[feat] Support extra_buffer in Mamba2-based models (#15829)

Signed-off-by: Roi Koren <roik@nvidia.com>

test/manual/models/test_granite_moe_hybrid.py

@@ -0,0 +1,33 @@
+import unittest
+
+from sglang.test.kits.eval_accuracy_kit import GSM8KMixin
+from sglang.test.kits.kl_divergence_kit import KLDivergenceMixin
+from sglang.test.kits.prefix_cache_branching_kit import PrefixCacheBranchingMixin
+from sglang.test.server_fixtures.default_fixture import DefaultServerBase
+
+GRANITE_MOE_HYBRID_MODEL = "ibm-granite/granite-4.0-h-micro"
+
+
+class TestGraniteMoeHybrid(GSM8KMixin, DefaultServerBase):
+    model = GRANITE_MOE_HYBRID_MODEL
+    gsm8k_accuracy_thres = 0.78
+
+
+class TestGraniteMoeHybridExtraBuffer(
+    GSM8KMixin, KLDivergenceMixin, PrefixCacheBranchingMixin, DefaultServerBase
+):
+    model = GRANITE_MOE_HYBRID_MODEL
+    cache_chunk_size = 256
+    gsm8k_accuracy_thres = 0.78
+    kl_div_thres = 0.002
+    kl_div_thres_prefill = 0.02
+    other_args = [
+        "--mem-fraction-static",
+        "0.8",
+        "--mamba-scheduler-strategy",
+        "extra_buffer",
+    ]
+
+
+if __name__ == "__main__":
+    unittest.main()