acl-plugin: optimize hash memory usage + fix the startup config parsing for memory sizes [VPP-1502]

In a couple of places vec_add1()-style was repeatedly called in a loop for
smallish vectors where the number of additions was known in advance.
With a test with large number of ACEs these numbers contribute to heap
fragmentation noticeably.

Minimize the number of allocations by preallocating the known size and
then resetting the length accordingly, and then calling vec_add1()

Also unify the parsing of the memory-related startup config parameters.

Change-Id: If8fba344eb1dee8f865ffe7b396ca3b6bd9dc1d0
Signed-off-by: Andrew Yourtchenko <ayourtch@gmail.com>

1 files changed, 22 insertions, 0 deletions

diff --git a/src/plugins/acl/hash_lookup.c b/src/plugins/acl/hash_lookup.c
index aeec004d77a..0568a67affe 100644
--- a/src/plugins/acl/hash_lookup.c
+++ b/src/plugins/acl/hash_lookup.c
@@ -603,6 +603,17 @@ hash_acl_set_heap(acl_main_t *am)
     am->hash_lookup_mheap = mheap_alloc_with_lock (0 /* use VM */ , 
                                                    am->hash_lookup_mheap_size,
                                                    1 /* locked */);
+#if USE_DLMALLOC != 0
+    /*
+     * DLMALLOC is being "helpful" in that it ignores the heap size parameter
+     * by default and tries to allocate the larger amount of memory.
+     *
+     * Pin the heap so this does not happen and if we run out of memory
+     * in this heap, we will bail out with "out of memory", rather than
+     * an obscure error sometime later.
+     */
+    mspace_disable_expand(am->hash_lookup_mheap);
+#endif
     if (0 == am->hash_lookup_mheap) {
         clib_error("ACL plugin failed to allocate lookup heap of %U bytes", 
                    format_memory_size, am->hash_lookup_mheap_size);
@@ -736,6 +747,12 @@ hash_acl_apply(acl_main_t *am, u32 lc_index, int acl_index, u32 acl_position)
 
 
   vec_validate(am->hash_applied_mask_info_vec_by_lc_index, lc_index);
+
+  /* since we know (in case of no split) how much we expand, preallocate that space */
+  int old_vec_len = vec_len(*applied_hash_aces);
+  vec_validate((*applied_hash_aces), old_vec_len + vec_len(ha->rules) - 1);
+  _vec_len((*applied_hash_aces)) = old_vec_len;
+
   /* add the rules from the ACL to the hash table for lookup and append to the vector*/
   for(i=0; i < vec_len(ha->rules); i++) {
     /*
@@ -1171,6 +1188,11 @@ void hash_acl_add(acl_main_t *am, int acl_index)
 
   /* walk the newly added ACL entries and ensure that for each of them there
      is a mask type, increment a reference count for that mask type */
+
+  /* avoid small requests by preallocating the entire vector before running the additions */
+  vec_validate(ha->rules, a->count-1);
+  vec_reset_length(ha->rules);
+
   for(i=0; i < a->count; i++) {
     hash_ace_info_t ace_info;
     fa_5tuple_t mask;