Review of #3787 asked for no retries after an error in Jit.cpp.
Linux: memfd_create is called once with MFD_CLOEXEC. MFD_EXEC was
tried first and dropped on EINVAL; the flag only sets the file's execute
permission bits (Linux 6.3 and later), not whether the object maps
PROT_EXEC, which is decided by the mapping protection, as for the direct
memory memfd in DirectMemory.cpp. A one-shot choice from the headers
would fail on older kernels, so the flag is dropped; TechnicalDebt
records it.
Windows: the delete-on-close backing file is named from the process id,
a process-wide atomic counter and the performance counter, so CREATE_NEW
cannot meet an existing name, and any CreateFileW failure throws with
the Win32 error instead of looping up to 64 times on ERROR_FILE_EXISTS.
The descriptor stays a CRT descriptor on the file, so close, dup and
dup2 keep working as before.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
3b7ac1596d