From 01b904b446bc9822e83b3fbc8155c2bb33776ea0 Mon Sep 17 00:00:00 2001
From: Alfred Chen <cchalpha@gmail.com>
Date: Tue, 9 Apr 2024 10:14:52 +0000
Subject: [PATCH] sched/bmq: BMQ boost priority adjustment

This is BMQ boost priority adjustment after the just fix commit for #89.
---
 kernel/sched/alt_core.c  |  3 ---
 kernel/sched/alt_sched.h |  3 ---
 kernel/sched/bmq.h       | 17 +++++++----------
 3 files changed, 7 insertions(+), 16 deletions(-)

diff --git a/kernel/sched/alt_core.c b/kernel/sched/alt_core.c
index 4ef5e29e48154f..6fd9663c1d8032 100644
--- a/kernel/sched/alt_core.c
+++ b/kernel/sched/alt_core.c
@@ -4875,9 +4875,6 @@ static void __sched notrace __schedule(unsigned int sched_mode)
 #endif
 
 	if (likely(prev != next)) {
-#ifdef CONFIG_SCHED_BMQ
-		rq->last_ts_switch = rq->clock;
-#endif
 		next->last_ran = rq->clock_task;
 
 		/*printk(KERN_INFO "sched: %px -> %px\n", prev, next);*/
diff --git a/kernel/sched/alt_sched.h b/kernel/sched/alt_sched.h
index ba1b7b805f1a56..81c3ed9ebb7d77 100644
--- a/kernel/sched/alt_sched.h
+++ b/kernel/sched/alt_sched.h
@@ -235,9 +235,6 @@ struct rq {
 	/* Ensure that all clocks are in the same cache line */
 	u64			clock ____cacheline_aligned;
 	u64			clock_task;
-#ifdef CONFIG_SCHED_BMQ
-	u64			last_ts_switch;
-#endif
 
 	unsigned int  nr_running;
 	unsigned long nr_uninterruptible;
diff --git a/kernel/sched/bmq.h b/kernel/sched/bmq.h
index b7c9813f6fa713..87a6d304f174fb 100644
--- a/kernel/sched/bmq.h
+++ b/kernel/sched/bmq.h
@@ -3,10 +3,7 @@
 /*
  * BMQ only routines
  */
-#define rq_switch_time(rq)	((rq)->clock - (rq)->last_ts_switch)
-#define boost_threshold(p)	(sysctl_sched_base_slice >> ((20 - (p)->boost_prio) / 2))
-
-static inline void boost_task(struct task_struct *p)
+static inline void boost_task(struct task_struct *p, int n)
 {
 	int limit;
 
@@ -21,8 +18,7 @@ static inline void boost_task(struct task_struct *p)
 		return;
 	}
 
-	if (p->boost_prio > limit)
-		p->boost_prio--;
+	p->boost_prio = max(limit, p->boost_prio - n);
 }
 
 static inline void deboost_task(struct task_struct *p)
@@ -90,12 +86,13 @@ static inline void do_sched_yield_type_1(struct task_struct *p, struct rq *rq)
 
 static inline void sched_task_ttwu(struct task_struct *p)
 {
-	if(this_rq()->clock_task - p->last_ran > sysctl_sched_base_slice)
-		boost_task(p);
+	s64 delta = this_rq()->clock_task > p->last_ran;
+
+	if (likely(delta > 0))
+		boost_task(p, delta  >> 22);
 }
 
 static inline void sched_task_deactivate(struct task_struct *p, struct rq *rq)
 {
-	if (rq_switch_time(rq) < boost_threshold(p))
-		boost_task(p);
+	boost_task(p, 1);
 }