Placed a comment to not the location of the blocker
[tpg/acess2.git] / Kernel / threads.c
index 863b5e4..b9d59f3 100644 (file)
@@ -36,7 +36,7 @@ tThread       *Threads_CloneTCB(Uint *Err, Uint Flags);
  int   Threads_WaitTID(int TID, int *status);
 tThread        *Threads_GetThread(Uint TID);
 void   Threads_AddToDelete(tThread *Thread);
-tThread        *Threads_int_GetPrev(tThread **List, tThread *Thread);
+tThread        *Threads_int_DelFromQueue(tThread **List, tThread *Thread);
 void   Threads_Exit(int TID, int Status);
 void   Threads_Kill(tThread *Thread, int Status);
 void   Threads_Yield(void);
@@ -51,6 +51,7 @@ tUID  Threads_GetUID(void);
 tGID   Threads_GetGID(void);
  int   Threads_SetGID(Uint *Errno, tUID ID);
 void   Threads_Dump(void);
+void   Threads_DumpActive(void);
 void   Mutex_Acquire(tMutex *Mutex);
 void   Mutex_Release(tMutex *Mutex);
  int   Mutex_IsLocked(tMutex *Mutex);
@@ -69,15 +70,16 @@ tThread     gThreadZero = {
 // --- Locks ---
 tShortSpinlock glThreadListLock;       ///\note NEVER use a heap function while locked
 // --- Current State ---
-volatile int   giNumActiveThreads = 0;
-volatile int   giFreeTickets = 0;
-volatile Uint  giNextTID = 1;
+volatile int   giNumActiveThreads = 0; // Number of threads on the active queue
+volatile int   giFreeTickets = 0;      // Number of tickets held by non-scheduled threads
+volatile Uint  giNextTID = 1;  // Next TID to allocate
 // --- Thread Lists ---
 tThread        *gAllThreads = NULL;            // All allocated threads
 tThread        *gActiveThreads = NULL;         // Currently Running Threads
 tThread        *gSleepingThreads = NULL;       // Sleeping Threads
 tThread        *gDeleteThreads = NULL;         // Threads to delete
- int   giNumCPUs = 1;
+ int   giNumCPUs = 1;  // Number of CPUs
+BOOL     gaThreads_NoTaskSwitch[MAX_CPUS];     // Disables task switches for each core (Pseudo-IF)
 
 // === CODE ===
 /**
@@ -108,6 +110,9 @@ int Threads_SetName(char *NewName)
        tThread *cur = Proc_GetCurThread();
        char    *oldname = cur->ThreadName;
        
+       // NOTE: There is a possibility of non-thread safety here
+       // A thread could read the current name pointer before it is zeroed
+       
        cur->ThreadName = NULL;
        
        if( IsHeap(oldname) )   free( oldname );
@@ -128,8 +133,7 @@ char *Threads_GetName(tTID ID)
        if(ID == -1) {
                return Proc_GetCurThread()->ThreadName;
        }
-       // TODO: Find a thread and get its name
-       return NULL;
+       return Threads_GetThread(ID)->ThreadName;
 }
 
 /**
@@ -172,6 +176,7 @@ tThread *Threads_CloneTCB(Uint *Err, Uint Flags)
         int    i;
        cur = Proc_GetCurThread();
        
+       // Allocate and duplicate
        new = malloc(sizeof(tThread));
        if(new == NULL) {
                *Err = -ENOMEM;
@@ -182,7 +187,7 @@ tThread *Threads_CloneTCB(Uint *Err, Uint Flags)
        new->CurCPU = -1;
        new->Next = NULL;
        memset( &new->IsLocked, 0, sizeof(new->IsLocked));
-       new->Status = THREAD_STAT_ACTIVE;
+       new->Status = THREAD_STAT_PREINIT;
        new->RetStatus = 0;
        
        // Get Thread ID
@@ -237,7 +242,6 @@ tThread *Threads_CloneTCB(Uint *Err, Uint Flags)
 }
 
 /**
- * \fn Uint *Threads_GetCfgPtr(int Id)
  * \brief Get a configuration pointer from the Per-Thread data area
  * \param ID   Config slot ID
  * \return Pointer at ID
@@ -253,7 +257,6 @@ Uint *Threads_GetCfgPtr(int ID)
 }
 
 /**
- * \fn tTID Threads_WaitTID(int TID, int *Status)
  * \brief Wait for a task to change state
  * \param TID  Thread ID to wait on (-1: Any child thread, 0: Any Child/Sibling, <-1: -PID)
  * \param Status       Thread return status
@@ -285,6 +288,7 @@ tTID Threads_WaitTID(int TID, int *Status)
                 int    initStatus = t->Status;
                tTID    ret;
                
