Commit de6318f7 authored by Ondrej Zajicek (work)'s avatar Ondrej Zajicek (work)
Browse files

Nest: Implement prefix trie pruning 

When rtable is pruned and network fib nodes are removed, we also need to
prune prefix trie. Unfortunately, rebuilding prefix trie takes long time
(got about 400 ms for 1M networks), so must not be atomic, we have to
rebuild a new trie while current one is still active. That may require
some considerable amount of temporary memory, so we do that only if
we expect significant trie size reduction.
parent ba5aec94

nest/route.h

+2 −0
Original line number Original line Diff line number Diff line
@@ -185,10 +185,12 @@ typedef struct rtable { 
  btime gc_time;			/* Time of last GC */

  btime gc_time;			/* Time of last GC */

  int gc_counter;			/* Number of operations since last GC */

  int gc_counter;			/* Number of operations since last GC */

  byte prune_state;			/* Table prune state, 1 -> scheduled, 2-> running */

  byte prune_state;			/* Table prune state, 1 -> scheduled, 2-> running */

  byte prune_trie;			/* Prune prefix trie during next table prune */

  byte hcu_scheduled;			/* Hostcache update is scheduled */

  byte hcu_scheduled;			/* Hostcache update is scheduled */

  byte nhu_state;			/* Next Hop Update state */

  byte nhu_state;			/* Next Hop Update state */

  struct fib_iterator prune_fit;	/* Rtable prune FIB iterator */

  struct fib_iterator prune_fit;	/* Rtable prune FIB iterator */

  struct fib_iterator nhu_fit;		/* Next Hop Update FIB iterator */

  struct fib_iterator nhu_fit;		/* Next Hop Update FIB iterator */

  struct f_trie *trie_new;		/* New prefix trie defined during pruning */





  list subscribers;			/* Subscribers for notifications */

  list subscribers;			/* Subscribers for notifications */

  struct timer *settle_timer;		/* Settle time for notifications */

  struct timer *settle_timer;		/* Settle time for notifications */

nest/rt-table.c

+42 −14
Original line number Original line Diff line number Diff line
@@ -134,6 +134,9 @@ net_init_with_trie(struct fib *f, void *N) 




  if (tab->trie)

  if (tab->trie)

    trie_add_prefix(tab->trie, n->n.addr, n->n.addr->pxlen, n->n.addr->pxlen);

    trie_add_prefix(tab->trie, n->n.addr, n->n.addr->pxlen, n->n.addr->pxlen);



  if (tab->trie_new)

    trie_add_prefix(tab->trie_new, n->n.addr, n->n.addr->pxlen, n->n.addr->pxlen);

}

}





static inline net *

static inline net *
@@ -2399,6 +2402,13 @@ rt_prune_table(rtable *tab) 




    FIB_ITERATE_INIT(fit, &tab->fib);

    FIB_ITERATE_INIT(fit, &tab->fib);

    tab->prune_state = 2;

    tab->prune_state = 2;



    if (tab->prune_trie)

    {

      /* Init prefix trie pruning */

      tab->trie_new = f_new_trie(lp_new_default(tab->rp), 0);

      tab->trie_new->ipv4 = tab->trie->ipv4;

    }

  }

  }





again:

again:
@@ -2407,10 +2417,6 @@ again: 
      rte *e;

      rte *e;





    rescan:

    rescan:

      for (e=n->routes; e; e=e->next)

      {

	if (e->sender->flush_active || (e->flags & REF_DISCARD))

	  {

      if (limit <= 0)

      if (limit <= 0)

      {

      {

	FIB_ITERATE_PUT(fit);

	FIB_ITERATE_PUT(fit);
@@ -2418,6 +2424,10 @@ again: 
	return;

	return;

      }

      }





      for (e=n->routes; e; e=e->next)

      {

	if (e->sender->flush_active || (e->flags & REF_DISCARD))

	  {

	    rte_discard(e);

	    rte_discard(e);

	    limit--;

	    limit--;
@@ -2426,13 +2436,6 @@ again: 




	if (e->flags & REF_MODIFY)

	if (e->flags & REF_MODIFY)

	  {

	  {

	    if (limit <= 0)

	      {

		FIB_ITERATE_PUT(fit);

		ev_schedule(tab->rt_event);

		return;

	      }



	    rte_modify(e);

	    rte_modify(e);

	    limit--;

	    limit--;
@@ -2446,6 +2449,12 @@ again: 
	  fib_delete(&tab->fib, n);

	  fib_delete(&tab->fib, n);

	  goto again;

	  goto again;

	}

	}



      if (tab->trie_new)

      {

	trie_add_prefix(tab->trie_new, n->n.addr, n->n.addr->pxlen, n->n.addr->pxlen);

	limit--;

      }

    }

    }

  FIB_ITERATE_END;

  FIB_ITERATE_END;
@@ -2459,6 +2468,25 @@ again: 
  /* state change 2->0, 3->1 */

  /* state change 2->0, 3->1 */

  tab->prune_state &= 1;

  tab->prune_state &= 1;





  if (tab->trie_new)

  {

    /* Finish prefix trie pruning */

    rfree(tab->trie->lp);

    tab->trie = tab->trie_new;

    tab->trie_new = NULL;

    tab->prune_trie = 0;

  }

  else

  {

    /* Schedule prefix trie pruning */

    if (tab->trie && (tab->trie->prefix_count > (2 * tab->fib.entries)))

    {

      /* state change 0->1, 2->3 */

      tab->prune_state |= 1;

      tab->prune_trie = 1;

    }

  }



  if (tab->prune_state > 0)

  if (tab->prune_state > 0)

    ev_schedule(tab->rt_event);

    ev_schedule(tab->rt_event);

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