From 66e07f986d77e0b16fd236bbe3518790717d1a4d Mon Sep 17 00:00:00 2001
From: Yinan Zhang <zyn8950@gmail.com>
Date: Thu, 3 Oct 2019 13:01:12 -0700
Subject: [PATCH] Suppress tdata creation in reentrancy

This change suppresses tdata initialization and prof sample threshold
update in interrupting malloc calls.  Interrupting calls have no need
for tdata.  Delaying tdata creation aligns better with our lazy tdata
creation principle, and it also helps us gain control back from
interrupting calls more quickly and reduces any risk of delegating
tdata creation to an interrupting call.
---
 include/jemalloc/internal/prof_inlines_b.h | 10 ++++++----
 src/prof.c                                 | 17 +++++++++++++++--
 src/prof_data.c                            |  2 ++
 3 files changed, 23 insertions(+), 6 deletions(-)

diff --git a/include/jemalloc/internal/prof_inlines_b.h b/include/jemalloc/internal/prof_inlines_b.h
index 860dfbee..c750a25b 100644
--- a/include/jemalloc/internal/prof_inlines_b.h
+++ b/include/jemalloc/internal/prof_inlines_b.h
@@ -22,6 +22,7 @@ prof_tdata_get(tsd_t *tsd, bool create) {
 
 	tdata = tsd_prof_tdata_get(tsd);
 	if (create) {
+		assert(tsd_reentrancy_level_get(tsd) == 0);
 		if (unlikely(tdata == NULL)) {
 			if (tsd_nominal(tsd)) {
 				tdata = prof_tdata_init(tsd);
@@ -109,7 +110,11 @@ prof_sample_accum_update(tsd_t *tsd, size_t usize, bool update,
 		return true;
 	}
 
-	bool booted = tsd_prof_tdata_get(tsd);
+	if (tsd_reentrancy_level_get(tsd) > 0) {
+		return true;
+	}
+
+	bool booted = prof_tdata_get(tsd, false);
 	tdata = prof_tdata_get(tsd, true);
 	if (unlikely((uintptr_t)tdata <= (uintptr_t)PROF_TDATA_STATE_MAX)) {
 		tdata = NULL;
@@ -132,9 +137,6 @@ prof_sample_accum_update(tsd_t *tsd, size_t usize, bool update,
 		return true;
 	}
 
-	if (tsd_reentrancy_level_get(tsd) > 0) {
-		return true;
-	}
 	/* Compute new sample threshold. */
 	if (update) {
 		prof_sample_threshold_update(tdata);
diff --git a/src/prof.c b/src/prof.c
index e00151d3..a702cc2b 100644
--- a/src/prof.c
+++ b/src/prof.c
@@ -127,10 +127,15 @@ prof_tctx_should_destroy(tsdn_t *tsdn, prof_tctx_t *tctx) {
 
 void
 prof_alloc_rollback(tsd_t *tsd, prof_tctx_t *tctx, bool updated) {
-	prof_tdata_t *tdata;
-
 	cassert(config_prof);
 
+	if (tsd_reentrancy_level_get(tsd) > 0) {
+		assert((uintptr_t)tctx == (uintptr_t)1U);
+		return;
+	}
+
+	prof_tdata_t *tdata;
+
 	if (updated) {
 		/*
 		 * Compute a new sample threshold.  This isn't very important in
@@ -810,6 +815,8 @@ prof_active_set(tsdn_t *tsdn, bool active) {
 
 const char *
 prof_thread_name_get(tsd_t *tsd) {
+	assert(tsd_reentrancy_level_get(tsd) == 0);
+
 	prof_tdata_t *tdata;
 
 	tdata = prof_tdata_get(tsd, true);
@@ -821,6 +828,8 @@ prof_thread_name_get(tsd_t *tsd) {
 
 int
 prof_thread_name_set(tsd_t *tsd, const char *thread_name) {
+	assert(tsd_reentrancy_level_get(tsd) == 0);
+
 	prof_tdata_t *tdata;
 	unsigned i;
 	char *s;
@@ -859,6 +868,8 @@ prof_thread_name_set(tsd_t *tsd, const char *thread_name) {
 
 bool
 prof_thread_active_get(tsd_t *tsd) {
+	assert(tsd_reentrancy_level_get(tsd) == 0);
+
 	prof_tdata_t *tdata;
 
 	tdata = prof_tdata_get(tsd, true);
@@ -870,6 +881,8 @@ prof_thread_active_get(tsd_t *tsd) {
 
 bool
 prof_thread_active_set(tsd_t *tsd, bool active) {
+	assert(tsd_reentrancy_level_get(tsd) == 0);
+
 	prof_tdata_t *tdata;
 
 	tdata = prof_tdata_get(tsd, true);
diff --git a/src/prof_data.c b/src/prof_data.c
index bab8e5c0..cd92ee61 100644
--- a/src/prof_data.c
+++ b/src/prof_data.c
@@ -1199,6 +1199,8 @@ prof_bt_keycomp(const void *k1, const void *k2) {
 prof_tdata_t *
 prof_tdata_init_impl(tsd_t *tsd, uint64_t thr_uid, uint64_t thr_discrim,
     char *thread_name, bool active) {
+	assert(tsd_reentrancy_level_get(tsd) == 0);
+
 	prof_tdata_t *tdata;
 
 	cassert(config_prof);