diff --git a/core/clist.c b/core/clist.c
deleted file mode 100644
index f5da2f73752e0ef5ed3d06483f34aca9d20b7269..0000000000000000000000000000000000000000
--- a/core/clist.c
+++ /dev/null
@@ -1,79 +0,0 @@
-/*
- * Copyright (C) 2013 Freie Universität Berlin
- *
- * This file is subject to the terms and conditions of the GNU Lesser
- * General Public License v2.1. See the file LICENSE in the top level
- * directory for more details.
- */
-
-/**
- * @ingroup core_util
- * @{
- *
- * @file
- * @brief Circular linked list implementation
- *
- * @author Kaspar Schleiser <kaspar@schleiser.de>
- *
- * @}
- */
-
-#include <stddef.h>
-#include "clist.h"
-#include <stdio.h>
-
-/* inserts new_node after node */
-void clist_add(clist_node_t **node, clist_node_t *new_node)
-{
- if (*node != NULL) {
- new_node->next = (*node);
- new_node->prev = (*node)->prev;
- (*node)->prev->next = new_node;
- (*node)->prev = new_node;
-
- if ((*node)->prev == *node) {
- (*node)->prev = new_node;
- }
- }
- else {
- *node = new_node;
- new_node->next = new_node;
- new_node->prev = new_node;
- }
-}
-
-/* removes node. */
-void clist_remove(clist_node_t **list, clist_node_t *node)
-{
- if (node->next != node) {
- node->prev->next = node->next;
- node->next->prev = node->prev;
-
- if (node == *list) {
- *list = node->next;
- }
- }
- else {
- *list = NULL;
- }
-}
-
-#if ENABLE_DEBUG
-void clist_print(clist_node_t *clist)
-{
- clist_node_t *start = clist, *node = start;
- if (!start) {
- return;
- }
-
- do {
- printf("list entry: %p: prev=%p next=%p\n",
- (void *)clist, (void *)clist->prev, (void *)clist->next);
- clist = clist->next;
-
- if (clist == start) {
- break;
- }
- } while (node != start);
-}
-#endif
diff --git a/core/include/clist.h b/core/include/clist.h
index 8ab57e034ce742bcda66e8cbc178ad417f53e72f..beda190a5af640166071a4bbd8e2deb5b762f074 100644
--- a/core/include/clist.h
+++ b/core/include/clist.h
@@ -1,5 +1,6 @@
/*
- * Copyright (C) 2013 Freie Universität Berlin
+ * Copyright (C) 2016 Kaspar Schleiser <kaspar@schleiser.de>
+ * 2013 Freie Universität Berlin
*
* This file is subject to the terms and conditions of the GNU Lesser
* General Public License v2.1. See the file LICENSE in the top level
@@ -13,6 +14,14 @@
* @file
* @brief Circular linked list
*
+ * This file contains a circularly linked list implementation.
+ *
+ * clist_insert(), clist_remove_head() and clist_advance() take constant time.
+ *
+ * Each list is represented as a "clist_node_t". It's only member, the "next"
+ * pointer, points to the last entry in the list, whose "next" pointer points to
+ * the first entry.
+ *
* @author Kaspar Schleiser <kaspar@schleiser.de>
*/
@@ -20,51 +29,67 @@
#define CLIST_H
#include "kernel_defines.h"
+#include "list.h"
#ifdef __cplusplus
extern "C" {
#endif
/**
- * @def clist_get_container(NODE, TYPE, MEMBER)
- * @brief Returns the container of the circular list
- * @details For a struct `TYPE` with a member `MEMBER`, which is a `clist_node_t`,
- * given a pointer `NODE` to `TYPE::MEMBER` this function returns a pointer
- * to the instance of `TYPE`.
- * @details E.g. for `struct my_struct_t { ...; clist_node_t n; ... } my_struct;`,
- * `&my_struct == clist_get_container(&my_struct.n, struct my_struct_t, n)`.
