*/
/*
- * MMP statistics - Information exported regarding each MMP update
+ * MMP statistics - Information exported regarding attempted MMP writes
+ * For MMP writes issued, fields used as per comments below.
+ * For MMP writes skipped, an entry represents a span of time when
+ * writes were skipped for same reason (error from mmp_random_leaf).
+ * Differences are:
+ * timestamp time first write skipped, if >1 skipped in a row
+ * mmp_delay delay value at timestamp
+ * vdev_guid number of writes skipped
+ * io_error one of enum mmp_error
+ * duration time span (ns) of skipped writes
*/
typedef struct spa_mmp_history {
uint64_t mmp_kstat_id; /* unique # for updates */
uint64_t txg; /* txg of last sync */
- uint64_t timestamp; /* UTC time of of last sync */
- uint64_t mmp_delay; /* nanosec since last MMP write */
+ uint64_t timestamp; /* UTC time MMP write issued */
+ uint64_t mmp_delay; /* mmp_thread.mmp_delay at timestamp */
uint64_t vdev_guid; /* unique ID of leaf vdev */
char *vdev_path;
- uint64_t vdev_label; /* vdev label */
+ int vdev_label; /* vdev label */
int io_error; /* error status of MMP write */
+ hrtime_t error_start; /* hrtime of start of error period */
hrtime_t duration; /* time from submission to completion */
list_node_t smh_link;
} spa_mmp_history_t;
spa_mmp_history_data(char *buf, size_t size, void *data)
{
spa_mmp_history_t *smh = (spa_mmp_history_t *)data;
+ char skip_fmt[] = "%-10llu %-10llu %10llu %#6llx %10lld %12llu %-24llu "
+ "%-10lld %s\n";
+ char write_fmt[] = "%-10llu %-10llu %10llu %6lld %10lld %12llu %-24llu "
+ "%-10lld %s\n";
- (void) snprintf(buf, size, "%-10llu %-10llu %-10llu %-6lld %-10lld "
- "%-12llu %-24llu %-10llu %s\n",
+ (void) snprintf(buf, size, (smh->error_start ? skip_fmt : write_fmt),
(u_longlong_t)smh->mmp_kstat_id, (u_longlong_t)smh->txg,
(u_longlong_t)smh->timestamp, (longlong_t)smh->io_error,
(longlong_t)smh->duration, (u_longlong_t)smh->mmp_delay,
mutex_destroy(&ssh->lock);
}
+/*
+ * Set duration in existing "skip" record to how long we have waited for a leaf
+ * vdev to become available.
+ *
+ * Important that we start search at the head of the list where new
+ * records are inserted, so this is normally an O(1) operation.
+ */
+int
+spa_mmp_history_set_skip(spa_t *spa, uint64_t mmp_kstat_id)
+{
+ spa_stats_history_t *ssh = &spa->spa_stats.mmp_history;
+ spa_mmp_history_t *smh;
+ int error = ENOENT;
+
+ if (zfs_multihost_history == 0 && ssh->size == 0)
+ return (0);
+
+ mutex_enter(&ssh->lock);
+ for (smh = list_head(&ssh->list); smh != NULL;
+ smh = list_next(&ssh->list, smh)) {
+ if (smh->mmp_kstat_id == mmp_kstat_id) {
+ ASSERT3U(smh->io_error, !=, 0);
+ smh->duration = gethrtime() - smh->error_start;
+ smh->vdev_guid++;
+ error = 0;
+ break;
+ }
+ }
+ mutex_exit(&ssh->lock);
+
+ return (error);
+}
+
/*
* Set MMP write duration and error status in existing record.
+ * See comment re: search order above spa_mmp_history_set_skip().
*/
int
spa_mmp_history_set(spa_t *spa, uint64_t mmp_kstat_id, int io_error,
for (smh = list_head(&ssh->list); smh != NULL;
smh = list_next(&ssh->list, smh)) {
if (smh->mmp_kstat_id == mmp_kstat_id) {
+ ASSERT(smh->io_error == 0);
smh->io_error = io_error;
smh->duration = duration;
error = 0;
}
/*
- * Add a new MMP write to historical record.
+ * Add a new MMP historical record.
+ * error == 0 : a write was issued.
+ * error != 0 : a write was not issued because no leaves were found.
*/
-void
-spa_mmp_history_add(uint64_t txg, uint64_t timestamp, uint64_t mmp_delay,
- vdev_t *vd, int label, uint64_t mmp_kstat_id)
+void *
+spa_mmp_history_add(spa_t *spa, uint64_t txg, uint64_t timestamp,
+ uint64_t mmp_delay, vdev_t *vd, int label, uint64_t mmp_kstat_id,
+ int error)
{
- spa_t *spa = vd->vdev_spa;
spa_stats_history_t *ssh = &spa->spa_stats.mmp_history;
spa_mmp_history_t *smh, *rm;
if (zfs_multihost_history == 0 && ssh->size == 0)
- return;
+ return (NULL);
smh = kmem_zalloc(sizeof (spa_mmp_history_t), KM_SLEEP);
smh->txg = txg;
smh->timestamp = timestamp;
smh->mmp_delay = mmp_delay;
- smh->vdev_guid = vd->vdev_guid;
- if (vd->vdev_path)
- smh->vdev_path = strdup(vd->vdev_path);
+ if (vd) {
+ smh->vdev_guid = vd->vdev_guid;
+ if (vd->vdev_path)
+ smh->vdev_path = strdup(vd->vdev_path);
+ }
smh->vdev_label = label;
smh->mmp_kstat_id = mmp_kstat_id;
+ if (error) {
+ smh->io_error = error;
+ smh->error_start = gethrtime();
+ smh->vdev_guid = 1;
+ }
+
mutex_enter(&ssh->lock);
list_insert_head(&ssh->list, smh);
}
mutex_exit(&ssh->lock);
+ return ((void *)smh);
}
void
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