Decoupling loops from threads to allow fixed thread count

On large configurations, too many threads would spawn with one thread
per loop. Therefore, threads may now run multiple loops at once. The
thread count is configurable and may be changed during run. All threads
are spawned on startup.

This change helps with memory bloating. BIRD filters need large
temporary memory blocks to store their stack and also memory management
keeps its hot page storage per-thread.

Known bugs:
* Thread autobalancing is not yet implemented.
* Low latency loops are executed together with standard loops.

1 files changed, 12 insertions, 12 deletions

diff --git a/lib/rcu.c b/lib/rcu.c
index 83fdd022..8ae4f2ab 100644
--- a/lib/rcu.c
+++ b/lib/rcu.c
@@ -17,11 +17,11 @@
 #include "lib/locking.h"
 
 _Atomic uint rcu_gp_ctl = RCU_NEST_CNT;
-_Thread_local struct rcu_birdloop *this_rcu_birdloop = NULL;
+_Thread_local struct rcu_thread *this_rcu_thread = NULL;
 
-static list rcu_birdloop_list;
+static list rcu_thread_list;
 
-static struct rcu_birdloop main_rcu_birdloop;
+static struct rcu_thread main_rcu_thread;
 
 DEFINE_DOMAIN(resource);
 static DOMAIN(resource) rcu_domain;
@@ -37,8 +37,8 @@ static void
 update_counter_and_wait(void)
 {
   atomic_fetch_xor(&rcu_gp_ctl, RCU_GP_PHASE);
-  struct rcu_birdloop *rc;
-  WALK_LIST(rc, rcu_birdloop_list)
+  struct rcu_thread *rc;
+  WALK_LIST(rc, rcu_thread_list)
     while (rcu_gp_ongoing(&rc->ctl))
       birdloop_yield();
 }
@@ -53,19 +53,19 @@ synchronize_rcu(void)
 }
 
 void
-rcu_birdloop_start(struct rcu_birdloop *rc)
+rcu_thread_start(struct rcu_thread *rc)
 {
   LOCK_DOMAIN(resource, rcu_domain);
-  add_tail(&rcu_birdloop_list, &rc->n);
-  this_rcu_birdloop = rc;
+  add_tail(&rcu_thread_list, &rc->n);
+  this_rcu_thread = rc;
   UNLOCK_DOMAIN(resource, rcu_domain);
 }
 
 void
-rcu_birdloop_stop(struct rcu_birdloop *rc)
+rcu_thread_stop(struct rcu_thread *rc)
 {
   LOCK_DOMAIN(resource, rcu_domain);
-  this_rcu_birdloop = NULL;
+  this_rcu_thread = NULL;
   rem_node(&rc->n);
   UNLOCK_DOMAIN(resource, rcu_domain);
 }
@@ -74,6 +74,6 @@ void
 rcu_init(void)
 {
   rcu_domain = DOMAIN_NEW(resource, "Read-Copy-Update");
-  init_list(&rcu_birdloop_list);
-  rcu_birdloop_start(&main_rcu_birdloop);
+  init_list(&rcu_thread_list);
+  rcu_thread_start(&main_rcu_thread);
 }