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[/] [or1k/] [trunk/] [ecos-2.0/] [packages/] [kernel/] [v2_0/] [include/] [sched.hxx] - Rev 1773
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#ifndef CYGONCE_KERNEL_SCHED_HXX
#define CYGONCE_KERNEL_SCHED_HXX
//==========================================================================
//
// sched.hxx
//
// Scheduler class declaration(s)
//
//==========================================================================
//####ECOSGPLCOPYRIGHTBEGIN####
// -------------------------------------------
// This file is part of eCos, the Embedded Configurable Operating System.
// Copyright (C) 1998, 1999, 2000, 2001, 2002 Red Hat, Inc.
//
// eCos is free software; you can redistribute it and/or modify it under
// the terms of the GNU General Public License as published by the Free
// Software Foundation; either version 2 or (at your option) any later version.
//
// eCos is distributed in the hope that it will be useful, but WITHOUT ANY
// WARRANTY; without even the implied warranty of MERCHANTABILITY or
// FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
// for more details.
//
// You should have received a copy of the GNU General Public License along
// with eCos; if not, write to the Free Software Foundation, Inc.,
// 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
//
// As a special exception, if other files instantiate templates or use macros
// or inline functions from this file, or you compile this file and link it
// with other works to produce a work based on this file, this file does not
// by itself cause the resulting work to be covered by the GNU General Public
// License. However the source code for this file must still be made available
// in accordance with section (3) of the GNU General Public License.
//
// This exception does not invalidate any other reasons why a work based on
// this file might be covered by the GNU General Public License.
//
// Alternative licenses for eCos may be arranged by contacting Red Hat, Inc.
// at http://sources.redhat.com/ecos/ecos-license/
// -------------------------------------------
//####ECOSGPLCOPYRIGHTEND####
//==========================================================================
//#####DESCRIPTIONBEGIN####
//
// Author(s): nickg
// Contributors: nickg
// Date: 1997-09-09
// Purpose: Define Scheduler class interfaces
// Description: These class definitions supply the internal API
// used to scheduler threads.
// Usage: #include <cyg/kernel/sched.hxx>
//
//####DESCRIPTIONEND####
//
//==========================================================================
#include <cyg/kernel/ktypes.h>
#include <cyg/infra/cyg_ass.h> // assertion macros
#include <cyg/kernel/smp.hxx> // SMP support
// -------------------------------------------------------------------------
// Miscellaneous types
#ifdef CYGSEM_KERNEL_SCHED_ASR_SUPPORT
typedef void Cyg_ASR( CYG_ADDRWORD data ); // ASR type signature
#endif
__externC void cyg_scheduler_set_need_reschedule();
// -------------------------------------------------------------------------
// Scheduler base class. This defines stuff that is needed by the
// specific scheduler implementation. Each scheduler comprises three
// classes: Cyg_Scheduler_Base, Cyg_Scheduler_Implementation which
// inherits from it and Cyg_Scheduler which inherits from _it_ in turn.
class Cyg_Scheduler_Base
: public Cyg_Scheduler_SchedLock
{
friend class Cyg_HardwareThread;
friend class Cyg_SchedThread;
protected:
// The following variables are implicit in the API, but are
// not publically visible.
// Current running thread
static Cyg_Thread * volatile current_thread[CYGNUM_KERNEL_CPU_MAX]
CYGBLD_ANNOTATE_VARIABLE_SCHED;
// Set when reschedule needed
static volatile cyg_bool need_reschedule[CYGNUM_KERNEL_CPU_MAX]
CYGBLD_ANNOTATE_VARIABLE_SCHED;
// Count of number of thread switches
static volatile cyg_ucount32 thread_switches[CYGNUM_KERNEL_CPU_MAX]
CYGBLD_ANNOTATE_VARIABLE_SCHED;
public:
// return a pointer to the current thread
static Cyg_Thread *get_current_thread();
// Set current thread pointer
static void set_current_thread(Cyg_Thread *thread);
static void set_current_thread(Cyg_Thread *thread, HAL_SMP_CPU_TYPE cpu);
// Set need_reschedule flag
static void set_need_reschedule();
static void set_need_reschedule(Cyg_Thread *thread);
// Get need_reschedule flag
static cyg_bool get_need_reschedule();
// Return current value of lock
static cyg_ucount32 get_sched_lock();
// Clear need_reschedule flag
static void clear_need_reschedule();
// Return current number of thread switches
static cyg_ucount32 get_thread_switches();
};
// -------------------------------------------------------------------------
// Include the scheduler implementation header
#include CYGPRI_KERNEL_SCHED_IMPL_HXX
// Do some checking that we have a consistent universe.
