de-prometheus the stats, add more metaclasses

Author: cleverca22

include/sys/spa.h

@@ -900,7 +900,7 @@ typedef struct spa_stats {
 	spa_history_kstat_t	state;		/* pool state */
 	spa_history_kstat_t	guid;		/* pool guid */
 	spa_history_kstat_t	iostats;
-	spa_history_kstat_t	fragmentation;
+	spa_history_kstat_t	fragmentation[5];
 } spa_stats_t;
 
 typedef enum txg_state {

module/zfs/spa_stats.c

@@ -303,67 +303,88 @@ spa_txg_history_init(spa_t *spa)
 	    offsetof(spa_txg_history_t, sth_node));
 }
 
+typedef struct {
+  spa_t *spa;
+  int metaclass;
+} freespace_histogram_stat_t;
+
 static void *
 spa_frag_addr(kstat_t *ksp, loff_t n)
 {
-  if (n == 0)
-    return ksp->ks_private;
+  if (n == 0) {
+    freespace_histogram_stat_t *stat = ksp->ks_private;
+    switch (stat->metaclass) {
+    case 0:
+      return spa_normal_class(stat->spa);
+    case 1:
+      return spa_log_class(stat->spa);
+    case 2:
+      return spa_embedded_log_class(stat->spa);
+    case 3:
+      return spa_special_class(stat->spa);
+    case 4:
+      return spa_dedup_class(stat->spa);
+    }
+  }
   return NULL;
 }
 
 static int
 spa_frag_data(char *buf, size_t size, void *data) {
-  spa_t *spa = (spa_t *)data;
+  metaslab_class_t *mc = data;
   size_t offset = 0;
-  const char *name = spa_name(spa);
+  int res;
+  // without this, it becomes a data-leak, and un-initialized strings can be returned if all buckets are 0
+  buf[0] = 0;
 
-  metaslab_class_t *mc = spa_normal_class(spa);
   for (int i=0; i<RANGE_TREE_HISTOGRAM_SIZE; i++) {
     if (mc->mc_histogram[i] > 0) {
-      int res = snprintf(buf + offset, size, "zfs_fragmentation_normal{power=\"%d\",pool=\"%s\"} %llu\n", i, name, (u_longlong_t)mc->mc_histogram[i]);
+      res = snprintf(buf + offset, size, "%d %llu\n", i, (u_longlong_t)mc->mc_histogram[i]);
       offset += res;
       size -= res;
     }
   }
 
-  metaslab_class_t *smc = spa_special_class(spa);
-  for (int i=0; i<RANGE_TREE_HISTOGRAM_SIZE; i++) {
-    if (smc->mc_histogram[i] > 0) {
-      int res = snprintf(buf + offset, size, "zfs_fragmentation_special{power=\"%d\",pool=\"%s\"} %llu\n", i, name, (u_longlong_t)smc->mc_histogram[i]);
-      offset += res;
-      size -= res;
-    }
-  }
   return 0;
 }
 
 static void
 spa_fragmentation_init(spa_t *spa)
 {
-  char *name;
-  spa_history_kstat_t *shk = &spa->spa_stats.fragmentation;
-  kstat_t *ksp;
-
-  name = kmem_asprintf("zfs/%s", spa_name(spa));
-  ksp = kstat_create(name, 0, "fragmentation", "misc", KSTAT_TYPE_RAW, 0, KSTAT_FLAG_VIRTUAL);
-
-  shk->kstat = ksp;
-  if (ksp) {
-    ksp->ks_private = spa;
-    ksp->ks_flags |= KSTAT_FLAG_NO_HEADERS;
-    kstat_set_raw_ops(ksp, NULL, spa_frag_data, spa_frag_addr);
-    kstat_install(ksp);
+  char *dirname;
+  const char *statnames[] = { "fragmentation_normal", "fragmentation_log", "fragmentation_embedded_log", "fragmentation_special", "fragmentation_dedup" };
+  for (int i=0; i<5; i++) {
+    spa_history_kstat_t *shk = &spa->spa_stats.fragmentation[i];
+    kstat_t *ksp;
+
+    dirname = kmem_asprintf("zfs/%s", spa_name(spa));
+    ksp = kstat_create(dirname, 0, statnames[i], "misc", KSTAT_TYPE_RAW, 0, KSTAT_FLAG_VIRTUAL);
+    kmem_strfree(dirname);
+
+    shk->kstat = ksp;
+    if (ksp) {
+      freespace_histogram_stat_t *stat = kmem_zalloc(sizeof(freespace_histogram_stat_t), KM_SLEEP);
+      stat->spa = spa;
+      stat->metaclass = i;
+      ksp->ks_private = stat;
+      ksp->ks_flags |= KSTAT_FLAG_NO_HEADERS;
+      kstat_set_raw_ops(ksp, NULL, spa_frag_data, spa_frag_addr);
+      kstat_install(ksp);
+    }
   }
-  kmem_strfree(name);
 }
 
 static void
 spa_fragmentation_destroy(spa_t *spa)
 {
-  spa_history_kstat_t *shk = &spa->spa_stats.fragmentation;
-  kstat_t *ksp = shk->kstat;
-  if (ksp)
-    kstat_delete(ksp);
+  for (int i=0; i<5; i++) {
+    spa_history_kstat_t *shk = &spa->spa_stats.fragmentation[i];
+    kstat_t *ksp = shk->kstat;
+    if (ksp) {
+      if (ksp->ks_private) kmem_free(ksp->ks_private, sizeof(freespace_histogram_stat_t));
+      kstat_delete(ksp);
+    }
+  }
 }
 
 static void