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Reviewed By: haowu14

Differential Revision: D53291622

fbshipit-source-id: 244995b225bcb9860f011156a08e43fd895e6b77

website/docs/Cache_Library_Architecture_Guide/Hybrid_Cache.md

@@ -11,7 +11,7 @@ CacheLib supports use of multiple HW mediums through [hybrid cache](/docs/Cache_
 Currently we support SSDs as the NVM medium for Hybrid Cache. Navy is our SSD optimized cache engine. To interface  with Navy,  CacheAllocator uses the `NvmCache` wrapper. CacheAllocator delegates the responsibility of performing thread safe lookups,  inserts and deletes for Navy to `NvmCache`. `NvmCache` implements the functionality that handles transitions of Item to and from NVM. Since there is no global key level lock in CacheAllocator to synchronize operations that change Item's state between DRAM and NVM, `NvmCache` employs optimistic concurrency control primitives to enforce data correctness.
 
 ### Item allocation and eviction
-CacheAllocator allocates the Item in DRAM when `allocate` is called. Once the Item becomes a victim for eviction in the MMContainer, CacheAllocator evicts the Item to `NvmCache`. Since NVM has constraints on write endurance, CacheAllocator supports a pluggabble eviction policy that can reject Items when needed or suitable.  Items read from NVM are also inserted into DRAM. When these Items get evicted, CacheAllocator can choose to not write them into NVM since it is already present by inferring if `it->isNvmClean()`.
+CacheAllocator allocates the Item in DRAM when `allocate` is called. Once the Item becomes a victim for eviction in the MMContainer, CacheAllocator evicts the Item to `NvmCache`. Since NVM has constraints on write endurance, CacheAllocator supports a pluggable admission policy that can reject Items when needed or suitable.  Items read from NVM are also inserted into DRAM. When these Items get evicted, CacheAllocator can choose to not write them into NVM since it is already present by inferring if `it->isNvmClean()`.
 ![](Hybrid_Cache_allocate.png "allocate with hybrid cache ")
 
 ### Item lookups