>>> On 17.02.15 at 07:51, <xiaoming.wang@xxxxxxxxx> wrote: > --- a/Documentation/kernel-parameters.txt > +++ b/Documentation/kernel-parameters.txt > @@ -3438,10 +3438,12 @@ bytes respectively. Such letter suffixes can also be > entirely omitted. > it if 0 is given (See Documentation/cgroups/memory.txt) > > swiotlb= [ARM,IA-64,PPC,MIPS,X86] > - Format: { <int> | force } > + Format: { <int> | force | <int> | <int>} > <int> -- Number of I/O TLB slabs > force -- force using of bounce buffers even if they > wouldn't be automatically used by the kernel > + <int> -- Maximum allowable number of contiguous slabs to map > + <int> -- The size of SW-MMU mapped. This makes no sense - the new numbers added aren't position independent (nor were the previous <int> and "force"). Also you are (supposedly) removing all uses of IO_TLB_DEFAULT_SIZE, yet you don't seem to remove the definition itself. Finally - are arbitrary numbers really okay for the newly added command line options? I.e. shouldn't you add some checking of their validity? Jan