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mertcanekiz/fork.c

Created April 2, 2020 06:19
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fork.c
/*
* 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 bitch. 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/compiler.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
#include <asm/uaccess.h>
#include <asm/mmu_context.h>
/* The idle threads do not count.. */
int nr_threads;
int nr_running;
int max_threads;
unsigned long total_forks; /* Handle normal Linux uptimes. */
int last_pid;
struct task_struct *pidhash[PIDHASH_SZ];
void add_wait_queue(wait_queue_head_t *q, wait_queue_t * wait)
{
unsigned long flags;
wait->flags &= ~WQ_FLAG_EXCLUSIVE;
wq_write_lock_irqsave(&q->lock, flags);
__add_wait_queue(q, wait);
wq_write_unlock_irqrestore(&q->lock, flags);
}
void add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_t * wait)
{
unsigned long flags;
wait->flags |= WQ_FLAG_EXCLUSIVE;
wq_write_lock_irqsave(&q->lock, flags);
__add_wait_queue_tail(q, wait);
wq_write_unlock_irqrestore(&q->lock, flags);
}
void remove_wait_queue(wait_queue_head_t *q, wait_queue_t * wait)
{
unsigned long flags;
wq_write_lock_irqsave(&q->lock, flags);
__remove_wait_queue(q, wait);
wq_write_unlock_irqrestore(&q->lock, flags);
}
void __init fork_init(unsigned long mempages)
{
/*
* The default maximum number of threads is set to a safe
* value: the thread structures can take up at most half
* of memory.
*/
max_threads = mempages / (THREAD_SIZE/PAGE_SIZE) / 8;
init_task.rlim[RLIMIT_NPROC].rlim_cur = max_threads/2;
init_task.rlim[RLIMIT_NPROC].rlim_max = max_threads/2;
}
/* Protects next_safe and last_pid. */
spinlock_t lastpid_lock = SPIN_LOCK_UNLOCKED;
static int get_pid(unsigned long flags)
{
static int next_safe = PID_MAX;
struct task_struct *p;
int pid, beginpid;
if (flags & CLONE_PID)
return current->pid;
spin_lock(&lastpid_lock);
beginpid = last_pid;
if((++last_pid) & 0xffff8000) {
last_pid = 300; /* Skip daemons etc. */
goto inside;
}
if(last_pid >= next_safe) {
inside:
next_safe = PID_MAX;
read_lock(&tasklist_lock);
repeat:
for_each_task(p) {
if(p->pid == last_pid ||
p->pgrp == last_pid ||
p->tgid == last_pid ||
p->session == last_pid) {
if(++last_pid >= next_safe) {
if(last_pid & 0xffff8000)
last_pid = 300;
next_safe = PID_MAX;
}
if(unlikely(last_pid == beginpid))
goto nomorepids;
goto repeat;
}
if(p->pid > last_pid && next_safe > p->pid)
next_safe = p->pid;
if(p->pgrp > last_pid && next_safe > p->pgrp)
next_safe = p->pgrp;
if(p->tgid > last_pid && next_safe > p->tgid)
next_safe = p->tgid;
if(p->session > last_pid && next_safe > p->session)
next_safe = p->session;
}
read_unlock(&tasklist_lock);
}
pid = last_pid;
spin_unlock(&lastpid_lock);
return pid;
nomorepids:
read_unlock(&tasklist_lock);
spin_unlock(&lastpid_lock);
return 0;
}
static inline int dup_mmap(struct mm_struct * mm)
{
struct vm_area_struct * mpnt, *tmp, **pprev;
int retval;
flush_cache_mm(current->mm);
mm->locked_vm = 0;
mm->mmap = NULL;
mm->mmap_cache = NULL;
mm->map_count = 0;
mm->rss = 0;
mm->cpu_vm_mask = 0;
mm->swap_address = 0;
pprev = &mm->mmap;
/*
* Add it to the mmlist after the parent.
* Doing it this way means that we can order the list,
* and fork() won't mess up the ordering significantly.
* Add it first so that swapoff can see any swap entries.
*/
spin_lock(&mmlist_lock);
list_add(&mm->mmlist, &current->mm->mmlist);
mmlist_nr++;
spin_unlock(&mmlist_lock);
for (mpnt = current->mm->mmap ; mpnt ; mpnt = mpnt->vm_next) {
struct file *file;
retval = -ENOMEM;
if(mpnt->vm_flags & VM_DONTCOPY)
continue;
tmp = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL);
if (!tmp)
goto fail_nomem;
*tmp = *mpnt;
tmp->vm_flags &= ~VM_LOCKED;
tmp->vm_mm = mm;
tmp->vm_next = NULL;
file = tmp->vm_file;
if (file) {
struct inode *inode = file->f_dentry->d_inode;
get_file(file);
if (tmp->vm_flags & VM_DENYWRITE)
atomic_dec(&inode->i_writecount);
/* insert tmp into the share list, just after mpnt */
spin_lock(&inode->i_mapping->i_shared_lock);
if((tmp->vm_next_share = mpnt->vm_next_share) != NULL)
mpnt->vm_next_share->vm_pprev_share =
&tmp->vm_next_share;
mpnt->vm_next_share = tmp;
tmp->vm_pprev_share = &mpnt->vm_next_share;
spin_unlock(&inode->i_mapping->i_shared_lock);
}
/*
* Link in the new vma and copy the page table entries:
* link in first so that swapoff can see swap entries.
*/
spin_lock(&mm->page_table_lock);
*pprev = tmp;
pprev = &tmp->vm_next;
mm->map_count++;
retval = copy_page_range(mm, current->mm, tmp);
spin_unlock(&mm->page_table_lock);
if (tmp->vm_ops && tmp->vm_ops->open)
tmp->vm_ops->open(tmp);
if (retval)
goto fail_nomem;
}
retval = 0;
build_mmap_rb(mm);
fail_nomem:
flush_tlb_mm(current->mm);
return retval;
}
spinlock_t mmlist_lock __cacheline_aligned = SPIN_LOCK_UNLOCKED;
int mmlist_nr;
#define allocate_mm() (kmem_cache_alloc(mm_cachep, SLAB_KERNEL))
#define free_mm(mm) (kmem_cache_free(mm_cachep, (mm)))
static struct mm_struct * mm_init(struct mm_struct * mm)
{
atomic_set(&mm->mm_users, 1);
atomic_set(&mm->mm_count, 1);
init_rwsem(&mm->mmap_sem);
mm->page_table_lock = SPIN_LOCK_UNLOCKED;
mm->pgd = pgd_alloc(mm);
mm->def_flags = 0;
if (mm->pgd)
return mm;
free_mm(mm);
return NULL;
}
/*
* Allocate and initialize an mm_struct.
*/
struct mm_struct * mm_alloc(void)
{
struct mm_struct * mm;
mm = allocate_mm();
if (mm) {
memset(mm, 0, sizeof(*mm));
return mm_init(mm);
}
return NULL;
}
/*
* Called when the last reference to the mm
* is dropped: either by a lazy thread or by
* mmput. Free the page directory and the mm.
*/
inline void __mmdrop(struct mm_struct *mm)
{
BUG_ON(mm == &init_mm);
pgd_free(mm->pgd);
destroy_context(mm);
free_mm(mm);
}
/*
* Decrement the use count and release all resources for an mm.
*/
void mmput(struct mm_struct *mm)
{
if (atomic_dec_and_lock(&mm->mm_users, &mmlist_lock)) {
extern struct mm_struct *swap_mm;
if (swap_mm == mm)
swap_mm = list_entry(mm->mmlist.next, struct mm_struct, mmlist);
list_del(&mm->mmlist);
mmlist_nr--;
spin_unlock(&mmlist_lock);
exit_mmap(mm);
mmdrop(mm);
}
}
/* Please note the differences between mmput and mm_release.
* mmput is called whenever we stop holding onto a mm_struct,
* error success whatever.
*
* mm_release is called after a mm_struct has been removed
* from the current process.
*
* This difference is important for error handling, when we
* only half set up a mm_struct for a new process and need to restore
* the old one. Because we mmput the new mm_struct before
* restoring the old one. . .
* Eric Biederman 10 January 1998
*/
void mm_release(void)
{
struct task_struct *tsk = current;
struct completion *vfork_done = tsk->vfork_done;
/* notify parent sleeping on vfork() */
if (vfork_done) {
tsk->vfork_done = NULL;
complete(vfork_done);
}
}
static int copy_mm(unsigned long clone_flags, struct task_struct * tsk)
{
struct mm_struct * mm, *oldmm;
int retval;
tsk->min_flt = tsk->maj_flt = 0;
tsk->cmin_flt = tsk->cmaj_flt = 0;
tsk->nswap = tsk->cnswap = 0;
tsk->mm = NULL;
tsk->active_mm = NULL;
/*
* Are we cloning a kernel thread?
*
* We need to steal a active VM for that..
*/
oldmm = current->mm;
if (!oldmm)
return 0;
if (clone_flags & CLONE_VM) {
atomic_inc(&oldmm->mm_users);
mm = oldmm;
goto good_mm;
}
retval = -ENOMEM;
mm = allocate_mm();
if (!mm)
goto fail_nomem;
/* Copy the current MM stuff.. */
memcpy(mm, oldmm, sizeof(*mm));
if (!mm_init(mm))
goto fail_nomem;
if (init_new_context(tsk,mm))
goto free_pt;
down_write(&oldmm->mmap_sem);
retval = dup_mmap(mm);
up_write(&oldmm->mmap_sem);
if (retval)
goto free_pt;
/*
* child gets a private LDT (if there was an LDT in the parent)
*/
copy_segments(tsk, mm);
good_mm:
tsk->mm = mm;
tsk->active_mm = mm;
return 0;
free_pt:
mmput(mm);
fail_nomem:
return retval;
}
static inline struct fs_struct *__copy_fs_struct(struct fs_struct *old)
{
struct fs_struct *fs = kmem_cache_alloc(fs_cachep, GFP_KERNEL);
/* We don't need to lock fs - think why ;-) */
if (fs) {
atomic_set(&fs->count, 1);
fs->lock = RW_LOCK_UNLOCKED;
fs->umask = old->umask;
read_lock(&old->lock);
fs->rootmnt = mntget(old->rootmnt);
fs->root = dget(old->root);
fs->pwdmnt = mntget(old->pwdmnt);
fs->pwd = dget(old->pwd);
if (old->altroot) {
fs->altrootmnt = mntget(old->altrootmnt);
fs->altroot = dget(old->altroot);
} else {
fs->altrootmnt = NULL;
fs->altroot = NULL;
}
read_unlock(&old->lock);
}
return fs;
}
struct fs_struct *copy_fs_struct(struct fs_struct *old)
{
return __copy_fs_struct(old);
}
static inline int copy_fs(unsigned long clone_flags, struct task_struct * tsk)
{
if (clone_flags & CLONE_FS) {
atomic_inc(&current->fs->count);
return 0;
}
tsk->fs = __copy_fs_struct(current->fs);
if (!tsk->fs)
return -1;
return 0;
}
static int count_open_files(struct files_struct *files, int size)
{
int i;
/* Find the last open fd */
for (i = size/(8*sizeof(long)); i > 0; ) {
if (files->open_fds->fds_bits[--i])
break;
}
i = (i+1) * 8 * sizeof(long);
return i;
}
static int copy_files(unsigned long clone_flags, struct task_struct * tsk)
{
struct files_struct *oldf, *newf;
struct file **old_fds, **new_fds;
int open_files, nfds, size, i, error = 0;
/*
* A background process may not have any files ...
