diff --git a/test/test_copy_speed.py b/test/test_copy_speed.py
index bd27153574..8eac7b9c57 100644
--- a/test/test_copy_speed.py
+++ b/test/test_copy_speed.py
@@ -9,11 +9,10 @@ class TestCopySpeed(unittest.TestCase):
   @classmethod
   def setUpClass(cls): Device[Device.DEFAULT].synchronize()
 
-  @unittest.skipIf(OSX, "no shm on OSX")
   def testCopySHMtoDefault(self):
     s = shared_memory.SharedMemory(name="test_X", create=True, size=N*N*4)
     s.close()
-    if CI:
+    if CI and not OSX:
       t = Tensor.empty(N, N, device="disk:/dev/shm/test_X").realize()
     else:
       t = Tensor.empty(N, N, device="disk:shm:test_X").realize()
diff --git a/tinygrad/runtime/ops_disk.py b/tinygrad/runtime/ops_disk.py
index 41bf8230e2..4c6f341add 100644
--- a/tinygrad/runtime/ops_disk.py
+++ b/tinygrad/runtime/ops_disk.py
@@ -1,6 +1,4 @@
-import os, mmap
-try: import _posixshmem
-except Exception: pass
+import os, mmap, _posixshmem
 from typing import Callable, Dict, Tuple
 from tinygrad.helpers import prod, DType, OSX, dtypes
 from tinygrad.device import Interpreted, Allocator
@@ -27,21 +25,15 @@ class DiskBuffer:
 
 disk_fxn_for_op: Dict[Op, Callable] = { UnaryOps.CAST: DiskBuffer.cast, MovementOps.AS_STRIDED: DiskBuffer.as_strided }
 
-MAP_LOCKED, MAP_POPULATE = 0x2000, 0x008000
+MAP_LOCKED, MAP_POPULATE = 0 if OSX else 0x2000, getattr(mmap, "MAP_POPULATE", 0 if OSX else 0x008000)
 class DiskAllocator(Allocator):
   def __init__(self, device): self.device = device
   def _alloc(self, size):
     if str(self.device).startswith("shm:"):
-      if OSX:
-        with open(f"/tmp/shm_{self.device[4:]}", "w+b") as f:
-          f.truncate(size)
-          shm = mmap.mmap(f.fileno(), size, flags=mmap.MAP_SHARED)
-      else:
-        fd = _posixshmem.shm_open(self.device[4:], os.O_RDWR, 0o600)
-        # TODO: these flags are somewhat platform specific, but python doesn't expose the ones we need
-        shm = mmap.mmap(fd, size, flags=mmap.MAP_SHARED | MAP_LOCKED | MAP_POPULATE)
-        shm.madvise(mmap.MADV_HUGEPAGE)     # type: ignore   # not on OSX
-        os.close(fd)
+      fd = _posixshmem.shm_open("/"+self.device[4:].lstrip("/"), os.O_RDWR, 0o600)
+      shm = mmap.mmap(fd, size, flags=mmap.MAP_SHARED | MAP_POPULATE | MAP_LOCKED)
+      if (hp := getattr(mmap, "MADV_HUGEPAGE", None)) is not None: shm.madvise(hp) # type: ignore
+      os.close(fd)
       buf = UnderlyingDiskBuffer(None, shm)
     else:
       f = open(self.device, "a+b")