Adding KVZCHEvictionTBEConfig in FBGEEM (#5058)

Summary:
Pull Request resolved: #5058

X-link: https://github.com/facebookresearch/FBGEMM/pull/2067

See diff D85604160, this KVZCHEvictionTBEConfig is in FBGEMM and used in torchrec. Both FBGEEM and torchrec are open source in github. It is required to land first, otherwise torchrec github build will throw error {F1983027645}

Reviewed By: emlin

Differential Revision: D83896528

fbshipit-source-id: 7a8bacc3d0ee1f53a797dac6ba2647d372a15074

Author: EddyLXJ

fbgemm_gpu/fbgemm_gpu/split_table_batched_embeddings_ops_common.py

@@ -240,6 +240,19 @@ def validate(self) -> None:
         ), "backend_return_whole_row can only be enabled when enable_optimizer_offloading is enabled"
 
 
+class KVZCHEvictionTBEConfig(NamedTuple):
+    # Eviction trigger model for kvzch table: 0: disabled, 1: iteration, 2: mem_util, 3: manual, 4: id count, 5: free_mem
+    kvzch_eviction_trigger_mode: int = 2  # mem_util
+    # Minimum free memory (in GB) required before triggering eviction when using free_mem trigger mode.
+    eviction_free_mem_threshold_gb: int = 200  # 200GB
+    # Number of batches between checks for free memory threshold when using free_mem trigger mode.
+    eviction_free_mem_check_interval_batch: int = 1000
+    # The width of each feature score bucket used for threshold calculation in feature score-based eviction.
+    threshold_calculation_bucket_stride: float = 0.2
+    # Total number of feature score buckets used for threshold calculation in feature score-based eviction.
+    threshold_calculation_bucket_num: Optional[int] = 1000000  # 1M
+
+
 class BackendType(enum.IntEnum):
     SSD = 0
     DRAM = 1