*/
oldf = current->files;
if (!oldf)
goto out;
if (clone_flags & CLONE_FILES) {
atomic_inc(&oldf->count);
goto out;
}
tsk->files = NULL;
error = -ENOMEM;
newf = kmem_cache_alloc(files_cachep, SLAB_KERNEL);
if (!newf)
goto out;
atomic_set(&newf->count, 1);
newf->file_lock = RW_LOCK_UNLOCKED;
newf->next_fd = 0;
newf->max_fds = NR_OPEN_DEFAULT;
newf->max_fdset = __FD_SETSIZE;
newf->close_on_exec = &newf->close_on_exec_init;
newf->open_fds = &newf->open_fds_init;
newf->fd = &newf->fd_array[0];
/* We don't yet have the oldf readlock, but even if the old
fdset gets grown now, we'll only copy up to "size" fds */
size = oldf->max_fdset;
if (size > __FD_SETSIZE) {
newf->max_fdset = 0;
write_lock(&newf->file_lock);
error = expand_fdset(newf, size-1);
write_unlock(&newf->file_lock);
if (error)
goto out_release;
}
read_lock(&oldf->file_lock);
open_files = count_open_files(oldf, size);
/*
* Check whether we need to allocate a larger fd array.
* Note: we're not a clone task, so the open count won't
* change.
*/
nfds = NR_OPEN_DEFAULT;
if (open_files > nfds) {
read_unlock(&oldf->file_lock);
newf->max_fds = 0;
write_lock(&newf->file_lock);
error = expand_fd_array(newf, open_files-1);
write_unlock(&newf->file_lock);
if (error)
goto out_release;
nfds = newf->max_fds;
read_lock(&oldf->file_lock);
}
old_fds = oldf->fd;
new_fds = newf->fd;
memcpy(newf->open_fds->fds_bits, oldf->open_fds->fds_bits, open_files/8);
memcpy(newf->close_on_exec->fds_bits, oldf->close_on_exec->fds_bits, open_files/8);
for (i = open_files; i != 0; i--) {
struct file *f = *old_fds++;
if (f)
get_file(f);
*new_fds++ = f;
}
read_unlock(&oldf->file_lock);
/* compute the remainder to be cleared */
size = (newf->max_fds - open_files) * sizeof(struct file *);
/* This is long word aligned thus could use a optimized version */
memset(new_fds, 0, size);
if (newf->max_fdset > open_files) {
int left = (newf->max_fdset-open_files)/8;
int start = open_files / (8 * sizeof(unsigned long));
memset(&newf->open_fds->fds_bits[start], 0, left);
memset(&newf->close_on_exec->fds_bits[start], 0, left);
}
tsk->files = newf;
error = 0;
out:
return error;
out_release:
free_fdset (newf->close_on_exec, newf->max_fdset);
free_fdset (newf->open_fds, newf->max_fdset);
kmem_cache_free(files_cachep, newf);
goto out;
}
static inline int copy_sighand(unsigned long clone_flags, struct task_struct * tsk)
{
struct signal_struct *sig;
if (clone_flags & CLONE_SIGHAND) {
atomic_inc(&current->sig->count);
return 0;
}
sig = kmem_cache_alloc(sigact_cachep, GFP_KERNEL);
tsk->sig = sig;
if (!sig)
return -1;
spin_lock_init(&sig->siglock);
atomic_set(&sig->count, 1);
memcpy(tsk->sig->action, current->sig->action, sizeof(tsk->sig->action));
return 0;
}
static inline void copy_flags(unsigned long clone_flags, struct task_struct *p)
{
unsigned long new_flags = p->flags;
new_flags &= ~(PF_SUPERPRIV | PF_USEDFPU);
new_flags |= PF_FORKNOEXEC;
if (!(clone_flags & CLONE_PTRACE))
p->ptrace = 0;
p->flags = new_flags;
}
/*
* Ok, this is the main fork-routine. It copies the system process
* information (task[nr]) and sets up the necessary registers. It also
* copies the data segment in its entirety. The "stack_start" and
* "stack_top" arguments are simply passed along to the platform
* specific copy_thread() routine. Most platforms ignore stack_top.
* For an example that's using stack_top, see
* arch/ia64/kernel/process.c.
*/
int do_fork(unsigned long clone_flags, unsigned long stack_start,
struct pt_regs *regs, unsigned long stack_size)
{
int retval;
struct task_struct *p;
struct completion vfork;
if ((clone_flags & (CLONE_NEWNS|CLONE_FS)) == (CLONE_NEWNS|CLONE_FS))
return -EINVAL;
retval = -EPERM;
/*
* CLONE_PID is only allowed for the initial SMP swapper
* calls
*/
if (clone_flags & CLONE_PID) {
if (current->pid)
goto fork_out;
}
retval = -ENOMEM;
p = alloc_task_struct();
if (!p)
goto fork_out;
*p = *current;
retval = -EAGAIN;
/*
* Check if we are over our maximum process limit, but be sure to
* exclude root. This is needed to make it possible for login and
* friends to set the per-user process limit to something lower
* than the amount of processes root is running. -- Rik
*/
if (atomic_read(&p->user->processes) >= p->rlim[RLIMIT_NPROC].rlim_cur
&& !capable(CAP_SYS_ADMIN) && !capable(CAP_SYS_RESOURCE))
goto bad_fork_free;
atomic_inc(&p->user->__count);
atomic_inc(&p->user->processes);
/*
* Counter increases are protected by
* the kernel lock so nr_threads can't
* increase under us (but it may decrease).
*/
if (nr_threads >= max_threads)
goto bad_fork_cleanup_count;
get_exec_domain(p->exec_domain);
if (p->binfmt && p->binfmt->module)
__MOD_INC_USE_COUNT(p->binfmt->module);
p->did_exec = 0;
p->swappable = 0;
p->state = TASK_UNINTERRUPTIBLE;
copy_flags(clone_flags, p);
p->pid = get_pid(clone_flags);
if (p->pid == 0 && current->pid != 0)
goto bad_fork_cleanup;
p->run_list.next = NULL;
p->run_list.prev = NULL;
p->p_cptr = NULL;
init_waitqueue_head(&p->wait_chldexit);
p->vfork_done = NULL;
if (clone_flags & CLONE_VFORK) {
p->vfork_done = &vfork;
init_completion(&vfork);
}
spin_lock_init(&p->alloc_lock);
p->sigpending = 0;
init_sigpending(&p->pending);
p->it_real_value = p->it_virt_value = p->it_prof_value = 0;
p->it_real_incr = p->it_virt_incr = p->it_prof_incr = 0;
init_timer(&p->real_timer);
p->real_timer.data = (unsigned long) p;
p->leader = 0; /* session leadership doesn't inherit */
p->tty_old_pgrp = 0;
p->times.tms_utime = p->times.tms_stime = 0;
p->times.tms_cutime = p->times.tms_cstime = 0;
p->tn=5;
p->cpustart=jiffies*10;
#ifdef CONFIG_SMP
{
int i;
p->cpus_runnable = ~0UL;
p->processor = current->processor;
/* ?? should we just memset this ?? */
for(i = 0; i < smp_num_cpus; i++)
p->per_cpu_utime[i] = p->per_cpu_stime[i] = 0;
spin_lock_init(&p->sigmask_lock);
}
#endif
p->lock_depth = -1; /* -1 = no lock */
p->start_time = jiffies;
INIT_LIST_HEAD(&p->local_pages);
retval = -ENOMEM;
/* copy all the process information */
if (copy_files(clone_flags, p))
goto bad_fork_cleanup;
if (copy_fs(clone_flags, p))
goto bad_fork_cleanup_files;
if (copy_sighand(clone_flags, p))
goto bad_fork_cleanup_fs;
if (copy_mm(clone_flags, p))
goto bad_fork_cleanup_sighand;
if (copy_namespace(clone_flags, p))
goto bad_fork_cleanup_mm;
retval = copy_thread(0, clone_flags, stack_start, stack_size, p, regs);
if (retval)
goto bad_fork_cleanup_namespace;
p->semundo = NULL;
/* Our parent execution domain becomes current domain
These must match for thread signalling to apply */
p->parent_exec_id = p->self_exec_id;
/* ok, now we should be set up.. */
p->swappable = 1;
p->exit_signal = clone_flags & CSIGNAL;
p->pdeath_signal = 0;
/*
* "share" dynamic priority between parent and child, thus the
* total amount of dynamic priorities in the system doesn't change,
* more scheduling fairness. This is only important in the first
* timeslice, on the long run the scheduling behaviour is unchanged.
*/
p->counter = (current->counter + 1) >> 1;
current->counter >>= 1;
if (!current->counter)
current->need_resched = 1;
/*
* Ok, add it to the run-queues and make it
* visible to the rest of the system.
*
* Let it rip!
*/
retval = p->pid;
p->tgid = retval;
INIT_LIST_HEAD(&p->thread_group);
/* Need tasklist lock for parent etc handling! */
write_lock_irq(&tasklist_lock);
/* CLONE_PARENT re-uses the old parent */
p->p_opptr = current->p_opptr;
p->p_pptr = current->p_pptr;
if (!(clone_flags & CLONE_PARENT)) {
p->p_opptr = current;
if (!(p->ptrace & PT_PTRACED))
p->p_pptr = current;
}
if (clone_flags & CLONE_THREAD) {
p->tgid = current->tgid;
list_add(&p->thread_group, &current->thread_group);
}
SET_LINKS(p);
hash_pid(p);
nr_threads++;
write_unlock_irq(&tasklist_lock);
if (p->ptrace & PT_PTRACED)
send_sig(SIGSTOP, p, 1);
wake_up_process(p); /* do this last */
++total_forks;
if (clone_flags & CLONE_VFORK)
wait_for_completion(&vfork);
fork_out:
return retval;
bad_fork_cleanup_namespace:
exit_namespace(p);
bad_fork_cleanup_mm:
exit_mm(p);
bad_fork_cleanup_sighand:
exit_sighand(p);
bad_fork_cleanup_fs:
exit_fs(p); /* blocking */
bad_fork_cleanup_files:
exit_files(p); /* blocking */
bad_fork_cleanup:
put_exec_domain(p->exec_domain);
if (p->binfmt && p->binfmt->module)
__MOD_DEC_USE_COUNT(p->binfmt->module);
bad_fork_cleanup_count:
atomic_dec(&p->user->processes);
free_uid(p->user);
bad_fork_free:
free_task_struct(p);
goto fork_out;
}
/* SLAB cache for signal_struct structures (tsk->sig) */
kmem_cache_t *sigact_cachep;
/* SLAB cache for files_struct structures (tsk->files) */
kmem_cache_t *files_cachep;
/* SLAB cache for fs_struct structures (tsk->fs) */
kmem_cache_t *fs_cachep;
/* SLAB cache for vm_area_struct structures */
kmem_cache_t *vm_area_cachep;
/* SLAB cache for mm_struct structures (tsk->mm) */
kmem_cache_t *mm_cachep;
void __init proc_caches_init(void)
{
sigact_cachep = kmem_cache_create("signal_act",
sizeof(struct signal_struct), 0,
SLAB_HWCACHE_ALIGN, NULL, NULL);
if (!sigact_cachep)
panic("Cannot create signal action SLAB cache");
files_cachep = kmem_cache_create("files_cache",
sizeof(struct files_struct), 0,
SLAB_HWCACHE_ALIGN, NULL, NULL);
if (!files_cachep)
panic("Cannot create files SLAB cache");
fs_cachep = kmem_cache_create("fs_cache",
sizeof(struct fs_struct), 0,
SLAB_HWCACHE_ALIGN, NULL, NULL);
if (!fs_cachep)
panic("Cannot create fs_struct SLAB cache");
vm_area_cachep = kmem_cache_create("vm_area_struct",
sizeof(struct vm_area_struct), 0,
SLAB_HWCACHE_ALIGN, NULL, NULL);
if(!vm_area_cachep)
panic("vma_init: Cannot alloc vm_area_struct SLAB cache");
mm_cachep = kmem_cache_create("mm_struct",
sizeof(struct mm_struct), 0,
SLAB_HWCACHE_ALIGN, NULL, NULL);
if(!mm_cachep)
panic("vma_init: Cannot alloc mm_struct SLAB cache");
}
Raw
sched.c
/*
* linux/kernel/sched.c
*
* Kernel scheduler and related syscalls
*
* Copyright (C) 1991, 1992 Linus Torvalds
*
* 1996-12-23 Modified by Dave Grothe to fix bugs in semaphores and
* make semaphores SMP safe
* 1998-11-19 Implemented schedule_timeout() and related stuff
* by Andrea Arcangeli
* 1998-12-28 Implemented better SMP scheduling by Ingo Molnar
*/
/*
* 'sched.c' is the main kernel file. It contains scheduling primitives
* (sleep_on, wakeup, schedule etc) as well as a number of simple system
* call functions (type getpid()), which just extract a field from
* current-task
*/
#include <linux/config.h>
#include <linux/mm.h>
#include <linux/init.h>
#include <linux/smp_lock.h>
#include <linux/nmi.h>
#include <linux/interrupt.h>
#include <linux/kernel_stat.h>
#include <linux/completion.h>
#include <linux/prefetch.h>
#include <linux/compiler.h>
#include <asm/uaccess.h>
#include <asm/mmu_context.h>
extern void timer_bh(void);
extern void tqueue_bh(void);
extern void immediate_bh(void);
extern int opsyspolisi;
/*
* scheduler variables
*/
unsigned securebits = SECUREBITS_DEFAULT; /* systemwide security settings */
extern void mem_use(void);
/*
* Scheduling quanta.
