New subject: [PATCH openEuler-1.0-LTS 2/2] dm thin: Fix ABBA deadlock between shrink_slab and dm_pool_abort_metadata

16 Dec 2022

From: Zhang Qiao zhangqiao22@huawei.com
hulk inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I64OUS
CVE: NA
-------------------------------
When a cfs_rq throttled by qos, mark cfs_rq->throttled as 1,
and cfs bw will unthrottled this cfs_rq by mistake, it cause
a list_del_valid warning.
So add macro QOS_THROTTLED(=2), when a cfs_rq is throttled by
qos, we mark the cfs_rq->throttled as QOS_THROTTLED, will check
the value of cfs_rq->throttled before unthrottle a cfs_rq.
Signed-off-by: Zhang Qiao zhangqiao22@huawei.com
Reviewed-by: Chen Hui judy.chenhui@huawei.com
Reviewed-by: zheng zucheng zhengzucheng@huawei.com
Signed-off-by: Yongqiang Liu liuyongqiang13@huawei.com
---
 kernel/sched/fair.c | 59 ++++++++++++++++++++++++++-------------------
 1 file changed, 34 insertions(+), 25 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index a34ca843bf0a..0dba06ce0677 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -103,6 +103,13 @@ int __weak arch_asym_cpu_priority(int cpu)
 #endif
#ifdef CONFIG_QOS_SCHED
+
+/*
+ * To distinguish cfs bw, use QOS_THROTTLED mark cfs_rq->throttled
+ * when qos throttled(and cfs bw throttle mark cfs_rq->throttled as 1).
+ */
+#define QOS_THROTTLED	2
+
 static DEFINE_PER_CPU_SHARED_ALIGNED(struct list_head, qos_throttled_cfs_rq);
 static DEFINE_PER_CPU_SHARED_ALIGNED(struct hrtimer, qos_overload_timer);
 static DEFINE_PER_CPU(int, qos_cpu_overload);
@@ -4649,6 +4656,14 @@ void unthrottle_cfs_rq(struct cfs_rq *cfs_rq)
se = cfs_rq->tg->se[cpu_of(rq)];
+#ifdef CONFIG_QOS_SCHED
+	/*
+	 * if this cfs_rq throttled by qos, not need unthrottle it.
+	 */
+	if (cfs_rq->throttled == QOS_THROTTLED)
+		return;
+#endif
+
    cfs_rq->throttled = 0;
update_rq_clock(rq);
@@ -7066,37 +7081,18 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int wake_
 #ifdef CONFIG_QOS_SCHED
 static void start_qos_hrtimer(int cpu);
-static int qos_tg_unthrottle_up(struct task_group *tg, void *data)
-{
-	struct rq *rq = data;
-	struct cfs_rq *cfs_rq = tg->cfs_rq[cpu_of(rq)];
-
-	cfs_rq->throttle_count--;
-
-	return 0;
-}
-
-static int qos_tg_throttle_down(struct task_group *tg, void *data)
-{
-	struct rq *rq = data;
-	struct cfs_rq *cfs_rq = tg->cfs_rq[cpu_of(rq)];
-
-	cfs_rq->throttle_count++;
-
-	return 0;
-}
-
 static void throttle_qos_cfs_rq(struct cfs_rq *cfs_rq)
 {
    struct rq *rq = rq_of(cfs_rq);
    struct sched_entity *se;
    long task_delta, idle_task_delta, dequeue = 1;
+	unsigned int prev_nr = rq->cfs.h_nr_running;
se = cfs_rq->tg->se[cpu_of(rq_of(cfs_rq))];
/* freeze hierarchy runnable averages while throttled */
    rcu_read_lock();
-	walk_tg_tree_from(cfs_rq->tg, qos_tg_throttle_down, tg_nop, (void *)rq);
+	walk_tg_tree_from(cfs_rq->tg, tg_throttle_down, tg_nop, (void *)rq);
    rcu_read_unlock();
task_delta = cfs_rq->h_nr_running;
@@ -7118,12 +7114,14 @@ static void throttle_qos_cfs_rq(struct cfs_rq *cfs_rq)
if (!se) {
    	sub_nr_running(rq, task_delta);
+		if (prev_nr >= 2 && prev_nr - task_delta < 2)
+			overload_clear(rq);
    }
if (list_empty(&per_cpu(qos_throttled_cfs_rq, cpu_of(rq))))
    	start_qos_hrtimer(cpu_of(rq));
-	cfs_rq->throttled = 1;
+	cfs_rq->throttled = QOS_THROTTLED;
list_add(&cfs_rq->qos_throttled_list,
    	 &per_cpu(qos_throttled_cfs_rq, cpu_of(rq)));
@@ -7135,8 +7133,11 @@ static void unthrottle_qos_cfs_rq(struct cfs_rq *cfs_rq)
    struct sched_entity *se;
    int enqueue = 1;
    long task_delta, idle_task_delta;
+	unsigned int prev_nr = rq->cfs.h_nr_running;
se = cfs_rq->tg->se[cpu_of(rq)];
+	if (cfs_rq->throttled != QOS_THROTTLED)
+		return;
cfs_rq->throttled = 0;
@@ -7145,7 +7146,7 @@ static void unthrottle_qos_cfs_rq(struct cfs_rq *cfs_rq)
/* update hierarchical throttle state */
    rcu_read_lock();
-	walk_tg_tree_from(cfs_rq->tg, tg_nop, qos_tg_unthrottle_up, (void *)rq);
+	walk_tg_tree_from(cfs_rq->tg, tg_nop, tg_unthrottle_up, (void *)rq);
    rcu_read_unlock();
if (!cfs_rq->load.weight)
@@ -7167,12 +7168,20 @@ static void unthrottle_qos_cfs_rq(struct cfs_rq *cfs_rq)
    		break;
    }
-	assert_list_leaf_cfs_rq(rq);
-
    if (!se) {
    	add_nr_running(rq, task_delta);
+		if (prev_nr < 2 && prev_nr + task_delta >= 2)
+			overload_set(rq);
+	}
+
+	for_each_sched_entity(se) {
+		cfs_rq = cfs_rq_of(se);
+
+		list_add_leaf_cfs_rq(cfs_rq);
    }
+	assert_list_leaf_cfs_rq(rq);
+
    /* Determine whether we need to wake up potentially idle CPU: */
    if (rq->curr == rq->idle && rq->cfs.nr_running)
    	resched_curr(rq);
-- 
2.25.1

    

[PATCH openEuler-1.0-LTS 1/2] sched/qos: Don't unthrottle cfs_rq when cfs_rq is throttled by qos