- * @param[in] NODE pointer to a member
- * @param[in] TYPE a type name (a struct or union), container of NODE
- * @param[in] MEMBER name of the member of TYPE which NODE points to
- * @return Pointer to the container of NODE.
- */
-#define clist_get_container(NODE, TYPE, MEMBER) container_of(NODE, TYPE, MEMBER)
-
-/**
- * @brief Structure representing a node in the clist.
+ * @brief List node structure
+ *
+ * Used as is as reference to a list.
+ *
+ * clist stores a pointer to the last element of a list. That way, both
+ * appending to end of list and removing head can be done in constant time.
+ *
+ * Actual list objects should have a @c clist_node_t as member and then use
+ * the container_of() macro in list operations.
+ * See @ref thread_add_to_list() as example.
*/
-typedef struct clist_node_t {
- struct clist_node_t *next; /**< pointer to next node */
- struct clist_node_t *prev; /**< pointer to the previous node */
-} clist_node_t;
+typedef list_node_t clist_node_t;
/**
- * @brief Inserts *new_node* after *node* into list
+ * @brief inserts *new_node* into *list*
*
- * @param[in,out] node Node after which *new_node* gets inserted
- * @param[in,out] new_node Node which gets inserted after *node*.
+ * @param[in,out] list Ptr to clist
+ * @param[in,out] new_node Node which gets inserted.
* Must not be NULL.
*/
-void clist_add(clist_node_t **node, clist_node_t *new_node);
+static inline void clist_insert(clist_node_t *list, clist_node_t *new_node)
+{
+ if (list->next) {
+ new_node->next = list->next->next;
+ list->next->next = new_node;
+ }
+ else {
+ new_node->next = new_node;
+ }
+ list->next = new_node;
+}
/**
- * @brief Removes *node* from list
+ * @brief Removes and returns first element from list
*
- * @param[in,out] list Pointer to the *list* to remove *node* from.
- * @param[in] node Node to remove from *list*
- * Must not be NULL.
+ * @param[in,out] list Pointer to the *list* to remove first element
+ * from.
*/
-void clist_remove(clist_node_t **list, clist_node_t *node);
+static inline clist_node_t *clist_remove_head(clist_node_t *list)
+{
+ if (list->next) {
+ clist_node_t *first = list->next->next;
+ if (list->next == first) {
+ list->next = NULL;
+ }
+ else {
+ list->next->next = first->next;
+ }
+ return first;
+ }
+ else {
+ return NULL;
+ }
+}
/**
* @brief Advances the circle list.
@@ -75,9 +100,11 @@ void clist_remove(clist_node_t **list, clist_node_t *node);
*
* @param[in,out] list The list to work upon.
*/
-static inline void clist_advance(clist_node_t **list)
+static inline void clist_advance(clist_node_t *list)
{
- *list = (*list)->next;
+ if (list->next) {
+ list->next = list->next->next;
+ }
}
#if ENABLE_DEBUG
diff --git a/core/include/sched.h b/core/include/sched.h
index b179a636b7e5dc9df13df06383f1567bd5f38a4b..346f4d66823d73d86db2574e9be70b91cc445f25 100644
--- a/core/include/sched.h
+++ b/core/include/sched.h
@@ -167,7 +167,7 @@ extern volatile kernel_pid_t sched_active_pid;
/**
* List of runqueues per priority level
*/
-extern clist_node_t *sched_runqueues[SCHED_PRIO_LEVELS];
+extern clist_node_t sched_runqueues[SCHED_PRIO_LEVELS];
/**
* @brief Removes thread from scheduler and set status to #STATUS_STOPPED
diff --git a/core/include/thread.h b/core/include/thread.h
