Rename most remaining *chunk* APIs to *extent*.

src/extent_mmap.c

@@ -0,0 +1,76 @@
+#define	JEMALLOC_EXTENT_MMAP_C_
+#include "jemalloc/internal/jemalloc_internal.h"
+
+/******************************************************************************/
+
+static void *
+extent_alloc_mmap_slow(size_t size, size_t alignment, bool *zero, bool *commit)
+{
+	void *ret;
+	size_t alloc_size;
+
+	alloc_size = size + alignment;
+	/* Beware size_t wrap-around. */
+	if (alloc_size < size)
+		return (NULL);
+	do {
+		void *pages;
+		size_t leadsize;
+		pages = pages_map(NULL, alloc_size, commit);
+		if (pages == NULL)
+			return (NULL);
+		leadsize = ALIGNMENT_CEILING((uintptr_t)pages, alignment) -
+		    (uintptr_t)pages;
+		ret = pages_trim(pages, alloc_size, leadsize, size, commit);
+	} while (ret == NULL);
+
+	assert(ret != NULL);
+	*zero = true;
+	return (ret);
+}
+
+void *
+extent_alloc_mmap(void *new_addr, size_t size, size_t alignment, bool *zero,
+    bool *commit)
+{
+	void *ret;
+	size_t offset;
+
+	/*
+	 * Ideally, there would be a way to specify alignment to mmap() (like
+	 * NetBSD has), but in the absence of such a feature, we have to work
+	 * hard to efficiently create aligned mappings.  The reliable, but
+	 * slow method is to create a mapping that is over-sized, then trim the
+	 * excess.  However, that always results in one or two calls to
+	 * pages_unmap().
+	 *
+	 * Optimistically try mapping precisely the right amount before falling
+	 * back to the slow method, with the expectation that the optimistic
+	 * approach works most of the time.
+	 */
+
+	assert(alignment != 0);
+
+	ret = pages_map(new_addr, size, commit);
+	if (ret == NULL || ret == new_addr)
+		return (ret);
+	assert(new_addr == NULL);
+	offset = ALIGNMENT_ADDR2OFFSET(ret, alignment);
+	if (offset != 0) {
+		pages_unmap(ret, size);
+		return (extent_alloc_mmap_slow(size, alignment, zero, commit));
+	}
+
+	assert(ret != NULL);
+	*zero = true;
+	return (ret);
+}
+
+bool
+extent_dalloc_mmap(void *addr, size_t size)
+{
+
+	if (config_munmap)
+		pages_unmap(addr, size);
+	return (!config_munmap);
+}