cmux: Remove round-robin circuit policy

Since 0.2.4, tor uses EWMA circuit policy to prioritize. The previous
algorithm, round-robin, hasn't been used since then but was still used as a
fallback.

Now that EWMA is mandatory, remove that code entirely and enforce a cmux
policy to be set.

This is part of a circuitmux cleanup to improve performance and reduce
complexity in the code. We'll be able to address future optimization with this
work.

Closes #25268

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

1 files changed, 2 insertions, 0 deletions

diff --git a/src/test/test_circuitmux.c b/src/test/test_circuitmux.c
index 854f725054..75b7a0ea47 100644
--- a/src/test/test_circuitmux.c
+++ b/src/test/test_circuitmux.c
@@ -7,6 +7,7 @@
 #include "or.h"
 #include "channel.h"
 #include "circuitmux.h"
+#include "circuitmux_ewma.h"
 #include "relay.h"
 #include "scheduler.h"
 #include "test.h"
@@ -45,6 +46,7 @@ test_cmux_destroy_cell_queue(void *arg)
   cmux = circuitmux_alloc();
   tt_assert(cmux);
   ch = new_fake_channel();
+  circuitmux_set_policy(cmux, &ewma_policy);
   ch->has_queued_writes = has_queued_writes;
   ch->wide_circ_ids = 1;