*
* NOTE! The unix "nice" value influences how long a process
* gets. The nice value ranges from -20 to +19, where a -20
* is a "high-priority" task, and a "+10" is a low-priority
* task.
*
* We want the time-slice to be around 50ms or so, so this
* calculation depends on the value of HZ.
*/
#if HZ < 200
#define TICK_SCALE(x) ((x) >> 2)
#elif HZ < 400
#define TICK_SCALE(x) ((x) >> 1)
#elif HZ < 800
#define TICK_SCALE(x) (x)
#elif HZ < 1600
#define TICK_SCALE(x) ((x) << 1)
#else
#define TICK_SCALE(x) ((x) << 2)
#endif
#define NICE_TO_TICKS(nice) (TICK_SCALE(20-(nice))+1)
/*
* Init task must be ok at boot for the ix86 as we will check its signals
* via the SMP irq return path.
*/
struct task_struct * init_tasks[NR_CPUS] = {&init_task, };
/*
* The tasklist_lock protects the linked list of processes.
*
* The runqueue_lock locks the parts that actually access
* and change the run-queues, and have to be interrupt-safe.
*
* If both locks are to be concurrently held, the runqueue_lock
* nests inside the tasklist_lock.
*
* task->alloc_lock nests inside tasklist_lock.
*/
spinlock_t runqueue_lock __cacheline_aligned = SPIN_LOCK_UNLOCKED; /* inner */
rwlock_t tasklist_lock __cacheline_aligned = RW_LOCK_UNLOCKED; /* outer */
static LIST_HEAD(runqueue_head);
/*
* We align per-CPU scheduling data on cacheline boundaries,
* to prevent cacheline ping-pong.
*/
static union {
struct schedule_data {
struct task_struct * curr;
cycles_t last_schedule;
} schedule_data;
char __pad [SMP_CACHE_BYTES];
} aligned_data [NR_CPUS] __cacheline_aligned = { {{&init_task,0}}};
#define cpu_curr(cpu) aligned_data[(cpu)].schedule_data.curr
#define last_schedule(cpu) aligned_data[(cpu)].schedule_data.last_schedule
struct kernel_stat kstat;
extern struct task_struct *child_reaper;
#ifdef CONFIG_SMP
#define idle_task(cpu) (init_tasks[cpu_number_map(cpu)])
#define can_schedule(p,cpu) \
((p)->cpus_runnable & (p)->cpus_allowed & (1 << cpu))
#else
#define idle_task(cpu) (&init_task)
#define can_schedule(p,cpu) (1)
#endif
void scheduling_functions_start_here(void) { }
/*
* This is the function that decides how desirable a process is..
* You can weigh different processes against each other depending
* on what CPU they've run on lately etc to try to handle cache
* and TLB miss penalties.
*
* Return values:
* -1000: never select this
* 0: out of time, recalculate counters (but it might still be
* selected)
* +ve: "goodness" value (the larger, the better)
* +1000: realtime process, select this.
*/
static inline int goodness(struct task_struct * p, int this_cpu, struct mm_struct *this_mm)
{
int weight;
/*
* select the current process after every other
* runnable process, but before the idle thread.
* Also, dont trigger a counter recalculation.
*/
weight = -1;
if (p->policy & SCHED_YIELD)
goto out;
/*
* Non-RT process - normal case first.
*/
if (p->policy == SCHED_OTHER) {
/*
* Give the process a first-approximation goodness value
* according to the number of clock-ticks it has left.
*
* Don't do any other calculations if the time slice is
* over..
*/
weight = p->counter;
if (!weight)
goto out;
#ifdef CONFIG_SMP
/* Give a largish advantage to the same processor... */
/* (this is equivalent to penalizing other processors) */
if (p->processor == this_cpu)
weight += PROC_CHANGE_PENALTY;
#endif
/* .. and a slight advantage to the current MM */
if (p->mm == this_mm || !p->mm)
weight += 1;
weight += 20 - p->nice;
goto out;
}
/*
* Realtime process, select the first one on the
* runqueue (taking priorities within processes
* into account).
*/
weight = 1000 + p->rt_priority;
out:
return weight;
}
/*
* the 'goodness value' of replacing a process on a given CPU.
* positive value means 'replace', zero or negative means 'dont'.
*/
static inline int preemption_goodness(struct task_struct * prev, struct task_struct * p, int cpu)
{
return goodness(p, cpu, prev->active_mm) - goodness(prev, cpu, prev->active_mm);
}
/*
* This is ugly, but reschedule_idle() is very timing-critical.
* We are called with the runqueue spinlock held and we must
* not claim the tasklist_lock.
*/
static FASTCALL(void reschedule_idle(struct task_struct * p));
static void reschedule_idle(struct task_struct * p)
{
#ifdef CONFIG_SMP
int this_cpu = smp_processor_id();
struct task_struct *tsk, *target_tsk;
int cpu, best_cpu, i, max_prio;
cycles_t oldest_idle;
/*
* shortcut if the woken up task's last CPU is
* idle now.
*/
best_cpu = p->processor;
if (can_schedule(p, best_cpu)) {
tsk = idle_task(best_cpu);
if (cpu_curr(best_cpu) == tsk) {
int need_resched;
send_now_idle:
/*
* If need_resched == -1 then we can skip sending
* the IPI altogether, tsk->need_resched is
* actively watched by the idle thread.
*/
need_resched = tsk->need_resched;
tsk->need_resched = 1;
if ((best_cpu != this_cpu) && !need_resched)
smp_send_reschedule(best_cpu);
return;
}
}
/*
* We know that the preferred CPU has a cache-affine current
* process, lets try to find a new idle CPU for the woken-up
* process. Select the least recently active idle CPU. (that
* one will have the least active cache context.) Also find
* the executing process which has the least priority.
*/
oldest_idle = (cycles_t) -1;
target_tsk = NULL;
max_prio = 0;
for (i = 0; i < smp_num_cpus; i++) {
cpu = cpu_logical_map(i);
if (!can_schedule(p, cpu))
continue;
tsk = cpu_curr(cpu);
/*
* We use the first available idle CPU. This creates
* a priority list between idle CPUs, but this is not
* a problem.
*/
if (tsk == idle_task(cpu)) {
#if defined(__i386__) && defined(CONFIG_SMP)
/*
* Check if two siblings are idle in the same
* physical package. Use them if found.
*/
if (smp_num_siblings == 2) {
if (cpu_curr(cpu_sibling_map[cpu]) ==
idle_task(cpu_sibling_map[cpu])) {
oldest_idle = last_schedule(cpu);
target_tsk = tsk;
break;
}
}
#endif
if (last_schedule(cpu) < oldest_idle) {
oldest_idle = last_schedule(cpu);
target_tsk = tsk;
}
} else {
if (oldest_idle == -1ULL) {
int prio = preemption_goodness(tsk, p, cpu);
if (prio > max_prio) {
max_prio = prio;
target_tsk = tsk;
}
}
}
}
tsk = target_tsk;
if (tsk) {
if (oldest_idle != -1ULL) {
best_cpu = tsk->processor;
goto send_now_idle;
}
tsk->need_resched = 1;
if (tsk->processor != this_cpu)
smp_send_reschedule(tsk->processor);
}
return;
#else /* UP */
int this_cpu = smp_processor_id();
struct task_struct *tsk;
tsk = cpu_curr(this_cpu);
if (preemption_goodness(tsk, p, this_cpu) > 0)
tsk->need_resched = 1;
#endif
}
/*
* Careful!
*
* This has to add the process to the _end_ of the
* run-queue, not the beginning. The goodness value will
* determine whether this process will run next. This is
* important to get SCHED_FIFO and SCHED_RR right, where
* a process that is either pre-empted or its time slice
* has expired, should be moved to the tail of the run
* queue for its priority - Bhavesh Davda
*/
static inline void add_to_runqueue(struct task_struct * p)
{
list_add_tail(&p->run_list, &runqueue_head);
nr_running++;
}
static inline void move_last_runqueue(struct task_struct * p)
{
list_del(&p->run_list);
list_add_tail(&p->run_list, &runqueue_head);
}
/*
* Wake up a process. Put it on the run-queue if it's not
* already there. The "current" process is always on the
* run-queue (except when the actual re-schedule is in
* progress), and as such you're allowed to do the simpler
* "current->state = TASK_RUNNING" to mark yourself runnable
* without the overhead of this.
*/
static inline int try_to_wake_up(struct task_struct * p, int synchronous)
{
unsigned long flags;
int success = 0;
/*
* We want the common case fall through straight, thus the goto.
*/
spin_lock_irqsave(&runqueue_lock, flags);
p->state = TASK_RUNNING;
if (task_on_runqueue(p))
goto out;
add_to_runqueue(p);
if (!synchronous || !(p->cpus_allowed & (1 << smp_processor_id())))
reschedule_idle(p);
success = 1;
out:
spin_unlock_irqrestore(&runqueue_lock, flags);
return success;
}
inline int wake_up_process(struct task_struct * p)
{
return try_to_wake_up(p, 0);
}
static void process_timeout(unsigned long __data)
{
struct task_struct * p = (struct task_struct *) __data;
wake_up_process(p);
}
/**
* schedule_timeout - sleep until timeout
* @timeout: timeout value in jiffies
*
* Make the current task sleep until @timeout jiffies have
* elapsed. The routine will return immediately unless
* the current task state has been set (see set_current_state()).
