job.c

   1 /* job.c - a job in the queue */
   2
   3 /* Copyright (C) 2007 Keith Rarick and Philotic Inc.
   4
   5  * This program is free software: you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation, either version 3 of the License, or
   8  * (at your option) any later version.
   9
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  17  */
  18
  19 #include <stdlib.h>
  20 #include <string.h>
  21
  22 #include "tube.h"
  23 #include "job.h"
  24 #include "primes.h"
  25 #include "util.h"
  26
  27 static unsigned long long int next_id = 1;
  28
  29 static int cur_prime = 0;
  30
  31 static job *all_jobs=NULL;
  32 static size_t all_jobs_cap = 12289; /* == primes[0] */
  33 static size_t all_jobs_used = 0;
  34
  35 static int hash_table_was_oom = 0;
  36
  37 static void rehash();
  38
  39 static int
  40 _get_job_hash_index(unsigned long long int job_id)
  41 {
  42     return job_id % all_jobs_cap;
  43 }
  44
  45 static void
  46 store_job(job j)
  47 {
  48     int index=0;
  49
  50     index = _get_job_hash_index(j->id);
  51
  52     j->ht_next = all_jobs[index];
  53     all_jobs[index] = j;
  54     all_jobs_used++;
  55
  56     /* accept a load factor of 4 */
  57     if (all_jobs_used > (all_jobs_cap << 2)) rehash();
  58 }
  59
  60 static void
  61 rehash()
  62 {
  63     job *old = all_jobs;
  64     size_t old_cap = all_jobs_cap, old_used = all_jobs_used, i;
  65
  66     if (cur_prime >= NUM_PRIMES) return;
  67     if (hash_table_was_oom) return;
  68
  69     all_jobs_cap = primes[++cur_prime];
  70     all_jobs = calloc(all_jobs_cap, sizeof(job));
  71     if (!all_jobs) {
  72         twarnx("Failed to allocate %d new hash buckets", all_jobs_cap);
  73         hash_table_was_oom = 1;
  74         --cur_prime;
  75         all_jobs = old;
  76         all_jobs_cap = old_cap;
  77         all_jobs_used = old_used;
  78         return;
  79     }
  80     all_jobs_used = 0;
  81
  82     for (i = 0; i < old_cap; i++) {
  83         while (old[i]) {
  84             job j = old[i];
  85             old[i] = j->ht_next;
  86             j->ht_next = NULL;
  87             store_job(j);
  88         }
  89     }
  90 }
  91
  92 job
  93 job_find(unsigned long long int job_id)
  94 {
  95     job jh = NULL;
  96     int index = _get_job_hash_index(job_id);
  97
  98     for (jh = all_jobs[index]; jh && jh->id != job_id; jh = jh->ht_next);
  99
 100     return jh;
 101 }
 102
 103 job
 104 allocate_job(int body_size)
 105 {
 106     job j;
 107
 108     j = malloc(sizeof(struct job) + body_size);
 109     if (!j) return twarnx("OOM"), NULL;
 110
 111     j->id = 0;
 112     j->state = JOB_STATE_INVALID;
 113     j->creation = time(NULL);
 114     j->timeout_ct = j->release_ct = j->bury_ct = j->kick_ct = 0;
 115     j->body_size = body_size;
 116     j->next = j->prev = j; /* not in a linked list */
 117     j->ht_next = NULL;
 118     j->tube = NULL;
 119
 120     return j;
 121 }
 122
 123 job
 124 make_job(unsigned int pri, unsigned int delay, unsigned int ttr, int body_size,
 125          tube tube)
 126 {
 127     job j;
 128
 129     j = allocate_job(body_size);
 130     if (!j) return twarnx("OOM"), NULL;
 131
 132     j->id = next_id++;
 133     j->pri = pri;
 134     j->delay = delay;
 135     j->ttr = ttr;
 136
