Robust/src/Runtime/DSTM/interface/threadnotify.c

   1 #include "threadnotify.h"
   2
   3 notifyhashtable_t nlookup; //Global hash table
   4
   5 /* This function creates a new node in the linked list of threads waiting
   6  * for an update notification from a particular object.
   7  * This takes in the head of the linked list and inserts the new node to it */
   8 void insNode(threadlist_t *head, unsigned int threadid, unsigned int mid) {
   9         threadlist_t *ptr;
  10         if(head == NULL) {
  11                 if((head = calloc(1, sizeof(threadlist_t))) == NULL) {
  12                         printf("Calloc Error %s, %d,\n", __FILE__, __LINE__);
  13                         return;
  14                 }
  15                 head->threadid = threadid;
  16                 head->mid = mid;
  17                 head->next = NULL;
  18         } else {
  19                 if((ptr = calloc(1, sizeof(threadlist_t))) == NULL) {
  20                         printf("Calloc Error %s, %d,\n", __FILE__, __LINE__);
  21                         return;
  22                 }
  23                 ptr->threadid = threadid;
  24                 ptr->mid = mid;
  25                 ptr->next = head;
  26                 head = ptr;
  27         }
  28 }
  29
  30 /* This function displays the linked list of threads waiting on update notification
  31  * from an object */
  32 void display(threadlist_t *head) {
  33         threadlist_t *ptr;
  34         if(head == NULL) {
  35                 printf("No thread is waiting\n");
  36                 return;
  37         } else {
  38                 while(head != NULL) {
  39                         ptr = head;
  40                         printf("The threadid waiting is = %d\n", ptr->threadid);
  41                         printf("The mid on which thread present = %d\n", ptr->mid);
  42                         head = ptr->next;
  43                 }
  44         }
  45 }
  46
  47 /* This function creates a new hash table that stores a mapping between the threadid and
  48  * a pointer to the thread notify data */
  49 unsigned int notifyhashCreate(unsigned int size, float loadfactor) {
  50         notifylistnode_t *nodes;
  51
  52         // Allocate space for the hash table
  53         if((nodes = calloc(size, sizeof(notifylistnode_t))) == NULL) {
  54                 printf("Calloc error %s %d\n", __FILE__, __LINE__);
  55                 return 1;
  56         }
  57
  58         nlookup.table = nodes;
  59         nlookup.size = size;
  60         nlookup.numelements = 0; // Initial number of elements in the hash
  61         nlookup.loadfactor = loadfactor;
  62         //Initialize the pthread_mutex variable
  63         pthread_mutex_init(&nlookup.locktable, NULL);
  64         return 0;
  65 }
  66
  67 // Assign to tids to bins inside hash table
  68 unsigned int notifyhashFunction(unsigned int tid) {
  69         return( tid % (nlookup.size));
  70 }
  71
  72 // Insert pointer to the notify data and threadid mapping into the hash table
  73 unsigned int notifyhashInsert(unsigned int tid, notifydata_t *ndata) {
  74         unsigned int newsize;
  75         int index;
  76         notifylistnode_t *ptr, *node;
  77
  78         if (nlookup.numelements > (nlookup.loadfactor * nlookup.size)) {
  79                 //Resize Table
  80                 newsize = 2 * nlookup.size + 1;
  81                 pthread_mutex_lock(&nlookup.locktable);
  82                 notifyhashResize(newsize);
  83                 pthread_mutex_unlock(&nlookup.locktable);
  84         }
  85         ptr = nlookup.table;
  86         nlookup.numelements++;
  87
  88         index = notifyhashFunction(tid);
  89 #ifdef DEBUG
  90         printf("DEBUG -> index = %d, threadid = %d\n", index, tid);
  91 #endif
  92         pthread_mutex_lock(&nlookup.locktable);
  93         if(ptr[index].next == NULL && ptr[index].threadid == 0) {       // Insert at the first position in the hashtable
  94                 ptr[index].threadid = tid;
  95                 ptr[index].ndata = ndata;
  96         } else {                        // Insert in the beginning of linked list
  97                 if ((node = calloc(1, sizeof(notifylistnode_t))) == NULL) {
  98                         printf("Calloc error %s, %d\n", __FILE__, __LINE__);
  99                         pthread_mutex_unlock(&nlookup.locktable);
 100                         return 1;
 101                 }
 102                 node->threadid = tid;
 103                 node->ndata = ndata;
 104                 node->next = ptr[index].next;
 105                 ptr[index].next = node;
 106         }
 107         pthread_mutex_unlock(&nlookup.locktable);
 108         return 0;
 109 }
 110
 111 // Return pointer to thread notify data for a given threadid in the hash table
 112 notifydata_t  *notifyhashSearch(unsigned int tid) {
 113         int index;
 114         notifylistnode_t *ptr, *node;
 115
 116         ptr = nlookup.table;    // Address of the beginning of hash table
 117         index = notifyhashFunction(tid);
 118         node = &ptr[index];
 119         pthread_mutex_lock(&nlookup.locktable);
 120         while(node != NULL) {
 121                 if(node->threadid == tid) {
 122                         pthread_mutex_unlock(&nlookup.locktable);
 123                         return node->ndata;
 124                 }
