source: libcfa/src/concurrency/locks.cfa@ 5465377c

#include "locks.hfa"
#include "kernel_private.hfa"
#include <stdlib.h>
#include <stdio.h>

#include <kernel.hfa>
#include <stdlib.hfa>
#include <thread.hfa>

///////////////////////////////////////////////////////////////////
//// info_thread
///////////////////////////////////////////////////////////////////
forall(dtype L | is_blocking_lock(L)) {
        void ?{}( info_thread(L) & this, $thread * t ) {
                this.t = t;
                this.lock = 0p;
                this.listed = false;
        }

        void ?{}( info_thread(L) & this, $thread * t, uintptr_t info ) {
                this.t = t;
                this.info = info;
                this.lock = 0p;
                this.listed = false;
        }

        void ^?{}( info_thread(L) & this ){
                // default
        }

        info_thread(L) *& get_next( info_thread(L) & this ) {
                return this.next;
        }
}
///////////////////////////////////////////////////////////////////
//// Blocking Locks
///////////////////////////////////////////////////////////////////

void ?{}( blocking_lock & this, bool multi_acquisition, bool strict_owner ) {
        this.lock{};
        this.blocked_threads{};
        this.wait_count = 0;
        this.multi_acquisition = multi_acquisition;
        this.strict_owner = strict_owner;
        this.owner = 0p;
        this.recursion_count = 0;
}

void ^?{}( blocking_lock & this ) {
        // default
}

void ?{}( mutex_lock & this ) {
        ((blocking_lock &)this){ false, false };
}

void ^?{}( mutex_lock & this ) {
        // default
}

void ?{}( owner_lock & this ) {
        ((blocking_lock &)this){ true, true };
}

void ^?{}( owner_lock & this ) {
        // default
}

void ?{}( recursive_mutex_lock & this ) {
        ((blocking_lock &)this){ true, false };
}

void ^?{}( recursive_mutex_lock & this ) {
        // default
}

void lock( blocking_lock & this ) with( this ) {
        $thread * thrd = active_thread();
        lock( lock __cfaabi_dbg_ctx2 );
        if ( owner == thrd && !multi_acquisition) {
                fprintf(stderr, "A single acquisition lock holder attempted to reacquire the lock resulting in a deadlock."); // Possibly throw instead
        exit(EXIT_FAILURE);
        } else if ( owner != 0p && owner != thrd ) {
                append( blocked_threads, thrd );
                wait_count++;
                unlock( lock );
                park( );
        } else if ( owner == thrd && multi_acquisition ) {
                recursion_count++;
                unlock( lock );
        } else {
                owner = thrd;
                recursion_count = 1;
                unlock( lock );
        }
}

bool try_lock( blocking_lock & this ) with( this ) {
        $thread * thrd = active_thread();
        bool ret = false;
        lock( lock __cfaabi_dbg_ctx2 );
        if ( owner == 0p ) {
                owner = thrd;
                if ( multi_acquisition ) recursion_count = 1;
                ret = true;
        } else if ( owner == thrd && multi_acquisition ) {
                recursion_count++;
                ret = true;
        }
        unlock( lock );
        return ret;
}

void unlock( blocking_lock & this ) with( this ) {
        lock( lock __cfaabi_dbg_ctx2 );
        if ( owner == 0p ){ // no owner implies lock isn't held
                fprintf( stderr, "There was an attempt to release a lock that isn't held" );
                return;
        } else if ( strict_owner && active_thread() ) {
                fprintf( stderr, "A thread other than the owner attempted to release an owner lock" );
                return;
        }
        recursion_count--;
        if ( recursion_count == 0 ) {
                $thread * thrd = pop_head( blocked_threads );
                owner = thrd;
                recursion_count = ( thrd && multi_acquisition ? 1 : 0 );
                wait_count--;
                unpark( thrd );
        }
        unlock( lock );
}

size_t wait_count( blocking_lock & this ) with( this ) {
        return wait_count;
}


void set_recursion_count( blocking_lock & this, size_t recursion ) with( this ) {
        recursion_count = recursion;
}

size_t get_recursion_count( blocking_lock & this ) with( this ) {
        return recursion_count;
}

void add_( blocking_lock & this, $thread * t ) with( this ) {
    lock( lock __cfaabi_dbg_ctx2 );
        if ( owner != 0p ) {
                append( blocked_threads, t );
                wait_count++;
                unlock( lock );
        } else {
                owner = t;
                if ( multi_acquisition ) recursion_count = 1;
                #if !defined( __CFA_NO_STATISTICS__ )
                        kernelTLS.this_stats = t->curr_cluster->stats;
                #endif
                unpark( t );
                unlock( lock );
        }
}

