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Message-Id: <20231201022704.3526377-2-yajun.deng@linux.dev>
Date: Fri, 1 Dec 2023 10:27:03 +0800
From: Yajun Deng <yajun.deng@...ux.dev>
To: mingo@...hat.com, peterz@...radead.org, juri.lelli@...hat.com,
vincent.guittot@...aro.org, dietmar.eggemann@....com,
rostedt@...dmis.org, bsegall@...gle.com, mgorman@...e.de,
bristot@...hat.com, vschneid@...hat.com
Cc: linux-kernel@...r.kernel.org, Yajun Deng <yajun.deng@...ux.dev>
Subject: [PATCH 1/2] sched/fair: Return NULL when entity isn't a task in task_of()
Before calling task_of(), we need to make sure that the entity is a task.
There is also a warning in task_of() if the entity isn't a task. That
means we need to check the entity twice. If the entity isn't a task,
return the task struct is meaningless.
Return NULL when entity isn't a task in task_of(), and call task_of()
instead of entity_is_task() when we need a task_struct.
Signed-off-by: Yajun Deng <yajun.deng@...ux.dev>
---
kernel/sched/fair.c | 50 +++++++++++++++++++++-----------------------
kernel/sched/sched.h | 4 +++-
2 files changed, 27 insertions(+), 27 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 34e23a8984ac..e8d444fad2d6 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -470,8 +470,10 @@ static int cfs_rq_is_idle(struct cfs_rq *cfs_rq)
static int se_is_idle(struct sched_entity *se)
{
- if (entity_is_task(se))
- return task_has_idle_policy(task_of(se));
+ struct task_struct *p = task_of(se);
+
+ if (p)
+ return task_has_idle_policy(p);
return cfs_rq_is_idle(group_cfs_rq(se));
}
@@ -1156,6 +1158,7 @@ s64 update_curr_common(struct rq *rq)
static void update_curr(struct cfs_rq *cfs_rq)
{
struct sched_entity *curr = cfs_rq->curr;
+ struct task_struct *p;
s64 delta_exec;
if (unlikely(!curr))
@@ -1169,8 +1172,9 @@ static void update_curr(struct cfs_rq *cfs_rq)
update_deadline(cfs_rq, curr);
update_min_vruntime(cfs_rq);
- if (entity_is_task(curr))
- update_curr_task(task_of(curr), delta_exec);
+ p = task_of(curr);
+ if (p)
+ update_curr_task(p, delta_exec);
account_cfs_rq_runtime(cfs_rq, delta_exec);
}
@@ -1184,24 +1188,19 @@ static inline void
update_stats_wait_start_fair(struct cfs_rq *cfs_rq, struct sched_entity *se)
{
struct sched_statistics *stats;
- struct task_struct *p = NULL;
if (!schedstat_enabled())
return;
stats = __schedstats_from_se(se);
- if (entity_is_task(se))
- p = task_of(se);
-
- __update_stats_wait_start(rq_of(cfs_rq), p, stats);
+ __update_stats_wait_start(rq_of(cfs_rq), task_of(se), stats);
}
static inline void
update_stats_wait_end_fair(struct cfs_rq *cfs_rq, struct sched_entity *se)
{
struct sched_statistics *stats;
- struct task_struct *p = NULL;
if (!schedstat_enabled())
return;
@@ -1217,27 +1216,20 @@ update_stats_wait_end_fair(struct cfs_rq *cfs_rq, struct sched_entity *se)
if (unlikely(!schedstat_val(stats->wait_start)))
return;
- if (entity_is_task(se))
- p = task_of(se);
-
- __update_stats_wait_end(rq_of(cfs_rq), p, stats);
+ __update_stats_wait_end(rq_of(cfs_rq), task_of(se), stats);
}
static inline void
update_stats_enqueue_sleeper_fair(struct cfs_rq *cfs_rq, struct sched_entity *se)
{
struct sched_statistics *stats;
- struct task_struct *tsk = NULL;
if (!schedstat_enabled())
return;
stats = __schedstats_from_se(se);
- if (entity_is_task(se))
- tsk = task_of(se);
-
- __update_stats_enqueue_sleeper(rq_of(cfs_rq), tsk, stats);
+ __update_stats_enqueue_sleeper(rq_of(cfs_rq), task_of(se), stats);
}
/*
@@ -1263,6 +1255,7 @@ update_stats_enqueue_fair(struct cfs_rq *cfs_rq, struct sched_entity *se, int fl
static inline void
update_stats_dequeue_fair(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
{
+ struct task_struct *tsk;
if (!schedstat_enabled())
return;
@@ -1274,8 +1267,8 @@ update_stats_dequeue_fair(struct cfs_rq *cfs_rq, struct sched_entity *se, int fl
if (se != cfs_rq->curr)
update_stats_wait_end_fair(cfs_rq, se);
- if ((flags & DEQUEUE_SLEEP) && entity_is_task(se)) {
- struct task_struct *tsk = task_of(se);
+ tsk = task_of(se);
+ if ((flags & DEQUEUE_SLEEP) && tsk) {
unsigned int state;
/* XXX racy against TTWU */
@@ -3569,12 +3562,14 @@ static inline void update_scan_period(struct task_struct *p, int new_cpu)
static void
account_entity_enqueue(struct cfs_rq *cfs_rq, struct sched_entity *se)
{
+ struct task_struct *p = task_of(se);
+
update_load_add(&cfs_rq->load, se->load.weight);
#ifdef CONFIG_SMP
- if (entity_is_task(se)) {
+ if (p) {
struct rq *rq = rq_of(cfs_rq);
- account_numa_enqueue(rq, task_of(se));
+ account_numa_enqueue(rq, p);
list_add(&se->group_node, &rq->cfs_tasks);
}
#endif
@@ -3586,10 +3581,12 @@ account_entity_enqueue(struct cfs_rq *cfs_rq, struct sched_entity *se)
static void
account_entity_dequeue(struct cfs_rq *cfs_rq, struct sched_entity *se)
{
+ struct task_struct *p = task_of(se);
+
update_load_sub(&cfs_rq->load, se->load.weight);
#ifdef CONFIG_SMP
- if (entity_is_task(se)) {
- account_numa_dequeue(rq_of(cfs_rq), task_of(se));
+ if (p) {
+ account_numa_dequeue(rq_of(cfs_rq), p);
list_del_init(&se->group_node);
}
#endif
@@ -5323,9 +5320,10 @@ static __always_inline void return_cfs_rq_runtime(struct cfs_rq *cfs_rq);
static void
dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
{
+ struct task_struct *p = task_of(se);
int action = UPDATE_TG;
- if (entity_is_task(se) && task_on_rq_migrating(task_of(se)))
+ if (p && task_on_rq_migrating(p))
action |= DO_DETACH;
/*
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 001fe047bd5d..6baba9ebcde1 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -1432,7 +1432,9 @@ static inline void update_idle_core(struct rq *rq) { }
#ifdef CONFIG_FAIR_GROUP_SCHED
static inline struct task_struct *task_of(struct sched_entity *se)
{
- SCHED_WARN_ON(!entity_is_task(se));
+ if (!entity_is_task(se))
+ return NULL;
+
return container_of(se, struct task_struct, se);
}
--
2.25.1
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