1 files changed, 31 insertions, 0 deletions
diff --git a/tools/perf/check-header_ignore_hunks/lib/list_sort.c b/tools/perf/check-header_ignore_hunks/lib/list_sort.c
new file mode 100644
index 000000000000..32d98cb34f80
--- /dev/null
+++ b/tools/perf/check-header_ignore_hunks/lib/list_sort.c
@@ -0,0 +1,31 @@
+@@ -1,5 +1,6 @@
+ // SPDX-License-Identifier: GPL-2.0
+ #include <linux/kernel.h>
++#include <linux/bug.h>
+ #include <linux/compiler.h>
+ #include <linux/export.h>
+ #include <linux/string.h>
+@@ -52,6 +53,7 @@
+ 			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 */
+@@ -77,6 +79,15 @@
+ 	/* 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;