From f77cec311e102a46a58402570b43aa74dc5d7ae7 Mon Sep 17 00:00:00 2001
From: David Goldblatt <davidgoldblatt@fb.com>
Date: Tue, 10 Mar 2020 08:52:58 -0700
Subject: [PATCH] Decay: Take current time as an argument.

This better facilitates testing.
---
 include/jemalloc/internal/decay.h |  4 ++--
 src/arena.c                       | 11 ++++++++---
 src/decay.c                       |  8 ++++----
 3 files changed, 14 insertions(+), 9 deletions(-)

diff --git a/include/jemalloc/internal/decay.h b/include/jemalloc/internal/decay.h
index 6a260fca..df396658 100644
--- a/include/jemalloc/internal/decay.h
+++ b/include/jemalloc/internal/decay.h
@@ -133,14 +133,14 @@ bool decay_ms_valid(ssize_t decay_ms);
  *
  * Returns true on error.
  */
-bool decay_init(decay_t *decay, ssize_t decay_ms);
+bool decay_init(decay_t *decay, nstime_t *cur_time, ssize_t decay_ms);
 
 /*
  * Given an already-initialized decay_t, reinitialize it with the given decay
  * time.  The decay_t must have previously been initialized (and should not then
  * be zeroed).
  */
-void decay_reinit(decay_t *decay, ssize_t decay_ms);
+void decay_reinit(decay_t *decay, nstime_t *cur_time, ssize_t decay_ms);
 
 /* Returns true if the epoch advanced and there are pages to purge. */
 bool decay_maybe_advance_epoch(decay_t *decay, nstime_t *new_time,
diff --git a/src/arena.c b/src/arena.c
index 055b36f1..16be6b1e 100644
--- a/src/arena.c
+++ b/src/arena.c
@@ -619,7 +619,9 @@ arena_decay_ms_set(tsdn_t *tsdn, arena_t *arena, decay_t *decay,
 	 * infrequent, either between the {-1, 0, >0} states, or a one-time
 	 * arbitrary change during initial arena configuration.
 	 */
-	decay_reinit(decay, decay_ms);
+	nstime_t cur_time;
+	nstime_init_update(&cur_time);
+	decay_reinit(decay, &cur_time, decay_ms);
 	arena_maybe_decay(tsdn, arena, decay, decay_stats, ecache, false);
 	malloc_mutex_unlock(tsdn, &decay->mtx);
 
@@ -1846,11 +1848,14 @@ arena_new(tsdn_t *tsdn, unsigned ind, extent_hooks_t *extent_hooks) {
 		goto label_error;
 	}
 
-	if (decay_init(&arena->pa_shard.decay_dirty,
+	nstime_t cur_time;
+	nstime_init_update(&cur_time);
+
+	if (decay_init(&arena->pa_shard.decay_dirty, &cur_time,
 	    arena_dirty_decay_ms_default_get())) {
 		goto label_error;
 	}
-	if (decay_init(&arena->pa_shard.decay_muzzy,
+	if (decay_init(&arena->pa_shard.decay_muzzy, &cur_time,
 	    arena_muzzy_decay_ms_default_get())) {
 		goto label_error;
 	}
diff --git a/src/decay.c b/src/decay.c
index 462b9bfe..23d59da9 100644
--- a/src/decay.c
+++ b/src/decay.c
@@ -21,7 +21,7 @@ decay_deadline_init(decay_t *decay) {
 }
 
 void
-decay_reinit(decay_t *decay, ssize_t decay_ms) {
+decay_reinit(decay_t *decay, nstime_t *cur_time, ssize_t decay_ms) {
 	atomic_store_zd(&decay->time_ms, decay_ms, ATOMIC_RELAXED);
 	if (decay_ms > 0) {
 		nstime_init(&decay->interval, (uint64_t)decay_ms *
@@ -29,7 +29,7 @@ decay_reinit(decay_t *decay, ssize_t decay_ms) {
 		nstime_idivide(&decay->interval, SMOOTHSTEP_NSTEPS);
 	}
 
-	nstime_init_update(&decay->epoch);
+	nstime_copy(&decay->epoch, cur_time);
 	decay->jitter_state = (uint64_t)(uintptr_t)decay;
 	decay_deadline_init(decay);
 	decay->nunpurged = 0;
@@ -37,7 +37,7 @@ decay_reinit(decay_t *decay, ssize_t decay_ms) {
 }
 
 bool
-decay_init(decay_t *decay, ssize_t decay_ms) {
+decay_init(decay_t *decay, nstime_t *cur_time, ssize_t decay_ms) {
 	if (config_debug) {
 		for (size_t i = 0; i < sizeof(decay_t); i++) {
 			assert(((char *)decay)[i] == 0);
@@ -49,7 +49,7 @@ decay_init(decay_t *decay, ssize_t decay_ms) {
 		return true;
 	}
 	decay->purging = false;
-	decay_reinit(decay, decay_ms);
+	decay_reinit(decay, cur_time, decay_ms);
 	return false;
 }