controller if no parameter or 1 is given or disable
it if 0 is given (See Documentation/cgroups/memory.txt)
- swiotlb= [IA-64] Number of I/O TLB slabs
+ swiotlb= [ARM,IA-64,PPC,MIPS,X86]
+ Format: { <int> | force }
+ <int> -- Number of I/O TLB slabs
+ force -- force using of bounce buffers even if they
+ wouldn't be automatically used by the kernel
switches= [HW,M68k]