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Change the wake_up from dream algo. to wake up in a cascading fashion…
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… individual dreamers on each level with a per dreamer wake up wind up rather than a wake up all across all levels. Also introduced a limbo state updated by the dreamer entering into limbo on all the levels in which he is dreaming so he doesn't become eligible to take the kick back into reality this remaining in limbo till infinity
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@karthick18
karthick18 committed Jul 25, 2010
1 parent cb70bc6 commit fe563a4
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Showing 2 changed files with 67 additions and 23 deletions.
2 changes: 1 addition & 1 deletion Makefile
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Expand Up @@ -14,4 +14,4 @@ $(TARGET): $(OBJ_FILES)
$(CC) $(CFLAGS) -c -o $@ $<

clean:
rm -f $(OBJ_FILES) *~ $(TARGET)
rm -f $(OBJ_FILES) *~ $(TARGET)
88 changes: 66 additions & 22 deletions inception.c
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Expand Up @@ -234,14 +234,33 @@ static void set_thread_priority(struct dreamer_attr *dattr, int level)

}

/*
* Wake up an individual dreamer in one level and let him propagate the kick down to levels below.
*/
static void wake_up_dreamer(struct dreamer_attr *dattr, int level)
{
register struct list *iter;
if(!level || (dattr->shared_state & DREAMER_IN_LIMBO)) return;
pthread_mutex_lock(&dreamer_mutex[level-1]);
for(iter = dreamer_queue[level-1].head; iter; iter = iter->next)
{
struct dreamer_attr *dreamer = LIST_ENTRY(iter, struct dreamer_attr, list);
if( !(dreamer->role ^ dattr->role) )
{
dream_enqueue_cmd(dreamer, DREAMER_KICK_BACK, NULL, dreamer->level);
break;
}
}
pthread_mutex_unlock(&dreamer_mutex[level-1]);
}

/*
* Level 0 is wake up dreamers on all levels.
* Skip guys in a limbo from that level to all the way down.
*/
static void wake_up_dreamers(int level)
{
int start = DREAM_LEVELS-1,end = 0;
int role_in_limbo = 0;
register int i;
if(level > 0)
{
Expand All @@ -256,17 +275,37 @@ static void wake_up_dreamers(int level)
{
struct dreamer_attr *dattr = LIST_ENTRY(iter, struct dreamer_attr, list);
if( (dattr->shared_state & DREAMER_IN_LIMBO) )
continue;
dream_enqueue_cmd(dattr, DREAMER_KICK_BACK, NULL, dattr->level);
}
pthread_mutex_unlock(&dreamer_mutex[i]);
}
}

/*
* Set the limbo state on all levels of this dreamer so he cannot get a kick back
* Called with the lock on that level.
*/
static void set_limbo_state(struct dreamer_attr *dattr)
{
register int i;
for(i = DREAM_LEVELS - 1; i >= 0 ; --i)
{
register struct list *iter;

if(i != dattr->level-1)
pthread_mutex_lock(&dreamer_mutex[i]);
for(iter = dreamer_queue[i].head; iter; iter = iter->next)
{
struct dreamer_attr *dreamer = LIST_ENTRY(iter, struct dreamer_attr, list);
if( !(dreamer->role ^ dattr->role) )
{
role_in_limbo |= dattr->role;
dreamer->shared_state |= DREAMER_IN_LIMBO;
break;
}

if( !(dattr->role & role_in_limbo) )
dream_enqueue_cmd(dattr, DREAMER_KICK_BACK, NULL, dattr->level);
else if(!(dattr->shared_state & DREAMER_IN_LIMBO))
dattr->shared_state |= DREAMER_IN_LIMBO;
}
pthread_mutex_unlock(&dreamer_mutex[i]);
usleep(10000); /* breather to the dreamers in the level woken up */
if(i != dattr->level-1)
pthread_mutex_unlock(&dreamer_mutex[i]);
}
}

Expand Down Expand Up @@ -366,8 +405,9 @@ static void infinite_subconsciousness(struct dreamer_attr *dattr)
if((dattr->role & DREAM_INCEPTION_PERFORMER))
{
output("\n\nCobbs. search for Saito ends in Limbo. Now either both take the kick back to reality "
"or the ending is still a state of limbo from Cobbs. perspective. which is what Nolan wants us to think\n");
output("So let me end the limbo state abruptly and leave it to the reviewers to decide with an infinite sleep:-)\n\n");
"or the ending is still a state of limbo from Cobbs. perspective which is what Nolan wants us to think\n");
output("This is inspite of witnessing his children turn back for the first time which were earlier shown to appear only in his projections.\n");
output("So let me end the limbo state abruptly like in the Movie with the totem spinning and leave it to the reviewers to decide with an infinite sleep:-)\n\n");
}
pthread_cond_signal(&limbo_cond);
pthread_mutex_unlock(&limbo_mutex);
Expand Down Expand Up @@ -449,6 +489,7 @@ static void enter_limbo(struct dreamer_attr *dattr)
else
{
search_saito:
set_limbo_state(clone);
pthread_mutex_unlock(&dreamer_mutex[3]);
usleep(10000);
infinite_subconsciousness(clone);
Expand Down Expand Up @@ -560,6 +601,7 @@ static void enter_limbo(struct dreamer_attr *dattr)

