From fa2d64c94b07ee21a0f6f44b9fe6e3bbefa51c6c Mon Sep 17 00:00:00 2001
From: Jason Evans <jasone@canonware.com>
Date: Sun, 12 Feb 2017 17:03:46 -0800
Subject: [PATCH] Convert arena->prof_accumbytes synchronization to atomics.

---
 include/jemalloc/internal/arena_inlines_a.h   | 34 +--------
 include/jemalloc/internal/arena_structs_b.h   |  3 +-
 include/jemalloc/internal/atomic_inlines.h    |  4 +-
 include/jemalloc/internal/atomic_types.h      |  8 ++
 .../jemalloc/internal/jemalloc_internal.h.in  |  7 +-
 include/jemalloc/internal/private_symbols.txt |  5 +-
 include/jemalloc/internal/prof_externs.h      |  1 +
 include/jemalloc/internal/prof_inlines_a.h    | 76 +++++++++++++++++++
 .../{prof_inlines.h => prof_inlines_b.h}      |  6 +-
 include/jemalloc/internal/prof_structs.h      |  7 ++
 include/jemalloc/internal/prof_types.h        |  1 +
 include/jemalloc/internal/witness_types.h     |  1 +
 src/arena.c                                   | 18 +----
 src/prof.c                                    | 14 ++++
 src/tcache.c                                  |  2 +-
 15 files changed, 128 insertions(+), 59 deletions(-)
 create mode 100644 include/jemalloc/internal/atomic_types.h
 create mode 100644 include/jemalloc/internal/prof_inlines_a.h
 rename include/jemalloc/internal/{prof_inlines.h => prof_inlines_b.h} (98%)

diff --git a/include/jemalloc/internal/arena_inlines_a.h b/include/jemalloc/internal/arena_inlines_a.h
index a81aaf56..ea7e0995 100644
--- a/include/jemalloc/internal/arena_inlines_a.h
+++ b/include/jemalloc/internal/arena_inlines_a.h
@@ -6,8 +6,6 @@ unsigned	arena_ind_get(const arena_t *arena);
 void	arena_internal_add(arena_t *arena, size_t size);
 void	arena_internal_sub(arena_t *arena, size_t size);
 size_t	arena_internal_get(arena_t *arena);
-bool	arena_prof_accum_impl(arena_t *arena, uint64_t accumbytes);
-bool	arena_prof_accum_locked(arena_t *arena, uint64_t accumbytes);
 bool	arena_prof_accum(tsdn_t *tsdn, arena_t *arena, uint64_t accumbytes);
 #endif /* JEMALLOC_ENABLE_INLINE */
 
@@ -33,29 +31,6 @@ arena_internal_get(arena_t *arena) {
 	return atomic_read_zu(&arena->stats.internal);
 }
 
-JEMALLOC_INLINE bool
-arena_prof_accum_impl(arena_t *arena, uint64_t accumbytes) {
-	cassert(config_prof);
-	assert(prof_interval != 0);
-
-	arena->prof_accumbytes += accumbytes;
-	if (arena->prof_accumbytes >= prof_interval) {
-		arena->prof_accumbytes %= prof_interval;
-		return true;
-	}
-	return false;
-}
-
-JEMALLOC_INLINE bool
-arena_prof_accum_locked(arena_t *arena, uint64_t accumbytes) {
-	cassert(config_prof);
-
-	if (likely(prof_interval == 0)) {
-		return false;
-	}
-	return arena_prof_accum_impl(arena, accumbytes);
-}
-
 JEMALLOC_INLINE bool
 arena_prof_accum(tsdn_t *tsdn, arena_t *arena, uint64_t accumbytes) {
 	cassert(config_prof);
@@ -64,14 +39,7 @@ arena_prof_accum(tsdn_t *tsdn, arena_t *arena, uint64_t accumbytes) {
 		return false;
 	}
 
-	{
-		bool ret;
-
-		malloc_mutex_lock(tsdn, &arena->lock);
-		ret = arena_prof_accum_impl(arena, accumbytes);
-		malloc_mutex_unlock(tsdn, &arena->lock);
-		return ret;
-	}
+	return prof_accum_add(tsdn, &arena->prof_accum, accumbytes);
 }
 