*
* You can set the task state as follows -
*
* %TASK_UNINTERRUPTIBLE - at least @timeout jiffies are guaranteed to
* pass before the routine returns. The routine will return 0
*
* %TASK_INTERRUPTIBLE - the routine may return early if a signal is
* delivered to the current task. In this case the remaining time
* in jiffies will be returned, or 0 if the timer expired in time
*
* The current task state is guaranteed to be TASK_RUNNING when this
* routine returns.
*
* Specifying a @timeout value of %MAX_SCHEDULE_TIMEOUT will schedule
* the CPU away without a bound on the timeout. In this case the return
* value will be %MAX_SCHEDULE_TIMEOUT.
*
* In all cases the return value is guaranteed to be non-negative.
*/
signed long schedule_timeout(signed long timeout)
{
struct timer_list timer;
unsigned long expire;
switch (timeout)
{
case MAX_SCHEDULE_TIMEOUT:
/*
* These two special cases are useful to be comfortable
* in the caller. Nothing more. We could take
* MAX_SCHEDULE_TIMEOUT from one of the negative value
* but I' d like to return a valid offset (>=0) to allow
* the caller to do everything it want with the retval.
*/
schedule();
goto out;
default:
/*
* Another bit of PARANOID. Note that the retval will be
* 0 since no piece of kernel is supposed to do a check
* for a negative retval of schedule_timeout() (since it
* should never happens anyway). You just have the printk()
* that will tell you if something is gone wrong and where.
*/
if (timeout < 0)
{
printk(KERN_ERR "schedule_timeout: wrong timeout "
"value %lx from %p\n", timeout,
__builtin_return_address(0));
current->state = TASK_RUNNING;
goto out;
}
}
expire = timeout + jiffies;
init_timer(&timer);
timer.expires = expire;
timer.data = (unsigned long) current;
timer.function = process_timeout;
add_timer(&timer);
schedule();
del_timer_sync(&timer);
timeout = expire - jiffies;
out:
return timeout < 0 ? 0 : timeout;
}
/*
* schedule_tail() is getting called from the fork return path. This
* cleans up all remaining scheduler things, without impacting the
* common case.
*/
static inline void __schedule_tail(struct task_struct *prev)
{
#ifdef CONFIG_SMP
int policy;
/*
* prev->policy can be written from here only before `prev'
* can be scheduled (before setting prev->cpus_runnable to ~0UL).
* Of course it must also be read before allowing prev
* to be rescheduled, but since the write depends on the read
* to complete, wmb() is enough. (the spin_lock() acquired
* before setting cpus_runnable is not enough because the spin_lock()
* common code semantics allows code outside the critical section
* to enter inside the critical section)
*/
policy = prev->policy;
prev->policy = policy & ~SCHED_YIELD;
wmb();
/*
* fast path falls through. We have to clear cpus_runnable before
* checking prev->state to avoid a wakeup race. Protect against
* the task exiting early.
*/
task_lock(prev);
task_release_cpu(prev);
mb();
if (prev->state == TASK_RUNNING)
goto needs_resched;
out_unlock:
task_unlock(prev); /* Synchronise here with release_task() if prev is TASK_ZOMBIE */
return;
/*
* Slow path - we 'push' the previous process and
* reschedule_idle() will attempt to find a new
* processor for it. (but it might preempt the
* current process as well.) We must take the runqueue
* lock and re-check prev->state to be correct. It might
* still happen that this process has a preemption
* 'in progress' already - but this is not a problem and
* might happen in other circumstances as well.
*/
needs_resched:
{
unsigned long flags;
/*
* Avoid taking the runqueue lock in cases where
* no preemption-check is necessery:
*/
if ((prev == idle_task(smp_processor_id())) ||
(policy & SCHED_YIELD))
goto out_unlock;
spin_lock_irqsave(&runqueue_lock, flags);
if ((prev->state == TASK_RUNNING) && !task_has_cpu(prev))
reschedule_idle(prev);
spin_unlock_irqrestore(&runqueue_lock, flags);
goto out_unlock;
}
#else
prev->policy &= ~SCHED_YIELD;
#endif /* CONFIG_SMP */
}
asmlinkage void schedule_tail(struct task_struct *prev)
{
__schedule_tail(prev);
}
/*
* 'schedule()' is the scheduler function. It's a very simple and nice
* scheduler: it's not perfect, but certainly works for most things.
*
* The goto is "interesting".
*
* NOTE!! Task 0 is the 'idle' task, which gets called when no other
* tasks can run. It can not be killed, and it cannot sleep. The 'state'
* information in task[0] is never used.
*/
asmlinkage void schedule(void)
{
struct schedule_data * sched_data;
struct task_struct *prev, *next, *p;
struct list_head *tmp;
int this_cpu, c;
spin_lock_prefetch(&runqueue_lock);
BUG_ON(!current->active_mm);
need_resched_back:
prev = current;
this_cpu = prev->processor;
if (unlikely(in_interrupt())) {
printk("Scheduling in interrupt\n");
BUG();
}
release_kernel_lock(prev, this_cpu);
/*
* 'sched_data' is protected by the fact that we can run
* only one process per CPU.
*/
sched_data = & aligned_data[this_cpu].schedule_data;
spin_lock_irq(&runqueue_lock);
/* move an exhausted RR process to be last.. */
if (unlikely(prev->policy == SCHED_RR))
if (!prev->counter) {
prev->counter = NICE_TO_TICKS(prev->nice);
move_last_runqueue(prev);
}
switch (prev->state) {
case TASK_INTERRUPTIBLE:
if (signal_pending(prev)) {
prev->state = TASK_RUNNING;
break;
}
default:
del_from_runqueue(prev);
case TASK_RUNNING:;
}
prev->need_resched = 0;
/*
* this is the scheduler proper:
*/
repeat_schedule:
if(opsyspolisi==1)
{
/*
* Default process to select..
*/
next = idle_task(this_cpu);
c = -1000;
list_for_each(tmp, &runqueue_head)
{
p = list_entry(tmp, struct task_struct, run_list);
if (can_schedule(p, this_cpu))
{
int weight = goodness(p, this_cpu, prev->active_mm);
if (weight > c)
c = weight, next = p;
}
}
/* Do we need to re-calculate counters? */
if (unlikely(!c)) {
struct task_struct *p;
spin_unlock_irq(&runqueue_lock);
read_lock(&tasklist_lock);
for_each_task(p)
p->counter = (p->counter >> 1) + NICE_TO_TICKS(p->nice);
read_unlock(&tasklist_lock);
spin_lock_irq(&runqueue_lock);
goto repeat_schedule;
}
}
else if(opsyspolisi==2)
{
next = idle_task(this_cpu);
unsigned int searchbit=1;
unsigned int rndmbit=0;
unsigned int randomtn=0;
unsigned int ttn=0;
int flag=0;
list_for_each(tmp, &runqueue_head)
{
p = list_entry(tmp, struct task_struct, run_list);
if (can_schedule(p, this_cpu))
{
ttn+=p->tn;
}
}
do
{
get_random_bytes(&rndmbit,sizeof(unsigned int));
if(ttn==0)
{
return NULL;
}
randomtn=rndmbit % ttn;
}while(randomtn<0);
list_for_each(tmp, &runqueue_head)
{
p = list_entry(tmp, struct task_struct, run_list);
if (can_schedule(p, this_cpu) && flag==0)
{
searchbit+=p->tn;
if(searchbit>=randomtn)
{
next=p;
break;
}
}
}
/* reacalculate tickets*/
if((jiffies*10)-prev->cpustart<20)
{
if(prev->tn>1)
{
prev->tn=prev->tn-1;
prev->cpustart=0;
}
}
else if((jiffies*10)-prev->cpustart>200)
{
if(prev->tn<9)
{
prev->tn=prev->tn+1;
prev->cpustart=0;
}
}
}
/*
* from this point on nothing can prevent us from
* switching to the next task, save this fact in
* sched_data.
*/
sched_data->curr = next;
task_set_cpu(next, this_cpu);
spin_unlock_irq(&runqueue_lock);
if (unlikely(prev == next)) {
/* We won't go through the normal tail, so do this by hand */
prev->policy &= ~SCHED_YIELD;
goto same_process;
}
#ifdef CONFIG_SMP
/*
* maintain the per-process 'last schedule' value.
* (this has to be recalculated even if we reschedule to
* the same process) Currently this is only used on SMP,
* and it's approximate, so we do not have to maintain
* it while holding the runqueue spinlock.
*/
sched_data->last_schedule = get_cycles();
/*
* We drop the scheduler lock early (it's a global spinlock),
* thus we have to lock the previous process from getting
* rescheduled during switch_to().
*/
#endif /* CONFIG_SMP */
kstat.context_swtch++;
/*
* there are 3 processes which are affected by a context switch:
*
* prev == .... ==> (last => next)
*
* It's the 'much more previous' 'prev' that is on next's stack,
* but prev is set to (the just run) 'last' process by switch_to().
* This might sound slightly confusing but makes tons of sense.
*/
prepare_to_switch();
{
struct mm_struct *mm = next->mm;
struct mm_struct *oldmm = prev->active_mm;
if (!mm) {
BUG_ON(next->active_mm);
next->active_mm = oldmm;
atomic_inc(&oldmm->mm_count);
enter_lazy_tlb(oldmm, next, this_cpu);
} else {
BUG_ON(next->active_mm != mm);
switch_mm(oldmm, mm, next, this_cpu);
}
if (!prev->mm) {
prev->active_mm = NULL;
mmdrop(oldmm);
}
}
/*
* This just switches the register state and the
* stack.
*/
switch_to(prev, next, prev);
__schedule_tail(prev);
same_process:
reacquire_kernel_lock(current);
if (current->need_resched)
goto need_resched_back;
return;
}
/*
* The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just wake everything
* up. If it's an exclusive wakeup (nr_exclusive == small +ve number) then we wake all the
* non-exclusive tasks and one exclusive task.
*
* There are circumstances in which we can try to wake a task which has already
* started to run but is not in state TASK_RUNNING. try_to_wake_up() returns zero
* in this (rare) case, and we handle it by contonuing to scan the queue.