void remove_( blocking_lock & this ) with( this ) {
    lock( lock __cfaabi_dbg_ctx2 );
        if ( owner == 0p ){ // no owner implies lock isn't held
                fprintf( stderr, "A lock that is not held was passed to a synchronization lock" );
        } else if ( strict_owner && active_thread() ) {
                fprintf( stderr, "A thread other than the owner of a lock passed it to a synchronization lock" );
        } else {
                $thread * thrd = pop_head( blocked_threads );
                owner = thrd;
                recursion_count = ( thrd && multi_acquisition ? 1 : 0 );
                wait_count--;
                unpark( thrd );
        }
        unlock( lock );
}

///////////////////////////////////////////////////////////////////
//// Overloaded routines for traits
///////////////////////////////////////////////////////////////////

// This is temporary until an inheritance bug is fixed

void lock( mutex_lock & this ){
        lock( (blocking_lock &)this );
}

void unlock( mutex_lock & this ){
        unlock( (blocking_lock &)this );
}

void add_( mutex_lock & this, struct $thread * t ){
        add_( (blocking_lock &)this, t );
}

void remove_( mutex_lock & this ){
        remove_( (blocking_lock &)this );
}

void set_recursion_count( mutex_lock & this, size_t recursion ){
        set_recursion_count( (blocking_lock &)this, recursion );
}

size_t get_recursion_count( mutex_lock & this ){
        get_recursion_count( (blocking_lock &)this );
}

void lock( recursive_mutex_lock & this ){
        lock( (blocking_lock &)this );
}

void unlock( recursive_mutex_lock & this ){
        unlock( (blocking_lock &)this );
}

void add_( recursive_mutex_lock & this, struct $thread * t ){
        add_( (blocking_lock &)this, t );
}

void remove_( recursive_mutex_lock & this ){
        remove_( (blocking_lock &)this );
}

void set_recursion_count( recursive_mutex_lock & this, size_t recursion ){
        set_recursion_count( (blocking_lock &)this, recursion );
}

size_t get_recursion_count( recursive_mutex_lock & this ){
        get_recursion_count( (blocking_lock &)this );
}

///////////////////////////////////////////////////////////////////
//// condition variable
///////////////////////////////////////////////////////////////////

forall(dtype L | is_blocking_lock(L)) {

        void timeout_handler ( alarm_node_wrap(L) & this ) with( this ) {
        // This condition_variable member is called from the kernel, and therefore, cannot block, but it can spin.
            lock( cond->lock __cfaabi_dbg_ctx2 );
            if ( (*i)->listed ) {                       // is thread on queue
                info_thread(L) * copy = *i;
                        remove( cond->blocked_threads, i );              //remove this thread O(1)
                        cond->wait_count--;
                        if( !copy->lock ) {
                                unlock( cond->lock );
                                #if !defined( __CFA_NO_STATISTICS__ )
                                        #warning unprotected access to tls TODO discuss this
                                        kernelTLS.this_stats = copy->t->curr_cluster->stats;
                                #endif
                                unpark( copy->t );
                } else {
                        add_(*copy->lock, copy->t);                     // call lock's add_
                }
            }
            unlock( cond->lock );
        }

        void alarm_node_wrap_cast( alarm_node_t & a ) {
                timeout_handler( (alarm_node_wrap(L) &)a );
        }

        void ?{}( condition_variable(L) & this ){
                this.lock{};
                this.blocked_threads{};
                this.count = 0;
        }

        void ^?{}( condition_variable(L) & this ){
                // default
        }

        void ?{}( alarm_node_wrap(L) & this, $thread * thrd, Time alarm, Duration period, Alarm_Callback callback ) {
                this.alarm_node{ thrd, alarm, period, callback };
        }

        void ^?{}( alarm_node_wrap(L) & this ) {
                // default
        }

        bool notify_one( condition_variable(L) & this ) with( this ) {
                lock( lock __cfaabi_dbg_ctx2 );
                bool ret = !!blocked_threads;
                info_thread(L) * popped = pop_head( blocked_threads );
                popped->listed = false;
                if(popped != 0p) {
                        count--;
                        if (popped->lock) {
                                add_(*popped->lock, popped->t);
                        } else {
                                unpark(popped->t);
                        }
                }
                unlock( lock );
                return ret;
        }

        bool notify_all( condition_variable(L) & this ) with(this) {
                lock( lock __cfaabi_dbg_ctx2 );
                bool ret = blocked_threads ? true : false;
                while( blocked_threads ) {
                        info_thread(L) * popped = pop_head( blocked_threads );
                        popped->listed = false;
                        if(popped != 0p){
                                count--;
                                if (popped->lock) {
                                        add_(*popped->lock, popped->t);
                                } else {
                                        unpark(popped->t);
                                }
                        }
                }
                unlock( lock );
                return ret;
        }

        uintptr_t front( condition_variable(L) & this ) with(this) {
                if(!blocked_threads) return NULL;
                return peek(blocked_threads)->info;
        }

        bool empty( condition_variable(L) & this ) with(this) {
                return blocked_threads ? false : true;
        }

        int counter( condition_variable(L) & this ) with(this) {
                return count;
        }