 #endif /* (defined(JEMALLOC_ENABLE_INLINE) || defined(JEMALLOC_ARENA_C_)) */
diff --git a/include/jemalloc/internal/arena_structs_b.h b/include/jemalloc/internal/arena_structs_b.h
index dde26894..2ee5690e 100644
--- a/include/jemalloc/internal/arena_structs_b.h
+++ b/include/jemalloc/internal/arena_structs_b.h
@@ -138,7 +138,8 @@ struct arena_s {
 	 */
 	ql_head(tcache_t)	tcache_ql;
 
-	/* Synchronization: lock. */
+	/* Synchronization: internal. */
+	prof_accum_t		prof_accum;
 	uint64_t		prof_accumbytes;
 
 	/*
diff --git a/include/jemalloc/internal/atomic_inlines.h b/include/jemalloc/internal/atomic_inlines.h
index 7c1902f8..de66d57d 100644
--- a/include/jemalloc/internal/atomic_inlines.h
+++ b/include/jemalloc/internal/atomic_inlines.h
@@ -23,7 +23,7 @@
  */
 
 #ifndef JEMALLOC_ENABLE_INLINE
-#  if (LG_SIZEOF_PTR == 3 || LG_SIZEOF_INT == 3)
+#  ifdef JEMALLOC_ATOMIC_U64
 uint64_t	atomic_add_u64(uint64_t *p, uint64_t x);
 uint64_t	atomic_sub_u64(uint64_t *p, uint64_t x);
 bool	atomic_cas_u64(uint64_t *p, uint64_t c, uint64_t s);
@@ -50,7 +50,7 @@ void	atomic_write_u(unsigned *p, unsigned x);
 #if (defined(JEMALLOC_ENABLE_INLINE) || defined(JEMALLOC_ATOMIC_C_))
 /******************************************************************************/
 /* 64-bit operations. */
-#if (LG_SIZEOF_PTR == 3 || LG_SIZEOF_INT == 3)
+#ifdef JEMALLOC_ATOMIC_U64
 #  if (defined(__amd64__) || defined(__x86_64__))
 JEMALLOC_INLINE uint64_t
 atomic_add_u64(uint64_t *p, uint64_t x) {
diff --git a/include/jemalloc/internal/atomic_types.h b/include/jemalloc/internal/atomic_types.h
new file mode 100644
index 00000000..0fd5e5b5
--- /dev/null
+++ b/include/jemalloc/internal/atomic_types.h
@@ -0,0 +1,8 @@
+#ifndef JEMALLOC_INTERNAL_ATOMIC_TYPES_H
+#define JEMALLOC_INTERNAL_ATOMIC_TYPES_H
+
+#if (LG_SIZEOF_PTR == 3 || LG_SIZEOF_INT == 3)
+#  define JEMALLOC_ATOMIC_U64
+#endif
+
+#endif /* JEMALLOC_INTERNAL_ATOMIC_TYPES_H */
diff --git a/include/jemalloc/internal/jemalloc_internal.h.in b/include/jemalloc/internal/jemalloc_internal.h.in
index bace9c46..7e9c24b7 100644
--- a/include/jemalloc/internal/jemalloc_internal.h.in
+++ b/include/jemalloc/internal/jemalloc_internal.h.in
@@ -380,6 +380,7 @@ typedef unsigned szind_t;
 
 #include "jemalloc/internal/nstime_types.h"
 #include "jemalloc/internal/util_types.h"
+#include "jemalloc/internal/atomic_types.h"
 #include "jemalloc/internal/spin_types.h"
 #include "jemalloc/internal/prng_types.h"
 #include "jemalloc/internal/ticker_types.h"
@@ -419,10 +420,10 @@ typedef unsigned szind_t;
 #include "jemalloc/internal/extent_structs.h"
 #include "jemalloc/internal/extent_dss_structs.h"
 #include "jemalloc/internal/base_structs.h"
+#include "jemalloc/internal/prof_structs.h"
 #include "jemalloc/internal/arena_structs_b.h"
 #include "jemalloc/internal/rtree_structs.h"
 #include "jemalloc/internal/tcache_structs.h"
-#include "jemalloc/internal/prof_structs.h"
 #include "jemalloc/internal/tsd_structs.h"
 
