Add B200 files to labeler and update codeowners (#165767)

Pull Request resolved: https://github.com/pytorch/pytorch/pull/165767
Approved by: https://github.com/slayton58

.github/labeler.yml

@@ -133,3 +133,32 @@
 
 "ciflow/vllm":
 - .github/ci_commit_pins/vllm.txt
+
+"ciflow/b200":
+- test/test_matmul_cuda.py
+- test/test_scaled_matmul_cuda.py
+- test/inductor/test_fp8.py
+- aten/src/ATen/native/cuda/Blas.cpp
+- torch/**/*cublas*
+- torch/_inductor/kernel/mm.py
+- test/inductor/test_max_autotune.py
+- third_party/fbgemm
+
+"ciflow/h100":
+- test/test_matmul_cuda.py
+- test/test_scaled_matmul_cuda.py
+- test/inductor/test_fp8.py
+- aten/src/ATen/native/cuda/Blas.cpp
+- torch/**/*cublas*
+- torch/_inductor/kernel/mm.py
+- test/inductor/test_max_autotune.py
+- third_party/fbgemm
+
+"ciflow/rocm":
+- test/test_matmul_cuda.py
+- test/test_scaled_matmul_cuda.py
+- test/inductor/test_fp8.py
+- aten/src/ATen/native/cuda/Blas.cpp
+- torch/_inductor/kernel/mm.py
+- test/inductor/test_max_autotune.py
+- third_party/fbgemm

CODEOWNERS

@@ -201,3 +201,17 @@ torch/backends/cudnn/ @eqy @syed-ahmed @Aidyn-A
 /torch/csrc/stable/ @janeyx99 @mikaylagawarecki
 /torch/headeronly/ @janeyx99
 /torch/header_only_apis.txt @janeyx99
+
+# FlexAttention
+/torch/nn/attention/flex_attention.py @drisspg
+/torch/_higher_order_ops/flex_attention.py @drisspg
+/torch/_inductor/kernel/flex/ @drisspg
+/torch/_inductor/codegen/cpp_flex_attention_template.py @drisspg
+/test/inductor/test_flex_attention.py @drisspg
+/test/inductor/test_flex_decoding.py @drisspg
+
+# Low Precision GEMMs
+/aten/src/ATen/native/cuda/Blas.cpp @drisspg @slayton58
+/aten/src/ATen/cuda/CUDABlas.cpp @drisspg @slayton58
+/aten/src/ATen/cuda/CUDABlas.h @drisspg @slayton58
+/test/test_scaled_matmul_cuda.py @drisspg @slayton58