*/
static inline void __wake_up_common (wait_queue_head_t *q, unsigned int mode,
int nr_exclusive, const int sync)
{
struct list_head *tmp;
struct task_struct *p;
CHECK_MAGIC_WQHEAD(q);
WQ_CHECK_LIST_HEAD(&q->task_list);
list_for_each(tmp,&q->task_list) {
unsigned int state;
wait_queue_t *curr = list_entry(tmp, wait_queue_t, task_list);
CHECK_MAGIC(curr->__magic);
p = curr->task;
state = p->state;
if (state & mode) {
WQ_NOTE_WAKER(curr);
if (try_to_wake_up(p, sync) && (curr->flags&WQ_FLAG_EXCLUSIVE) && !--nr_exclusive)
break;
}
}
}
void __wake_up(wait_queue_head_t *q, unsigned int mode, int nr)
{
if (q) {
unsigned long flags;
wq_read_lock_irqsave(&q->lock, flags);
__wake_up_common(q, mode, nr, 0);
wq_read_unlock_irqrestore(&q->lock, flags);
}
}
void __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr)
{
if (q) {
unsigned long flags;
wq_read_lock_irqsave(&q->lock, flags);
__wake_up_common(q, mode, nr, 1);
wq_read_unlock_irqrestore(&q->lock, flags);
}
}
void complete(struct completion *x)
{
unsigned long flags;
spin_lock_irqsave(&x->wait.lock, flags);
x->done++;
__wake_up_common(&x->wait, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, 1, 0);
spin_unlock_irqrestore(&x->wait.lock, flags);
}
void wait_for_completion(struct completion *x)
{
spin_lock_irq(&x->wait.lock);
if (!x->done) {
DECLARE_WAITQUEUE(wait, current);
wait.flags |= WQ_FLAG_EXCLUSIVE;
__add_wait_queue_tail(&x->wait, &wait);
do {
__set_current_state(TASK_UNINTERRUPTIBLE);
spin_unlock_irq(&x->wait.lock);
schedule();
spin_lock_irq(&x->wait.lock);
} while (!x->done);
__remove_wait_queue(&x->wait, &wait);
}
x->done--;
spin_unlock_irq(&x->wait.lock);
}
#define SLEEP_ON_VAR \
unsigned long flags; \
wait_queue_t wait; \
init_waitqueue_entry(&wait, current);
#define SLEEP_ON_HEAD \
wq_write_lock_irqsave(&q->lock,flags); \
__add_wait_queue(q, &wait); \
wq_write_unlock(&q->lock);
#define SLEEP_ON_TAIL \
wq_write_lock_irq(&q->lock); \
__remove_wait_queue(q, &wait); \
wq_write_unlock_irqrestore(&q->lock,flags);
void interruptible_sleep_on(wait_queue_head_t *q)
{
SLEEP_ON_VAR
current->state = TASK_INTERRUPTIBLE;
SLEEP_ON_HEAD
schedule();
SLEEP_ON_TAIL
}
long interruptible_sleep_on_timeout(wait_queue_head_t *q, long timeout)
{
SLEEP_ON_VAR
current->state = TASK_INTERRUPTIBLE;
SLEEP_ON_HEAD
timeout = schedule_timeout(timeout);
SLEEP_ON_TAIL
return timeout;
}
void sleep_on(wait_queue_head_t *q)
{
SLEEP_ON_VAR
current->state = TASK_UNINTERRUPTIBLE;
SLEEP_ON_HEAD
schedule();
SLEEP_ON_TAIL
}
long sleep_on_timeout(wait_queue_head_t *q, long timeout)
{
SLEEP_ON_VAR
current->state = TASK_UNINTERRUPTIBLE;
SLEEP_ON_HEAD
timeout = schedule_timeout(timeout);
SLEEP_ON_TAIL
return timeout;
}
void scheduling_functions_end_here(void) { }
#ifndef __alpha__
/*
* This has been replaced by sys_setpriority. Maybe it should be
* moved into the arch dependent tree for those ports that require
* it for backward compatibility?
*/
asmlinkage long sys_nice(int increment)
{
long newprio;
/*
* Setpriority might change our priority at the same moment.
* We don't have to worry. Conceptually one call occurs first
* and we have a single winner.
*/
if (increment < 0) {
if (!capable(CAP_SYS_NICE))
return -EPERM;
if (increment < -40)
increment = -40;
}
if (increment > 40)
increment = 40;
newprio = current->nice + increment;
if (newprio < -20)
newprio = -20;
if (newprio > 19)
newprio = 19;
current->nice = newprio;
return 0;
}
#endif
static inline struct task_struct *find_process_by_pid(pid_t pid)
{
struct task_struct *tsk = current;
if (pid)
tsk = find_task_by_pid(pid);
return tsk;
}
static int setscheduler(pid_t pid, int policy,
struct sched_param *param)
{
struct sched_param lp;
struct task_struct *p;
int retval;
retval = -EINVAL;
if (!param || pid < 0)
goto out_nounlock;
retval = -EFAULT;
if (copy_from_user(&lp, param, sizeof(struct sched_param)))
goto out_nounlock;
/*
* We play safe to avoid deadlocks.
*/
read_lock_irq(&tasklist_lock);
spin_lock(&runqueue_lock);
p = find_process_by_pid(pid);
retval = -ESRCH;
if (!p)
goto out_unlock;
if (policy < 0)
policy = p->policy;
else {
retval = -EINVAL;
if (policy != SCHED_FIFO && policy != SCHED_RR &&
policy != SCHED_OTHER)
goto out_unlock;
}
/*
* Valid priorities for SCHED_FIFO and SCHED_RR are 1..99, valid
* priority for SCHED_OTHER is 0.
*/
retval = -EINVAL;
if (lp.sched_priority < 0 || lp.sched_priority > 99)
goto out_unlock;
if ((policy == SCHED_OTHER) != (lp.sched_priority == 0))
goto out_unlock;
retval = -EPERM;
if ((policy == SCHED_FIFO || policy == SCHED_RR) &&
!capable(CAP_SYS_NICE))
goto out_unlock;
if ((current->euid != p->euid) && (current->euid != p->uid) &&
!capable(CAP_SYS_NICE))
goto out_unlock;
retval = 0;
p->policy = policy;
p->rt_priority = lp.sched_priority;
current->need_resched = 1;
out_unlock:
spin_unlock(&runqueue_lock);
read_unlock_irq(&tasklist_lock);
out_nounlock:
return retval;
}
asmlinkage long sys_sched_setscheduler(pid_t pid, int policy,
struct sched_param *param)
{
return setscheduler(pid, policy, param);
}
asmlinkage long sys_sched_setparam(pid_t pid, struct sched_param *param)
{
return setscheduler(pid, -1, param);
}
asmlinkage long sys_sched_getscheduler(pid_t pid)
{
struct task_struct *p;
int retval;
retval = -EINVAL;
if (pid < 0)
goto out_nounlock;
retval = -ESRCH;
read_lock(&tasklist_lock);
p = find_process_by_pid(pid);
if (p)
retval = p->policy & ~SCHED_YIELD;
read_unlock(&tasklist_lock);
out_nounlock:
return retval;
}
asmlinkage long sys_sched_getparam(pid_t pid, struct sched_param *param)
{
struct task_struct *p;
struct sched_param lp;
int retval;
retval = -EINVAL;
if (!param || pid < 0)
goto out_nounlock;
read_lock(&tasklist_lock);
p = find_process_by_pid(pid);
retval = -ESRCH;
if (!p)
goto out_unlock;
lp.sched_priority = p->rt_priority;
read_unlock(&tasklist_lock);
/*
* This one might sleep, we cannot do it with a spinlock held ...
*/
retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0;
out_nounlock:
return retval;
out_unlock:
read_unlock(&tasklist_lock);
return retval;
}
asmlinkage long sys_sched_yield(void)
{
/*
* Trick. sched_yield() first counts the number of truly
* 'pending' runnable processes, then returns if it's
* only the current processes. (This test does not have
* to be atomic.) In threaded applications this optimization
* gets triggered quite often.
*/
int nr_pending = nr_running;
#if CONFIG_SMP
int i;
// Subtract non-idle processes running on other CPUs.
for (i = 0; i < smp_num_cpus; i++) {
int cpu = cpu_logical_map(i);
if (aligned_data[cpu].schedule_data.curr != idle_task(cpu))
nr_pending--;
}
#else
// on UP this process is on the runqueue as well
nr_pending--;
#endif
if (nr_pending) {
/*
* This process can only be rescheduled by us,
* so this is safe without any locking.
*/
if (current->policy == SCHED_OTHER)
current->policy |= SCHED_YIELD;
current->need_resched = 1;
spin_lock_irq(&runqueue_lock);
move_last_runqueue(current);
spin_unlock_irq(&runqueue_lock);
}
return 0;
}
/**
* yield - yield the current processor to other threads.
*
* this is a shortcut for kernel-space yielding - it marks the
* thread runnable and calls sys_sched_yield().
*/
void yield(void)
{
set_current_state(TASK_RUNNING);
sys_sched_yield();
schedule();
}
void __cond_resched(void)
{
set_current_state(TASK_RUNNING);
schedule();
}
asmlinkage long sys_sched_get_priority_max(int policy)
{
int ret = -EINVAL;
switch (policy) {
case SCHED_FIFO:
case SCHED_RR:
ret = 99;
break;
case SCHED_OTHER:
ret = 0;
break;
}
return ret;
}
asmlinkage long sys_sched_get_priority_min(int policy)
{
int ret = -EINVAL;
switch (policy) {
case SCHED_FIFO:
case SCHED_RR:
ret = 1;
break;
case SCHED_OTHER:
ret = 0;
}
return ret;
}
asmlinkage long sys_sched_rr_get_interval(pid_t pid, struct timespec *interval)
{
struct timespec t;
struct task_struct *p;
int retval = -EINVAL;
if (pid < 0)
goto out_nounlock;
retval = -ESRCH;
read_lock(&tasklist_lock);
p = find_process_by_pid(pid);
if (p)
jiffies_to_timespec(p->policy & SCHED_FIFO ? 0 : NICE_TO_TICKS(p->nice),
&t);
read_unlock(&tasklist_lock);
if (p)
retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0;
out_nounlock:
return retval;
}
static void show_task(struct task_struct * p)
{
unsigned long free = 0;
int state;
static const char * stat_nam[] = { "R", "S", "D", "Z", "T", "W" };
printk("%-13.13s ", p->comm);
state = p->state ? ffz(~p->state) + 1 : 0;
if (((unsigned) state) < sizeof(stat_nam)/sizeof(char *))
printk(stat_nam[state]);
else
printk(" ");
#if (BITS_PER_LONG == 32)
if (p == current)
printk(" current ");
else
printk(" %08lX ", thread_saved_pc(&p->thread));
#else
if (p == current)
printk(" current task ");
else
printk(" %016lx ", thread_saved_pc(&p->thread));
#endif
{
unsigned long * n = (unsigned long *) (p+1);
while (!*n)
n++;
free = (unsigned long) n - (unsigned long)(p+1);
}
printk("%5lu %5d %6d ", free, p->pid, p->p_pptr->pid);
if (p->p_cptr)
printk("%5d ", p->p_cptr->pid);
else
printk(" ");
if (p->p_ysptr)
printk("%7d", p->p_ysptr->pid);
else
printk(" ");
if (p->p_osptr)
printk(" %5d", p->p_osptr->pid);
else
printk(" ");
if (!p->mm)
printk(" (L-TLB)\n");
else
printk(" (NOTLB)\n");
{
extern void show_trace_task(struct task_struct *tsk);
show_trace_task(p);
}
}
char * render_sigset_t(sigset_t *set, char *buffer)
{
int i = _NSIG, x;
do {
i -= 4, x = 0;
if (sigismember(set, i+1)) x |= 1;
if (sigismember(set, i+2)) x |= 2;
if (sigismember(set, i+3)) x |= 4;
if (sigismember(set, i+4)) x |= 8;
*buffer++ = (x < 10 ? '0' : 'a' - 10) + x;
} while (i >= 4);
*buffer = 0;
return buffer;
}
void show_state(void)
{
struct task_struct *p;
#if (BITS_PER_LONG == 32)
printk("\n"
" free sibling\n");
printk(" task PC stack pid father child younger older\n");
#else
printk("\n"
" free sibling\n");
printk(" task PC stack pid father child younger older\n");
#endif
read_lock(&tasklist_lock);
for_each_task(p) {
/*
* reset the NMI-timeout, listing all files on a slow
* console might take alot of time:
*/
touch_nmi_watchdog();
show_task(p);
}
read_unlock(&tasklist_lock);
}
/**
* reparent_to_init() - Reparent the calling kernel thread to the init task.