 
@@ -902,6 +903,7 @@ decay_ticker_get(tsd_t *tsd, unsigned ind) {
  * Include portions of arena code interleaved with tcache code in order to
  * resolve circular dependencies.
  */
+#include "jemalloc/internal/prof_inlines_a.h"
 #include "jemalloc/internal/arena_inlines_a.h"
 
 #ifndef JEMALLOC_ENABLE_INLINE
@@ -1163,8 +1165,7 @@ ixalloc(tsdn_t *tsdn, extent_t *extent, void *ptr, size_t oldsize, size_t size,
 }
 #endif
 
-#include "jemalloc/internal/prof_inlines.h"
-
+#include "jemalloc/internal/prof_inlines_b.h"
 
 #ifdef __cplusplus
 }
diff --git a/include/jemalloc/internal/private_symbols.txt b/include/jemalloc/internal/private_symbols.txt
index ab5a672c..4e799915 100644
--- a/include/jemalloc/internal/private_symbols.txt
+++ b/include/jemalloc/internal/private_symbols.txt
@@ -54,8 +54,6 @@ arena_prefork1
 arena_prefork2
 arena_prefork3
 arena_prof_accum
-arena_prof_accum_impl
-arena_prof_accum_locked
 arena_prof_promote
 arena_prof_tctx_get
 arena_prof_tctx_reset
@@ -364,6 +362,9 @@ prng_range_zu
 prng_state_next_u32
 prng_state_next_u64
 prng_state_next_zu
+prof_accum_add
+prof_accum_cancel
+prof_accum_init
 prof_active
 prof_active_get
 prof_active_get_unlocked
diff --git a/include/jemalloc/internal/prof_externs.h b/include/jemalloc/internal/prof_externs.h
index 76505f82..f3b6f8d3 100644
--- a/include/jemalloc/internal/prof_externs.h
+++ b/include/jemalloc/internal/prof_externs.h
@@ -55,6 +55,7 @@ extern prof_dump_header_t *prof_dump_header;
 void	prof_cnt_all(uint64_t *curobjs, uint64_t *curbytes,
     uint64_t *accumobjs, uint64_t *accumbytes);
 #endif
+bool prof_accum_init(tsdn_t *tsdn, prof_accum_t *prof_accum);
 void	prof_idump(tsdn_t *tsdn);
 bool	prof_mdump(tsd_t *tsd, const char *filename);
 void	prof_gdump(tsdn_t *tsdn);
diff --git a/include/jemalloc/internal/prof_inlines_a.h b/include/jemalloc/internal/prof_inlines_a.h
new file mode 100644
index 00000000..d77635a8
--- /dev/null
+++ b/include/jemalloc/internal/prof_inlines_a.h
@@ -0,0 +1,76 @@
+#ifndef JEMALLOC_INTERNAL_PROF_INLINES_A_H
+#define JEMALLOC_INTERNAL_PROF_INLINES_A_H
+
+#ifndef JEMALLOC_ENABLE_INLINE
+bool prof_accum_add(tsdn_t *tsdn, prof_accum_t *prof_accum,
+    uint64_t accumbytes);
+void prof_accum_cancel(tsdn_t *tsdn, prof_accum_t *prof_accum, size_t usize);
+#endif
+
+#if (defined(JEMALLOC_ENABLE_INLINE) || defined(JEMALLOC_PROF_C_))
+JEMALLOC_INLINE bool
+prof_accum_add(tsdn_t *tsdn, prof_accum_t *prof_accum, uint64_t accumbytes) {
+	cassert(config_prof);
+
+	bool overflow;
+	uint64_t a0, a1;
+
+	/*
+	 * If the application allocates fast enough (and/or if idump is slow
+	 * enough), extreme overflow here (a1 >= prof_interval * 2) can cause
+	 * idump trigger coalescing.  This is an intentional mechanism that
+	 * avoids rate-limiting allocation.
+	 */
+#ifdef JEMALLOC_ATOMIC_U64
+	do {
+		a0 = atomic_read_u64(&prof_accum->accumbytes);
+		a1 = a0 + accumbytes;
+		assert(a1 >= a0);
+		overflow = (a1 >= prof_interval);
+		if (overflow) {
+			a1 %= prof_interval;
+		}
+	} while (atomic_cas_u64(&prof_accum->accumbytes, a0, a1));
+#else
+	malloc_mutex_lock(tsdn, &prof_accum->mtx);
+	a0 = prof_accum->accumbytes;
+	a1 = a0 + accumbytes;
+	overflow = (a1 >= prof_interval);
+	if (overflow) {
+		a1 %= prof_interval;
+	}
+	prof_accum->accumbytes = a1;
+	malloc_mutex_unlock(tsdn, &prof_accum->mtx);
+#endif
+	return overflow;
+}
+
+JEMALLOC_INLINE void
+prof_accum_cancel(tsdn_t *tsdn, prof_accum_t *prof_accum, size_t usize) {
+	cassert(config_prof);
+
+	/*
+	 * Cancel out as much of the excessive prof_accumbytes increase as
+	 * possible without underflowing.  Interval-triggered dumps occur
+	 * slightly more often than intended as a result of incomplete
+	 * canceling.
+	 */
+	uint64_t a0, a1;
+#ifdef JEMALLOC_ATOMIC_U64
+	do {
+		a0 = atomic_read_u64(&prof_accum->accumbytes);
+		a1 = (a0 >= LARGE_MINCLASS - usize) ?  a0 - (LARGE_MINCLASS -
+		    usize) : 0;
+	} while (atomic_cas_u64(&prof_accum->accumbytes, a0, a1));
+#else
+	malloc_mutex_lock(tsdn, &prof_accum->mtx);
+	a0 = prof_accum->accumbytes;
+	a1 = (a0 >= LARGE_MINCLASS - usize) ?  a0 - (LARGE_MINCLASS - usize) :
+	    0;
+	prof_accum->accumbytes = a1;
+	malloc_mutex_unlock(tsdn, &prof_accum->mtx);
+#endif
+}
+#endif
+
+#endif /* JEMALLOC_INTERNAL_PROF_INLINES_A_H */
diff --git a/include/jemalloc/internal/prof_inlines.h b/include/jemalloc/internal/prof_inlines_b.h
similarity index 98%
rename from include/jemalloc/internal/prof_inlines.h
rename to include/jemalloc/internal/prof_inlines_b.h
index aba2936a..9e969a07 100644
--- a/include/jemalloc/internal/prof_inlines.h
+++ b/include/jemalloc/internal/prof_inlines_b.h
@@ -1,5 +1,5 @@
-#ifndef JEMALLOC_INTERNAL_PROF_INLINES_H
-#define JEMALLOC_INTERNAL_PROF_INLINES_H
+#ifndef JEMALLOC_INTERNAL_PROF_INLINES_B_H
+#define JEMALLOC_INTERNAL_PROF_INLINES_B_H
 