+               // Wait for the thread to die!
                if(initStatus != THREAD_STAT_ZOMBIE) {
                        // TODO: Handle child also being suspended if wanted
                        while(t->Status != THREAD_STAT_ZOMBIE) {
@@ -294,6 +298,7 @@ tTID Threads_WaitTID(int TID, int *Status)
                        }
                }
                
+               // Set return status
                Log_Debug("Threads", "%i waiting for %i, t->Status = %i",
                        Threads_GetTID(), t->TID, t->Status);
                ret = t->TID;
@@ -318,7 +323,6 @@ tTID Threads_WaitTID(int TID, int *Status)
 }
 
 /**
- * \fn tThread *Threads_GetThread(Uint TID)
  * \brief Gets a thread given its TID
  * \param TID  Thread ID
  * \return Thread pointer
@@ -342,13 +346,13 @@ tThread *Threads_GetThread(Uint TID)
 }
 
 /**
- * \fn void Threads_AddToDelete(tThread *Thread)
  * \brief Adds a thread to the delete queue
  * \param Thread       Thread to delete
  */
 void Threads_AddToDelete(tThread *Thread)
 {
        // Add to delete queue
+       // TODO: Is locking needed?
        if(gDeleteThreads) {
                Thread->Next = gDeleteThreads;
                gDeleteThreads = Thread;
@@ -359,35 +363,39 @@ void Threads_AddToDelete(tThread *Thread)
 }
 
 /**
- * \fn tThread *Threads_int_GetPrev(tThread **List, tThread *Thread)
- * \brief Gets the previous entry in a thead linked list
+ * \brief Deletes an entry from a list
  * \param List Pointer to the list head
  * \param Thread       Thread to find
- * \return Thread before \a Thread on \a List
+ * \return \a Thread
  */
-tThread *Threads_int_GetPrev(tThread **List, tThread *Thread)
+tThread *Threads_int_DelFromQueue(tThread **List, tThread *Thread)
 {
-       tThread *ret;
-       // First Entry
-       if(*List == Thread) {
-               return (tThread*)List;
+       tThread *ret, *prev = NULL;
+       
+       for(ret = *List;
+               ret && ret != Thread;
+               prev = ret, ret = ret->Next
+               );
+       
+       // Is the thread on the list
+       if(!ret) {
+               //LogF("%p(%s) is not on list %p\n", Thread, Thread->ThreadName, List);
+               return NULL;
+       }
+       
+       if( !prev ) {
+               *List = Thread->Next;
+               //LogF("%p(%s) removed from head of %p\n", Thread, Thread->ThreadName, List);
        }
-       // Or not
        else {
-               for(ret = *List;
-                       ret->Next && ret->Next != Thread;
-                       ret = ret->Next
-                       );
-               // Error if the thread is not on the list
-               if(!ret->Next || ret->Next != Thread) {
-                       return NULL;
-               }
+               prev->Next = Thread->Next;
+               //LogF("%p(%s) removed from %p (prev=%p)\n", Thread, Thread->ThreadName, List, prev);
        }
-       return ret;
+       
+       return Thread;
 }
 
 /**
- * \fn void Threads_Exit(int TID, int Status)
  * \brief Exit the current process (or another?)
  * \param TID  Thread ID to kill
  * \param Status       Exit status
@@ -398,9 +406,9 @@ void Threads_Exit(int TID, int Status)
                Threads_Kill( Proc_GetCurThread(), (Uint)Status & 0xFF );
        else
                Threads_Kill( Threads_GetThread(TID), (Uint)Status & 0xFF );
+       
        // Halt forever, just in case
-       for(;;)
-               HALT();
+       for(;;) HALT();
 }
 
 /**
@@ -411,13 +419,13 @@ void Threads_Exit(int TID, int Status)
  */
 void Threads_Kill(tThread *Thread, int Status)
 {
-       tThread *prev;
        tMsg    *msg;
        
        // TODO: Kill all children
        #if 0
        {
                tThread *child;
+               // TODO: I should keep a .Parent pointer, and a .Children list
                for(child = gActiveThreads;
                        child;
                        child = child->Next)
@@ -433,30 +441,31 @@ void Threads_Kill(tThread *Thread, int Status)
        // Lock thread (stop us recieving messages)
        SHORTLOCK( &Thread->IsLocked );
        
+       // Clear Message Queue
+       while( Thread->Messages )
+       {
+               msg = Thread->Messages->Next;
+               free( Thread->Messages );
+               Thread->Messages = msg;
+       }
+       
        // Lock thread list
        SHORTLOCK( &glThreadListLock );
        
