[RFC PATCH 25/86] Revert "sched: Add /debug/sched_preempt"

[Ankur Arora]

This reverts commit e59e10f8ef63d42fbb99776a5a112841e798b3b5.

Signed-off-by: Ankur Arora <ankur.a.arora@xxxxxxxxxx>
---
 kernel/sched/core.c | 137 +++-----------------------------------------
 1 file changed, 9 insertions(+), 128 deletions(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 7ea22244c540..b8dacc7feb47 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -6989,156 +6989,37 @@ EXPORT_STATIC_CALL(preempt_schedule_notrace);
  *   preempt_schedule_notrace   <- preempt_schedule_notrace
  *   irqentry_exit_cond_resched <- irqentry_exit_cond_resched
  */
-
-enum {
-	preempt_dynamic_none = 0,
-	preempt_dynamic_voluntary,
-	preempt_dynamic_full,
-};
-
-static int preempt_dynamic_mode = preempt_dynamic_full;
-
-static int sched_dynamic_mode(const char *str)
+static int __init setup_preempt_mode(char *str)
 {
-	if (!strcmp(str, "none"))
-		return 0;
-
-	if (!strcmp(str, "voluntary"))
-		return 1;
-
-	if (!strcmp(str, "full"))
-		return 2;
-
-	return -1;
-}
-
-static void sched_dynamic_update(int mode)
-{
-	/*
-	 * Avoid {NONE,VOLUNTARY} -> FULL transitions from ever ending up in
-	 * the ZERO state, which is invalid.
-	 */
-	static_call_update(cond_resched, __cond_resched);
-	static_call_update(might_resched, __cond_resched);
-	static_call_update(preempt_schedule, __preempt_schedule_func);
-	static_call_update(preempt_schedule_notrace, __preempt_schedule_notrace_func);
-	static_call_update(irqentry_exit_cond_resched, irqentry_exit_cond_resched);
-
-	switch (mode) {
-	case preempt_dynamic_none:
+	if (!strcmp(str, "none")) {
 		static_call_update(cond_resched, __cond_resched);
 		static_call_update(might_resched, (typeof(&__cond_resched)) __static_call_return0);
 		static_call_update(preempt_schedule, (typeof(&preempt_schedule)) NULL);
 		static_call_update(preempt_schedule_notrace, (typeof(&preempt_schedule_notrace)) NULL);
 		static_call_update(irqentry_exit_cond_resched, (typeof(&irqentry_exit_cond_resched)) NULL);
-		pr_info("Dynamic Preempt: none\n");
-		break;
-
-	case preempt_dynamic_voluntary:
+		pr_info("Dynamic Preempt: %s\n", str);
+	} else if (!strcmp(str, "voluntary")) {
 		static_call_update(cond_resched, __cond_resched);
 		static_call_update(might_resched, __cond_resched);
 		static_call_update(preempt_schedule, (typeof(&preempt_schedule)) NULL);
 		static_call_update(preempt_schedule_notrace, (typeof(&preempt_schedule_notrace)) NULL);
 		static_call_update(irqentry_exit_cond_resched, (typeof(&irqentry_exit_cond_resched)) NULL);
-		pr_info("Dynamic Preempt: voluntary\n");
-		break;
-
-	case preempt_dynamic_full:
+		pr_info("Dynamic Preempt: %s\n", str);
+	} else if (!strcmp(str, "full")) {
 		static_call_update(cond_resched, (typeof(&__cond_resched)) __static_call_return0);
 		static_call_update(might_resched, (typeof(&__cond_resched)) __static_call_return0);
 		static_call_update(preempt_schedule, __preempt_schedule_func);
 		static_call_update(preempt_schedule_notrace, __preempt_schedule_notrace_func);
 		static_call_update(irqentry_exit_cond_resched, irqentry_exit_cond_resched);
-		pr_info("Dynamic Preempt: full\n");
-		break;
-	}
-
-	preempt_dynamic_mode = mode;
-}
-
-static int __init setup_preempt_mode(char *str)
-{
-	int mode = sched_dynamic_mode(str);
-	if (mode < 0) {
-		pr_warn("Dynamic Preempt: unsupported mode: %s\n", str);
+		pr_info("Dynamic Preempt: %s\n", str);
+	} else {
+		pr_warn("Dynamic Preempt: Unsupported preempt mode %s, default to full\n", str);
 		return 1;
 	}
-
-	sched_dynamic_update(mode);
 	return 0;
 }
 __setup("preempt=", setup_preempt_mode);
 
-#ifdef CONFIG_SCHED_DEBUG
-
-static ssize_t sched_dynamic_write(struct file *filp, const char __user *ubuf,
-				   size_t cnt, loff_t *ppos)
-{
-	char buf[16];
-	int mode;
-
-	if (cnt > 15)
-		cnt = 15;
-
-	if (copy_from_user(&buf, ubuf, cnt))
-		return -EFAULT;
-
-	buf[cnt] = 0;
-	mode = sched_dynamic_mode(strstrip(buf));
-	if (mode < 0)
-		return mode;
-
-	sched_dynamic_update(mode);
-
-	*ppos += cnt;
-
-	return cnt;
-}
-
-static int sched_dynamic_show(struct seq_file *m, void *v)
-{
-	static const char * preempt_modes[] = {
-		"none", "voluntary", "full"
-	};
-	int i;
-
-	for (i = 0; i < ARRAY_SIZE(preempt_modes); i++) {
-		if (preempt_dynamic_mode == i)
-			seq_puts(m, "(");
-		seq_puts(m, preempt_modes[i]);
-		if (preempt_dynamic_mode == i)
-			seq_puts(m, ")");
-
-		seq_puts(m, " ");
-	}
-
-	seq_puts(m, "\n");
-	return 0;
-}
-
-static int sched_dynamic_open(struct inode *inode, struct file *filp)
-{
-	return single_open(filp, sched_dynamic_show, NULL);
-}
-
-static const struct file_operations sched_dynamic_fops = {
-	.open		= sched_dynamic_open,
-	.write		= sched_dynamic_write,
-	.read		= seq_read,
-	.llseek		= seq_lseek,
-	.release	= single_release,
-};
-
-extern struct dentry *debugfs_sched;
-
-static __init int sched_init_debug_dynamic(void)
-{
-	debugfs_create_file("sched_preempt", 0644, debugfs_sched, NULL, &sched_dynamic_fops);
-	return 0;
-}
-late_initcall(sched_init_debug_dynamic);
-
-#endif /* CONFIG_SCHED_DEBUG */
 #endif /* CONFIG_PREEMPT_DYNAMIC */
 
 
-- 
2.31.1