43 lines
1.3 KiB
C
43 lines
1.3 KiB
C
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#include "../system.h"
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#include <signal.h>
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#include <sys/sigcontext.h>
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#include <minix/endpoint.h>
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/*===========================================================================*
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* do_schedule *
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*===========================================================================*/
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PUBLIC int do_schedule(struct proc * caller, message * m_ptr)
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{
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struct proc *p;
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p = proc_addr(_ENDPOINT_P(m_ptr->SCHEDULING_ENDPOINT));
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/* Make sure the priority number given is within the allowed range.*/
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if (m_ptr->SCHEDULING_PRIORITY < TASK_Q ||
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m_ptr->SCHEDULING_PRIORITY > NR_SCHED_QUEUES)
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return(EINVAL);
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/* Only system processes can schedule processes */
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if (! (priv(caller)->s_flags & SYS_PROC))
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return(EPERM);
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/* Only this process' scheduler can schedule it */
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if (caller != p->p_scheduler)
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return(EPERM);
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/* In some cases, we might be rescheduling a runnable process. In such
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* a case (i.e. if we are updating the priority) we set the NO_QUANTUM
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* flag before the generic unset to dequeue/enqueue the process
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*/
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if (proc_is_runnable(p))
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RTS_SET(p, RTS_NO_QUANTUM);
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/* Clear the scheduling bit and enqueue the process */
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p->p_priority = m_ptr->SCHEDULING_PRIORITY;
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p->p_ticks_left = m_ptr->SCHEDULING_QUANTUM;
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RTS_UNSET(p, RTS_NO_QUANTUM);
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return(OK);
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}
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