-       // Get previous thread on list
-       prev = Threads_int_GetPrev( &gActiveThreads, Thread );
-       if(!prev) {
+       // Delete from active list
+       if( !Threads_int_DelFromQueue( &gActiveThreads, Thread ) )
+       {
                Warning("Proc_Exit - Current thread is not on the active queue");
                SHORTREL( &glThreadListLock );
                SHORTREL( &Thread->IsLocked );
                return;
        }
        
-       // Clear Message Queue
-       while( Thread->Messages )
-       {
-               msg = Thread->Messages->Next;
-               free( Thread->Messages );
-               Thread->Messages = msg;
-       }
-       
+       // Ensure that we are not rescheduled
        Thread->Remaining = 0;  // Clear Remaining Quantum
        Thread->Quantum = 0;    // Clear Quantum to indicate dead thread
-       prev->Next = Thread->Next;      // Remove from active
        
+       // Update bookkeeping
        giNumActiveThreads --;
        if( Thread != Proc_GetCurThread() )
                giFreeTickets -= Thread->NumTickets;
@@ -464,7 +473,7 @@ void Threads_Kill(tThread *Thread, int Status)
        // Save exit status
        Thread->RetStatus = Status;
        
-       // Don't Zombie if we are being killed as part of a tree
+       // Don't Zombie if we are being killed because our parent is
        if(Status == -1)
        {
                Thread->Status = THREAD_STAT_DEAD;
@@ -478,20 +487,25 @@ void Threads_Kill(tThread *Thread, int Status)
        Log("Thread %i went *hurk* (%i)", Thread->TID, Thread->Status);
        
        // Release spinlocks
-       SHORTREL( &Thread->IsLocked );
        SHORTREL( &glThreadListLock );
+       SHORTREL( &Thread->IsLocked );  // TODO: We may not actually be released...
        
-       if(Status != -1)        HALT();
+       // And, reschedule
+       if(Status != -1) {
+               for( ;; )
+                       HALT();
+       }
 }
 
 /**
- * \fn void Threads_Yield(void)
  * \brief Yield remainder of the current thread's timeslice
  */
 void Threads_Yield(void)
 {
-       Proc_GetCurThread()->Remaining = 0;
-       HALT();
+       tThread *thread = Proc_GetCurThread();
+       thread->Remaining = 0;
+       //while(thread->Remaining == 0)
+               HALT();
 }
 
 /**
@@ -513,13 +527,13 @@ void Threads_Sleep(void)
        
        // Remove us from running queue
        Threads_RemActive();
+       // Mark thread as sleeping
+       cur->Status = THREAD_STAT_SLEEPING;
        
        // Add to Sleeping List (at the top)
        cur->Next = gSleepingThreads;
        gSleepingThreads = cur;
        
-       // Mark thread as sleeping
-       cur->Status = THREAD_STAT_SLEEPING;
        
        #if DEBUG_TRACE_STATE
        Log("Threads_Sleep: %p (%i %s) sleeping", cur, cur->TID, cur->ThreadName);
@@ -541,8 +555,6 @@ void Threads_Sleep(void)
  */
 int Threads_Wake(tThread *Thread)
 {
-       tThread *prev;
-       
        if(!Thread)
                return -EINVAL;
        
@@ -553,26 +565,16 @@ int Threads_Wake(tThread *Thread)
                return -EALREADY;
        
        case THREAD_STAT_SLEEPING:
+               SHORTLOCK( &glThreadListLock );
                // Remove from sleeping queue
-               prev = Threads_int_GetPrev(&gSleepingThreads, Thread);
-               prev->Next = Thread->Next;
-               
-               // Add to active queue
-               Thread->Next = gActiveThreads;
-               gActiveThreads = Thread;
+               Threads_int_DelFromQueue(&gSleepingThreads, Thread);
                
-               // Update bookkeeping
-               giNumActiveThreads ++;
-               giFreeTickets += Thread->NumTickets;
-               #if DEBUG_TRACE_TICKETS
-               Log("Threads_Wake: new giFreeTickets = %i", giFreeTickets);
-               #endif
+               Threads_AddActive( Thread );
                
