Remove double declaration of CacheAdmin config

Summary: remove double declaration of config in CacheAdmin and fix some comments in BlockCache which does not explain correctly what happens during reclaim.

Reviewed By: AlnisM

Differential Revision: D86651012

fbshipit-source-id: d5e6c2419471c56a61bd1a6fd7ba6f02b84d4f47

Author: pbhandar2

cachelib/navy/block_cache/BlockCache.cpp

@@ -479,11 +479,15 @@ Status BlockCache::remove(HashedKey hk) {
 //
 // See @RegionEvictCallback for details
 uint32_t BlockCache::onRegionReclaim(RegionId rid, BufferView buffer) {
-  // Eviction callback guarantees are the following:
+  // Eviction callback guarantees are the following assuming no checksum errors:
   //   - Every value inserted will get eviction callback at some point of
   //     time.
   //   - It is invoked only once per insertion.
   //
+  // If there is a checksum error of an item descriptor, we abort the reclaim
+  // and we will not be able to call the eviction callback for rest of the item
+  // that have not been evaluated in the region.
+  //
   // We do not guarantee time between remove and callback invocation. If a
   // value v1 was replaced with v2 user will get callbacks for both v1 and
   // v2 when they are evicted (in no particular order).