Since cond_resched() is not called in userspace, remove the redundant
code in userspace's list_sort() implementation. This change eliminates
the unused 'count' variable and the associated logic for invoking cmp()
periodically, which was intended to trigger cond_resched() in kernel
space.
The removed code includes:
- Declaration and increment of the 'count' variable.
- Conditional invocation of cmp() based on 'count'.
This cleanup simplifies the merge_final function, avoids unnecessary
overhead, and has no impact on the functionality of list_sort() in
userspace.
Signed-off-by: Kuan-Wei Chiu <[email protected]>
---
I've also Cc'd the maintainers and reviewers of the performance events
subsystem because the perf tool is the only user of userspace
list_sort().
tools/lib/list_sort.c | 10 ----------
1 file changed, 10 deletions(-)
diff --git a/tools/lib/list_sort.c b/tools/lib/list_sort.c
index 10c067e3a8d2..69affa251fa7 100644
--- a/tools/lib/list_sort.c
+++ b/tools/lib/list_sort.c
@@ -52,7 +52,6 @@ static void merge_final(void *priv, list_cmp_func_t cmp, struct list_head *head,
struct list_head *a, struct list_head *b)
{
struct list_head *tail = head;
- u8 count = 0;
for (;;) {
/* if equal, take 'a' -- important for sort stability */
@@ -78,15 +77,6 @@ static void merge_final(void *priv, list_cmp_func_t cmp, struct list_head *head,
/* Finish linking remainder of list b on to tail */
tail->next = b;
do {
- /*
- * If the merge is highly unbalanced (e.g. the input is
- * already sorted), this loop may run many iterations.
- * Continue callbacks to the client even though no
- * element comparison is needed, so the client's cmp()
- * routine can invoke cond_resched() periodically.
- */
- if (unlikely(!++count))
- cmp(priv, b, b);
b->prev = tail;
tail = b;
b = b->next;
--
2.34.1