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(bugfix): block_size check for flex attn #41363

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Merged
vllm-bot merged 4 commits into from
May 1, 2026
Merged

(bugfix): block_size check for flex attn #41363

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dbfe6be
(bugfix): flex attn not support block_size < 16
JisoLya Apr 30, 2026
ce97067
Merge branch 'main' into invalid_block_size
JisoLya Apr 30, 2026
561581a
reformat&update docs
JisoLya Apr 30, 2026
f9ec521
Merge branch 'main' into invalid_block_size
MatthewBonanni Apr 30, 2026
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5 changes: 5 additions & 0 deletions vllm/v1/attention/backends/flex_attention.py
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Original file line number Diff line number Diff line change
Expand Up @@ -35,6 +35,7 @@
AttentionMetadataBuilder,
AttentionType,
CommonAttentionMetadata,
MultipleOf,
)
from vllm.v1.kv_cache_interface import AttentionSpec, EncoderOnlyAttentionSpec

Expand Down Expand Up @@ -133,6 +134,10 @@ def use_cascade_attention(*args, **kwargs) -> bool:
@classmethod
def get_supported_head_sizes(cls) -> list[int]:
return []

@staticmethod
def get_supported_kernel_block_sizes() -> list[int | MultipleOf]:
return [MultipleOf(16)]


# @torch.compile(fullgraph=True, mode="reduce-overhead")
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