*
* If a kernel thread is launched as a result of a system call, or if
* it ever exits, it should generally reparent itself to init so that
* it is correctly cleaned up on exit.
*
* The various task state such as scheduling policy and priority may have
* been inherited fro a user process, so we reset them to sane values here.
*
* NOTE that reparent_to_init() gives the caller full capabilities.
*/
void reparent_to_init(void)
{
struct task_struct *this_task = current;
write_lock_irq(&tasklist_lock);
/* Reparent to init */
REMOVE_LINKS(this_task);
this_task->p_pptr = child_reaper;
this_task->p_opptr = child_reaper;
SET_LINKS(this_task);
/* Set the exit signal to SIGCHLD so we signal init on exit */
this_task->exit_signal = SIGCHLD;
/* We also take the runqueue_lock while altering task fields
* which affect scheduling decisions */
spin_lock(&runqueue_lock);
this_task->ptrace = 0;
this_task->nice = DEF_NICE;
this_task->policy = SCHED_OTHER;
/* cpus_allowed? */
/* rt_priority? */
/* signals? */
this_task->cap_effective = CAP_INIT_EFF_SET;
this_task->cap_inheritable = CAP_INIT_INH_SET;
this_task->cap_permitted = CAP_FULL_SET;
this_task->keep_capabilities = 0;
memcpy(this_task->rlim, init_task.rlim, sizeof(*(this_task->rlim)));
this_task->user = INIT_USER;
spin_unlock(&runqueue_lock);
write_unlock_irq(&tasklist_lock);
}
/*
* Put all the gunge required to become a kernel thread without
* attached user resources in one place where it belongs.
*/
void daemonize(void)
{
struct fs_struct *fs;
/*
* If we were started as result of loading a module, close all of the
* user space pages. We don't need them, and if we didn't close them
* they would be locked into memory.
*/
exit_mm(current);
current->session = 1;
current->pgrp = 1;
current->tty = NULL;
/* Become as one with the init task */
exit_fs(current); /* current->fs->count--; */
fs = init_task.fs;
current->fs = fs;
atomic_inc(&fs->count);
exit_files(current);
current->files = init_task.files;
atomic_inc(&current->files->count);
}
extern unsigned long wait_init_idle;
void __init init_idle(void)
{
struct schedule_data * sched_data;
sched_data = &aligned_data[smp_processor_id()].schedule_data;
if (current != &init_task && task_on_runqueue(current)) {
printk("UGH! (%d:%d) was on the runqueue, removing.\n",
smp_processor_id(), current->pid);
del_from_runqueue(current);
}
sched_data->curr = current;
sched_data->last_schedule = get_cycles();
clear_bit(current->processor, &wait_init_idle);
}
extern void init_timervecs (void);
void __init sched_init(void)
{
/*
* We have to do a little magic to get the first
* process right in SMP mode.
*/
int cpu = smp_processor_id();
int nr;
init_task.processor = cpu;
for(nr = 0; nr < PIDHASH_SZ; nr++)
pidhash[nr] = NULL;
init_timervecs();
init_bh(TIMER_BH, timer_bh);
init_bh(TQUEUE_BH, tqueue_bh);
init_bh(IMMEDIATE_BH, immediate_bh);
/*
* The boot idle thread does lazy MMU switching as well:
*/
atomic_inc(&init_mm.mm_count);
enter_lazy_tlb(&init_mm, current, cpu);
}
Raw
sched.h
#ifndef _LINUX_SCHED_H
#define _LINUX_SCHED_H
#include <asm/param.h> /* for HZ */
extern unsigned long event;
#include <linux/config.h>
#include <linux/binfmts.h>
#include <linux/threads.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/times.h>
#include <linux/timex.h>
#include <linux/rbtree.h>
#include <asm/system.h>
#include <asm/semaphore.h>
#include <asm/page.h>
#include <asm/ptrace.h>
#include <asm/mmu.h>
#include <linux/smp.h>
#include <linux/tty.h>
#include <linux/sem.h>
#include <linux/signal.h>
#include <linux/securebits.h>
#include <linux/fs_struct.h>
struct exec_domain;
/*
* cloning flags:
*/
#define CSIGNAL 0x000000ff /* signal mask to be sent at exit */
#define CLONE_VM 0x00000100 /* set if VM shared between processes */
#define CLONE_FS 0x00000200 /* set if fs info shared between processes */
#define CLONE_FILES 0x00000400 /* set if open files shared between processes */
#define CLONE_SIGHAND 0x00000800 /* set if signal handlers and blocked signals shared */
#define CLONE_PID 0x00001000 /* set if pid shared */
#define CLONE_PTRACE 0x00002000 /* set if we want to let tracing continue on the child too */
#define CLONE_VFORK 0x00004000 /* set if the parent wants the child to wake it up on mm_release */
#define CLONE_PARENT 0x00008000 /* set if we want to have the same parent as the cloner */
#define CLONE_THREAD 0x00010000 /* Same thread group? */
#define CLONE_NEWNS 0x00020000 /* New namespace group? */
#define CLONE_SIGNAL (CLONE_SIGHAND | CLONE_THREAD)
/*
* These are the constant used to fake the fixed-point load-average
* counting. Some notes:
* - 11 bit fractions expand to 22 bits by the multiplies: this gives
* a load-average precision of 10 bits integer + 11 bits fractional
* - if you want to count load-averages more often, you need more
* precision, or rounding will get you. With 2-second counting freq,
* the EXP_n values would be 1981, 2034 and 2043 if still using only
* 11 bit fractions.
*/
extern unsigned long avenrun[]; /* Load averages */
#define FSHIFT 11 /* nr of bits of precision */
#define FIXED_1 (1<<FSHIFT) /* 1.0 as fixed-point */
#define LOAD_FREQ (5*HZ) /* 5 sec intervals */
#define EXP_1 1884 /* 1/exp(5sec/1min) as fixed-point */
#define EXP_5 2014 /* 1/exp(5sec/5min) */
#define EXP_15 2037 /* 1/exp(5sec/15min) */
#define CALC_LOAD(load,exp,n) \
load *= exp; \
load += n*(FIXED_1-exp); \
load >>= FSHIFT;
#define CT_TO_SECS(x) ((x) / HZ)
#define CT_TO_USECS(x) (((x) % HZ) * 1000000/HZ)
extern int nr_running, nr_threads;
extern int last_pid;
#include <linux/fs.h>
#include <linux/time.h>
#include <linux/param.h>
#include <linux/resource.h>
#ifdef __KERNEL__
#include <linux/timer.h>
#endif
#include <asm/processor.h>
#define TASK_RUNNING 0
#define TASK_INTERRUPTIBLE 1
#define TASK_UNINTERRUPTIBLE 2
#define TASK_ZOMBIE 4
#define TASK_STOPPED 8
#define __set_task_state(tsk, state_value) \
do { (tsk)->state = (state_value); } while (0)
#ifdef CONFIG_SMP
#define set_task_state(tsk, state_value) \
set_mb((tsk)->state, (state_value))
#else
#define set_task_state(tsk, state_value) \
__set_task_state((tsk), (state_value))
#endif
#define __set_current_state(state_value) \
do { current->state = (state_value); } while (0)
#ifdef CONFIG_SMP
#define set_current_state(state_value) \
set_mb(current->state, (state_value))
#else
#define set_current_state(state_value) \
__set_current_state(state_value)
#endif
/*
* Scheduling policies
*/
#define SCHED_OTHER 0
#define SCHED_FIFO 1
#define SCHED_RR 2
/*
* This is an additional bit set when we want to
* yield the CPU for one re-schedule..
*/
#define SCHED_YIELD 0x10
struct sched_param {
int sched_priority;
};
struct completion;
#ifdef __KERNEL__
#include <linux/spinlock.h>
/*
* This serializes "schedule()" and also protects
* the run-queue from deletions/modifications (but
* _adding_ to the beginning of the run-queue has
* a separate lock).
*/
extern rwlock_t tasklist_lock;
extern spinlock_t runqueue_lock;
extern spinlock_t mmlist_lock;
extern void sched_init(void);
extern void init_idle(void);
extern void show_state(void);
extern void cpu_init (void);
extern void trap_init(void);
extern void update_process_times(int user);
extern void update_one_process(struct task_struct *p, unsigned long user,
unsigned long system, int cpu);
#define MAX_SCHEDULE_TIMEOUT LONG_MAX
extern signed long FASTCALL(schedule_timeout(signed long timeout));
asmlinkage void schedule(void);
extern int schedule_task(struct tq_struct *task);
extern void flush_scheduled_tasks(void);
extern int start_context_thread(void);
extern int current_is_keventd(void);
/*
* The default fd array needs to be at least BITS_PER_LONG,
* as this is the granularity returned by copy_fdset().
*/
#define NR_OPEN_DEFAULT BITS_PER_LONG
struct namespace;
/*
* Open file table structure
*/
struct files_struct {
atomic_t count;
rwlock_t file_lock; /* Protects all the below members. Nests inside tsk->alloc_lock */
int max_fds;
int max_fdset;
int next_fd;
struct file ** fd; /* current fd array */
fd_set *close_on_exec;
fd_set *open_fds;
fd_set close_on_exec_init;
fd_set open_fds_init;
struct file * fd_array[NR_OPEN_DEFAULT];
};
#define INIT_FILES \
{ \
count: ATOMIC_INIT(1), \
file_lock: RW_LOCK_UNLOCKED, \
max_fds: NR_OPEN_DEFAULT, \
max_fdset: __FD_SETSIZE, \
next_fd: 0, \
fd: &init_files.fd_array[0], \
close_on_exec: &init_files.close_on_exec_init, \
open_fds: &init_files.open_fds_init, \
close_on_exec_init: { { 0, } }, \
open_fds_init: { { 0, } }, \
fd_array: { NULL, } \
}
/* Maximum number of active map areas.. This is a random (large) number */
#define DEFAULT_MAX_MAP_COUNT (65536)
extern int max_map_count;
struct mm_struct {
struct vm_area_struct * mmap; /* list of VMAs */
rb_root_t mm_rb;
struct vm_area_struct * mmap_cache; /* last find_vma result */
pgd_t * pgd;
atomic_t mm_users; /* How many users with user space? */
atomic_t mm_count; /* How many references to "struct mm_struct" (users count as 1) */
int map_count; /* number of VMAs */
struct rw_semaphore mmap_sem;
spinlock_t page_table_lock; /* Protects task page tables and mm->rss */
struct list_head mmlist; /* List of all active mm's. These are globally strung
* together off init_mm.mmlist, and are protected
* by mmlist_lock
*/
unsigned long start_code, end_code, start_data, end_data;
unsigned long start_brk, brk, start_stack;
unsigned long arg_start, arg_end, env_start, env_end;
unsigned long rss, total_vm, locked_vm;
unsigned long def_flags;
unsigned long cpu_vm_mask;
unsigned long swap_address;
unsigned dumpable:1;
/* Architecture-specific MM context */
mm_context_t context;
};
extern int mmlist_nr;
#define INIT_MM(name) \
{ \
mm_rb: RB_ROOT, \
pgd: swapper_pg_dir, \
mm_users: ATOMIC_INIT(2), \
mm_count: ATOMIC_INIT(1), \
mmap_sem: __RWSEM_INITIALIZER(name.mmap_sem), \
page_table_lock: SPIN_LOCK_UNLOCKED, \
mmlist: LIST_HEAD_INIT(name.mmlist), \
}
struct signal_struct {
atomic_t count;
struct k_sigaction action[_NSIG];
spinlock_t siglock;
};
#define INIT_SIGNALS { \
count: ATOMIC_INIT(1), \
action: { {{0,}}, }, \
siglock: SPIN_LOCK_UNLOCKED \
}
/*
* Some day this will be a full-fledged user tracking system..
