Commit 904cbab7 authored by Matthew Wilcox (Oracle)'s avatar Matthew Wilcox (Oracle) Committed by Peter Zijlstra
Browse files

sched: Make const-safe 



With a modified container_of() that preserves constness, the compiler
finds some pointers which should have been marked as const.  task_of()
also needs to become const-preserving for the !FAIR_GROUP_SCHED case so
that cfs_rq_of() can take a const argument.  No change to generated code.

Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20221212144946.2657785-1-willy@infradead.org
parent b344b8f2

kernel/sched/core.c

+5 −3
Original line number Diff line number Diff line
@@ -152,7 +152,7 @@ __read_mostly int scheduler_running; 
DEFINE_STATIC_KEY_FALSE(__sched_core_enabled);



/* kernel prio, less is more */

static inline int __task_prio(struct task_struct *p)

static inline int __task_prio(const struct task_struct *p)

{

	if (p->sched_class == &stop_sched_class) /* trumps deadline */

		return -2;
@@ -174,7 +174,8 @@ static inline int __task_prio(struct task_struct *p) 
 */



/* real prio, less is less */

static inline bool prio_less(struct task_struct *a, struct task_struct *b, bool in_fi)

static inline bool prio_less(const struct task_struct *a,

			     const struct task_struct *b, bool in_fi)

{



	int pa = __task_prio(a), pb = __task_prio(b);
@@ -194,7 +195,8 @@ static inline bool prio_less(struct task_struct *a, struct task_struct *b, bool 
	return false;

}



static inline bool __sched_core_less(struct task_struct *a, struct task_struct *b)

static inline bool __sched_core_less(const struct task_struct *a,

				     const struct task_struct *b)

{

	if (a->core_cookie < b->core_cookie)

		return true;

kernel/sched/fair.c

+9 −7
Original line number Diff line number Diff line
@@ -468,7 +468,7 @@ is_same_group(struct sched_entity *se, struct sched_entity *pse) 
	return NULL;

}



static inline struct sched_entity *parent_entity(struct sched_entity *se)

static inline struct sched_entity *parent_entity(const struct sched_entity *se)

{

	return se->parent;

}
@@ -595,8 +595,8 @@ static inline u64 min_vruntime(u64 min_vruntime, u64 vruntime) 
	return min_vruntime;

}



static inline bool entity_before(struct sched_entity *a,

				struct sched_entity *b)

static inline bool entity_before(const struct sched_entity *a,

				 const struct sched_entity *b)

{

	return (s64)(a->vruntime - b->vruntime) < 0;

}
@@ -11852,7 +11852,8 @@ static inline void task_tick_core(struct rq *rq, struct task_struct *curr) 
/*

 * se_fi_update - Update the cfs_rq->min_vruntime_fi in a CFS hierarchy if needed.

 */

static void se_fi_update(struct sched_entity *se, unsigned int fi_seq, bool forceidle)

static void se_fi_update(const struct sched_entity *se, unsigned int fi_seq,

			 bool forceidle)

{

	for_each_sched_entity(se) {

		struct cfs_rq *cfs_rq = cfs_rq_of(se);
@@ -11877,11 +11878,12 @@ void task_vruntime_update(struct rq *rq, struct task_struct *p, bool in_fi) 
	se_fi_update(se, rq->core->core_forceidle_seq, in_fi);

}



bool cfs_prio_less(struct task_struct *a, struct task_struct *b, bool in_fi)

bool cfs_prio_less(const struct task_struct *a, const struct task_struct *b,

			bool in_fi)

{

	struct rq *rq = task_rq(a);

	struct sched_entity *sea = &a->se;

	struct sched_entity *seb = &b->se;

	const struct sched_entity *sea = &a->se;

	const struct sched_entity *seb = &b->se;

	struct cfs_rq *cfs_rqa;

	struct cfs_rq *cfs_rqb;

	s64 delta;

kernel/sched/sched.h

+10 −12
Original line number Diff line number Diff line
@@ -248,7 +248,7 @@ static inline void update_avg(u64 *avg, u64 sample) 


#define SCHED_DL_FLAGS (SCHED_FLAG_RECLAIM | SCHED_FLAG_DL_OVERRUN | SCHED_FLAG_SUGOV)



static inline bool dl_entity_is_special(struct sched_dl_entity *dl_se)

static inline bool dl_entity_is_special(const struct sched_dl_entity *dl_se)

{

#ifdef CONFIG_CPU_FREQ_GOV_SCHEDUTIL

	return unlikely(dl_se->flags & SCHED_FLAG_SUGOV);
@@ -260,8 +260,8 @@ static inline bool dl_entity_is_special(struct sched_dl_entity *dl_se) 
/*

 * Tells if entity @a should preempt entity @b.

 */

static inline bool

dl_entity_preempt(struct sched_dl_entity *a, struct sched_dl_entity *b)

static inline bool dl_entity_preempt(const struct sched_dl_entity *a,

				     const struct sched_dl_entity *b)

{

	return dl_entity_is_special(a) ||

	       dl_time_before(a->deadline, b->deadline);
@@ -1244,7 +1244,8 @@ static inline raw_spinlock_t *__rq_lockp(struct rq *rq) 
	return &rq->__lock;

}



bool cfs_prio_less(struct task_struct *a, struct task_struct *b, bool fi);

bool cfs_prio_less(const struct task_struct *a, const struct task_struct *b,

			bool fi);



/*

 * Helpers to check if the CPU's core cookie matches with the task's cookie
@@ -1423,7 +1424,7 @@ static inline struct cfs_rq *task_cfs_rq(struct task_struct *p) 
}



/* runqueue on which this entity is (to be) queued */

static inline struct cfs_rq *cfs_rq_of(struct sched_entity *se)

static inline struct cfs_rq *cfs_rq_of(const struct sched_entity *se)

{

	return se->cfs_rq;

}
@@ -1436,19 +1437,16 @@ static inline struct cfs_rq *group_cfs_rq(struct sched_entity *grp) 


#else



static inline struct task_struct *task_of(struct sched_entity *se)

{

	return container_of(se, struct task_struct, se);

}

#define task_of(_se)	container_of(_se, struct task_struct, se)



static inline struct cfs_rq *task_cfs_rq(struct task_struct *p)

static inline struct cfs_rq *task_cfs_rq(const struct task_struct *p)

{

	return &task_rq(p)->cfs;

}



static inline struct cfs_rq *cfs_rq_of(struct sched_entity *se)

static inline struct cfs_rq *cfs_rq_of(const struct sched_entity *se)

{

	struct task_struct *p = task_of(se);

	const struct task_struct *p = task_of(se);

	struct rq *rq = task_rq(p);



	return &rq->cfs;