 #ifndef JEMALLOC_ENABLE_INLINE
 bool	prof_active_get_unlocked(void);
@@ -237,4 +237,4 @@ prof_free(tsd_t *tsd, const extent_t *extent, const void *ptr, size_t usize) {
 }
 #endif
 
-#endif /* JEMALLOC_INTERNAL_PROF_INLINES_H */
+#endif /* JEMALLOC_INTERNAL_PROF_INLINES_B_H */
diff --git a/include/jemalloc/internal/prof_structs.h b/include/jemalloc/internal/prof_structs.h
index caae1257..afff6aa5 100644
--- a/include/jemalloc/internal/prof_structs.h
+++ b/include/jemalloc/internal/prof_structs.h
@@ -15,6 +15,13 @@ typedef struct {
 } prof_unwind_data_t;
 #endif
 
+struct prof_accum_s {
+#ifndef JEMALLOC_ATOMIC_U64
+	malloc_mutex_t	mtx;
+#endif
+	uint64_t	accumbytes;
+};
+
 struct prof_cnt_s {
 	/* Profiling counters. */
 	uint64_t	curobjs;
diff --git a/include/jemalloc/internal/prof_types.h b/include/jemalloc/internal/prof_types.h
index ff0db65e..1eff995e 100644
--- a/include/jemalloc/internal/prof_types.h
+++ b/include/jemalloc/internal/prof_types.h
@@ -2,6 +2,7 @@
 #define JEMALLOC_INTERNAL_PROF_TYPES_H
 
