Per-execution-context freelists

Global free cacheline list is divided into a set of freelists, one
per execution context. When attempting to map addres to cache, first
the freelist for current execution context is considered (fast path).
If current execution context freelist is empty (fast path failure),
mapping function attempts to get freelist from other execution context
list (slow path).

The purpose of this change is improve concurrency in freelist access.
It is part of fine granularity metadata lock implementation.

Signed-off-by: Adam Rutkowski <adam.j.rutkowski@intel.com>

src/metadata/metadata_partition_structs.h

@@ -10,12 +10,6 @@
 #include "../cleaning/cleaning.h"
 #include "../eviction/eviction.h"
 
-struct ocf_part {
-        ocf_cache_line_t head;
-        ocf_cache_line_t tail;
-        uint32_t curr_size;
-};
-
 struct ocf_user_part_config {
         char name[OCF_IO_CLASS_NAME_MAX];
         uint32_t min_size;