Optimize frame cache by realloc'ing the smallest frame when the cache is full.

This ensures that we don't just keep a cache of tiny frames, continually doing
an alloc/free for each data frame, thus negating the point of having a cache.

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@134867 65c4cc65-6c06-0410-ace0-fbb531ad65f3

diff --git a/channels/iax2-parser.c b/channels/iax2-parser.c
index 196093b..55c363f 100644 (file)
--- a/channels/iax2-parser.c
+++ b/channels/iax2-parser.c
@@ -999,9 +999,11 @@ struct iax_frame *iax_frame_new(int direction, int datalen, unsigned int cacheab
 
 #if !defined(LOW_MEMORY)
        struct iax_frames *iax_frames = NULL;
+       struct iax_frame *smallest;
 
        /* Attempt to get a frame from this thread's cache */
        if ((iax_frames = ast_threadstorage_get(&frame_cache, sizeof(*iax_frames)))) {
+               smallest = AST_LIST_FIRST(&iax_frames->list);
                AST_LIST_TRAVERSE_SAFE_BEGIN(&iax_frames->list, fr, list) {
                        if (fr->afdatalen >= datalen) {
                                size_t afdatalen = fr->afdatalen;
@@ -1010,12 +1012,21 @@ struct iax_frame *iax_frame_new(int direction, int datalen, unsigned int cacheab
                                memset(fr, 0, sizeof(*fr));
                                fr->afdatalen = afdatalen;
                                break;
+                       } else if (smallest->afdatalen > fr->afdatalen) {
+                               smallest = fr;
                        }
                }
                AST_LIST_TRAVERSE_SAFE_END;
        }
        if (!fr) {
-               if (!(fr = ast_calloc_cache(1, sizeof(*fr) + datalen)))
+               if (iax_frames->size >= FRAME_CACHE_MAX_SIZE && smallest) {
+                       /* Make useless cache into something more useful */
+                       AST_LIST_REMOVE(&iax_frames->list, smallest, list);
+                       if (!(fr = ast_realloc(smallest, sizeof(*fr) + datalen))) {
+                               AST_LIST_INSERT_TAIL(&iax_frames->list, smallest, list);
+                               return NULL;
+                       }
+               } else if (!(fr = ast_calloc_cache(1, sizeof(*fr) + datalen)))
                        return NULL;
                fr->afdatalen = datalen;
        }
@@ -1065,7 +1076,13 @@ void iax_frame_free(struct iax_frame *fr)
 
        if (iax_frames->size < FRAME_CACHE_MAX_SIZE) {
                fr->direction = 0;
-               AST_LIST_INSERT_HEAD(&iax_frames->list, fr, list);
+               /* Pseudo-sort: keep smaller frames at the top of the list. This should
+                * increase the chance that we pick the smallest applicable frame for use. */
+               if (AST_LIST_FIRST(&iax_frames->list) && AST_LIST_FIRST(&iax_frames->list)->afdatalen < fr->afdatalen) {
+                       AST_LIST_INSERT_TAIL(&iax_frames->list, fr, list);
+               } else {
+                       AST_LIST_INSERT_HEAD(&iax_frames->list, fr, list);
+               }
                iax_frames->size++;
                return;
        }