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, 119 insertions, 10 deletions

diff --git a/include/jemalloc/internal/ql.h b/include/jemalloc/internal/ql.h
index 802904077161..c7f52f862219 100644
--- a/include/jemalloc/internal/ql.h
+++ b/include/jemalloc/internal/ql.h
@@ -3,37 +3,85 @@
 
 #include "jemalloc/internal/qr.h"
 
+/*
+ * A linked-list implementation.
+ *
+ * This is built on top of the ring implementation, but that can be viewed as an
+ * implementation detail (i.e. trying to advance past the tail of the list
+ * doesn't wrap around).
+ *
+ * You define a struct like so:
+ * typedef strucy my_s my_t;
+ * struct my_s {
+ *   int data;
+ *   ql_elm(my_t) my_link;
+ * };
+ *
+ * // We wobble between "list" and "head" for this type; we're now mostly
+ * // heading towards "list".
+ * typedef ql_head(my_t) my_list_t;
+ *
+ * You then pass a my_list_t * for a_head arguments, a my_t * for a_elm
+ * arguments, the token "my_link" for a_field arguments, and the token "my_t"
+ * for a_type arguments.
+ */
+
 /* List definitions. */
 #define ql_head(a_type)							\
 struct {								\
 	a_type *qlh_first;						\
 }
 
+/* Static initializer for an empty list. */
 #define ql_head_initializer(a_head) {NULL}
 
+/* The field definition. */
 #define ql_elm(a_type)	qr(a_type)
 
-/* List functions. */
+/* A pointer to the first element in the list, or NULL if the list is empty. */
+#define ql_first(a_head) ((a_head)->qlh_first)
+
+/* Dynamically initializes a list. */
 #define ql_new(a_head) do {						\
-	(a_head)->qlh_first = NULL;					\
+	ql_first(a_head) = NULL;					\
 } while (0)
 
-#define ql_elm_new(a_elm, a_field) qr_new((a_elm), a_field)
+/*
+ * Sets dest to be the contents of src (overwriting any elements there), leaving
+ * src empty.
+ */
+#define ql_move(a_head_dest, a_head_src) do {				\
+	ql_first(a_head_dest) = ql_first(a_head_src);			\
+	ql_new(a_head_src);						\
+} while (0)
 
-#define ql_first(a_head) ((a_head)->qlh_first)
+/* True if the list is empty, otherwise false. */
+#define ql_empty(a_head) (ql_first(a_head) == NULL)
+
+/*
+ * Initializes a ql_elm.  Must be called even if the field is about to be
+ * overwritten.
+ */
+#define ql_elm_new(a_elm, a_field) qr_new((a_elm), a_field)
 
+/*
+ * Obtains the last item in the list.
+ */
 #define ql_last(a_head, a_field)					\
-	((ql_first(a_head) != NULL)					\
-	    ? qr_prev(ql_first(a_head), a_field) : NULL)
+	(ql_empty(a_head) ? NULL : qr_prev(ql_first(a_head), a_field))
 
+/*
+ * Gets a pointer to the next/prev element in the list.  Trying to advance past
+ * the end or retreat before the beginning of the list returns NULL.
+ */
 #define ql_next(a_head, a_elm, a_field)					\
 	((ql_last(a_head, a_field) != (a_elm))				\
 	    ? qr_next((a_elm), a_field)	: NULL)
-
 #define ql_prev(a_head, a_elm, a_field)					\
 	((ql_first(a_head) != (a_elm)) ? qr_prev((a_elm), a_field)	\
 				       : NULL)
 
+/* Inserts a_elm before a_qlelm in the list. */
 #define ql_before_insert(a_head, a_qlelm, a_elm, a_field) do {		\
 	qr_before_insert((a_qlelm), (a_elm), a_field);			\
 	if (ql_first(a_head) == (a_qlelm)) {				\
@@ -41,23 +89,41 @@ struct {								\
 	}								\
 } while (0)
 
+/* Inserts a_elm after a_qlelm in the list. */
 #define ql_after_insert(a_qlelm, a_elm, a_field)			\
 	qr_after_insert((a_qlelm), (a_elm), a_field)
 
