Slab allocator changes

If the first slab in the list of slabs which share the same chunk size has no more room, it means that all other slabs following it have no room either. This speeds up the test to find a slab with free space, which can now abort and directly proceed to allocate memory for a new slab.

If an empty slab's decay count hits zero, it is moved to the front of the empty slab list to be reclaimed more quickly.

Allocations made from the slab now carry a pointer back to the slab which they are a part of. This speeds up deallocation but has the downside of making the smallest usable slab chunk size 64 bytes, which is double what used to be the minimum before.

library/changes

@@ -1,3 +1,24 @@
+c.lib 1.210 (22.11.2016)
+
+- Added __get_slab_allocations() function which will report information
+  about each memory allocation made by the slab allocator which does
+  not come from a slab.
+
+- If the first slab in the list of slabs which share the same chunk
+  size has no more room, it means that all other slabs following
+  it have no room either. This speeds up the test to find a slab with
+  free space, which can now abort and directly proceed to allocate
+  memory for a new slab.
+
+- If an empty slab's decay count hits zero, it is moved to the front
+  of the empty slab list to be reclaimed more quickly.
+
+- Allocations made from the slab now carry a pointer back to the
+  slab which they are a part of. This speeds up deallocation but
+  has the downside of making the smallest usable slab chunk size
+  64 bytes, which is double what used to be the minimum before.
+
+
 c.lib 1.209 (21.11.2016)
 
 - The maximum slab size is now 2^17 bytes (= 131072). If you request