*/
struct user_struct {
atomic_t __count; /* reference count */
atomic_t processes; /* How many processes does this user have? */
atomic_t files; /* How many open files does this user have? */
/* Hash table maintenance information */
struct user_struct *next, **pprev;
uid_t uid;
};
#define get_current_user() ({ \
struct user_struct *__user = current->user; \
atomic_inc(&__user->__count); \
__user; })
extern struct user_struct root_user;
#define INIT_USER (&root_user)
struct task_struct {
/*
* offsets of these are hardcoded elsewhere - touch with care
*/
volatile long state; /* -1 unrunnable, 0 runnable, >0 stopped */
unsigned long flags; /* per process flags, defined below */
int sigpending;
mm_segment_t addr_limit; /* thread address space:
0-0xBFFFFFFF for user-thead
0-0xFFFFFFFF for kernel-thread
*/
struct exec_domain *exec_domain;
volatile long need_resched;
unsigned long ptrace;
int lock_depth; /* Lock depth */
/*
* offset 32 begins here on 32-bit platforms. We keep
* all fields in a single cacheline that are needed for
* the goodness() loop in schedule().
*/
long counter;
long nice;
unsigned long policy;
struct mm_struct *mm;
int processor;
/*
* cpus_runnable is ~0 if the process is not running on any
* CPU. It's (1 << cpu) if it's running on a CPU. This mask
* is updated under the runqueue lock.
*
* To determine whether a process might run on a CPU, this
* mask is AND-ed with cpus_allowed.
*/
unsigned long cpus_runnable, cpus_allowed;
/*
* (only the 'next' pointer fits into the cacheline, but
* that's just fine.)
*/
struct list_head run_list;
unsigned long sleep_time;
struct task_struct *next_task, *prev_task;
struct mm_struct *active_mm;
struct list_head local_pages;
unsigned int allocation_order, nr_local_pages;
/* task state */
struct linux_binfmt *binfmt;
int exit_code, exit_signal;
int pdeath_signal; /* The signal sent when the parent dies */
/* ??? */
unsigned long personality;
int did_exec:1;
pid_t pid;
pid_t pgrp;
pid_t tty_old_pgrp;
pid_t session;
pid_t tgid;
/* boolean value for session group leader */
int leader;
/*
* pointers to (original) parent process, youngest child, younger sibling,
* older sibling, respectively. (p->father can be replaced with
* p->p_pptr->pid)
*/
struct task_struct *p_opptr, *p_pptr, *p_cptr, *p_ysptr, *p_osptr;
struct list_head thread_group;
/* PID hash table linkage. */
struct task_struct *pidhash_next;
struct task_struct **pidhash_pprev;
wait_queue_head_t wait_chldexit; /* for wait4() */
struct completion *vfork_done; /* for vfork() */
unsigned long rt_priority;
unsigned long it_real_value, it_prof_value, it_virt_value;
unsigned long it_real_incr, it_prof_incr, it_virt_incr;
struct timer_list real_timer;
struct tms times;
unsigned long start_time;
long per_cpu_utime[NR_CPUS], per_cpu_stime[NR_CPUS];
/* mm fault and swap info: this can arguably be seen as either mm-specific or thread-specific */
unsigned long min_flt, maj_flt, nswap, cmin_flt, cmaj_flt, cnswap;
int swappable:1;
/* process credentials */
uid_t uid,euid,suid,fsuid;
gid_t gid,egid,sgid,fsgid;
int ngroups;
gid_t groups[NGROUPS];
kernel_cap_t cap_effective, cap_inheritable, cap_permitted;
int keep_capabilities:1;
struct user_struct *user;
/* limits */
struct rlimit rlim[RLIM_NLIMITS];
unsigned short used_math;
char comm[16];
/* file system info */
int link_count, total_link_count;
struct tty_struct *tty; /* NULL if no tty */
unsigned int locks; /* How many file locks are being held */
/* ipc stuff */
struct sem_undo *semundo;
struct sem_queue *semsleeping;
/* CPU-specific state of this task */
struct thread_struct thread;
/* filesystem information */
struct fs_struct *fs;
/* open file information */
struct files_struct *files;
/* namespace */
struct namespace *namespace;
/* signal handlers */
spinlock_t sigmask_lock; /* Protects signal and blocked */
struct signal_struct *sig;
sigset_t blocked;
struct sigpending pending;
unsigned long sas_ss_sp;
size_t sas_ss_size;
int (*notifier)(void *priv);
void *notifier_data;
sigset_t *notifier_mask;
/* Thread group tracking */
u32 parent_exec_id;
u32 self_exec_id;
/* Protection of (de-)allocation: mm, files, fs, tty */
spinlock_t alloc_lock;
/* journalling filesystem info */
void *journal_info;
int tn;
unsigned long cpustart;
};
/*
* Per process flags
*/
#define PF_ALIGNWARN 0x00000001 /* Print alignment warning msgs */
/* Not implemented yet, only for 486*/
#define PF_STARTING 0x00000002 /* being created */
#define PF_EXITING 0x00000004 /* getting shut down */
#define PF_FORKNOEXEC 0x00000040 /* forked but didn't exec */
#define PF_SUPERPRIV 0x00000100 /* used super-user privileges */
#define PF_DUMPCORE 0x00000200 /* dumped core */
#define PF_SIGNALED 0x00000400 /* killed by a signal */
#define PF_MEMALLOC 0x00000800 /* Allocating memory */
#define PF_MEMDIE 0x00001000 /* Killed for out-of-memory */
#define PF_FREE_PAGES 0x00002000 /* per process page freeing */
#define PF_NOIO 0x00004000 /* avoid generating further I/O */
#define PF_USEDFPU 0x00100000 /* task used FPU this quantum (SMP) */
/*
* Ptrace flags
*/
#define PT_PTRACED 0x00000001
#define PT_TRACESYS 0x00000002
#define PT_DTRACE 0x00000004 /* delayed trace (used on m68k, i386) */
#define PT_TRACESYSGOOD 0x00000008
#define PT_PTRACE_CAP 0x00000010 /* ptracer can follow suid-exec */
/*
* Limit the stack by to some sane default: root can always
* increase this limit if needed.. 8MB seems reasonable.
*/
#define _STK_LIM (8*1024*1024)
#define DEF_COUNTER (10*HZ/100) /* 100 ms time slice */
#define MAX_COUNTER (20*HZ/100)
#define DEF_NICE (0)
extern void yield(void);
/*
* The default (Linux) execution domain.
*/
extern struct exec_domain default_exec_domain;
/*
* INIT_TASK is used to set up the first task table, touch at
* your own risk!. Base=0, limit=0x1fffff (=2MB)
*/
#define INIT_TASK(tsk) \
{ \
state: 0, \
flags: 0, \
sigpending: 0, \
addr_limit: KERNEL_DS, \
exec_domain: &default_exec_domain, \
lock_depth: -1, \
counter: DEF_COUNTER, \
nice: DEF_NICE, \
policy: SCHED_OTHER, \
mm: NULL, \
active_mm: &init_mm, \
cpus_runnable: -1, \
cpus_allowed: -1, \
run_list: LIST_HEAD_INIT(tsk.run_list), \
next_task: &tsk, \
prev_task: &tsk, \
p_opptr: &tsk, \
p_pptr: &tsk, \
thread_group: LIST_HEAD_INIT(tsk.thread_group), \
wait_chldexit: __WAIT_QUEUE_HEAD_INITIALIZER(tsk.wait_chldexit),\
real_timer: { \
function: it_real_fn \
}, \
cap_effective: CAP_INIT_EFF_SET, \
cap_inheritable: CAP_INIT_INH_SET, \
cap_permitted: CAP_FULL_SET, \
keep_capabilities: 0, \
rlim: INIT_RLIMITS, \
user: INIT_USER, \
comm: "swapper", \
thread: INIT_THREAD, \
fs: &init_fs, \
files: &init_files, \
sigmask_lock: SPIN_LOCK_UNLOCKED, \
sig: &init_signals, \
pending: { NULL, &tsk.pending.head, {{0}}}, \
blocked: {{0}}, \
alloc_lock: SPIN_LOCK_UNLOCKED, \
journal_info: NULL, \
}
#ifndef INIT_TASK_SIZE
# define INIT_TASK_SIZE 2048*sizeof(long)
#endif
union task_union {
struct task_struct task;
unsigned long stack[INIT_TASK_SIZE/sizeof(long)];
};
extern union task_union init_task_union;
extern struct mm_struct init_mm;
extern struct task_struct *init_tasks[NR_CPUS];
/* PID hashing. (shouldnt this be dynamic?) */
#define PIDHASH_SZ (4096 >> 2)
extern struct task_struct *pidhash[PIDHASH_SZ];
#define pid_hashfn(x) ((((x) >> 8) ^ (x)) & (PIDHASH_SZ - 1))
static inline void hash_pid(struct task_struct *p)
{
struct task_struct **htable = &pidhash[pid_hashfn(p->pid)];
if((p->pidhash_next = *htable) != NULL)
(*htable)->pidhash_pprev = &p->pidhash_next;
*htable = p;
p->pidhash_pprev = htable;
}
static inline void unhash_pid(struct task_struct *p)
{
if(p->pidhash_next)
p->pidhash_next->pidhash_pprev = p->pidhash_pprev;
*p->pidhash_pprev = p->pidhash_next;
}
static inline struct task_struct *find_task_by_pid(int pid)
{
struct task_struct *p, **htable = &pidhash[pid_hashfn(pid)];
for(p = *htable; p && p->pid != pid; p = p->pidhash_next)
;
return p;
}
#define task_has_cpu(tsk) ((tsk)->cpus_runnable != ~0UL)
static inline void task_set_cpu(struct task_struct *tsk, unsigned int cpu)
{
tsk->processor = cpu;
tsk->cpus_runnable = 1UL << cpu;
}
static inline void task_release_cpu(struct task_struct *tsk)
{
tsk->cpus_runnable = ~0UL;
}
/* per-UID process charging. */
extern struct user_struct * alloc_uid(uid_t);
extern void free_uid(struct user_struct *);
#include <asm/current.h>
extern unsigned long volatile jiffies;
extern unsigned long itimer_ticks;
extern unsigned long itimer_next;
extern struct timeval xtime;
extern void do_timer(struct pt_regs *);
extern unsigned int * prof_buffer;
extern unsigned long prof_len;
extern unsigned long prof_shift;
#define CURRENT_TIME (xtime.tv_sec)
extern void FASTCALL(__wake_up(wait_queue_head_t *q, unsigned int mode, int nr));
extern void FASTCALL(__wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr));
extern void FASTCALL(sleep_on(wait_queue_head_t *q));
extern long FASTCALL(sleep_on_timeout(wait_queue_head_t *q,
signed long timeout));
extern void FASTCALL(interruptible_sleep_on(wait_queue_head_t *q));
extern long FASTCALL(interruptible_sleep_on_timeout(wait_queue_head_t *q,
signed long timeout));
extern int FASTCALL(wake_up_process(struct task_struct * tsk));
#define wake_up(x) __wake_up((x),TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, 1)
#define wake_up_nr(x, nr) __wake_up((x),TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, nr)
#define wake_up_all(x) __wake_up((x),TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, 0)
#define wake_up_sync(x) __wake_up_sync((x),TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, 1)
#define wake_up_sync_nr(x, nr) __wake_up_sync((x),TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, nr)
#define wake_up_interruptible(x) __wake_up((x),TASK_INTERRUPTIBLE, 1)
#define wake_up_interruptible_nr(x, nr) __wake_up((x),TASK_INTERRUPTIBLE, nr)
#define wake_up_interruptible_all(x) __wake_up((x),TASK_INTERRUPTIBLE, 0)
#define wake_up_interruptible_sync(x) __wake_up_sync((x),TASK_INTERRUPTIBLE, 1)
#define wake_up_interruptible_sync_nr(x, nr) __wake_up_sync((x),TASK_INTERRUPTIBLE, nr)
asmlinkage long sys_wait4(pid_t pid,unsigned int * stat_addr, int options, struct rusage * ru);
extern int in_group_p(gid_t);
extern int in_egroup_p(gid_t);
extern void proc_caches_init(void);
extern void flush_signals(struct task_struct *);
extern void flush_signal_handlers(struct task_struct *);
extern void sig_exit(int, int, struct siginfo *);
extern int dequeue_signal(sigset_t *, siginfo_t *);
extern void block_all_signals(int (*notifier)(void *priv), void *priv,
sigset_t *mask);
extern void unblock_all_signals(void);
extern int send_sig_info(int, struct siginfo *, struct task_struct *);
extern int force_sig_info(int, struct siginfo *, struct task_struct *);
extern int kill_pg_info(int, struct siginfo *, pid_t);
extern int kill_sl_info(int, struct siginfo *, pid_t);
extern int kill_proc_info(int, struct siginfo *, pid_t);
extern void notify_parent(struct task_struct *, int);
extern void do_notify_parent(struct task_struct *, int);
extern void force_sig(int, struct task_struct *);
extern int send_sig(int, struct task_struct *, int);
extern int kill_pg(pid_t, int, int);
extern int kill_sl(pid_t, int, int);
extern int kill_proc(pid_t, int, int);
extern int do_sigaction(int, const struct k_sigaction *, struct k_sigaction *);
extern int do_sigaltstack(const stack_t *, stack_t *, unsigned long);
static inline int signal_pending(struct task_struct *p)
{
return (p->sigpending != 0);
}
/*
* Re-calculate pending state from the set of locally pending
* signals, globally pending signals, and blocked signals.
