kernel: preemptive and cooperative scheduler refactoring.

[bertos.git] / bertos / kern / preempt.c

diff --git a/bertos/kern/preempt.c b/bertos/kern/preempt.c
index ab3fc7a8f7db005e5f1e3f2c8623b8647a6a737e..078724b42a8e38095fb93e3c6e226d2e2b5e2d70 100644 (file)
--- a/bertos/kern/preempt.c
+++ b/bertos/kern/preempt.c
@@ -26,183 +26,7 @@
  * invalidate any other reasons why the executable file might be covered by
  * the GNU General Public License.
  *
- * Copyright 2001, 2004 Develer S.r.l. (http://www.develer.com/)
- * Copyright 1999, 2000, 2001, 2008 Bernie Innocenti <bernie@codewiz.org>
- * -->
- *
- * \brief Simple realtime multitasking scheduler.
- *        Context switching is only done cooperatively.
- *
- * \version $Id: proc.c 1616 2008-08-10 19:41:26Z bernie $
- * \author Bernie Innocenti <bernie@codewiz.org>
- * \author Stefano Fedrigo <aleph@develer.com>
- */
-
-#include "proc_p.h"
-#include "proc.h"
-
-#include <cpu/frame.h> // CPU_IDLE
-
-#include <unistd.h> // XXX alarm()
-
-
-/*
- * The time sharing scheduler forces a task switch when the current
- * process has exhausted its quantum.
- */
-uint16_t Quantum;
-
-/**
- * Disable preemptive task switching.
+ * \note This file is deprecated and kept only for backward compatibility.
  *
- * The scheduler maintains a per-process nesting counter.  Task switching is
- * effectively re-enabled only when the number of calls to proc_permit()
- * matches the number of calls to proc_forbid().
- *
- * Calling functions that could sleep while task switching is disabled
- * is dangerous, although supported.  Preemptive task switching is
- * resumed while the process is sleeping and disabled again as soon as
- * it wakes up again.
- *
- * \sa proc_permit()
- */
-void proc_forbid(void)
-{
-       /* No need to protect against interrupts here. */
-       ++CurrentProcess->forbid_cnt;
-}
-
-/**
- * Re-enable preemptive task switching.
- *
- * \sa proc_forbid()
+ * -->
  */
-void proc_permit(void)
-{
-       /* No need to protect against interrupts here. */
-       --CurrentProcess->forbid_cnt;
-}
-
-static void (*irq_handlers[100])(void); // FIXME
-
-
-void proc_preempt(void)
-{
-       TRACE;
-
-       ATOMIC(LIST_ASSERT_VALID(&ProcReadyList));
-
-       TRACEMSG("hello1");
-       IRQ_DISABLE;
-       /* Poll on the ready queue for the first ready process */
-       while (!(CurrentProcess = (struct Process *)list_remHead(&ProcReadyList)))
-       {
-       TRACEMSG("hello2");
-               /*
-                * Make sure we physically reenable interrupts here, no matter what
-                * the current task status is. This is important because if we
-                * are idle-spinning, we must allow interrupts, otherwise no
-                * process will ever wake up.
-                *
-                * During idle-spinning, an interrupt can occur and it may
-                * modify \p ProcReadyList. To ensure that compiler reload this
-                * variable every while cycle we call CPU_MEMORY_BARRIER.
-                * The memory barrier ensure that all variables used in this context
-                * are reloaded.
-                */
-               IRQ_ENABLE;
-               //FIXME: calls Qt stuff from sighandler! CPU_IDLE;
-               MEMORY_BARRIER;
-               IRQ_DISABLE;
-       TRACEMSG("hello3");
-       }
-       IRQ_ENABLE;
-       TRACEMSG("hello4");
-}
-
-void proc_preempt_timer(void)
-{
-       // TODO: check Quantum
-
-       alarm(1);
-
-       if (CurrentProcess)
-       {
-               TRACEMSG("preempting %p:%s", CurrentProcess, CurrentProcess->monitor.name);
-               ATOMIC(SCHED_ENQUEUE(CurrentProcess));
-               proc_schedule();
-       }
-}
-
-void proc_schedule(void)
-{
-       TRACE;
-
-       // Will invoke proc_preempt() in interrupt context
-       kill(0, SIGUSR1);
-}
-
-void proc_yield(void)
-{
-       ATOMIC(SCHED_ENQUEUE(CurrentProcess));
-
-       proc_schedule();
-}
-
-void proc_entry(void (*user_entry)(void))
-{
-       user_entry();
-       proc_exit();
-}
-
-/* signal handler */
-void irq_entry(int signum)
-{
-       Process *old_process;
-
-//     TRACEMSG("storing %p:%s", CurrentProcess, CurrentProcess->monitor.name);
-//     CurrentProcess->leaving = false;
-//     getcontext(&CurrentProcess->context);
-       /* We get here in two ways: directly, and after setcontext() below */
-
-//     if (CurrentProcess->leaving)
-//     {
-//             TRACEMSG("leaving to %p:%s", CurrentProcess, CurrentProcess->monitor.name);
-//             return;
-//     }
-
-       old_process = CurrentProcess;
-
-       irq_handlers[signum]();
-
-       if (old_process != CurrentProcess)
-       {
-               TRACEMSG("switching from %p:%s to %p:%s",
-                       old_process, old_process->monitor.name,
-                       CurrentProcess, CurrentProcess->monitor.name);
-               swapcontext(&old_process->context, &CurrentProcess->context);
-//             TRACEMSG("launching %p:%s", CurrentProcess, CurrentProcess->monitor.name);
-//             CurrentProcess->leaving = true;
-//             setcontext(&CurrentProcess->context);
-               /* not reached */
-       }
-
-       TRACEMSG("keeping %p:%s", CurrentProcess, CurrentProcess->monitor.name);
-}
-
-void preempt_init(void)
-{
-       struct sigaction act;
-       act.sa_handler = irq_entry;
-       sigemptyset(&act.sa_mask);
-       sigaddset(&act.sa_mask, SIGUSR1);
-       sigaddset(&act.sa_mask, SIGALRM);
-       act.sa_flags = SA_RESTART; /* | SA_SIGINFO; */
-
-       irq_handlers[SIGUSR1] = proc_preempt;
-       irq_handlers[SIGALRM] = proc_preempt_timer;
-       sigaction(SIGUSR1, &act, NULL);
-       sigaction(SIGALRM, &act, NULL);
-
-       alarm(1);  // FIXME
-}