jax-ml/jax · error · ValueError

Invalid memory space: {memory_space!r}

Error message

Invalid memory space: {memory_space!r}

What it means

The same mapping function validates that the memory space is one of the recognized types: an AccMemorySpace, a TPU MemorySpace, or pass-through ANY/Host spaces. Anything else (unknown enum, string, None) raises ValueError with the repr of the offending value.

Source

Thrown at jax/_src/pallas/mosaic/core.py:519

      return memory_space
    case (
        pallas_core.MemorySpace.ERROR
        | pallas_core.MemorySpace.INDEX
        | pallas_core.MemorySpace.KEY
    ):
      return MemorySpace.SMEM
    case pallas_core.CoreMemorySpace():
      return (
          memory_space.memory_space
          if memory_space.mesh.core_type is core_type
          else memory_space
      )
    case acc if isinstance(acc, AccMemorySpace):
      return acc
    case MemorySpace():
      return memory_space
    case _:
      raise ValueError(f"Invalid memory space: {memory_space!r}")

View on GitHub (pinned to 1e1c6a8fc0)

Solutions

1. Use TPU memory space objects (e.g., pltpu.VMEM / MemorySpace enum members or AccMemorySpace), never strings
2. Check imports: GPU-specific spaces (GMEM, SMEM from pl.gpu) are invalid on TPU
3. Align JAX/Mosaic versions so enum members match the mapping function

Example fix

// before
ref = pltpu.make_block_ref(..., memory_space='vmem')
// after
from jax.experimental.pallas import tpu as pltpu
ref = pltpu.make_block_ref(..., memory_space=pltpu.VMEM)

from jax._src.pallas import pallas_core
from jax._src import core as jax_core
def is_valid_space(ms):
    return isinstance(ms, (pallas_core.MemorySpace, jax_core.MemorySpace)) or hasattr(ms, 'tpu_memory_space')

When it happens

Trigger: Passing a raw string like 'vmem', a pallas_core memory-space constant not known to the TPU backend, or None as memory_space during kernel lowering or ref attribute construction.

Common situations: Using pl.gpu_memory_space constants in a TPU kernel; passing memory_space names as strings from config; API changes renaming enum members between versions.

Understand the failure class

Background: Invalid enum value errors: "Unknown type", "Invalid scope", "must be one of" — when a string is not on the library's allowed list — this error's family across 23 libraries.

Related errors

• Memory space {self.memory_space} is not supported by mesh {s
• Unsupported core type: {core_type}
• The Pallas TPU lowering currently supports in memory space A
• Loads are only allowed on VMEM and SMEM references.
• Loads and stores are only allowed on VMEM and SMEM reference

AI-assisted analysis of jax-ml/jax@1e1c6a8fc0 (2026-08-27). Data as JSON: /api/errors/90f8dde21141941e. Report an issue: GitHub.