Disallow decay during reentrancy.

Decay should not be triggered during reentrant calls (may cause lock order
reversal / deadlocks).  Added a delay_trigger flag to the tickers to bypass
decay when rentrancy_level is not zero.

2 files changed, 25 insertions, 11 deletions

diff --git a/include/jemalloc/internal/arena_inlines_b.h b/include/jemalloc/internal/arena_inlines_b.h
index c9d7db86..609e73d3 100644
--- a/include/jemalloc/internal/arena_inlines_b.h
+++ b/include/jemalloc/internal/arena_inlines_b.h
@@ -131,7 +131,8 @@ arena_decay_ticks(tsdn_t *tsdn, arena_t *arena, unsigned nticks) {
 	 */
 	ticker_geom_t *decay_ticker = tsd_arena_decay_tickerp_get(tsd);
 	uint64_t *prng_state = tsd_prng_statep_get(tsd);
-	if (unlikely(ticker_geom_ticks(decay_ticker, prng_state, nticks))) {
+	if (unlikely(ticker_geom_ticks(decay_ticker, prng_state, nticks,
+	    tsd_reentrancy_level_get(tsd) > 0))) {
 		arena_decay(tsdn, arena, false, false);
 	}
 }
diff --git a/include/jemalloc/internal/ticker.h b/include/jemalloc/internal/ticker.h
index 6b51ddec..de034995 100644
--- a/include/jemalloc/internal/ticker.h
+++ b/include/jemalloc/internal/ticker.h
@@ -57,23 +57,27 @@ ticker_read(const ticker_t *ticker) {
 JEMALLOC_NOINLINE
 #endif
 static bool
-ticker_fixup(ticker_t *ticker) {
+ticker_fixup(ticker_t *ticker, bool delay_trigger) {
+	if (delay_trigger) {
+		ticker->tick = 0;
+		return false;
+	}
 	ticker->tick = ticker->nticks;
 	return true;
 }
 
 static inline bool
-ticker_ticks(ticker_t *ticker, int32_t nticks) {
+ticker_ticks(ticker_t *ticker, int32_t nticks, bool delay_trigger) {
 	ticker->tick -= nticks;
 	if (unlikely(ticker->tick < 0)) {
-		return ticker_fixup(ticker);
+		return ticker_fixup(ticker, delay_trigger);
 	}
 	return false;
 }
 
 static inline bool
-ticker_tick(ticker_t *ticker) {
-	return ticker_ticks(ticker, 1);
+ticker_tick(ticker_t *ticker, bool delay_trigger) {
+	return ticker_ticks(ticker, 1, delay_trigger);
 }
 
 /*
@@ -150,26 +154,35 @@ ticker_geom_read(const ticker_geom_t *ticker) {
 JEMALLOC_NOINLINE
 #endif
 static bool
-ticker_geom_fixup(ticker_geom_t *ticker, uint64_t *prng_state) {
+ticker_geom_fixup(ticker_geom_t *ticker, uint64_t *prng_state,
+    bool delay_trigger) {
+	if (delay_trigger) {
+		ticker->tick = 0;
+		return false;
+	}
+
 	uint64_t idx = prng_lg_range_u64(prng_state, TICKER_GEOM_NBITS);
 	ticker->tick = (uint32_t)(
 	    (uint64_t)ticker->nticks * (uint64_t)ticker_geom_table[idx]
 	    / (uint64_t)TICKER_GEOM_MUL);
+
 	return true;
 }
 
 static inline bool
-ticker_geom_ticks(ticker_geom_t *ticker, uint64_t *prng_state, int32_t nticks) {
+ticker_geom_ticks(ticker_geom_t *ticker, uint64_t *prng_state, int32_t nticks,
+    bool delay_trigger) {
 	ticker->tick -= nticks;
 	if (unlikely(ticker->tick < 0)) {
-		return ticker_geom_fixup(ticker, prng_state);
+		return ticker_geom_fixup(ticker, prng_state, delay_trigger);
 	}
 	return false;
 }
 
 static inline bool
-ticker_geom_tick(ticker_geom_t *ticker, uint64_t *prng_state) {
-	return ticker_geom_ticks(ticker, prng_state, 1);
+ticker_geom_tick(ticker_geom_t *ticker, uint64_t *prng_state,
+    bool delay_trigger) {
+	return ticker_geom_ticks(ticker, prng_state, 1, delay_trigger);
 }
 
 #endif /* JEMALLOC_INTERNAL_TICKER_H */