by: Aruna Ramakrishna <aruna.ramakrishna@oracle.com>
---
 net/rds/ib_recv.c | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/net/rds/ib_recv.c b/net/rds/ib_recv.c
index 694d411dc72f..38d2894f6bb2 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 +406,16 @@ 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) {
+			static unsigned long warn_time;
+			/* warn max once per day. This should be enough to
+			 * warn users about low mem situation.
+			 */
+			if (printk_timed_ratelimit(&warn_time,
+						   24 * 60 * 60 * 1000))
+				pr_warn("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 +1030,7 @@ 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