Make the random and round-robin directors avoid backends which are

polled as unhealty.

This technically makes Varnish 2.0 "feature complete", but some further
polishing is to be expected.

git-svn-id: svn+ssh://projects.linpro.no/svn/varnish/trunk@3134 d4fa192b-c00b-0410-8231-f00ffab90ce4

diff --git a/varnish-cache/bin/varnishd/cache_dir_random.c b/varnish-cache/bin/varnishd/cache_dir_random.c
index b4dd545c70b7d7160aaa530209e9b22a17ca4482..dcb09ce8ebc9a924d7d52bb7c4584b5ec45b9278 100644 (file)
--- a/varnish-cache/bin/varnishd/cache_dir_random.c
+++ b/varnish-cache/bin/varnishd/cache_dir_random.c
@@ -50,7 +50,7 @@
 
 struct vdi_random_host {
        struct backend          *backend;
-       unsigned                weight;
+       double                  weight;
 };
 
 struct vdi_random {
@@ -61,25 +61,60 @@ struct vdi_random {
        unsigned                nhosts;
 };
 
-
 static struct vbe_conn *
 vdi_random_getfd(struct sess *sp)
 {
-       int i;
+       int i, j, k;
        struct vdi_random *vs;
-       uint32_t r;
-       struct vdi_random_host *vh;
+       double r, s1, s2;
+       struct vbe_conn *vbe;
 
        CHECK_OBJ_NOTNULL(sp, SESS_MAGIC);
        CHECK_OBJ_NOTNULL(sp->director, DIRECTOR_MAGIC);
        CAST_OBJ_NOTNULL(vs, sp->director->priv, VDI_RANDOM_MAGIC);
-       r = random();
-       r &= 0x7fffffff;
 
-       for (i = 0, vh = vs->hosts; i < vs->nhosts; vh++) 
-               if (r < vh->weight)
-                       return (VBE_GetVbe(sp, vh->backend));
-       assert(0 == __LINE__);
+       k = 0;
+       for (k = 0; k < 4; ) {  /* XXX: 4 is arbitrary */
+
+               r = random() / 2147483648.0;    /* 2^31 */
+               assert(r >= 0.0 && r < 1.0);
+
+               s1 = 0.0;
+               j = 0;
+               for (i = 0; i < vs->nhosts; i++) {
+                       if (!vs->hosts[i].backend->healthy)
+                               continue;
+                       s1 += vs->hosts[i].weight;
+                       j++;
+               }       
+
+               if (j == 0)             /* No healthy hosts */
+                       return (NULL);
+
+               r *= s1;
+
+               s2 = 0;
+               j = 0;
+               for (i = 0; i < vs->nhosts; i++)  {
+                       if (!vs->hosts[i].backend->healthy)
+                               continue;
+                       s2 += vs->hosts[i].weight;
+                       if (r > s2)
+                               j = i + 1;
+               }
+               if (s2 != s1) {
+                       /*
+                        * Health bit changed in an unusable way while we
+                        * worked the problem.  Usable changes are any that
+                        * result in the same sum we prepared for.
+                        */
+                       continue;
+               }
+               vbe = VBE_GetVbe(sp, vs->hosts[j].backend);
+               if (vbe != NULL)
+                       return (vbe);
+               k++;
+       } 
        return (NULL);
 }
 
@@ -108,8 +143,7 @@ VRT_init_dir_random(struct cli *cli, struct director **bp, const struct vrt_dir_
        struct vdi_random *vs;
        const struct vrt_dir_random_entry *te;
        struct vdi_random_host *vh;
-       double s, a, b;
-       unsigned v;
+       double s;
        int i;
        
        (void)cli;
@@ -130,24 +164,9 @@ VRT_init_dir_random(struct cli *cli, struct director **bp, const struct vrt_dir_
        te = t->members;
        for (i = 0; i < t->nmember; i++, vh++, te++) {
                assert(te->weight > 0.0);
-               s += te->weight;
+               vh->weight = te->weight;
                vh->backend = VBE_AddBackend(cli, te->host);
        }
        vs->nhosts = t->nmember;
-
-       /* Normalize weights */
-       i = 0;
-       a = 0.0;
-       assert(s > 0.0);
-       for (te = t->members; i < t->nmember; te++, i++) {
-               /* First normalize the specified weight in FP */
-               b = te->weight / s;     /*lint !e795 not zero division */
-               /* Then accumulate to eliminate rounding errors */
-               a += b;
-               /* Convert to unsigned in random() range */
-               v = (unsigned)((1U<<31) * a);
-               vs->hosts[i].weight = v;
-       }
-       assert(vs->hosts[t->nmember - 1].weight > 0x7fffffff);
        *bp = &vs->dir;
 }

diff --git a/varnish-cache/bin/varnishd/cache_dir_round_robin.c b/varnish-cache/bin/varnishd/cache_dir_round_robin.c
index 5304360ece91a9151b7fcdec8212874ad5c4a773..6b4688276ccce2b0307dc5c2c8aba437c69d8be0 100644 (file)
--- a/varnish-cache/bin/varnishd/cache_dir_round_robin.c
+++ b/varnish-cache/bin/varnishd/cache_dir_round_robin.c
@@ -47,32 +47,41 @@
 /*--------------------------------------------------------------------*/
 
 struct vdi_round_robin_host {
-       struct backend          *backend;
+       struct backend                  *backend;
 };
 
 struct vdi_round_robin {
-       unsigned                magic;
-#define VDI_ROUND_ROBIN_MAGIC  0x2114a178
-       struct director         dir;
+       unsigned                        magic;
+#define VDI_ROUND_ROBIN_MAGIC          0x2114a178
+       struct director                 dir;
        struct vdi_round_robin_host     *hosts;
-       unsigned                nhosts;
-       unsigned                next_host;
+       unsigned                        nhosts;
+       unsigned                        next_host;
 };
 
 static struct vbe_conn *
 vdi_round_robin_getfd(struct sess *sp)
 {
+       int i;
        struct vdi_round_robin *vs;
        struct backend *backend;
+       struct vbe_conn *vbe;
 
        CHECK_OBJ_NOTNULL(sp, SESS_MAGIC);
        CHECK_OBJ_NOTNULL(sp->director, DIRECTOR_MAGIC);
        CAST_OBJ_NOTNULL(vs, sp->director->priv, VDI_ROUND_ROBIN_MAGIC);
 
-       backend = vs->hosts[ vs->next_host ].backend;
-       vs->next_host = (vs->next_host + 1) % vs->nhosts;
-
-       return (VBE_GetVbe(sp, backend));
+       for (i = 0; i < vs->nhosts; i++) {
+               backend = vs->hosts[vs->next_host].backend;
+               vs->next_host = (vs->next_host + 1) % vs->nhosts;
+               if (!backend->healthy)
+                       continue;
+               vbe = VBE_GetVbe(sp, backend);
+               if (vbe != NULL)
+                       return (vbe);
+       }
+
+       return (NULL);
 }
 
 /*lint -e{818} not const-able */