We use CIRCQs in timeouts because updating a TAILQ_HEAD pointer
on each timeout in a bucket during hardclock(9) is too costly.
However, that doesn't mean CIRCQs cannot resemble TAILQs. They
perform functionally equivalent jobs and have equivalent macros.
So, this diff:
- CIRCQ_APPEND is really "CIRCQ_CONCAT"
- CIRCQ_INSERT is really "CIRCQ_INSERT_TAIL"
- add a CIRCQ_FOREACH macro and use it
- while here, use tabs to indent the preprocessor macros, like
we do with all other preprocessor macros
ok?
Index: kern_timeout.c
===================================================================
RCS file: /cvs/src/sys/kern/kern_timeout.c,v
retrieving revision 1.63
diff -u -p -r1.63 kern_timeout.c
--- kern_timeout.c 26 Nov 2019 15:27:08 -0000 1.63
+++ kern_timeout.c 26 Nov 2019 17:05:05 -0000
@@ -77,32 +77,32 @@ struct timespec timeout_late; /* [t] La
* Circular queue definitions.
*/
-#define CIRCQ_INIT(elem) do { \
- (elem)->next = (elem); \
- (elem)->prev = (elem); \
+#define CIRCQ_INIT(elem) do { \
+ (elem)->next = (elem); \
+ (elem)->prev = (elem); \
} while (0)
-#define CIRCQ_INSERT(elem, list) do { \
- (elem)->prev = (list)->prev; \
- (elem)->next = (list); \
- (list)->prev->next = (elem); \
- (list)->prev = (elem); \
- tostat.tos_pending++; \
+#define CIRCQ_INSERT_TAIL(elem, list) do { \
+ (elem)->prev = (list)->prev; \
+ (elem)->next = (list); \
+ (list)->prev->next = (elem); \
+ (list)->prev = (elem); \
+ tostat.tos_pending++; \
} while (0)
-#define CIRCQ_APPEND(fst, snd) do { \
- if (!CIRCQ_EMPTY(snd)) { \
- (fst)->prev->next = (snd)->next;\
- (snd)->next->prev = (fst)->prev;\
- (snd)->prev->next = (fst); \
- (fst)->prev = (snd)->prev; \
- CIRCQ_INIT(snd); \
- } \
+#define CIRCQ_CONCAT(fst, snd) do { \
+ if (!CIRCQ_EMPTY(snd)) { \
+ (fst)->prev->next = (snd)->next;\
+ (snd)->next->prev = (fst)->prev;\
+ (snd)->prev->next = (fst); \
+ (fst)->prev = (snd)->prev; \
+ CIRCQ_INIT(snd); \
+ } \
} while (0)
-#define CIRCQ_REMOVE(elem) do { \
- (elem)->next->prev = (elem)->prev; \
- (elem)->prev->next = (elem)->next; \
+#define CIRCQ_REMOVE(elem) do { \
+ (elem)->next->prev = (elem)->prev; \
+ (elem)->prev->next = (elem)->next; \
_Q_INVALIDATE((elem)->prev); \
_Q_INVALIDATE((elem)->next); \
tostat.tos_pending--; \
@@ -112,6 +112,11 @@ struct timespec timeout_late; /* [t] La
#define CIRCQ_EMPTY(elem) (CIRCQ_FIRST(elem) == (elem))
+#define CIRCQ_FOREACH(elem, head) \
+ for ((elem) = CIRCQ_FIRST(head); \
+ (elem) != (head); \
+ (elem) = CIRCQ_FIRST(elem))
+
#ifdef WITNESS
struct lock_object timeout_sleeplock_obj = {
.lo_name = "timeout",
@@ -358,13 +363,13 @@ timeout_at_ts_locked(struct timeout *to,
if (ISSET(to->to_flags, TIMEOUT_ONQUEUE)) {
if (timespeccmp(&to->to_time, &old_time, <)) {
CIRCQ_REMOVE(&to->to_list);
- CIRCQ_INSERT(&to->to_list, &timeout_todo);
+ CIRCQ_INSERT_TAIL(&to->to_list, &timeout_todo);
}
tostat.tos_readded++;
ret = 0;
} else {
SET(to->to_flags, TIMEOUT_ONQUEUE);
- CIRCQ_INSERT(&to->to_list, &timeout_todo);
+ CIRCQ_INSERT_TAIL(&to->to_list, &timeout_todo);
}
tostat.tos_added++;
@@ -423,7 +428,7 @@ timeout_barrier(struct timeout *to)
mtx_enter(&timeout_mutex);
SET(barrier.to_flags, TIMEOUT_ONQUEUE);
- CIRCQ_INSERT(&barrier.to_list, &timeout_proc);
+ CIRCQ_INSERT_TAIL(&barrier.to_list, &timeout_proc);
mtx_leave(&timeout_mutex);
wakeup_one(&timeout_proc);
@@ -518,7 +523,7 @@ timeout_hardclock_update(void)
}
offset = level * WHEELSIZE;
for (b = first;; b = (b + 1) % WHEELSIZE) {
- CIRCQ_APPEND(&timeout_todo, &timeout_wheel[offset + b]);
+ CIRCQ_CONCAT(&timeout_todo, &timeout_wheel[offset + b]);
if (b == last)
break;
}
@@ -582,14 +587,14 @@ softclock(void *arg)
*/
if (timespeccmp(&timeout_lastscan, &to->to_time, <)) {
b = timeout_bucket(&timeout_lastscan, &to->to_time);
- CIRCQ_INSERT(&to->to_list, &timeout_wheel[b]);
+ CIRCQ_INSERT_TAIL(&to->to_list, &timeout_wheel[b]);
tostat.tos_rescheduled++;
continue;
}
if (timespeccmp(&to->to_time, &timeout_late, <))
tostat.tos_late++;
if (ISSET(to->to_flags, TIMEOUT_NEEDPROCCTX)) {
- CIRCQ_INSERT(&to->to_list, &timeout_proc);
+ CIRCQ_INSERT_TAIL(&to->to_list, &timeout_proc);
needsproc = 1;
continue;
}
@@ -693,7 +698,7 @@ db_show_callout_bucket(struct circq *buc
char *name, *where;
int width = sizeof(long) * 2;
- for (p = CIRCQ_FIRST(bucket); p != bucket; p = CIRCQ_FIRST(p)) {
+ CIRCQ_FOREACH(p, bucket) {
to = timeout_from_circq(p);
db_find_sym_and_offset((vaddr_t)to->to_func, &name, &offset);
name = name ? name : "?";
