Add alignment support to chunk_alloc().

6 files changed, 84 insertions, 135 deletions

diff --git a/src/arena.c b/src/arena.c
index 6444099..c84aaf4 100644
--- a/src/arena.c
+++ b/src/arena.c
@@ -357,7 +357,8 @@ arena_chunk_alloc(arena_t *arena)
 
 		zero = false;
 		malloc_mutex_unlock(&arena->lock);
-		chunk = (arena_chunk_t *)chunk_alloc(chunksize, false, &zero);
+		chunk = (arena_chunk_t *)chunk_alloc(chunksize, chunksize,
+		    false, &zero);
 		malloc_mutex_lock(&arena->lock);
 		if (chunk == NULL)
 			return (NULL);
diff --git a/src/base.c b/src/base.c
index 696c362..bafaa74 100644
--- a/src/base.c
+++ b/src/base.c
@@ -32,7 +32,7 @@ base_pages_alloc(size_t minsize)
 	assert(minsize != 0);
 	csize = CHUNK_CEILING(minsize);
 	zero = false;
-	base_pages = chunk_alloc(csize, true, &zero);
+	base_pages = chunk_alloc(csize, chunksize, true, &zero);
 	if (base_pages == NULL)
 		return (true);
 	base_next_addr = base_pages;
diff --git a/src/chunk.c b/src/chunk.c
index 8fcd61e..797bd34 100644
--- a/src/chunk.c
+++ b/src/chunk.c
@@ -27,19 +27,20 @@ size_t		arena_maxclass; /* Max size class for arenas. */
  * advantage of them if they are returned.
  */
 void *
-chunk_alloc(size_t size, bool base, bool *zero)
+chunk_alloc(size_t size, size_t alignment, bool base, bool *zero)
 {
 	void *ret;
 
 	assert(size != 0);
 	assert((size & chunksize_mask) == 0);
+	assert((alignment & chunksize_mask) == 0);
 
 	if (config_dss) {
-		ret = chunk_alloc_dss(size, zero);
+		ret = chunk_alloc_dss(size, alignment, zero);
 		if (ret != NULL)
 			goto RETURN;
 	}
-	ret = chunk_alloc_mmap(size);
+	ret = chunk_alloc_mmap(size, alignment);
 	if (ret != NULL) {
 		*zero = true;
 		goto RETURN;
diff --git a/src/chunk_dss.c b/src/chunk_dss.c
index 405dc29..a81a271 100644
--- a/src/chunk_dss.c
+++ b/src/chunk_dss.c
@@ -28,41 +28,50 @@ static extent_tree_t	dss_chunks_ad;
 /******************************************************************************/
 /* Function prototypes for non-inline static functions. */
 
-static void	*chunk_recycle_dss(size_t size, bool *zero);
+static void	*chunk_recycle_dss(size_t size, size_t alignment, bool *zero);
 static extent_node_t *chunk_dealloc_dss_record(void *chunk, size_t size);
 
 /******************************************************************************/
 
 static void *
-chunk_recycle_dss(size_t size, bool *zero)
+chunk_recycle_dss(size_t size, size_t alignment, bool *zero)
 {
 	extent_node_t *node, key;
 
 	cassert(config_dss);
 
 	key.addr = NULL;
-	key.size = size;
+	key.size = size + alignment - chunksize;
 	malloc_mutex_lock(&dss_mtx);
 	node = extent_tree_szad_nsearch(&dss_chunks_szad, &key);
 	if (node != NULL) {
-		void *ret = node->addr;
+		size_t offset = (size_t)((uintptr_t)(node->addr) & (alignment -
+		    1));
+		void *ret;
+		if (offset > 0)
+			offset = alignment - offset;
+		ret = (void *)((uintptr_t)(node->addr) + offset);
 
