Author: ken
Date: Wed Jul 19 15:39:01 2017
New Revision: 321207
URL: https://svnweb.freebsd.org/changeset/base/321207
Log:
Fix spurious timeouts on commands sent to mps(4) and mpr(4) controllers.
mps_wait_command() and mpr_wait_command() were using getmicrotime() to
determine elapsed time when checking for a timeout in polled mode.
getmicrotime() isn't guaranteed to monotonically increase, and that
caused spurious timeouts occasionally.
Switch to using getmicrouptime(), which does increase monotonically.
This fixes the spurious timeouts in my test case.
Reviewed by: slm, scottl
MFC after: 3 days
Sponsored by: Spectra Logic
Modified:
head/sys/dev/mpr/mpr.c
head/sys/dev/mps/mps.c
Modified: head/sys/dev/mpr/mpr.c
==============================================================================
--- head/sys/dev/mpr/mpr.c Wed Jul 19 15:22:10 2017 (r321206)
+++ head/sys/dev/mpr/mpr.c Wed Jul 19 15:39:01 2017 (r321207)
@@ -3286,9 +3286,17 @@ mpr_wait_command(struct mpr_softc *sc, struct mpr_comm
if (curthread->td_pflags & TDP_NOSLEEPING)
#endif //__FreeBSD_version >= 1000029
sleep_flag = NO_SLEEP;
- getmicrotime(&start_time);
+ getmicrouptime(&start_time);
if (mtx_owned(&sc->mpr_mtx) && sleep_flag == CAN_SLEEP) {
error = msleep(cm, &sc->mpr_mtx, 0, "mprwait", timeout*hz);
+ if (error == EWOULDBLOCK) {
+ /*
+ * Record the actual elapsed time in the case of a
+ * timeout for the message below.
+ */
+ getmicrouptime(&cur_time);
+ timevalsub(&cur_time, &start_time);
+ }
} else {
while ((cm->cm_flags & MPR_CM_FLAGS_COMPLETE) == 0) {
mpr_intr_locked(sc);
@@ -3297,8 +3305,9 @@ mpr_wait_command(struct mpr_softc *sc, struct mpr_comm
else
DELAY(50000);
- getmicrotime(&cur_time);
- if ((cur_time.tv_sec - start_time.tv_sec) > timeout) {
+ getmicrouptime(&cur_time);
+ timevalsub(&cur_time, &start_time);
+ if (cur_time.tv_sec > timeout) {
error = EWOULDBLOCK;
break;
}
@@ -3306,7 +3315,9 @@ mpr_wait_command(struct mpr_softc *sc, struct mpr_comm
}
if (error == EWOULDBLOCK) {
- mpr_dprint(sc, MPR_FAULT, "Calling Reinit from %s\n", __func__);
+ mpr_dprint(sc, MPR_FAULT, "Calling Reinit from %s, timeout=%d,"
+ " elapsed=%jd\n", __func__, timeout,
+ (intmax_t)cur_time.tv_sec);
rc = mpr_reinit(sc);
mpr_dprint(sc, MPR_FAULT, "Reinit %s\n", (rc == 0) ? "success" :
"failed");
Modified: head/sys/dev/mps/mps.c
==============================================================================
--- head/sys/dev/mps/mps.c Wed Jul 19 15:22:10 2017 (r321206)
+++ head/sys/dev/mps/mps.c Wed Jul 19 15:39:01 2017 (r321207)
@@ -2551,10 +2551,18 @@ mps_wait_command(struct mps_softc *sc, struct mps_comm
*/
if (curthread->td_no_sleeping != 0)
sleep_flag = NO_SLEEP;
- getmicrotime(&start_time);
+ getmicrouptime(&start_time);
if (mtx_owned(&sc->mps_mtx) && sleep_flag == CAN_SLEEP) {
cm->cm_flags |= MPS_CM_FLAGS_WAKEUP;
error = msleep(cm, &sc->mps_mtx, 0, "mpswait", timeout*hz);
+ if (error == EWOULDBLOCK) {
+ /*
+ * Record the actual elapsed time in the case of a
+ * timeout for the message below.
+ */
+ getmicrouptime(&cur_time);
+ timevalsub(&cur_time, &start_time);
+ }
} else {
while ((cm->cm_flags & MPS_CM_FLAGS_COMPLETE) == 0) {
mps_intr_locked(sc);
@@ -2563,8 +2571,9 @@ mps_wait_command(struct mps_softc *sc, struct mps_comm
else
DELAY(50000);
- getmicrotime(&cur_time);
- if ((cur_time.tv_sec - start_time.tv_sec) > timeout) {
+ getmicrouptime(&cur_time);
+ timevalsub(&cur_time, &start_time);
+ if (cur_time.tv_sec > timeout) {
error = EWOULDBLOCK;
break;
}
@@ -2572,7 +2581,9 @@ mps_wait_command(struct mps_softc *sc, struct mps_comm
}
if (error == EWOULDBLOCK) {
- mps_dprint(sc, MPS_FAULT, "Calling Reinit from %s\n", __func__);
+ mps_dprint(sc, MPS_FAULT, "Calling Reinit from %s, timeout=%d,"
+ " elapsed=%jd\n", __func__, timeout,
+ (intmax_t)cur_time.tv_sec);
rc = mps_reinit(sc);
mps_dprint(sc, MPS_FAULT, "Reinit %s\n", (rc == 0) ? "success" :
"failed");
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