sched: Detect KIST support at compile time

Add a detection for the KIST scheduler in our build system and set
HAVE_KIST_SUPPORT if available.

Adapt the should use kist function with this new compile option.

Signed-off-by: David Goulet <dgoulet@torproject.org>

3 files changed, 24 insertions, 12 deletions

diff --git a/src/or/scheduler.c b/src/or/scheduler.c
index b04bdceb40..f02b70793a 100644
--- a/src/or/scheduler.c
+++ b/src/or/scheduler.c
@@ -215,17 +215,6 @@ get_run_sched_ev(void)
   return run_sched_ev;
 }
 
-/* Return true iff the scheduler subsystem should use KIST. */
-int
-scheduler_should_use_kist(void)
-{
-  int64_t run_freq = kist_scheduler_run_interval();
-  log_info(LD_SCHED, "Determined sched_run_interval should be %" PRId64 ". "
-                     "Will%s use KIST.",
-           run_freq, (run_freq > 0 ? "" : " not"));
-  return run_freq > 0;
-}
-
 /* Comparison function to use when sorting pending channels */
 MOCK_IMPL(int,
 scheduler_compare_channels, (const void *c1_v, const void *c2_v))
diff --git a/src/or/scheduler.h b/src/or/scheduler.h
index 3932e60490..ce5163b817 100644
--- a/src/or/scheduler.h
+++ b/src/or/scheduler.h
@@ -116,7 +116,6 @@ MOCK_DECL(void, scheduler_channel_has_waiting_cells, (channel_t *chan));
 /*********************************
  * Defined in scheduler.c
  *********************************/
-int scheduler_should_use_kist(void);
 smartlist_t *get_channels_pending(void);
 struct event *get_run_sched_ev(void);
 MOCK_DECL(int, scheduler_compare_channels,
@@ -156,6 +155,7 @@ MOCK_DECL(int, channel_should_write_to_kernel,
 MOCK_DECL(void, channel_write_to_kernel, (channel_t *chan));
 MOCK_DECL(void, update_socket_info_impl, (socket_table_ent_t *ent));
 
+int scheduler_should_use_kist(void);
 scheduler_t *get_kist_scheduler(void);
 int32_t kist_scheduler_run_interval(const networkstatus_t *ns);
 
diff --git a/src/or/scheduler_kist.c b/src/or/scheduler_kist.c
index 97722cb254..98b523f5ae 100644
--- a/src/or/scheduler_kist.c
+++ b/src/or/scheduler_kist.c
@@ -588,3 +588,26 @@ kist_scheduler_run_interval(const networkstatus_t *ns)
   return run_interval;
 }
 
+#ifdef HAVE_KIST_SUPPORT
+
+/* Return true iff the scheduler subsystem should use KIST. */
+int
+scheduler_should_use_kist(void)
+{
+  int64_t run_interval = kist_scheduler_run_interval(NULL);
+  log_info(LD_SCHED, "Determined sched_run_interval should be %" PRId64 ". "
+                     "Will%s use KIST.",
+           run_interval, (run_interval > 0 ? "" : " not"));
+  return run_interval > 0;
+}
+
+#else /* HAVE_KIST_SUPPORT */
+
+int
+scheduler_should_use_kist(void)
+{
+  return 0;
+}
+
+#endif /* HAVE_KIST_SUPPORT */
+