 125                 node = node->next;
 126         }
 127         pthread_mutex_unlock(&nlookup.locktable);
 128         return NULL;
 129 }
 130
 131 // Remove an entry from the hash table
 132 unsigned int notifyhashRemove(unsigned int tid) {
 133         int index;
 134         notifylistnode_t *curr, *prev, *ptr, *node;
 135
 136         ptr = nlookup.table;
 137         index = notifyhashFunction(tid);
 138         curr = &ptr[index];
 139
 140         pthread_mutex_lock(&nlookup.locktable);
 141         for (; curr != NULL; curr = curr->next) {
 142                 if (curr->threadid == tid) {         // Find a match in the hash table
 143                         nlookup.numelements--;  // Decrement the number of elements in the global hashtable
 144                         if ((curr == &ptr[index]) && (curr->next == NULL))  { // Delete the first item inside the hashtable with no linked list of notifylistnode_t
 145                                 curr->threadid = 0;
 146                                 curr->ndata = NULL;
 147                         } else if ((curr == &ptr[index]) && (curr->next != NULL)) { //Delete the first bin item with a linked list of notifylistnode_t  connected
 148                                 curr->threadid = curr->next->threadid;
 149                                 curr->ndata = curr->next->ndata;
 150                                 node = curr->next;
 151                                 curr->next = curr->next->next;
 152                                 free(node);
 153                         } else {                                                // Regular delete from linked listed
 154                                 prev->next = curr->next;
 155                                 free(curr);
 156                         }
 157                         pthread_mutex_unlock(&nlookup.locktable);
 158                         return 0;
 159                 }
 160                 prev = curr;
 161         }
 162         pthread_mutex_unlock(&nlookup.locktable);
 163         return 1;
 164 }
 165
 166 // Resize table
 167 unsigned int notifyhashResize(unsigned int newsize) {
 168         notifylistnode_t *node, *ptr, *curr, *next;     // curr and next keep track of the current and the next notifyhashlistnodes in a linked list
 169         unsigned int oldsize;
 170         int isfirst;    // Keeps track of the first element in the notifylistnode_t for each bin in hashtable
 171         int i,index;
 172         notifylistnode_t *newnode;
 173
 174         ptr = nlookup.table;
 175         oldsize = nlookup.size;
 176
 177         if((node = calloc(newsize, sizeof(notifylistnode_t))) == NULL) {
 178                 printf("Calloc error %s %d\n", __FILE__, __LINE__);
 179                 return 1;
 180         }
 181
 182         nlookup.table = node;           //Update the global hashtable upon resize()
 183         nlookup.size = newsize;
 184         nlookup.numelements = 0;
 185
 186         for(i = 0; i < oldsize; i++) {                  //Outer loop for each bin in hash table
 187                 curr = &ptr[i];
 188                 isfirst = 1;
 189                 while (curr != NULL) {                  //Inner loop to go through linked lists
 190                         if (curr->threadid == 0) {              //Exit inner loop if there the first element for a given bin/index is NULL
 191                                 break;                  //threadid = threadcond =0 for element if not present within the hash table
 192                         }
 193                         next = curr->next;
 194                         index = notifyhashFunction(curr->threadid);
 195 #ifdef DEBUG
 196                         printf("DEBUG(resize) -> index = %d, threadid = %d\n", index, curr->threadid);
 197 #endif
 198                         // Insert into the new table
 199                         if(nlookup.table[index].next == NULL && nlookup.table[index].threadid == 0) {
 200                                 nlookup.table[index].threadid = curr->threadid;
 201                                 nlookup.table[index].ndata = curr->ndata;
 202                                 nlookup.numelements++;
 203                         }else {
 204                                 if((newnode = calloc(1, sizeof(notifylistnode_t))) == NULL) {
 205                                         printf("Calloc error %s, %d\n", __FILE__, __LINE__);
 206                                         return 1;
 207                                 }
 208                                 newnode->threadid = curr->threadid;
 209                                 newnode->ndata = curr->ndata;
 210                                 newnode->next = nlookup.table[index].next;
 211                                 nlookup.table[index].next = newnode;
 212                                 nlookup.numelements++;
 213                         }
 214
 215                         //free the linked list of notifylistnode_t if not the first element in the hash table
 216                         if (isfirst != 1) {
 217                                 free(curr);
 218                         }
 219
 220                         isfirst = 0;
 221                         curr = next;
 222                 }
 223         }
 224
 225         free(ptr);              //Free the memory of the old hash table
 226         return 0;
 227 }