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proc_tree_lock -> wait_lock

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Robert Morris 2020-11-05 09:47:59 -05:00 • committed by Frans Kaashoek
parent ba8d9f4808
commit 38084bcea8
1 changed files with 15 additions and 14 deletions
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29
kernel/proc.c
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@ -20,10 +20,11 @@ static void freeproc(struct proc *p);
extern char trampoline[]; // trampoline.S
// protects parent/child relationships.
// must be held when using p->parent.
// helps ensure that wakeups of wait()ing
// parents are not lost. helps obey the
// memory model when using p->parent.
// must be acquired before any p->lock.
struct spinlock proc_tree_lock;
struct spinlock wait_lock;
// Allocate a page for each process's kernel stack.
// Map it high in memory, followed by an invalid
@ -48,7 +49,7 @@ procinit(void)
struct proc *p;
initlock(&pid_lock, "nextpid");
initlock(&proc_tree_lock, "proc_tree");
initlock(&wait_lock, "wait_lock");
for(p = proc; p < &proc[NPROC]; p++) {
initlock(&p->lock, "proc");
p->kstack = KSTACK((int) (p - proc));
@ -306,9 +307,9 @@ fork(void)
release(&np->lock);
acquire(&proc_tree_lock);
acquire(&wait_lock);
np->parent = p;
release(&proc_tree_lock);
release(&wait_lock);
acquire(&np->lock);
np->state = RUNNABLE;
@ -318,7 +319,7 @@ fork(void)
}
// Pass p's abandoned children to init.
// Caller must hold proc_tree_lock.
// Caller must hold wait_lock.
void
reparent(struct proc *p)
{
@ -357,7 +358,7 @@ exit(int status)
end_op();
p->cwd = 0;
acquire(&proc_tree_lock);
acquire(&wait_lock);
// Give any children to init.
reparent(p);
@ -370,7 +371,7 @@ exit(int status)
p->xstate = status;
p->state = ZOMBIE;
release(&proc_tree_lock);
release(&wait_lock);
// Jump into the scheduler, never to return.
sched();
@ -386,7 +387,7 @@ wait(uint64 addr)
int havekids, pid;
struct proc *p = myproc();
acquire(&proc_tree_lock);
acquire(&wait_lock);
for(;;){
// Scan through table looking for exited children.
@ -403,12 +404,12 @@ wait(uint64 addr)
if(addr != 0 && copyout(p->pagetable, addr, (char *)&np->xstate,
sizeof(np->xstate)) < 0) {
release(&np->lock);
release(&proc_tree_lock);
release(&wait_lock);
return -1;
}
freeproc(np);
release(&np->lock);
release(&proc_tree_lock);
release(&wait_lock);
return pid;
}
release(&np->lock);
@ -417,12 +418,12 @@ wait(uint64 addr)
// No point waiting if we don't have any children.
if(!havekids || p->killed){
release(&proc_tree_lock);
release(&wait_lock);
return -1;
}
// Wait for a child to exit.
sleep(p, &proc_tree_lock); //DOC: wait-sleep
sleep(p, &wait_lock); //DOC: wait-sleep
}
}