From bc97f4bb4490ff31b2be8e006f750d4187ef0c7e Mon Sep 17 00:00:00 2001 From: Rob Evers Date: Fri, 18 May 2012 14:08:56 -0400 Subject: [SCSI] scsi_dh_alua: backoff alua rtpg retry linearly vs. geometrically Currently the backoff algorithm for when to retry alua rtpg requests progresses geometrically as so: 2, 4, 8, 16, 32, 64... seconds. This progression can lead to un-needed delay in retrying alua rtpg requests when the rtpgs are delayed. A less aggressive backoff algorithm that is additive would not lead to such large jumps when delays start getting long, but would backoff linearly: 2, 4, 6, 8, 10... seconds. Signed-off-by: Martin George Signed-off-by: Rob Evers Reviewed-by: Babu Moger Signed-off-by: James Bottomley --- drivers/scsi/device_handler/scsi_dh_alua.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'drivers') diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c index 5a3448856962..0d573822bf43 100644 --- a/drivers/scsi/device_handler/scsi_dh_alua.c +++ b/drivers/scsi/device_handler/scsi_dh_alua.c @@ -527,7 +527,7 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_dh_data *h) unsigned char *ucp; unsigned err; bool rtpg_ext_hdr_req = 1; - unsigned long expiry, interval = 1000; + unsigned long expiry, interval = 0; unsigned int tpg_desc_tbl_off; unsigned char orig_transition_tmo; @@ -632,7 +632,7 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_dh_data *h) case TPGS_STATE_TRANSITIONING: if (time_before(jiffies, expiry)) { /* State transition, retry */ - interval *= 2; + interval += 2000; msleep(interval); goto retry; } -- cgit v1.2.3-59-g8ed1b