 typedef struct prof_bt_s prof_bt_t;
+typedef struct prof_accum_s prof_accum_t;
 typedef struct prof_cnt_s prof_cnt_t;
 typedef struct prof_tctx_s prof_tctx_t;
 typedef struct prof_gctx_s prof_gctx_t;
diff --git a/include/jemalloc/internal/witness_types.h b/include/jemalloc/internal/witness_types.h
index 29299168..f919cc5a 100644
--- a/include/jemalloc/internal/witness_types.h
+++ b/include/jemalloc/internal/witness_types.h
@@ -47,6 +47,7 @@ typedef int witness_comp_t (const witness_t *, void *, const witness_t *,
 #define WITNESS_RANK_ARENA_LARGE	WITNESS_RANK_LEAF
 #define WITNESS_RANK_DSS		WITNESS_RANK_LEAF
 #define WITNESS_RANK_PROF_ACTIVE	WITNESS_RANK_LEAF
+#define WITNESS_RANK_PROF_ACCUM		WITNESS_RANK_LEAF
 #define WITNESS_RANK_PROF_DUMP_SEQ	WITNESS_RANK_LEAF
 #define WITNESS_RANK_PROF_GDUMP		WITNESS_RANK_LEAF
 #define WITNESS_RANK_PROF_NEXT_THR_UID	WITNESS_RANK_LEAF
diff --git a/src/arena.c b/src/arena.c
index 345c57df..40db9d1d 100644
--- a/src/arena.c
+++ b/src/arena.c
@@ -1148,19 +1148,7 @@ arena_prof_promote(tsdn_t *tsdn, extent_t *extent, const void *ptr,
 
 	extent_usize_set(extent, usize);
 
-	/*
-	 * Cancel out as much of the excessive prof_accumbytes increase as
-	 * possible without underflowing.  Interval-triggered dumps occur
-	 * slightly more often than intended as a result of incomplete
-	 * canceling.
-	 */
-	malloc_mutex_lock(tsdn, &arena->lock);
-	if (arena->prof_accumbytes >= LARGE_MINCLASS - usize) {
-		arena->prof_accumbytes -= LARGE_MINCLASS - usize;
-	} else {
-		arena->prof_accumbytes = 0;
-	}
-	malloc_mutex_unlock(tsdn, &arena->lock);
+	prof_accum_cancel(tsdn, &arena->prof_accum, usize);
 
 	assert(isalloc(tsdn, extent, ptr) == usize);
 }
@@ -1574,7 +1562,9 @@ arena_new(tsdn_t *tsdn, unsigned ind, extent_hooks_t *extent_hooks) {
 	}
 
 	if (config_prof) {
-		arena->prof_accumbytes = 0;
+		if (prof_accum_init(tsdn, &arena->prof_accum)) {
+			goto label_error;
+		}
 	}
 
 	if (config_cache_oblivious) {
diff --git a/src/prof.c b/src/prof.c
index 5aeefb28..13fa20d3 100644
--- a/src/prof.c
+++ b/src/prof.c
@@ -1753,6 +1753,20 @@ prof_fdump(void) {
 	prof_dump(tsd, false, filename, opt_prof_leak);
 }
 
+bool
+prof_accum_init(tsdn_t *tsdn, prof_accum_t *prof_accum) {
+	cassert(config_prof);
+
+#ifndef JEMALLOC_ATOMIC_U64
+	if (malloc_mutex_init(&prof_accum->mtx, "prof_accum",
+	    WITNESS_RANK_PROF_ACCUM)) {
+		return true;
+	}
+#endif
+	prof_accum->accumbytes = 0;
+	return false;
+}
+
 void
 prof_idump(tsdn_t *tsdn) {
 	tsd_t *tsd;
diff --git a/src/tcache.c b/src/tcache.c
index 94c45707..f38c2d5d 100644
--- a/src/tcache.c
+++ b/src/tcache.c
@@ -200,7 +200,7 @@ tcache_bin_flush_large(tsd_t *tsd, tcache_bin_t *tbin, szind_t binind,
 		}
 		if ((config_prof || config_stats) && locked_arena == arena) {
 			if (config_prof) {
-				idump = arena_prof_accum_locked(arena,
+				idump = arena_prof_accum(tsd_tsdn(tsd), arena,
 				    tcache->prof_accumbytes);
 				tcache->prof_accumbytes = 0;
 			}