 137     store_job(j);
 138
 139     TUBE_ASSIGN(j->tube, tube);
 140
 141     return j;
 142 }
 143
 144 static void
 145 job_hash_free(job j)
 146 {
 147     int index=_get_job_hash_index(j->id);
 148     job jh = all_jobs ? all_jobs[index] : NULL;
 149
 150     if (jh) {
 151         if (jh == j) {
 152             /* Special case the first */
 153             all_jobs[index] = jh->ht_next;
 154         } else {
 155             job tmp;
 156             while (jh->ht_next && jh->ht_next != j) jh = jh->ht_next;
 157             if (jh->ht_next) {
 158                 tmp = jh->ht_next;
 159                 jh->ht_next = jh->ht_next->ht_next;
 160             }
 161         }
 162     }
 163
 164     all_jobs_used--;
 165 }
 166
 167 void
 168 job_free(job j)
 169 {
 170     if (j) {
 171         TUBE_ASSIGN(j->tube, NULL);
 172         job_hash_free(j);
 173     }
 174
 175     free(j);
 176 }
 177
 178 int
 179 job_pri_cmp(job a, job b)
 180 {
 181     if (a->pri == b->pri) {
 182         /* we can't just subtract because id has too many bits */
 183         if (a->id > b->id) return 1;
 184         if (a->id < b->id) return -1;
 185         return 0;
 186     }
 187     return a->pri - b->pri;
 188 }
 189
 190 int
 191 job_delay_cmp(job a, job b)
 192 {
 193     if (a->deadline == b->deadline) {
 194         /* we can't just subtract because id has too many bits */
 195         if (a->id > b->id) return 1;
 196         if (a->id < b->id) return -1;
 197         return 0;
 198     }
 199     return a->deadline - b->deadline;
 200 }
 201
 202 job
 203 job_copy(job j)
 204 {
 205     job n;
 206
 207     if (!j) return NULL;
 208
 209     n = malloc(sizeof(struct job) + j->body_size);
 210     if (!n) return twarnx("OOM"), NULL;
 211
 212     memcpy(n, j, sizeof(struct job) + j->body_size);
 213     n->next = n->prev = n; /* not in a linked list */
 214
 215     n->tube = 0; /* Don't use memcpy for the tube, which we must refcount. */
 216     TUBE_ASSIGN(n->tube, j->tube);
 217
 218     return n;
 219 }
 220
 221 const char *
 222 job_state(job j)
 223 {
 224     if (j->state == JOB_STATE_READY) return "ready";
 225     if (j->state == JOB_STATE_RESERVED) return "reserved";
 226     if (j->state == JOB_STATE_BURIED) return "buried";
 227     if (j->state == JOB_STATE_DELAYED) return "delayed";
 228     return "invalid";
 229 }
 230
 231 int
 232 job_list_any_p(job head)
 233 {
 234     return head->next != head || head->prev != head;
 235 }
 236
 237 job
 238 job_remove(job j)
 239 {
 240     if (!j) return NULL;
 241     if (!job_list_any_p(j)) return NULL; /* not in a doubly-linked list */
 242
 243     j->next->prev = j->prev;
 244     j->prev->next = j->next;
 245
 246     j->prev = j->next = j;
 247
 248     return j;
 249 }
 250
 251 void
 252 job_insert(job head, job j)
 253 {
 254     if (job_list_any_p(j)) return; /* already in a linked list */
 255
 256     j->prev = head->prev;
 257     j->next = head;
 258     head->prev->next = j;
 259     head->prev = j;
 260 }
 261
 262 unsigned long long int
 263 total_jobs()
 264 {
 265     return next_id - 1;
 266 }
 267
 268 void
 269 job_init()
 270 {
 271     all_jobs = calloc(all_jobs_cap, sizeof(job));
 272     if (!all_jobs) {
 273         twarnx("Failed to allocate %d hash buckets", all_jobs_cap);
 274     }
 275 }