/*
* linux/kernel/fork.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
*/
/*
* 'fork.c' contains the help-routines for the 'fork' system call
* (see also entry.S and others).
* Fork is rather simple, once you get the hang of it, but the memory
* management can be a *****. See 'mm/memory.c': 'copy_page_range()'
*/
#include <linux/config.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/unistd.h>
#include <linux/smp_lock.h>
#include <linux/module.h>
#include <linux/vmalloc.h>
#include <linux/completion.h>
#include <linux/namespace.h>
#include <linux/personality.h>
#include <linux/file.h>
#include <linux/binfmts.h>
#include <linux/mman.h>
#include <linux/fs.h>
#include <linux/security.h>
#include <linux/jiffies.h>
#include <linux/futex.h>
#include <linux/ptrace.h>
#include <linux/mount.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
#include <asm/uaccess.h>
#include <asm/mmu_context.h>
#include <asm/cacheflush.h>
#include <asm/tlbflush.h>
extern int copy_semundo(unsigned long clone_flags, struct task_struct *tsk);
extern void exit_sem(struct task_struct *tsk);
/* The idle threads do not count..
* Protected by write_lock_irq(&tasklist_lock)
*/
int nr_threads;
int max_threads;
unsigned long total_forks; /* Handle normal Linux uptimes. */
DEFINE_PER_CPU(unsigned long, process_counts) = 0;
rwlock_t tasklist_lock __cacheline_aligned = RW_LOCK_UNLOCKED; /* outer */
EXPORT_SYMBOL(tasklist_lock);
int nr_processes(void)
{
int cpu;
int total = 0;
for (cpu = 0; cpu < NR_CPUS; cpu++) {
if (cpu_online(cpu))
total += per_cpu(process_counts, cpu);
}
return total;
}
#ifndef __HAVE_ARCH_TASK_STRUCT_ALLOCATOR
# define alloc_task_struct() kmem_cache_alloc(task_struct_cachep, GFP_KERNEL)
# define free_task_struct(tsk) kmem_cache_free(task_struct_cachep, (tsk))
static kmem_cache_t *task_struct_cachep;
#endif
static void free_task(struct task_struct *tsk)
{
free_thread_info(tsk->thread_info);
free_task_struct(tsk);
}
void __put_task_struct(struct task_struct *tsk)
{
WARN_ON(!(tsk->state & (TASK_DEAD | TASK_ZOMBIE)));
WARN_ON(atomic_read(&tsk->usage));
WARN_ON(tsk == current);
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