>>> On 18.02.15 at 10:09, <xiaoming.wang@xxxxxxxxx> wrote: >> From: Jan Beulich [mailto:JBeulich@xxxxxxxx] >> Sent: Tuesday, February 17, 2015 6:09 PM >> >>> 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"). >> > Use "," can separate them one by one. > We do it at lib/swiotlb.c Right, but the documentation above doesn't say so. >> Also you are (supposedly) removing all uses of IO_TLB_DEFAULT_SIZE, yet >> you don't seem to remove the definition itself. >> > I have change all uses of IO_TLB_DEFAULT_SIZE to io_tlb_default_size in > lib/swiotlb.c Then are there any left elsewhere? If not, again - why don't you remove the definition of IO_TLB_DEFAULT_SIZE? >> Finally - are arbitrary numbers really okay for the newly added command line >> options? I.e. shouldn't you add some checking of their validity? >> > I have validity these code is OK. > Example: > BOARD_KERNEL_CMDLINE += swiotlb=, ,512,268435456 > Io_tlb_segsize has been changed from 128 to 512 > Io_tlb_default_size has been changed from 64M to 268435456 (256M) I specifically said "arbitrary numbers", which in particular includes zero and non-power-of-2 values. If there are any restrictions on which numbers can validly be passed here (and it very much looks like there are), such restrictions should be enforced imo. Jan
