1 2 #include <pthread.h> 3 #include <stdlib.h> 4 #include <unistd.h> 5 #include <assert.h> 6 /* Naive dining philosophers with inconsistent lock acquisition 7 ordering. */ 8 9 static pthread_t phil[5]; 10 static struct { 11 pthread_mutex_t m; 12 char pad[120 - sizeof(pthread_mutex_t)]; 13 } chop[5]; 14 15 void* dine ( void* arg ) 16 { 17 int i; 18 long left = (long)arg; 19 long right = (left + 1) % 5; 20 for (i = 0; i < 1000/*arbitrary*/; i++) { 21 pthread_mutex_lock(&chop[left].m); 22 pthread_mutex_lock(&chop[right].m); 23 /* eating */ 24 pthread_mutex_unlock(&chop[left].m); 25 pthread_mutex_unlock(&chop[right].m); 26 } 27 return NULL; 28 } 29 30 int main ( void ) 31 { 32 long i; 33 assert(sizeof(pthread_mutex_t) <= 120); 34 35 for (i = 0; i < 5; i++) 36 pthread_mutex_init( &chop[i].m, NULL); 37 38 for (i = 0; i < 5; i++) 39 pthread_create(&phil[i], NULL, dine, (void*)i ); 40 41 sleep(1); 42 43 for (i = 0; i < 5; i++) 44 pthread_join(phil[i], NULL); 45 46 return 0; 47 } 48