*/
static inline int has_pending_signals(sigset_t *signal, sigset_t *blocked)
{
unsigned long ready;
long i;
switch (_NSIG_WORDS) {
default:
for (i = _NSIG_WORDS, ready = 0; --i >= 0 ;)
ready |= signal->sig[i] &~ blocked->sig[i];
break;
case 4: ready = signal->sig[3] &~ blocked->sig[3];
ready |= signal->sig[2] &~ blocked->sig[2];
ready |= signal->sig[1] &~ blocked->sig[1];
ready |= signal->sig[0] &~ blocked->sig[0];
break;
case 2: ready = signal->sig[1] &~ blocked->sig[1];
ready |= signal->sig[0] &~ blocked->sig[0];
break;
case 1: ready = signal->sig[0] &~ blocked->sig[0];
}
return ready != 0;
}
/* Reevaluate whether the task has signals pending delivery.
This is required every time the blocked sigset_t changes.
All callers should have t->sigmask_lock. */
static inline void recalc_sigpending(struct task_struct *t)
{
t->sigpending = has_pending_signals(&t->pending.signal, &t->blocked);
}
/* True if we are on the alternate signal stack. */
static inline int on_sig_stack(unsigned long sp)
{
return (sp - current->sas_ss_sp < current->sas_ss_size);
}
static inline int sas_ss_flags(unsigned long sp)
{
return (current->sas_ss_size == 0 ? SS_DISABLE
: on_sig_stack(sp) ? SS_ONSTACK : 0);
}
extern int request_irq(unsigned int,
void (*handler)(int, void *, struct pt_regs *),
unsigned long, const char *, void *);
extern void free_irq(unsigned int, void *);
/*
* This has now become a routine instead of a macro, it sets a flag if
* it returns true (to do BSD-style accounting where the process is flagged
* if it uses root privs). The implication of this is that you should do
* normal permissions checks first, and check suser() last.
*
* [Dec 1997 -- Chris Evans]
* For correctness, the above considerations need to be extended to
* fsuser(). This is done, along with moving fsuser() checks to be
* last.
*
* These will be removed, but in the mean time, when the SECURE_NOROOT
* flag is set, uids don't grant privilege.
*/
static inline int suser(void)
{
if (!issecure(SECURE_NOROOT) && current->euid == 0) {
current->flags |= PF_SUPERPRIV;
return 1;
}
return 0;
}
static inline int fsuser(void)
{
if (!issecure(SECURE_NOROOT) && current->fsuid == 0) {
current->flags |= PF_SUPERPRIV;
return 1;
}
return 0;
}
/*
* capable() checks for a particular capability.
* New privilege checks should use this interface, rather than suser() or
* fsuser(). See include/linux/capability.h for defined capabilities.
*/
static inline int capable(int cap)
{
#if 1 /* ok now */
if (cap_raised(current->cap_effective, cap))
#else
if (cap_is_fs_cap(cap) ? current->fsuid == 0 : current->euid == 0)
#endif
{
current->flags |= PF_SUPERPRIV;
return 1;
}
return 0;
}
/*
* Routines for handling mm_structs
*/
extern struct mm_struct * mm_alloc(void);
extern struct mm_struct * start_lazy_tlb(void);
extern void end_lazy_tlb(struct mm_struct *mm);
/* mmdrop drops the mm and the page tables */
extern inline void FASTCALL(__mmdrop(struct mm_struct *));
static inline void mmdrop(struct mm_struct * mm)
{
if (atomic_dec_and_test(&mm->mm_count))
__mmdrop(mm);
}
/* mmput gets rid of the mappings and all user-space */
extern void mmput(struct mm_struct *);
/* Remove the current tasks stale references to the old mm_struct */
extern void mm_release(void);
/*
* Routines for handling the fd arrays
*/
extern struct file ** alloc_fd_array(int);
extern int expand_fd_array(struct files_struct *, int nr);
extern void free_fd_array(struct file **, int);
extern fd_set *alloc_fdset(int);
extern int expand_fdset(struct files_struct *, int nr);
extern void free_fdset(fd_set *, int);
extern int copy_thread(int, unsigned long, unsigned long, unsigned long, struct task_struct *, struct pt_regs *);
extern void flush_thread(void);
extern void exit_thread(void);
extern void exit_mm(struct task_struct *);
extern void exit_files(struct task_struct *);
extern void exit_sighand(struct task_struct *);
extern void reparent_to_init(void);
extern void daemonize(void);
extern int do_execve(char *, char **, char **, struct pt_regs *);
extern int do_fork(unsigned long, unsigned long, struct pt_regs *, unsigned long);
extern void FASTCALL(add_wait_queue(wait_queue_head_t *q, wait_queue_t * wait));
extern void FASTCALL(add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_t * wait));
extern void FASTCALL(remove_wait_queue(wait_queue_head_t *q, wait_queue_t * wait));
#define __wait_event(wq, condition) \
do { \
wait_queue_t __wait; \
init_waitqueue_entry(&__wait, current); \
\
add_wait_queue(&wq, &__wait); \
for (;;) { \
set_current_state(TASK_UNINTERRUPTIBLE); \
if (condition) \
break; \
schedule(); \
} \
current->state = TASK_RUNNING; \
remove_wait_queue(&wq, &__wait); \
} while (0)
#define wait_event(wq, condition) \
do { \
if (condition) \
break; \
__wait_event(wq, condition); \
} while (0)
#define __wait_event_interruptible(wq, condition, ret) \
do { \
wait_queue_t __wait; \
init_waitqueue_entry(&__wait, current); \
\
add_wait_queue(&wq, &__wait); \
for (;;) { \
set_current_state(TASK_INTERRUPTIBLE); \
if (condition) \
break; \
if (!signal_pending(current)) { \
schedule(); \
continue; \
} \
ret = -ERESTARTSYS; \
break; \
} \
current->state = TASK_RUNNING; \
remove_wait_queue(&wq, &__wait); \
} while (0)
#define wait_event_interruptible(wq, condition) \
({ \
int __ret = 0; \
if (!(condition)) \
__wait_event_interruptible(wq, condition, __ret); \
__ret; \
})
#define REMOVE_LINKS(p) do { \
(p)->next_task->prev_task = (p)->prev_task; \
(p)->prev_task->next_task = (p)->next_task; \
if ((p)->p_osptr) \
(p)->p_osptr->p_ysptr = (p)->p_ysptr; \
if ((p)->p_ysptr) \
(p)->p_ysptr->p_osptr = (p)->p_osptr; \
else \
(p)->p_pptr->p_cptr = (p)->p_osptr; \
} while (0)
#define SET_LINKS(p) do { \
(p)->next_task = &init_task; \
(p)->prev_task = init_task.prev_task; \
init_task.prev_task->next_task = (p); \
init_task.prev_task = (p); \
(p)->p_ysptr = NULL; \
if (((p)->p_osptr = (p)->p_pptr->p_cptr) != NULL) \
(p)->p_osptr->p_ysptr = p; \
(p)->p_pptr->p_cptr = p; \
} while (0)
#define for_each_task(p) \
for (p = &init_task ; (p = p->next_task) != &init_task ; )
#define for_each_thread(task) \
for (task = next_thread(current) ; task != current ; task = next_thread(task))
#define next_thread(p) \
list_entry((p)->thread_group.next, struct task_struct, thread_group)
#define thread_group_leader(p) (p->pid == p->tgid)
static inline void del_from_runqueue(struct task_struct * p)
{
nr_running--;
p->sleep_time = jiffies;
list_del(&p->run_list);
p->run_list.next = NULL;
}
static inline int task_on_runqueue(struct task_struct *p)
{
return (p->run_list.next != NULL);
}
static inline void unhash_process(struct task_struct *p)
{
if (task_on_runqueue(p))
out_of_line_bug();
write_lock_irq(&tasklist_lock);
nr_threads--;
unhash_pid(p);
REMOVE_LINKS(p);
list_del(&p->thread_group);
write_unlock_irq(&tasklist_lock);
}
/* Protects ->fs, ->files, ->mm, and synchronises with wait4(). Nests inside tasklist_lock */
static inline void task_lock(struct task_struct *p)
{
spin_lock(&p->alloc_lock);
}
static inline void task_unlock(struct task_struct *p)
{
spin_unlock(&p->alloc_lock);
}
/* write full pathname into buffer and return start of pathname */
static inline char * d_path(struct dentry *dentry, struct vfsmount *vfsmnt,
char *buf, int buflen)
{
char *res;
struct vfsmount *rootmnt;
struct dentry *root;
read_lock(&current->fs->lock);
rootmnt = mntget(current->fs->rootmnt);
root = dget(current->fs->root);
read_unlock(&current->fs->lock);
spin_lock(&dcache_lock);
res = __d_path(dentry, vfsmnt, root, rootmnt, buf, buflen);
spin_unlock(&dcache_lock);
dput(root);
mntput(rootmnt);
return res;
}
static inline int need_resched(void)
{
return (unlikely(current->need_resched));
}
extern void __cond_resched(void);
static inline void cond_resched(void)
{
if (need_resched())
__cond_resched();
}
#endif /* __KERNEL__ */
#endif
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