 		/* Remove node from the tree. */
 		extent_tree_szad_remove(&dss_chunks_szad, node);
-		if (node->size == size) {
-			extent_tree_ad_remove(&dss_chunks_ad, node);
-			base_node_dealloc(node);
-		} else {
-			/*
-			 * Insert the remainder of node's address range as a
-			 * smaller chunk.  Its position within dss_chunks_ad
-			 * does not change.
-			 */
-			assert(node->size > size);
-			node->addr = (void *)((uintptr_t)node->addr + size);
-			node->size -= size;
+		extent_tree_ad_remove(&dss_chunks_ad, node);
+		if (offset > 0) {
+			/* Insert the leading space as a smaller chunk. */
+			node->size = offset;
 			extent_tree_szad_insert(&dss_chunks_szad, node);
+			extent_tree_ad_insert(&dss_chunks_ad, node);
 		}
+		if (alignment - chunksize > offset) {
+			if (offset > 0)
+				node = base_node_alloc();
+			/* Insert the trailing space as a smaller chunk. */
+			node->addr = (void *)((uintptr_t)(ret) + size);
+			node->size = alignment - chunksize - offset;
+			extent_tree_szad_insert(&dss_chunks_szad, node);
+			extent_tree_ad_insert(&dss_chunks_ad, node);
+		} else if (offset == 0)
+			base_node_dealloc(node);
+
 		malloc_mutex_unlock(&dss_mtx);
 
 		if (*zero)
@@ -75,13 +84,15 @@ chunk_recycle_dss(size_t size, bool *zero)
 }
 
 void *
-chunk_alloc_dss(size_t size, bool *zero)
+chunk_alloc_dss(size_t size, size_t alignment, bool *zero)
 {
 	void *ret;
 
 	cassert(config_dss);
+	assert(size > 0 && (size & chunksize_mask) == 0);
+	assert(alignment > 0 && (alignment & chunksize_mask) == 0);
 
-	ret = chunk_recycle_dss(size, zero);
+	ret = chunk_recycle_dss(size, alignment, zero);
 	if (ret != NULL)
 		return (ret);
 
@@ -94,6 +105,8 @@ chunk_alloc_dss(size_t size, bool *zero)
 
 	malloc_mutex_lock(&dss_mtx);
 	if (dss_prev != (void *)-1) {
+		size_t gap_size, cpad_size;
+		void *cpad, *dss_next;
 		intptr_t incr;
 
 		/*
@@ -104,25 +117,36 @@ chunk_alloc_dss(size_t size, bool *zero)
 		do {
 			/* Get the current end of the DSS. */
 			dss_max = sbrk(0);
-
 			/*
 			 * Calculate how much padding is necessary to
 			 * chunk-align the end of the DSS.
 			 */
-			incr = (intptr_t)size
-			    - (intptr_t)CHUNK_ADDR2OFFSET(dss_max);
-			if (incr == (intptr_t)size)
-				ret = dss_max;
-			else {
-				ret = (void *)((intptr_t)dss_max + incr);
-				incr += size;
+			gap_size = (chunksize - CHUNK_ADDR2OFFSET(dss_max)) &
+			    chunksize_mask;
+			/*
+			 * Compute how much chunk-aligned pad space (if any) is
+			 * necessary to satisfy alignment.  This space can be
+			 * recycled for later use.
+			 */
+			cpad = (void *)((uintptr_t)dss_max + gap_size);
+			ret = (void *)(((uintptr_t)dss_max + (alignment - 1)) &
+			    ~(alignment - 1));
+			cpad_size = (uintptr_t)ret - (uintptr_t)cpad;
+			dss_next = (void *)((uintptr_t)ret + size);
+			if ((uintptr_t)ret < (uintptr_t)dss_max ||
+			    (uintptr_t)dss_next < (uintptr_t)dss_max) {
+				/* Wrap-around. */
+				malloc_mutex_unlock(&dss_mtx);
+				return (NULL);
 			}
-
+			incr = gap_size + cpad_size + size;
 			dss_prev = sbrk(incr);
 			if (dss_prev == dss_max) {
 				/* Success. */
-				dss_max = (void *)((intptr_t)dss_prev + incr);
+				dss_max = dss_next;
 				malloc_mutex_unlock(&dss_mtx);
+				if (cpad_size != 0)
+					chunk_dealloc_dss(cpad, cpad_size);
 				*zero = true;
 				return (ret);
 			}
diff --git a/src/chunk_mmap.c b/src/chunk_mmap.c
index 3a8105d..37dad20 100644
--- a/src/chunk_mmap.c
+++ b/src/chunk_mmap.c
@@ -17,8 +17,9 @@ malloc_tsd_funcs(JEMALLOC_INLINE, mmap_unaligned, bool, false,
 