-               Thread->CurCPU = -1;
-               Thread->Status = THREAD_STAT_ACTIVE;
                #if DEBUG_TRACE_STATE
                Log("Threads_Sleep: %p (%i %s) woken", Thread, Thread->TID, Thread->ThreadName);
                #endif
+               SHORTREL( &glThreadListLock );
                return -EOK;
        
        case THREAD_STAT_WAITING:
@@ -600,28 +602,50 @@ int Threads_WakeTID(tTID TID)
         int    ret;
        if(!thread)
                return -ENOENT;
-       SHORTLOCK( &glThreadListLock );
        ret = Threads_Wake( thread );
-       SHORTREL( &glThreadListLock );
        //Log_Debug("Threads", "TID %i woke %i (%p)", Threads_GetTID(), TID, thread);
        return ret;
 }
 
 /**
- * \fn void Threads_AddActive(tThread *Thread)
  * \brief Adds a thread to the active queue
  */
 void Threads_AddActive(tThread *Thread)
 {
        SHORTLOCK( &glThreadListLock );
+       
+       #if 1
+       {
+               tThread *t;
+               for( t = gActiveThreads; t; t = t->Next )
+               {
+                       if( t == Thread ) {
+                               Panic("Threads_AddActive: Attempting a double add of TID %i (0x%x)",
+                                       Thread->TID, __builtin_return_address(0));
+                       }
+                       
+                       if(t->Status != THREAD_STAT_ACTIVE) {
+                               Panic("Threads_AddActive: TID %i status != THREAD_STAT_ACTIVE",
+                                       Thread->TID);
+                       }
+               }
+       }
+       #endif
+       
+       // Set state
+       Thread->Status = THREAD_STAT_ACTIVE;
+       Thread->CurCPU = -1;
        // Add to active list
        Thread->Next = gActiveThreads;
        gActiveThreads = Thread;
+       
        // Update bookkeeping
        giNumActiveThreads ++;
        giFreeTickets += Thread->NumTickets;
+       
        #if DEBUG_TRACE_TICKETS
-       Log("Threads_AddActive: new giFreeTickets = %i", giFreeTickets);
+       Log("Threads_AddActive: %p %i (%s) added, new giFreeTickets = %i",
+               Thread, Thread->TID, Thread->ThreadName, giFreeTickets);
        #endif
        SHORTREL( &glThreadListLock );
 }
@@ -634,12 +658,28 @@ void Threads_AddActive(tThread *Thread)
 tThread *Threads_RemActive(void)
 {
        tThread *ret = Proc_GetCurThread();
-       tThread *prev = Threads_int_GetPrev(&gActiveThreads, ret);
-       if(!prev)       return NULL;
+       
+       SHORTLOCK( &glThreadListLock );
+       
+       // Delete from active queue
+       if( !Threads_int_DelFromQueue(&gActiveThreads, ret) ) {
+               SHORTREL( &glThreadListLock );
+               return NULL;
+       }
+       
        ret->Remaining = 0;
        ret->CurCPU = -1;
-       prev->Next = ret->Next;
+       
        giNumActiveThreads --;
+       // no need to decrement tickets, scheduler did it for us
+       
+       #if DEBUG_TRACE_TICKETS
+       Log("Threads_RemActive: %p %i (%s) removed, giFreeTickets = %i",
+               ret, ret->TID, ret->ThreadName, giFreeTickets);
+       #endif
+       
+       SHORTREL( &glThreadListLock );
+       
        return ret;
 }
 
@@ -734,13 +774,14 @@ int Threads_SetGID(Uint *Errno, tGID ID)
 
 /**
  * \fn void Threads_Dump(void)
- * \brief Dums a list of currently running threads
+ * \brief Dumps a list of currently running threads
  */
 void Threads_Dump(void)
 {
        tThread *thread;
        
-       Log("Active Threads:");
+       Log("--- Thread Dump ---");
+       Log("Active Threads: (%i reported)", giNumActiveThreads);
        for(thread=gActiveThreads;thread;thread=thread->Next)
        {
                Log(" %i (%i) - %s (CPU %i)",
@@ -761,9 +802,26 @@ void Threads_Dump(void)
                Log("  KStack 0x%x", thread->KernelStack);
        }
 }
+/**
+ * \fn void Threads_Dump(void)
+ */
+void Threads_DumpActive(void)
+{
+       tThread *thread;
+       
+       Log("Active Threads:");
+       for(thread=gActiveThreads;thread;thread=thread->Next)
+       {
+               Log(" %i (%i) - %s (CPU %i)",
+                       thread->TID, thread->TGID, thread->ThreadName, thread->CurCPU);
+               if(thread->Status != THREAD_STAT_ACTIVE)
+                       Log("  ERROR State (%i) != THREAD_STAT_ACTIVE (%i)", thread->Status, THREAD_STAT_ACTIVE);
+               Log("  %i Tickets, Quantum %i", thread->NumTickets, thread->Quantum);
+               Log("  KStack 0x%x", thread->KernelStack);
+       }
+}
 
