jemalloc: Import 5.3.0 54eaed1d8b56b1aa528be3bdd1877e59c56fa90cvendor/jemalloc/5.3.0vendor/jemalloc

Import jemalloc 5.3.0.

This import changes how manage the jemalloc vendor branch (which was
just started anyway). Starting with 5.3.0, we import a clean tree from
the upstream github, removing all the old files that are no longer
upstream, or that we've kept around for some reason. We do this because
we merge from this raw version of jemalloc into the FreeBSD
contrib/jemalloc, then we run autogen stuff, generate all the generated
.h files with gmake, then finally remove much of the generated files in
contrib/jemalloc using an update script.

Sponsored by:		Netflix

1 files changed, 38 insertions, 55 deletions

diff --git a/include/jemalloc/internal/prng.h b/include/jemalloc/internal/prng.h
index 15cc2d18fa4d..14542aa12d46 100644
--- a/include/jemalloc/internal/prng.h
+++ b/include/jemalloc/internal/prng.h
@@ -1,7 +1,6 @@
 #ifndef JEMALLOC_INTERNAL_PRNG_H
 #define JEMALLOC_INTERNAL_PRNG_H
 
-#include "jemalloc/internal/atomic.h"
 #include "jemalloc/internal/bit_util.h"
 
 /*
@@ -59,66 +58,38 @@ prng_state_next_zu(size_t state) {
 
 /*
  * The prng_lg_range functions give a uniform int in the half-open range [0,
- * 2**lg_range).  If atomic is true, they do so safely from multiple threads.
- * Multithreaded 64-bit prngs aren't supported.
+ * 2**lg_range).
  */
 
 JEMALLOC_ALWAYS_INLINE uint32_t
-prng_lg_range_u32(atomic_u32_t *state, unsigned lg_range, bool atomic) {
-	uint32_t ret, state0, state1;
-
+prng_lg_range_u32(uint32_t *state, unsigned lg_range) {
 	assert(lg_range > 0);
 	assert(lg_range <= 32);
 
-	state0 = atomic_load_u32(state, ATOMIC_RELAXED);
-
-	if (atomic) {
-		do {
-			state1 = prng_state_next_u32(state0);
-		} while (!atomic_compare_exchange_weak_u32(state, &state0,
-		    state1, ATOMIC_RELAXED, ATOMIC_RELAXED));
-	} else {
-		state1 = prng_state_next_u32(state0);
-		atomic_store_u32(state, state1, ATOMIC_RELAXED);
-	}
-	ret = state1 >> (32 - lg_range);
+	*state = prng_state_next_u32(*state);
+	uint32_t ret = *state >> (32 - lg_range);
 
 	return ret;
 }
 
 JEMALLOC_ALWAYS_INLINE uint64_t
 prng_lg_range_u64(uint64_t *state, unsigned lg_range) {
-	uint64_t ret, state1;
-
 	assert(lg_range > 0);
 	assert(lg_range <= 64);
 
-	state1 = prng_state_next_u64(*state);
-	*state = state1;
-	ret = state1 >> (64 - lg_range);
+	*state = prng_state_next_u64(*state);
+	uint64_t ret = *state >> (64 - lg_range);
 
 	return ret;
 }
 
 JEMALLOC_ALWAYS_INLINE size_t
-prng_lg_range_zu(atomic_zu_t *state, unsigned lg_range, bool atomic) {
-	size_t ret, state0, state1;
-
+prng_lg_range_zu(size_t *state, unsigned lg_range) {
 	assert(lg_range > 0);
 	assert(lg_range <= ZU(1) << (3 + LG_SIZEOF_PTR));
 
-	state0 = atomic_load_zu(state, ATOMIC_RELAXED);
-
-	if (atomic) {
-		do {
-			state1 = prng_state_next_zu(state0);
-		} while (atomic_compare_exchange_weak_zu(state, &state0,
-		    state1, ATOMIC_RELAXED, ATOMIC_RELAXED));
-	} else {
-		state1 = prng_state_next_zu(state0);
-		atomic_store_zu(state, state1, ATOMIC_RELAXED);
-	}
-	ret = state1 >> ((ZU(1) << (3 + LG_SIZEOF_PTR)) - lg_range);
+	*state = prng_state_next_zu(*state);
+	size_t ret = *state >> ((ZU(1) << (3 + LG_SIZEOF_PTR)) - lg_range);
 
 	return ret;
 }
@@ -129,18 +100,24 @@ prng_lg_range_zu(atomic_zu_t *state, unsigned lg_range, bool atomic) {
  */
 
 JEMALLOC_ALWAYS_INLINE uint32_t
-prng_range_u32(atomic_u32_t *state, uint32_t range, bool atomic) {
-	uint32_t ret;
-	unsigned lg_range;
-
-	assert(range > 1);
+prng_range_u32(uint32_t *state, uint32_t range) {
+	assert(range != 0);
+	/*
+	 * If range were 1, lg_range would be 0, so the shift in
+	 * prng_lg_range_u32 would be a shift of a 32-bit variable by 32 bits,
+	 * which is UB.  Just handle this case as a one-off.
+	 */
+	if (range == 1) {
+		return 0;
+	}
 
 	/* Compute the ceiling of lg(range). */
-	lg_range = ffs_u32(pow2_ceil_u32(range)) - 1;
+	unsigned lg_range = ffs_u32(pow2_ceil_u32(range));
 
 	/* Generate a result in [0..range) via repeated trial. */
+	uint32_t ret;
 	do {
-		ret = prng_lg_range_u32(state, lg_range, atomic);
+		ret = prng_lg_range_u32(state, lg_range);
 	} while (ret >= range);
 
 	return ret;
@@ -148,15 +125,18 @@ prng_range_u32(atomic_u32_t *state, uint32_t range, bool atomic) {
 
 JEMALLOC_ALWAYS_INLINE uint64_t
 prng_range_u64(uint64_t *state, uint64_t range) {
-	uint64_t ret;
-	unsigned lg_range;
+	assert(range != 0);
 
-	assert(range > 1);
+	/* See the note in prng_range_u32. */
+	if (range == 1) {
+		return 0;
+	}
 
 	/* Compute the ceiling of lg(range). */
-	lg_range = ffs_u64(pow2_ceil_u64(range)) - 1;
+	unsigned lg_range = ffs_u64(pow2_ceil_u64(range));
 
 	/* Generate a result in [0..range) via repeated trial. */
+	uint64_t ret;
 	do {
 		ret = prng_lg_range_u64(state, lg_range);
 	} while (ret >= range);
@@ -165,18 +145,21 @@ prng_range_u64(uint64_t *state, uint64_t range) {
 }
 
 JEMALLOC_ALWAYS_INLINE size_t
-prng_range_zu(atomic_zu_t *state, size_t range, bool atomic) {
-	size_t ret;
-	unsigned lg_range;
+prng_range_zu(size_t *state, size_t range) {
+	assert(range != 0);
 
-	assert(range > 1);
+	/* See the note in prng_range_u32. */
+	if (range == 1) {
+		return 0;
+	}
 
 	/* Compute the ceiling of lg(range). */
-	lg_range = ffs_u64(pow2_ceil_u64(range)) - 1;
+	unsigned lg_range = ffs_u64(pow2_ceil_u64(range));
 
 	/* Generate a result in [0..range) via repeated trial. */
+	size_t ret;
 	do {
-		ret = prng_lg_range_zu(state, lg_range, atomic);
+		ret = prng_lg_range_zu(state, lg_range);
 	} while (ret >= range);
 
 	return ret;