 static void	*pages_map(void *addr, size_t size);
 static void	pages_unmap(void *addr, size_t size);
-static void	*chunk_alloc_mmap_slow(size_t size, bool unaligned);
-static void	*chunk_alloc_mmap_internal(size_t size);
+static void	*chunk_alloc_mmap_slow(size_t size, size_t alignment,
+    bool unaligned);
+static void	*chunk_alloc_mmap_internal(size_t size, size_t alignment);
 
 /******************************************************************************/
 
@@ -73,7 +74,7 @@ pages_unmap(void *addr, size_t size)
 }
 
 static void *
-chunk_alloc_mmap_slow(size_t size, bool unaligned)
+chunk_alloc_mmap_slow(size_t size, size_t alignment, bool unaligned)
 {
 	void *ret;
 	size_t offset;
@@ -82,29 +83,26 @@ chunk_alloc_mmap_slow(size_t size, bool unaligned)
 	if (size + chunksize <= size)
 		return (NULL);
 
-	ret = pages_map(NULL, size + chunksize);
+	ret = pages_map(NULL, size + alignment);
 	if (ret == NULL)
 		return (NULL);
 
 	/* Clean up unneeded leading/trailing space. */
-	offset = CHUNK_ADDR2OFFSET(ret);
+	offset = (size_t)((uintptr_t)(ret) & (alignment - 1));
 	if (offset != 0) {
 		/* Note that mmap() returned an unaligned mapping. */
 		unaligned = true;
 
 		/* Leading space. */
-		pages_unmap(ret, chunksize - offset);
+		pages_unmap(ret, alignment - offset);
 
-		ret = (void *)((uintptr_t)ret +
-		    (chunksize - offset));
+		ret = (void *)((uintptr_t)ret + (alignment - offset));
 
 		/* Trailing space. */
-		pages_unmap((void *)((uintptr_t)ret + size),
-		    offset);
+		pages_unmap((void *)((uintptr_t)ret + size), offset);
 	} else {
 		/* Trailing space only. */
-		pages_unmap((void *)((uintptr_t)ret + size),
-		    chunksize);
+		pages_unmap((void *)((uintptr_t)ret + size), alignment);
 	}
 
 	/*
@@ -121,7 +119,7 @@ chunk_alloc_mmap_slow(size_t size, bool unaligned)
 }
 
 static void *
-chunk_alloc_mmap_internal(size_t size)
+chunk_alloc_mmap_internal(size_t size, size_t alignment)
 {
 	void *ret;
 
@@ -160,7 +158,7 @@ chunk_alloc_mmap_internal(size_t size)
 		if (ret == NULL)
 			return (NULL);
 
-		offset = CHUNK_ADDR2OFFSET(ret);
+		offset = (size_t)((uintptr_t)(ret) & (alignment - 1));
 		if (offset != 0) {
 			bool mu = true;
 			mmap_unaligned_tsd_set(&mu);
@@ -172,7 +170,8 @@ chunk_alloc_mmap_internal(size_t size)
 				 * the reliable-but-expensive method.
 				 */
 				pages_unmap(ret, size);
-				ret = chunk_alloc_mmap_slow(size, true);
+				ret = chunk_alloc_mmap_slow(size, alignment,
+				    true);
 			} else {
 				/* Clean up unneeded leading space. */
 				pages_unmap(ret, chunksize - offset);
@@ -181,16 +180,16 @@ chunk_alloc_mmap_internal(size_t size)
 			}
 		}
 	} else
-		ret = chunk_alloc_mmap_slow(size, false);
+		ret = chunk_alloc_mmap_slow(size, alignment, false);
 
 	return (ret);
 }
 
 void *
-chunk_alloc_mmap(size_t size)
+chunk_alloc_mmap(size_t size, size_t alignment)
 {
 
