Upstreaming plan (5/4/2022)

[victoria-mcgrath]

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Design overview:  facebook#102

 

Grouping	Description	Intel PR	Meta PR	Notes
Independent preparatory changes
	Shortened critical section		facebook#132	Performance improvement
	Per-pool cache stats		facebook#141	Benchmarking stats improvement
	Add value validation to cachebench		facebook#131	Benchmarking improvement
	Alternative locking approach for item movement	#36		Performance improvement
	File-mapped memory support in shared memory manager		facebook#146	Enables access to PMEM memory
	Initial set of changes to config API		facebook#138	First mention of memory tiers, only one DRAM tier is allowed
Tiers enabling changes
	Enable tiers in allocator	TBD		The feature is complete on the Intel fork
	Enable tiers in config API	TBD		The feature is complete on the Intel fork
	Enable multi-tier eviction	TBD		The feature is complete on the Intel fork
Future work
	Scalable eviction policy	TBD		Partition 2Q into independent structures so they use separate locks per region
	Background eviction thread	TBD		Performance improvement