 /**
- * \fn tThread *Threads_GetNextToRun(int CPU, tThread *Last)
  * \brief Gets the next thread to run
  * \param CPU  Current CPU
  * \param Last The thread the CPU was running
@@ -772,8 +830,17 @@ tThread *Threads_GetNextToRun(int CPU, tThread *Last)
 {
        tThread *thread;
         int    ticket;
-        int    number; 
+        int    number;
+       
+       // If this CPU has the lock, we must let it complete
+       if( CPU_HAS_LOCK( &glThreadListLock ) )
+               return Last;
        
+       // Don't change threads if the current CPU has switches disabled
+       if( gaThreads_NoTaskSwitch[CPU] )
+               return Last;
+
+
        // Lock thread list
        SHORTLOCK( &glThreadListLock );
        
@@ -811,9 +878,12 @@ tThread *Threads_GetNextToRun(int CPU, tThread *Last)
        if(giNumActiveThreads == 1) {
                if( gActiveThreads->CurCPU == -1 )
                        gActiveThreads->CurCPU = CPU;
+               
                SHORTREL( &glThreadListLock );
+               
                if( gActiveThreads->CurCPU == CPU )
                        return gActiveThreads;
+               
                return NULL;    // CPU has nothing to do
        }
        
@@ -828,15 +898,27 @@ tThread *Threads_GetNextToRun(int CPU, tThread *Last)
                }
                #if DEBUG_TRACE_TICKETS
                else
-                       LogF(" %p (%s)->Status = %i (Released)\n", Last, Last->ThreadName, Last->Status);
+                       LogF(" CPU %i released %p (%i %s)->Status = %i (Released)\n",
+                               CPU, Last, Last->TID, Last->ThreadName, Last->Status);
                #endif
                Last->CurCPU = -1;
        }
        
+       #if DEBUG_TRACE_TICKETS
+       //Threads_DumpActive();
+       #endif
+       
        #if 1
        number = 0;
        for(thread = gActiveThreads; thread; thread = thread->Next) {
                if(thread->CurCPU >= 0) continue;
+               if(thread->Status != THREAD_STAT_ACTIVE)
+                       Panic("Bookkeeping fail - %p %i(%s) is on the active queue with a status of %i",
+                               thread, thread->TID, thread->ThreadName, thread->Status);
+               if(thread->Next == thread) {
+                       Panic("Bookkeeping fail - %p %i(%s) loops back on itself",
+                               thread, thread->TID, thread->ThreadName, thread->Status);
+               }
                number += thread->NumTickets;
        }
        if(number != giFreeTickets) {
@@ -925,7 +1007,7 @@ void Mutex_Acquire(tMutex *Mutex)
        if( Mutex->Owner ) {
                SHORTLOCK( &glThreadListLock );
                // - Remove from active list
-               Threads_RemActive();
+               us = Threads_RemActive();
                // - Mark as sleeping
                us->Status = THREAD_STAT_OFFSLEEP;
                
@@ -961,10 +1043,18 @@ void Mutex_Release(tMutex *Mutex)
        if( Mutex->Waiting ) {
                Mutex->Owner = Mutex->Waiting;  // Set owner
                Mutex->Waiting = Mutex->Waiting->Next;  // Next!
+               // Reset ->LastWaiting to NULL if we have just removed the last waiting thread
+               // 2010-10-02 21:50 - Comemerating the death of the longest single
+               //                    blocker in the Acess2 history. REMEMBER TO
+               //                    FUCKING MAINTAIN YOUR FUCKING LISTS DIPWIT
+               if( Mutex->LastWaiting == Mutex->Owner )
+                       Mutex->LastWaiting = NULL;
+               
                // Wake new owner
-               Mutex->Owner->Status = THREAD_STAT_ACTIVE;
-               Threads_AddActive(Mutex->Owner);
-               //Log("Mutex %p Woke %p", Mutex, Mutex->Owner);
+               SHORTLOCK( &glThreadListLock );
+               if( Mutex->Owner->Status != THREAD_STAT_ACTIVE )
+                       Threads_AddActive(Mutex->Owner);
+               SHORTREL( &glThreadListLock );
        }
        else {
                Mutex->Owner = NULL;
@@ -983,6 +1073,7 @@ int Mutex_IsLocked(tMutex *Mutex)
 
 // === EXPORTS ===
 EXPORT(Threads_GetUID);
+EXPORT(Threads_GetGID);
 EXPORT(Mutex_Acquire);
 EXPORT(Mutex_Release);
 EXPORT(Mutex_IsLocked);

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