#ifdef CYGSEM_KERNEL_SYNCH_MUTEX_PRIORITY_INVERSION_PROTOCOL
# ifndef CYGIMP_THREAD_PRIORITY
# error Priority inversion protocols will not work without priorities!!!
# endif
#endif
// -------------------------------------------------------------------------
// Scheduler class. This is the public scheduler interface seen by the
// rest of the kernel.
class Cyg_Scheduler
: public Cyg_Scheduler_Implementation
{
friend class Cyg_Thread;
// This function is the actual implementation of the unlock
// function. The unlock() later is an inline shell that deals
// with the common case.
static void unlock_inner(cyg_uint32 new_lock = 0);
public:
CYGDBG_DEFINE_CHECK_THIS
// The following API functions are common to all scheduler
// implementations.
// claim the preemption lock
static void lock();
// release the preemption lock and possibly reschedule
static void unlock();
// release and reclaim the lock atomically, keeping the old
// value on restart
static void reschedule();
// decrement the lock but also look for a reschedule opportunity
static void unlock_reschedule();
// release the preemption lock without rescheduling
static void unlock_simple();
// Start execution of the scheduler
static void start() CYGBLD_ATTRIB_NORET;
// Start execution of the scheduler on the current CPU
static void start_cpu() CYGBLD_ATTRIB_NORET;
// The only scheduler instance should be this one...
static Cyg_Scheduler scheduler CYGBLD_ANNOTATE_VARIABLE_SCHED;
};
// -------------------------------------------------------------------------
// This class encapsulates the scheduling abstractions in a thread.
// Cyg_SchedThread is included as a base class of Cyg_Thread. The actual
// implementation of the abstractions is in Cyg_SchedThread_Implementation
// so this class has little to do.
class Cyg_SchedThread
: public Cyg_SchedThread_Implementation
{
friend class Cyg_ThreadQueue_Implementation;
friend class Cyg_Scheduler_Implementation;
friend class Cyg_Scheduler;
Cyg_ThreadQueue *queue;
public:
Cyg_SchedThread(Cyg_Thread *thread, CYG_ADDRWORD sched_info);
// Return current queue pointer
Cyg_ThreadQueue *get_current_queue();
// Remove this thread from current queue
void remove();
#ifdef CYGSEM_KERNEL_SCHED_ASR_SUPPORT
// ASR support.
// An ASR is an Asynchronous Service Routine. When set pending it
// is called when the thread exits the scheduler. ASRs are mainly
// used by compatibility subsystems, such as POSIX, to implement
// such things as thread cancellation and signal delivery.
private:
volatile cyg_ucount32 asr_inhibit; // If > 0, blocks calls to ASRs
volatile cyg_bool asr_pending; // If true, this thread's ASR should be called.
#ifdef CYGSEM_KERNEL_SCHED_ASR_GLOBAL
static
#endif
Cyg_ASR *asr; // ASR function
#ifdef CYGSEM_KERNEL_SCHED_ASR_DATA_GLOBAL
static
#endif
CYG_ADDRWORD asr_data; // ASR data pointer
// Default ASR function
static void asr_default(CYG_ADDRWORD data);
public:
// Public interface to ASR mechanism
// Set, clear and get inhibit flag.
inline void set_asr_inhibit() { asr_inhibit++; }
inline void clear_asr_inhibit() { asr_inhibit--; }
inline cyg_ucount32 get_asr_inhibit() { return asr_inhibit; }
// Set and get pending flag. The flag is only cleared when the
// ASR is called.
inline void set_asr_pending() { asr_pending = true; }
inline cyg_bool get_asr_pending() { return asr_pending; }
// Set a new ASR, returning the old one.
void set_asr( Cyg_ASR *new_asr, CYG_ADDRWORD new_data,
Cyg_ASR **old_asr, CYG_ADDRWORD *old_data);
// Clear the ASR function back to the default.
void clear_asr();
#else
public:
// Even when we do not have ASRs enabled, we keep these functions
// available. This avoids excessive ifdefs in the rest of the
// kernel code.
inline void set_asr_inhibit() { }
inline void clear_asr_inhibit() { }
#endif
#ifdef CYGSEM_KERNEL_SYNCH_MUTEX_PRIORITY_INVERSION_PROTOCOL
private:
// For all priority inversion protocols we need to keep track of how
// many mutexes we have locked, including one which we are waiting to
// lock, because we can inherit priority while sleeping just prior to
// wakeup.
cyg_count32 mutex_count;
protected:
// These are implementation functions that are common to all protocols.