+/* Inserts a_elm as the first item in the list. */
 #define ql_head_insert(a_head, a_elm, a_field) do {			\
-	if (ql_first(a_head) != NULL) {					\
+	if (!ql_empty(a_head)) {					\
 		qr_before_insert(ql_first(a_head), (a_elm), a_field);	\
 	}								\
 	ql_first(a_head) = (a_elm);					\
 } while (0)
 
+/* Inserts a_elm as the last item in the list. */
 #define ql_tail_insert(a_head, a_elm, a_field) do {			\
-	if (ql_first(a_head) != NULL) {					\
+	if (!ql_empty(a_head)) {					\
 		qr_before_insert(ql_first(a_head), (a_elm), a_field);	\
 	}								\
 	ql_first(a_head) = qr_next((a_elm), a_field);			\
 } while (0)
 
+/*
+ * Given lists a = [a_1, ..., a_n] and [b_1, ..., b_n], results in:
+ * a = [a1, ..., a_n, b_1, ..., b_n] and b = [].
+ */
+#define ql_concat(a_head_a, a_head_b, a_field) do {			\
+	if (ql_empty(a_head_a)) {					\
+		ql_move(a_head_a, a_head_b);				\
+	} else if (!ql_empty(a_head_b)) {				\
+		qr_meld(ql_first(a_head_a), ql_first(a_head_b),		\
+		    a_field);						\
+		ql_new(a_head_b);					\
+	}								\
+} while (0)
+
+/* Removes a_elm from the list. */
 #define ql_remove(a_head, a_elm, a_field) do {				\
 	if (ql_first(a_head) == (a_elm)) {				\
 		ql_first(a_head) = qr_next(ql_first(a_head), a_field);	\
@@ -65,20 +131,63 @@ struct {								\
 	if (ql_first(a_head) != (a_elm)) {				\
 		qr_remove((a_elm), a_field);				\
 	} else {							\
-		ql_first(a_head) = NULL;				\
+		ql_new(a_head);						\
 	}								\
 } while (0)
 
+/* Removes the first item in the list. */
 #define ql_head_remove(a_head, a_type, a_field) do {			\
 	a_type *t = ql_first(a_head);					\
 	ql_remove((a_head), t, a_field);				\
 } while (0)
 
+/* Removes the last item in the list. */
 #define ql_tail_remove(a_head, a_type, a_field) do {			\
 	a_type *t = ql_last(a_head, a_field);				\
 	ql_remove((a_head), t, a_field);				\
 } while (0)
 
+/*
+ * Given a = [a_1, a_2, ..., a_n-1, a_n, a_n+1, ...],
+ * ql_split(a, a_n, b, some_field) results in
+ *   a = [a_1, a_2, ..., a_n-1]
+ * and replaces b's contents with:
+ *   b = [a_n, a_n+1, ...]
+ */
+#define ql_split(a_head_a, a_elm, a_head_b, a_field) do {		\
+	if (ql_first(a_head_a) == (a_elm)) {				\
+		ql_move(a_head_b, a_head_a);				\
+	} else {							\
+		qr_split(ql_first(a_head_a), (a_elm), a_field);		\
+		ql_first(a_head_b) = (a_elm);				\
+	}								\
+} while (0)
+
+/*
+ * An optimized version of:
+ *	a_type *t = ql_first(a_head);
+ *	ql_remove((a_head), t, a_field);
+ *	ql_tail_insert((a_head), t, a_field);
+ */
+#define ql_rotate(a_head, a_field) do {					\
+	ql_first(a_head) = qr_next(ql_first(a_head), a_field);		\
+} while (0)
+
+/*
+ * Helper macro to iterate over each element in a list in order, starting from
+ * the head (or in reverse order, starting from the tail).  The usage is
+ * (assuming my_t and my_list_t defined as above).
+ *
+ * int sum(my_list_t *list) {
+ *   int sum = 0;
+ *   my_t *iter;
+ *   ql_foreach(iter, list, link) {
+ *     sum += iter->data;
+ *   }
+ *   return sum;
+ * }
+ */
+
 #define ql_foreach(a_var, a_head, a_field)				\
 	qr_foreach((a_var), ql_first(a_head), a_field)