iscsi-target: Bump defaults for nopin_timeout + nopin_response_timeout values

commit cf0eb28d3ba60098865bf7dbcbfdd6b1cc483e3b upstream.

This patch increases the default for nopin_timeout to 15 seconds (wait
between sending a new NopIN ping) and nopin_response_timeout to 30 seconds
(wait for NopOUT response before failing the connection) in order to avoid
false positives by iSCSI Initiators who are not always able (under load) to
respond to NopIN echo PING requests within the current 5 second window.

False positives have been observed recently using Open-iSCSI code on v3.3.x
with heavy large-block READ workloads over small MTU 1 Gb/sec ports, and
increasing these values to more reasonable defaults significantly reduces
the possibility of false positive NopIN response timeout events under
this specific workload.

Historically these have been set low to initiate connection recovery as
soon as possible if we don't hear a ping back, but for modern v3.x code
on 1 -> 10 Gb/sec ports these new defaults make alot more sense.

Cc: Christoph Hellwig <hch@lst.de>
Cc: Andy Grover <agrover@redhat.com>
Cc: Mike Christie <michaelc@cs.wisc.edu>
Cc: Hannes Reinecke <hare@suse.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/drivers/target/iscsi/iscsi_target_core.h b/drivers/target/iscsi/iscsi_target_core.h
index 0f68197..dae283f 100644 (file)
--- a/drivers/target/iscsi/iscsi_target_core.h
+++ b/drivers/target/iscsi/iscsi_target_core.h
@@ -25,10 +25,10 @@
 #define NA_DATAOUT_TIMEOUT_RETRIES     5
 #define NA_DATAOUT_TIMEOUT_RETRIES_MAX 15
 #define NA_DATAOUT_TIMEOUT_RETRIES_MIN 1
-#define NA_NOPIN_TIMEOUT               5
+#define NA_NOPIN_TIMEOUT               15
 #define NA_NOPIN_TIMEOUT_MAX           60
 #define NA_NOPIN_TIMEOUT_MIN           3
-#define NA_NOPIN_RESPONSE_TIMEOUT      5
+#define NA_NOPIN_RESPONSE_TIMEOUT      30
 #define NA_NOPIN_RESPONSE_TIMEOUT_MAX  60
 #define NA_NOPIN_RESPONSE_TIMEOUT_MIN  3
 #define NA_RANDOM_DATAIN_PDU_OFFSETS   0