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. fixed a recently introduced scheduler (run-queue) bug in proc.c

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. a little (optional) debugging code added to proc.c and associated
  data in proc.h
This commit is contained in:
Ben Gras 2005-05-24 12:32:34 +00:00
parent 0f55ebe90a
commit 168b7f2669
2 changed files with 23 additions and 2 deletions
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21
kernel/proc.c
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@ -415,6 +415,13 @@ register struct proc *rp; /* this process is now runnable */
/* Add 'rp' to one of the queues of runnable processes. */
int q = rp->p_priority; /* scheduling queue to use */
#if ENABLE_K_DEBUGGING
if(rp->p_ready) {
kprintf("ready() already ready process\n", NO_NUM);
}
rp->p_ready = 1;
#endif
/* Processes, in principle, are added to the end of the queue. However,
* user processes are added in front of the queue, because this is a bit
* fairer to I/O bound processes.
@ -453,6 +460,13 @@ register struct proc *rp; /* this process is no longer runnable */
register struct proc **qtail; /* queue's rdy_tail */
int q = rp->p_priority; /* queue to use */
#if ENABLE_K_DEBUGGING
if(!rp->p_ready) {
kprintf("unready() already unready process\n", NO_NUM);
}
rp->p_ready = 0;
#endif
/* Side-effect for tasks: check if the task's stack still is ok? */
if (istaskp(rp)) {
if (*rp->p_stguard != STACK_GUARD)
@ -468,16 +482,19 @@ register struct proc *rp; /* this process is no longer runnable */
rdy_head[q] = xp->p_nextready; /* new head of queue */
if (rp == proc_ptr) /* current process removed */
pick_proc(); /* pick new process to run */
}
if(rp == rdy_tail[q])
rdy_tail[q] = NIL_PROC;
}
else { /* check body of queue */
while (xp->p_nextready != rp) /* stop if process is next */
if ( (xp = xp->p_nextready) == NIL_PROC)
return;
xp->p_nextready = xp->p_nextready->p_nextready;
if (rdy_tail[q] == rp) /* possibly update tail */
rdy_tail[q] = rp;
rdy_tail[q] = xp;
}
}
}
/*===========================================================================*

4
kernel/proc.h
View file

@ -62,6 +62,10 @@ struct proc {
unsigned p_pendcount; /* count of pending and unfinished signals */
char p_name[PROC_NAME_LEN]; /* name of the process, including \0 */
#if ENABLE_K_DEBUGGING
int p_ready, p_found;
#endif
};
/* Guard word for task stacks. */