-	return (chunk_alloc_mmap_internal(size));
+	return (chunk_alloc_mmap_internal(size, alignment));
 }
 
 void
diff --git a/src/huge.c b/src/huge.c
index a4e6cc8..43c8f3b 100644
--- a/src/huge.c
+++ b/src/huge.c
@@ -18,6 +18,13 @@ static extent_tree_t	huge;
 void *
 huge_malloc(size_t size, bool zero)
 {
+
+	return (huge_palloc(size, chunksize, zero));
+}
+
+void *
+huge_palloc(size_t size, size_t alignment, bool zero)
+{
 	void *ret;
 	size_t csize;
 	extent_node_t *node;
@@ -35,7 +42,7 @@ huge_malloc(size_t size, bool zero)
 	if (node == NULL)
 		return (NULL);
 
-	ret = chunk_alloc(csize, false, &zero);
+	ret = chunk_alloc(csize, alignment, false, &zero);
 	if (ret == NULL) {
 		base_node_dealloc(node);
 		return (NULL);
@@ -64,89 +71,6 @@ huge_malloc(size_t size, bool zero)
 	return (ret);
 }
 
-/* Only handles large allocations that require more than chunk alignment. */
-void *
-huge_palloc(size_t size, size_t alignment, bool zero)
-{
-	void *ret;
-	size_t alloc_size, chunk_size, offset;
-	extent_node_t *node;
-
-	/*
-	 * This allocation requires alignment that is even larger than chunk
-	 * alignment.  This means that huge_malloc() isn't good enough.
-	 *
-	 * Allocate almost twice as many chunks as are demanded by the size or
-	 * alignment, in order to assure the alignment can be achieved, then
-	 * unmap leading and trailing chunks.
-	 */
-	assert(alignment > chunksize);
-
-	chunk_size = CHUNK_CEILING(size);
-
-	if (size >= alignment)
-		alloc_size = chunk_size + alignment - chunksize;
-	else
-		alloc_size = (alignment << 1) - chunksize;
-
-	/* Allocate an extent node with which to track the chunk. */
-	node = base_node_alloc();
-	if (node == NULL)
-		return (NULL);
-
-	ret = chunk_alloc(alloc_size, false, &zero);
-	if (ret == NULL) {
-		base_node_dealloc(node);
-		return (NULL);
-	}
-
-	offset = (uintptr_t)ret & (alignment - 1);
-	assert((offset & chunksize_mask) == 0);
-	assert(offset < alloc_size);
-	if (offset == 0) {
-		/* Trim trailing space. */
-		chunk_dealloc((void *)((uintptr_t)ret + chunk_size), alloc_size
-		    - chunk_size, true);
-	} else {
-		size_t trailsize;
-
-		/* Trim leading space. */
-		chunk_dealloc(ret, alignment - offset, true);
-
-		ret = (void *)((uintptr_t)ret + (alignment - offset));
-
-		trailsize = alloc_size - (alignment - offset) - chunk_size;
-		if (trailsize != 0) {
-		    /* Trim trailing space. */
-		    assert(trailsize < alloc_size);
-		    chunk_dealloc((void *)((uintptr_t)ret + chunk_size),
-			trailsize, true);
-		}
-	}
-
-	/* Insert node into huge. */
-	node->addr = ret;
-	node->size = chunk_size;
-
-	malloc_mutex_lock(&huge_mtx);
-	extent_tree_ad_insert(&huge, node);
-	if (config_stats) {
-		stats_cactive_add(chunk_size);
-		huge_nmalloc++;
-		huge_allocated += chunk_size;
-	}
-	malloc_mutex_unlock(&huge_mtx);
-
-	if (config_fill && zero == false) {
-		if (opt_junk)
-			memset(ret, 0xa5, chunk_size);
-		else if (opt_zero)
-			memset(ret, 0, chunk_size);
-	}
-
-	return (ret);
-}
-
 void *
 huge_ralloc_no_move(void *ptr, size_t oldsize, size_t size, size_t extra)
 {