case DREAM_OVERLOOKER: /* Saito */
{
set_limbo_state(clone);
pthread_mutex_unlock(&dreamer_mutex[3]);
usleep(1000);
infinite_subconsciousness(clone);
Expand Down Expand Up @@ -735,7 +777,8 @@ static void *dream_level_3(void *arg)
dream_enqueue_cmd(yusuf, DREAMER_SYNCHRONIZE_KICK, dattr, yusuf->level);
pthread_mutex_unlock(&dreamer_mutex[0]);
/*
* Take a breather while Yusuf does his work
* Take a breather while Yusuf does his work so we can rescan for a kick back
* Otherwise we miss and get it after our delayed sleep
*/
usleep(10000);
pthread_mutex_lock(&dreamer_mutex[2]);
Expand Down Expand Up @@ -913,7 +956,7 @@ static void *dream_level_3(void *arg)
}
out_unlock:
pthread_mutex_unlock(&dreamer_mutex[2]);
wake_up_dreamers(2);
wake_up_dreamer(dattr, 2);
return NULL;
}

Expand Down Expand Up @@ -1190,7 +1233,7 @@ static void *dream_level_2(void *arg)
/*
* Signal waiters at level 1
*/
wake_up_dreamers(1);
wake_up_dreamer(dattr, 1);
return NULL;
}

Expand All @@ -1212,11 +1255,13 @@ static void continue_dreaming_in_level_1(struct dreamer_attr *dattr)
{
struct dreamer_request *req = NULL;
struct dreamer_attr *arthur = NULL;
struct dreamer_attr *arthur_level2 = NULL; /* to wake him up at level 2*/
output("[%s] starts to fall into the bridge while fighting Fischers projections in level [%d]\n",
dattr->name, dattr->level);

arthur = dreamer_find(&dreamer_queue[0], "arthur", DREAM_ORGANIZER);
pthread_mutex_unlock(&dreamer_mutex[0]);
arthur_level2 = dreamer_find_sync(dattr, 2, "arthur", DREAM_ORGANIZER);
/*
* Wait for Arthur to enter level 2 before starting the fall.
*/
Expand All @@ -1227,13 +1272,12 @@ static void continue_dreaming_in_level_1(struct dreamer_attr *dattr)
while ( (req = dream_dequeue_cmd(dattr) ) )
{
/*
* The time to exit and wake up all dreamers
* The time to exit and wake up all dreamers with a synchronized kick
*/
if(req->cmd == DREAMER_SYNCHRONIZE_KICK)
{
free(req);
output("[%s] going to wake up all the others through a synchronized kick by effecting the VAN "
"to fall into the bridge\n", dattr->name);
output("[%s] going to take the kick back to reality and wake up all the others through a synchronized kick " "by effecting the VAN to fall into the bridge\n", dattr->name);
goto out_unlock;
}
free(req);
Expand All @@ -1248,7 +1292,8 @@ static void continue_dreaming_in_level_1(struct dreamer_attr *dattr)
out_unlock:
dattr->shared_state |= DREAMER_KICK_BACK;
pthread_mutex_unlock(&dreamer_mutex[0]);
wake_up_dreamers(0); /* wake up all */
wake_up_dreamers(3); /* wake up all */
wake_up_dreamer(arthur_level2, 2);
}

/*
Expand Down Expand Up @@ -1282,8 +1327,7 @@ static void fischer_dream_level1(void)
else if(req->cmd == DREAMER_KICK_BACK)
{
free(req);
output("[%s] got a Kick at level [%d]. Exiting back to reality with the inception thought\n",
dattr->name, dattr->level);
output("[%s] got a Kick at level [%d].\n", dattr->name, dattr->level);
goto out;
}
free(req);
Expand Down Expand Up @@ -1462,8 +1506,8 @@ static void meet_all_others_in_level_1(struct dreamer_attr *dattr)
}
else if(req->cmd == DREAMER_KICK_BACK)
{
output("[%s] got a Kick at level [%d]. Exiting back to level [%d]\n",
dattr->name, dattr->level, dattr->level-1);
output("[%s] got a Kick at level [%d]. Exiting back to reality\n",
dattr->name, dattr->level);
goto out_unlock;
}
free(req);
Expand Down

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