Arena stats: Give it its own "mapped".

This distinguishes it from the PA mapped stat, which is now named "pa_mapped" to
avoid confusion. The (derived) arena stat includes base memory, and the PA stat
is no longer partially derived.

include/jemalloc/internal/arena_stats.h

@@ -53,6 +53,7 @@ struct arena_stats_s {
 	size_t			base; /* Derived. */
 	size_t			resident; /* Derived. */
 	size_t			metadata_thp; /* Derived. */
+	size_t			mapped; /* Derived. */
 
 	atomic_zu_t		internal;
 

include/jemalloc/internal/pa.h

@@ -70,12 +70,13 @@ struct pa_shard_stats_s {
 	size_t retained; /* Derived. */
 
 	/*
-	 * Number of bytes currently mapped, excluding retained memory.
+	 * Number of bytes currently mapped, excluding retained memory (and any
+	 * base-allocated memory, which is tracked by the arena stats).
 	 *
-	 * Partially derived -- we maintain our own counter, but add in the
+	 * We name this "pa_mapped" to avoid confusion with the arena_stats
-	 * base's own counter at merge.
+	 * "mapped".
 	 */
-	atomic_zu_t mapped;
+	atomic_zu_t pa_mapped;
 
 	/* Number of edata_t structs allocated by base, but not being used. */
 	size_t edata_avail; /* Derived. */

src/arena.c

@@ -88,10 +88,9 @@ arena_stats_merge(tsdn_t *tsdn, arena_t *arena, unsigned *nthreads,
 	size_t base_allocated, base_resident, base_mapped, metadata_thp;
 	base_stats_get(tsdn, arena->base, &base_allocated, &base_resident,
 	    &base_mapped, &metadata_thp);
-	size_t mapped = atomic_load_zu(&arena->pa_shard.stats->mapped,
+	size_t pa_mapped = atomic_load_zu(&arena->pa_shard.stats->pa_mapped,
 	    ATOMIC_RELAXED);
-	atomic_load_add_store_zu(&astats->pa_shard_stats.mapped,
+	astats->mapped += base_mapped + pa_mapped;
-	    base_mapped + mapped);
 
 	LOCKEDINT_MTX_LOCK(tsdn, arena->stats.mtx);
 

src/ctl.c

@@ -855,9 +855,7 @@ ctl_arena_stats_sdmerge(ctl_arena_t *ctl_sdarena, ctl_arena_t *ctl_arena,
 		ctl_arena_stats_t *astats = ctl_arena->astats;
 
 		if (!destroyed) {
-			ctl_accum_atomic_zu(
+			sdstats->astats.mapped += astats->astats.mapped;
-			    &sdstats->astats.pa_shard_stats.mapped,
-			    &astats->astats.pa_shard_stats.mapped);
 			sdstats->astats.pa_shard_stats.retained
 			    += astats->astats.pa_shard_stats.retained;
 			sdstats->astats.pa_shard_stats.edata_avail
@@ -1085,9 +1083,7 @@ ctl_refresh(tsdn_t *tsdn) {
 		ctl_stats->resident = ctl_sarena->astats->astats.resident;
 		ctl_stats->metadata_thp =
 		    ctl_sarena->astats->astats.metadata_thp;
-		ctl_stats->mapped = atomic_load_zu(
+		ctl_stats->mapped = ctl_sarena->astats->astats.mapped;
-		    &ctl_sarena->astats->astats.pa_shard_stats.mapped,
-		    ATOMIC_RELAXED);
 		ctl_stats->retained =
 		    ctl_sarena->astats->astats.pa_shard_stats.retained;
 
@@ -2898,8 +2894,7 @@ CTL_RO_GEN(stats_arenas_i_pactive, arenas_i(mib[2])->pactive, size_t)
 CTL_RO_GEN(stats_arenas_i_pdirty, arenas_i(mib[2])->pdirty, size_t)
 CTL_RO_GEN(stats_arenas_i_pmuzzy, arenas_i(mib[2])->pmuzzy, size_t)
 CTL_RO_CGEN(config_stats, stats_arenas_i_mapped,
-    atomic_load_zu(&arenas_i(mib[2])->astats->astats.pa_shard_stats.mapped,
+    arenas_i(mib[2])->astats->astats.mapped, size_t)
-    ATOMIC_RELAXED), size_t)
 CTL_RO_CGEN(config_stats, stats_arenas_i_retained,
     arenas_i(mib[2])->astats->astats.pa_shard_stats.retained,
     size_t)

src/extent.c

@@ -967,7 +967,7 @@ extent_maximally_purge(tsdn_t *tsdn, pa_shard_t *shard, ehooks_t *ehooks,
 		    &shard->stats->decay_dirty.purged,
 		    extent_size >> LG_PAGE);
 		LOCKEDINT_MTX_UNLOCK(tsdn, *shard->stats_mtx);
-		atomic_fetch_sub_zu(&shard->stats->mapped, extent_size,
+		atomic_fetch_sub_zu(&shard->stats->pa_mapped, extent_size,
 		    ATOMIC_RELAXED);
 	}
 }

src/pa.c

@@ -101,8 +101,8 @@ pa_alloc(tsdn_t *tsdn, pa_shard_t *shard, size_t size, size_t alignment,
 	if (edata != NULL) {
 		pa_nactive_add(shard, size >> LG_PAGE);
 		if (config_stats && mapped_add > 0) {
-			atomic_fetch_add_zu(&shard->stats->mapped, mapped_add,
+			atomic_fetch_add_zu(&shard->stats->pa_mapped,
-			    ATOMIC_RELAXED);
+			    mapped_add, ATOMIC_RELAXED);
 		}
 	}
 	return edata;
@@ -147,7 +147,7 @@ pa_expand(tsdn_t *tsdn, pa_shard_t *shard, edata_t *edata, size_t old_size,
 		return true;
 	}
 	if (config_stats && mapped_add > 0) {
-		atomic_fetch_add_zu(&shard->stats->mapped, mapped_add,
+		atomic_fetch_add_zu(&shard->stats->pa_mapped, mapped_add,
 		    ATOMIC_RELAXED);
 	}
 	pa_nactive_add(shard, expand_amount >> LG_PAGE);
@@ -270,8 +270,8 @@ pa_decay_stashed(tsdn_t *tsdn, pa_shard_t *shard, decay_t *decay,
 		locked_inc_u64(tsdn, LOCKEDINT_MTX(*shard->stats_mtx),
 		    &decay_stats->purged, npurged);
 		LOCKEDINT_MTX_UNLOCK(tsdn, *shard->stats_mtx);
-		atomic_fetch_sub_zu(&shard->stats->mapped, nunmapped << LG_PAGE,
+		atomic_fetch_sub_zu(&shard->stats->pa_mapped,
-		    ATOMIC_RELAXED);
+		    nunmapped << LG_PAGE, ATOMIC_RELAXED);
 	}
 
 	return npurged;