diff --git a/include/jemalloc/internal/hpa_hooks.h b/include/jemalloc/internal/hpa_hooks.h
index 3e21d855..12e6b972 100644
--- a/include/jemalloc/internal/hpa_hooks.h
+++ b/include/jemalloc/internal/hpa_hooks.h
@@ -8,7 +8,7 @@ struct hpa_hooks_s {
 	void (*purge)(void *ptr, size_t size);
 	void (*hugify)(void *ptr, size_t size);
 	void (*dehugify)(void *ptr, size_t size);
-	void (*curtime)(nstime_t *r_time);
+	void (*curtime)(nstime_t *r_time, bool first_reading);
 };
 
 extern hpa_hooks_t hpa_hooks_default;
diff --git a/src/hpa.c b/src/hpa.c
index 5251655c..b2628dbf 100644
--- a/src/hpa.c
+++ b/src/hpa.c
@@ -347,7 +347,7 @@ hpa_update_purge_hugify_eligibility(tsdn_t *tsdn, hpa_shard_t *shard,
 	if (hpa_good_hugification_candidate(shard, ps)
 	    && !hpdata_huge_get(ps)) {
 		nstime_t now;
-		shard->central->hooks.curtime(&now);
+		shard->central->hooks.curtime(&now, /* first_reading */ true);
 		hpdata_allow_hugify(ps, now);
 	}
 	/*
@@ -437,7 +437,8 @@ hpa_try_purge(tsdn_t *tsdn, hpa_shard_t *shard) {
 	shard->npending_purge -= num_to_purge;
 	shard->stats.npurge_passes++;
 	shard->stats.npurges += purges_this_pass;
-	shard->central->hooks.curtime(&shard->last_purge);
+	shard->central->hooks.curtime(&shard->last_purge,
+	    /* first_reading */ false);
 	if (dehugify) {
 		shard->stats.ndehugifies++;
 	}
@@ -477,7 +478,7 @@ hpa_try_hugify(tsdn_t *tsdn, hpa_shard_t *shard) {
 	/* Make sure that it's been hugifiable for long enough. */
 	nstime_t time_hugify_allowed = hpdata_time_hugify_allowed(to_hugify);
 	nstime_t nstime;
-	shard->central->hooks.curtime(&nstime);
+	shard->central->hooks.curtime(&nstime, /* first_reading */ true);
 	nstime_subtract(&nstime, &time_hugify_allowed);
 	uint64_t millis = nstime_msec(&nstime);
 	if (millis < shard->opts.hugify_delay_ms) {
@@ -895,7 +896,8 @@ hpa_time_until_deferred_work(tsdn_t *tsdn, pai_t *self) {
 		nstime_t time_hugify_allowed =
 		    hpdata_time_hugify_allowed(to_hugify);
 		nstime_t nstime;
-		shard->central->hooks.curtime(&nstime);
+		shard->central->hooks.curtime(&nstime,
+		    /* first_reading */ true);
 		nstime_subtract(&nstime, &time_hugify_allowed);
 		uint64_t since_hugify_allowed_ms = nstime_msec(&nstime);
 		/*
@@ -921,7 +923,8 @@ hpa_time_until_deferred_work(tsdn_t *tsdn, pai_t *self) {
 			return BACKGROUND_THREAD_DEFERRED_MIN;
 		}
 		nstime_t nstime;
-		shard->central->hooks.curtime(&nstime);
+		shard->central->hooks.curtime(&nstime,
+		    /* first_reading */ true);
 		nstime_subtract(&nstime, &shard->last_purge);
 		uint64_t since_last_purge_ms = nstime_msec(&nstime);
 
diff --git a/src/hpa_hooks.c b/src/hpa_hooks.c
index 6f377613..116592f2 100644
--- a/src/hpa_hooks.c
+++ b/src/hpa_hooks.c
@@ -8,7 +8,7 @@ static void hpa_hooks_unmap(void *ptr, size_t size);
 static void hpa_hooks_purge(void *ptr, size_t size);
 static void hpa_hooks_hugify(void *ptr, size_t size);
 static void hpa_hooks_dehugify(void *ptr, size_t size);
-static void hpa_hooks_curtime(nstime_t *r_nstime);
+static void hpa_hooks_curtime(nstime_t *r_nstime, bool first_reading);
 
 hpa_hooks_t hpa_hooks_default = {
 	&hpa_hooks_map,
@@ -48,6 +48,9 @@ hpa_hooks_dehugify(void *ptr, size_t size) {
 }
 
 static void
-hpa_hooks_curtime(nstime_t *r_nstime) {
+hpa_hooks_curtime(nstime_t *r_nstime, bool first_reading) {
+	if (first_reading) {
+		nstime_init_zero(r_nstime);
+	}
 	nstime_update(r_nstime);
 }
diff --git a/test/unit/hpa.c b/test/unit/hpa.c
index bda0d46d..a63d51d4 100644
--- a/test/unit/hpa.c
+++ b/test/unit/hpa.c
@@ -349,7 +349,7 @@ defer_test_dehugify(void *ptr, size_t size) {
 
 static nstime_t defer_curtime;
 static void
-defer_test_curtime(nstime_t *r_time) {
+defer_test_curtime(nstime_t *r_time, bool first_reading) {
 	*r_time = defer_curtime;
 }