![Cheng Jian](/assets/img/avatar_default.png)
init_idle_bootup_task( ) is called in rest_init( ) to switch the scheduling class of the boot thread to the idle class. the function only sets: idle->sched_class = &idle_sched_class; which has been set in init_idle() called by sched_init(): /* * The idle tasks have their own, simple scheduling class: */ idle->sched_class = &idle_sched_class; We've already set the boot thread to idle class in start_kernel()->sched_init()->init_idle() so it's unnecessary to set it again in start_kernel()->rest_init()->init_idle_bootup_task() Signed-off-by: Cheng Jian <cj.chengjian@huawei.com> Signed-off-by: Xie XiuQi <xiexiuqi@huawei.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: <akpm@linux-foundation.org> Cc: <huawei.libin@huawei.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1501838377-109720-1-git-send-email-cj.chengjian@huawei.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
139 lines
3.8 KiB
C
139 lines
3.8 KiB
C
#ifndef _LINUX_SCHED_TASK_H
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#define _LINUX_SCHED_TASK_H
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/*
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* Interface between the scheduler and various task lifetime (fork()/exit())
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* functionality:
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*/
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#include <linux/sched.h>
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struct task_struct;
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struct rusage;
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union thread_union;
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/*
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* This serializes "schedule()" and also protects
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* the run-queue from deletions/modifications (but
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* _adding_ to the beginning of the run-queue has
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* a separate lock).
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*/
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extern rwlock_t tasklist_lock;
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extern spinlock_t mmlist_lock;
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extern union thread_union init_thread_union;
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extern struct task_struct init_task;
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#ifdef CONFIG_PROVE_RCU
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extern int lockdep_tasklist_lock_is_held(void);
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#endif /* #ifdef CONFIG_PROVE_RCU */
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extern asmlinkage void schedule_tail(struct task_struct *prev);
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extern void init_idle(struct task_struct *idle, int cpu);
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extern int sched_fork(unsigned long clone_flags, struct task_struct *p);
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extern void sched_dead(struct task_struct *p);
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void __noreturn do_task_dead(void);
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extern void proc_caches_init(void);
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extern void release_task(struct task_struct * p);
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#ifdef CONFIG_HAVE_COPY_THREAD_TLS
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extern int copy_thread_tls(unsigned long, unsigned long, unsigned long,
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struct task_struct *, unsigned long);
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#else
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extern int copy_thread(unsigned long, unsigned long, unsigned long,
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struct task_struct *);
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/* Architectures that haven't opted into copy_thread_tls get the tls argument
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* via pt_regs, so ignore the tls argument passed via C. */
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static inline int copy_thread_tls(
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unsigned long clone_flags, unsigned long sp, unsigned long arg,
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struct task_struct *p, unsigned long tls)
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{
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return copy_thread(clone_flags, sp, arg, p);
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}
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#endif
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extern void flush_thread(void);
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#ifdef CONFIG_HAVE_EXIT_THREAD
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extern void exit_thread(struct task_struct *tsk);
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#else
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static inline void exit_thread(struct task_struct *tsk)
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{
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}
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#endif
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extern void do_group_exit(int);
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extern void exit_files(struct task_struct *);
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extern void exit_itimers(struct signal_struct *);
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extern long _do_fork(unsigned long, unsigned long, unsigned long, int __user *, int __user *, unsigned long);
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extern long do_fork(unsigned long, unsigned long, unsigned long, int __user *, int __user *);
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struct task_struct *fork_idle(int);
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extern pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags);
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extern long kernel_wait4(pid_t, int *, int, struct rusage *);
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extern void free_task(struct task_struct *tsk);
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/* sched_exec is called by processes performing an exec */
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#ifdef CONFIG_SMP
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extern void sched_exec(void);
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#else
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#define sched_exec() {}
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#endif
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#define get_task_struct(tsk) do { atomic_inc(&(tsk)->usage); } while(0)
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extern void __put_task_struct(struct task_struct *t);
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static inline void put_task_struct(struct task_struct *t)
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{
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if (atomic_dec_and_test(&t->usage))
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__put_task_struct(t);
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}
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struct task_struct *task_rcu_dereference(struct task_struct **ptask);
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#ifdef CONFIG_ARCH_WANTS_DYNAMIC_TASK_STRUCT
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extern int arch_task_struct_size __read_mostly;
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#else
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# define arch_task_struct_size (sizeof(struct task_struct))
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#endif
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#ifdef CONFIG_VMAP_STACK
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static inline struct vm_struct *task_stack_vm_area(const struct task_struct *t)
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{
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return t->stack_vm_area;
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}
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#else
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static inline struct vm_struct *task_stack_vm_area(const struct task_struct *t)
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{
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return NULL;
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}
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#endif
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/*
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* Protects ->fs, ->files, ->mm, ->group_info, ->comm, keyring
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* subscriptions and synchronises with wait4(). Also used in procfs. Also
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* pins the final release of task.io_context. Also protects ->cpuset and
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* ->cgroup.subsys[]. And ->vfork_done.
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*
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* Nests both inside and outside of read_lock(&tasklist_lock).
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* It must not be nested with write_lock_irq(&tasklist_lock),
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* neither inside nor outside.
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*/
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static inline void task_lock(struct task_struct *p)
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{
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spin_lock(&p->alloc_lock);
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}
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static inline void task_unlock(struct task_struct *p)
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{
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spin_unlock(&p->alloc_lock);
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}
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#endif /* _LINUX_SCHED_TASK_H */
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