Memoize the soonest job.

conn.c

@@ -86,6 +86,7 @@ make_conn(int fd, char start_state, tube use, tube watch)
  c->type = 0;
  c->cmd_read = 0;
  c->pending_timeout = -1;
+ c->soonest_job = NULL;
  c->in_job = c->out_job = NULL;
  c->in_job_read = c->out_job_sent = 0;
  c->prev = c->next = c; /* must be out of a linked list right now */
@@ -220,11 +221,15 @@ conn_insert(conn head, conn c)
 job
 soonest_job(conn c)
 {
- job j, soonest = NULL;
+ job j = NULL;
+ job soonest = c->soonest_job;
 
- for (j = c->reserved_jobs.next; j != &c->reserved_jobs; j = j->next) {
- if (j->deadline <= (soonest ? : j)->deadline) soonest = j;
+ if (soonest == NULL) {
+ for (j = c->reserved_jobs.next; j != &c->reserved_jobs; j = j->next) {
+ if (j->deadline <= (soonest ? : j)->deadline) soonest = j;
+ }
  }
+ c->soonest_job = soonest;
  return soonest;
 }
 

conn.h

@@ -60,6 +60,9 @@ struct conn {
  /* A job to be read from the client. */
  job in_job;
 
+ /* Memoization of the soonest job */
+ job soonest_job;
+
  /* How many bytes of in_job->body have been read so far. If in_job is NULL
  * while in_job_read is nonzero, we are in bit bucket mode and
  * in_job_read's meaning is inverted -- then it counts the bytes that

prot.c

@@ -340,6 +340,13 @@ reserve_job(conn c, job j)
  conn_insert(&running, c);
  j->state = JOB_STATE_RESERVED;
  job_insert(&c->reserved_jobs, j);
+ if (c->soonest_job == NULL) {
+ c->soonest_job = j;
+ } else {
+ if (j->deadline < c->soonest_job->deadline) {
+ c->soonest_job = j;
+ }
+ }
  return reply_job(c, j, MSG_RESERVED);
 }
 
@@ -455,6 +462,7 @@ enqueue_reserved_jobs(conn c)
  if (!r) bury_job(j);
  global_stat.reserved_ct--;
  j->tube->stat.reserved_ct--;
+ c->soonest_job = NULL;
  if (!job_list_any_p(&c->reserved_jobs)) conn_remove(c);
  }
 }
@@ -1019,6 +1027,7 @@ remove_this_reserved_job(conn c, job j)
  global_stat.reserved_ct--;
  j->tube->stat.reserved_ct--;
  }
+ c->soonest_job = NULL;
  if (!job_list_any_p(&c->reserved_jobs)) conn_remove(c);
  return j;
 }