index 68ca58fedc71289a337cdad21ab1aab8e0222132..fdcb444a055eb5696ab104299b50aa39ed43ce71 100644
--- a/core/include/thread.h
+++ b/core/include/thread.h
@@ -30,6 +30,7 @@
#include "cpu_conf.h"
#include "sched.h"
#include "list.h"
+#include "clist.h"
#ifdef __cplusplus
extern "C" {
@@ -68,8 +69,8 @@
*/
struct _thread {
char *sp; /**< thread's stack pointer */
- uint8_t status; /**< thread's status */
- uint8_t priority; /**< thread's priority */
+ uint8_t status; /**< thread's status */
+ uint8_t priority; /**< thread's priority */
kernel_pid_t pid; /**< thread's process id */
diff --git a/core/mutex.c b/core/mutex.c
index f97e088eb8d02ea9e818661213744c56baf0c622..8bfae23d282b01a4a22d854920828113a1a12d09 100644
--- a/core/mutex.c
+++ b/core/mutex.c
@@ -89,7 +89,7 @@ void mutex_unlock(mutex_t *mutex)
return;
}
- list_node_t *next = (list_node_t*) list_remove_head(&mutex->queue);
+ list_node_t *next = list_remove_head(&mutex->queue);
thread_t *process = container_of((clist_node_t*)next, thread_t, rq_entry);
diff --git a/core/sched.c b/core/sched.c
index d3fe4e116f795ea303e9b03f5a41b2a0d3dfda2c..151649aad2b300fa3ad13ff2c424a3b9ec9dff1f 100644
--- a/core/sched.c
+++ b/core/sched.c
@@ -50,7 +50,7 @@ volatile thread_t *sched_active_thread;
volatile kernel_pid_t sched_active_pid = KERNEL_PID_UNDEF;
-clist_node_t *sched_runqueues[SCHED_PRIO_LEVELS];
+clist_node_t sched_runqueues[SCHED_PRIO_LEVELS];
static uint32_t runqueue_bitcache = 0;
#ifdef MODULE_SCHEDSTATISTICS
@@ -68,7 +68,7 @@ int sched_run(void)
* since the threading should not be started before at least the idle thread was started.
*/
int nextrq = bitarithm_lsb(runqueue_bitcache);
- thread_t *next_thread = clist_get_container(sched_runqueues[nextrq], thread_t, rq_entry);
+ thread_t *next_thread = container_of(sched_runqueues[nextrq].next->next, thread_t, rq_entry);
DEBUG("sched_run: active thread: %" PRIkernel_pid ", next thread: %" PRIkernel_pid "\n",
(active_thread == NULL) ? KERNEL_PID_UNDEF : active_thread->pid,
@@ -133,7 +133,7 @@ void sched_set_status(thread_t *process, unsigned int status)
if (!(process->status >= STATUS_ON_RUNQUEUE)) {
DEBUG("sched_set_status: adding thread %" PRIkernel_pid " to runqueue %" PRIu16 ".\n",
process->pid, process->priority);
- clist_add(&sched_runqueues[process->priority], &(process->rq_entry));
+ clist_insert(&sched_runqueues[process->priority], &(process->rq_entry));
runqueue_bitcache |= 1 << process->priority;
}
}
@@ -141,9 +141,9 @@ void sched_set_status(thread_t *process, unsigned int status)
if (process->status >= STATUS_ON_RUNQUEUE) {
DEBUG("sched_set_status: removing thread %" PRIkernel_pid " to runqueue %" PRIu16 ".\n",
process->pid, process->priority);
- clist_remove(&sched_runqueues[process->priority], &(process->rq_entry));
+ clist_remove_head(&sched_runqueues[process->priority]);
- if (!sched_runqueues[process->priority]) {
+ if (!sched_runqueues[process->priority].next) {
runqueue_bitcache &= ~(1 << process->priority);
}
}
diff --git a/core/thread.c b/core/thread.c
index a1c1ab56a8a1bfa4541c1745946fe5f3cbcc68f3..1cac0574b7a4f2d4a38b313a739b69d878bfd52a 100644
--- a/core/thread.c
+++ b/core/thread.c
@@ -224,7 +224,6 @@ kernel_pid_t thread_create(char *stack, int stacksize, char priority, int flags,
cb->status = 0;
cb->rq_entry.next = NULL;
- cb->rq_entry.prev = NULL;
cb->wait_data = NULL;