// Inherit the given priority. If thread is non-NULL the priority is
// being inherited from it, otherwise it has come from the mutex.
void set_inherited_priority( cyg_priority pri, Cyg_Thread *thread = 0 );
// Relay the priority of the ex-owner thread or from the queue if it
// has a higher priority than ours.
void relay_inherited_priority( Cyg_Thread *ex_owner, Cyg_ThreadQueue *pqueue);
// Lose priority inheritance
void clear_inherited_priority();
public:
// Count and uncount the number of mutexes held by
// this thread.
void count_mutex() { mutex_count++; };
void uncount_mutex() { mutex_count--; };
#if defined(CYGSEM_KERNEL_SYNCH_MUTEX_PRIORITY_INVERSION_PROTOCOL_SIMPLE)
protected:
// The simple priority inversion protocols simply needs
// somewhere to store the base priority of the current thread.
cyg_priority original_priority; // our original priority
cyg_bool priority_inherited; // have we inherited?
#endif
#ifdef CYGSEM_KERNEL_SYNCH_MUTEX_PRIORITY_INVERSION_PROTOCOL_INHERIT
public:
// Inherit the priority of the provided thread if it
// has higher priority than this.
void inherit_priority( Cyg_Thread *thread);
// Relay the priority of the ex-owner thread or from the queue if it
// has a higher priority than ours.
void relay_priority( Cyg_Thread *ex_owner, Cyg_ThreadQueue *pqueue);
// Lose priority inheritance
void disinherit_priority();
#endif
#ifdef CYGSEM_KERNEL_SYNCH_MUTEX_PRIORITY_INVERSION_PROTOCOL_CEILING
public:
// Set the priority of this thread to the given ceiling.
void set_priority_ceiling( cyg_priority pri );
// Clear the ceiling, if necessary.
void clear_priority_ceiling();
#endif
#endif
};
// -------------------------------------------------------------------------
// Simple inline accessor functions
inline Cyg_Thread *Cyg_Scheduler_Base::get_current_thread()
{
return current_thread[CYG_KERNEL_CPU_THIS()];
}
inline void Cyg_Scheduler_Base::set_current_thread(Cyg_Thread *thread )
{
current_thread[CYG_KERNEL_CPU_THIS()] = thread;
}
inline void Cyg_Scheduler_Base::set_current_thread(Cyg_Thread *thread,
HAL_SMP_CPU_TYPE cpu)
{
current_thread[cpu] = thread;
}
inline cyg_bool Cyg_Scheduler_Base::get_need_reschedule()
{
return need_reschedule[CYG_KERNEL_CPU_THIS()];
}
inline void Cyg_Scheduler_Base::set_need_reschedule()
{
need_reschedule[CYG_KERNEL_CPU_THIS()] = true;
}
inline void Cyg_Scheduler_Base::set_need_reschedule(Cyg_Thread *thread)
{
need_reschedule[CYG_KERNEL_CPU_THIS()] = true;
}
inline void Cyg_Scheduler_Base::clear_need_reschedule()
{
need_reschedule[CYG_KERNEL_CPU_THIS()] = false;
}
inline cyg_ucount32 Cyg_Scheduler_Base::get_sched_lock()
{
return Cyg_Scheduler_SchedLock::get_sched_lock();
}
// Return current number of thread switches
inline cyg_ucount32 Cyg_Scheduler_Base::get_thread_switches()
{
return thread_switches[CYG_KERNEL_CPU_THIS()];
}
// Return current queue pointer
inline Cyg_ThreadQueue *Cyg_SchedThread::get_current_queue()
{
return queue;
}
// -------------------------------------------------------------------------
#endif // ifndef __SCHED_HXX__
// EOF sched.hxx
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