From 36ea69e896c68d7581b006934619d39db571dc3d Mon Sep 17 00:00:00 2001
From: Dmitry Kolesnikov <dmkolesnikov@gmail.com>
Date: Tue, 16 Apr 2013 21:35:56 +0300
Subject: [PATCH] rotate chunk if chunk quota exeeded

---
 src/cache_bucket.erl | 31 ++++++++++++-------------------
 src/cache_heap.erl   | 13 +------------
 2 files changed, 13 insertions(+), 31 deletions(-)

diff --git a/src/cache_bucket.erl b/src/cache_bucket.erl
index cd3f099..0d8c049 100644
--- a/src/cache_bucket.erl
+++ b/src/cache_bucket.erl
@@ -237,13 +237,6 @@ evict(#cache{}=S) ->
       heap = cache_heap:alloc(cache_heap:free(Cell, S#cache.heap))
    }.
 
-drop(#cache{}=S) ->
-   Cell = cache_heap:last(S#cache.heap),
-   ?DEBUG("cache ~p: free cell ~p~n", [S#cache.name, Cell]),
-   S#cache{
-      heap = cache_heap:free(Cell, S#cache.heap)
-   }.
-
 %%
 %%
 quota(#cache{}=S) ->
@@ -255,23 +248,23 @@ quota(#cache{}=S) ->
 maybe_size_quota(#cache{quota_size=undefined}=S) ->
    S;
 maybe_size_quota(S) ->
-   case lists:sum(cache_heap:size(S#cache.heap)) of
-      Size when Size > S#cache.quota_size ->
-         maybe_size_quota(drop(S));
+   Quota      = S#cache.quota_size div S#cache.n,
+   [Head | _] = cache_heap:cells(S#cache.heap),
+   case ets:info(Head, size) of
+      Val when Val >= Quota ->
+         evict(S);
       _ ->
-         S#cache{
-            heap = cache_heap:talloc(S#cache.n, S#cache.heap)
-         }
+         S
    end.
 
 maybe_memory_quota(#cache{quota_memory=undefined}=S) ->
    S;
 maybe_memory_quota(S) ->
-   case lists:sum(cache_heap:memory(S#cache.heap)) of
-      Size when Size > S#cache.quota_memory ->
-         maybe_memory_quota(drop(S));
+   Quota      = S#cache.quota_size div S#cache.n,
+   [Head | _] = cache_heap:cells(S#cache.heap),
+   case ets:info(Head, memory) of
+      Val when Val >= Quota ->
+         evict(S);
       _ ->
-         S#cache{
-            heap = cache_heap:talloc(S#cache.n, S#cache.heap)
-         }
+         S
    end.
diff --git a/src/cache_heap.erl b/src/cache_heap.erl
index 7b32198..ac78756 100644
--- a/src/cache_heap.erl
+++ b/src/cache_heap.erl
@@ -21,7 +21,7 @@
 -module(cache_heap).
 
 -export([
-   new/1, alloc/1, talloc/2, free/1, free/2,
+   new/1, alloc/1, free/1, free/2,
    cells/1, size/1, memory/1, last/1, first/1
 ]).
 
@@ -45,17 +45,6 @@ alloc(#heap{}=H) ->
       cells = [create() | H#heap.cells]
    }.
 
-% tail alloc
-talloc(N, #heap{}=H) 
- when length(H#heap.cells) < N ->
-   talloc(N,
-      H#heap{
-         cells = H#heap.cells ++ [create()]
-      }
-   );
-talloc(_, #heap{}=H) ->
-   H.
-
 create() ->
    ets:new(undefined, [set, protected]).