cache memory adjustements

The delegation DB now uses the same amount of memory than ADB, which is
1/8 of the `max-cache-size`.

The main cache database, instead of using `max-cache-size`, now use the
"remaining" part of it, after the delegation DB and ADB took their part,
so 6/8.

This avoid blowing up the host memory, typically when specifying
`max-cache-size 95%`, as the global cache usage would go way ahead 100%.

diff --git a/bin/named/server.c b/bin/named/server.c
index 77a9edfef88a4109d7cb1d49caca8032a6133553..8deb3e7cb5eeb2a455b01bbf8ef9b136240545c8 100644 (file)
--- a/bin/named/server.c
+++ b/bin/named/server.c
@@ -3893,6 +3893,13 @@ configure_view(dns_view_t *view, dns_viewlist_t *viewlist, cfg_obj_t *config,
                }
        }
 
+       /*
+        * Since both the delegation DB and ADB uses 1/8 of the
+        * `max_cache_size`, let's use 6/8 for the main cache DB.
+        */
+       const size_t cache_size_slice = max_cache_size / 8;
+       const size_t main_cache_size = cache_size_slice * 6;
+
        /* Check-names. */
        obj = NULL;
        result = named_checknames_get(maps, response_synonyms, &obj);
@@ -4178,7 +4185,7 @@ configure_view(dns_view_t *view, dns_viewlist_t *viewlist, cfg_obj_t *config,
        }
        if (nsc != NULL) {
                if (!cache_sharable(nsc->primaryview, view, zero_no_soattl,
-                                   max_cache_size, max_stale_ttl,
+                                   main_cache_size, max_stale_ttl,
                                    stale_refresh_time))
                {
                        isc_log_write(NAMED_LOGCATEGORY_GENERAL,
@@ -4254,7 +4261,7 @@ configure_view(dns_view_t *view, dns_viewlist_t *viewlist, cfg_obj_t *config,
 
        dns_view_setcache(view, cache, shared_cache);
 
-       dns_cache_setcachesize(cache, max_cache_size);
+       dns_cache_setcachesize(cache, main_cache_size);
        dns_cache_setservestalettl(cache, max_stale_ttl);
        dns_cache_setservestalerefresh(cache, stale_refresh_time);
 
@@ -4288,11 +4295,7 @@ configure_view(dns_view_t *view, dns_viewlist_t *viewlist, cfg_obj_t *config,
        } else {
                dns_delegdb_create(&view->deleg);
        }
-
-       /*
-        * Totally arbitrary decision for now. This might need its own knob.
-        */
-       dns_delegdb_setsize(view->deleg, max_cache_size / 6);
+       dns_delegdb_setsize(view->deleg, cache_size_slice);
 
        /*
         * The previous view isn't needed anymore.
@@ -4327,8 +4330,8 @@ configure_view(dns_view_t *view, dns_viewlist_t *viewlist, cfg_obj_t *config,
         * MAX_ADB_SIZE_FOR_CACHESHARE when the cache is shared.
         */
        max_adb_size = 0;
-       if (max_cache_size != 0U) {
-               max_adb_size = max_cache_size / 8;
+       if (cache_size_slice != 0U) {
+               max_adb_size = cache_size_slice;
                if (max_adb_size == 0U) {
                        max_adb_size = 1; /* Force minimum. */
                }