        // helper for wait()'s' without a timeout
        void queue_info_thread( condition_variable(L) & this, info_thread(L) & i ) with(this) {
                lock( lock __cfaabi_dbg_ctx2 );
                append( this.blocked_threads, &i );
                count++;
                i.listed = true;
                size_t recursion_count;
                if (i.lock) {
                        recursion_count = get_recursion_count(*i.lock);
                        remove_( *i.lock );
                }

                unlock( lock );
                park( ); // blocks here

                if (i.lock) set_recursion_count(*i.lock, recursion_count); // resets recursion count here after waking
        }

        // helper for wait()'s' with a timeout
        void queue_info_thread_timeout( condition_variable(L) & this, info_thread(L) & info, Time t ) with(this) {
                lock( lock __cfaabi_dbg_ctx2 );

                info_thread(L) * queue_ptr = &info;

                alarm_node_wrap(L) node_wrap = { info.t, t, 0`s, alarm_node_wrap_cast };
                node_wrap.cond = &this;
                node_wrap.i = &queue_ptr;

                register_self( &node_wrap.alarm_node );

                append( blocked_threads, queue_ptr );
                info.listed = true;
                count++;

                size_t recursion_count;
                if (info.lock) {
                        recursion_count = get_recursion_count(*info.lock);
                        remove_( *info.lock );
                }

                unlock( lock );
                park();

                if (info.lock) set_recursion_count(*info.lock, recursion_count);
        }

        void wait( condition_variable(L) & this ) with(this) {
                info_thread( L ) i = { active_thread() };
                queue_info_thread( this, i );
        }

        void wait( condition_variable(L) & this, uintptr_t info ) with(this) {
                info_thread( L ) i = { active_thread(), info };
                queue_info_thread( this, i );
        }

        void wait( condition_variable(L) & this, Duration duration ) with(this) {
                info_thread( L ) i = { active_thread() };
                queue_info_thread_timeout(this, i, __kernel_get_time() + duration );
        }

        void wait( condition_variable(L) & this, uintptr_t info, Duration duration ) with(this) {
                info_thread( L ) i = { active_thread(), info };
                queue_info_thread_timeout(this, i, __kernel_get_time() + duration );
        }

        void wait( condition_variable(L) & this, Time time ) with(this) {
                info_thread( L ) i = { active_thread() };
                queue_info_thread_timeout(this, i, time);
        }

        void wait( condition_variable(L) & this, uintptr_t info, Time time ) with(this) {
                info_thread( L ) i = { active_thread(), info };
                queue_info_thread_timeout(this, i, time);
        }

        void wait( condition_variable(L) & this, L & l ) with(this) {
                info_thread(L) i = { active_thread() };
                i.lock = &l;
                queue_info_thread( this, i );
        }

        void wait( condition_variable(L) & this, L & l, uintptr_t info ) with(this) {
                info_thread(L) i = { active_thread(), info };
                i.lock = &l;
                queue_info_thread( this, i );
        }

        void wait( condition_variable(L) & this, L & l, Duration duration ) with(this) {
                info_thread(L) i = { active_thread() };
                i.lock = &l;
                queue_info_thread_timeout(this, i, __kernel_get_time() + duration );
        }

        void wait( condition_variable(L) & this, L & l, uintptr_t info, Duration duration ) with(this) {
                info_thread(L) i = { active_thread(), info };
                i.lock = &l;
                queue_info_thread_timeout(this, i, __kernel_get_time() + duration );
        }

        void wait( condition_variable(L) & this, L & l, Time time ) with(this) {
                info_thread(L) i = { active_thread() };
                i.lock = &l;
                queue_info_thread_timeout(this, i, time );
        }

        void wait( condition_variable(L) & this, L & l, uintptr_t info, Time time ) with(this) {
                info_thread(L) i = { active_thread(), info };
                i.lock = &l;
                queue_info_thread_timeout(this, i, time );
        }
}