Dear Jan > -----Original Message----- > From: Jan Beulich [mailto:JBeulich@xxxxxxxx] > Sent: Thursday, March 5, 2015 4:40 PM > To: Wang, Xiaoming > Cc: Liu@xxxxxxxxxxxxxxxxxxxx; Zhang@xxxxxxxxxxxxxxxxxxxx; chris@chris- > wilson.co.uk; david.vrabel@xxxxxxxxxx; lauraa@xxxxxxxxxxxxxx; > heiko.carstens@xxxxxxxxxx; linux@xxxxxxxxxxx; Liu, Chuansheng; Zhang, > Dongxing; takahiro.akashi@xxxxxxxxxx; akpm@xxxxxxxxxxxxxxxxxxxx; linux- > mips@xxxxxxxxxxxxxx; ralf@xxxxxxxxxxxxxx; xen-devel@xxxxxxxxxxxxxxxxxxxx; > boris.ostrovsky@xxxxxxxxxx; Konrad Rzeszutek Wilk; > d.kasatkin@xxxxxxxxxxx; pebolle@xxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx > Subject: RE: [PATCH v5] modify the IO_TLB_SEGSIZE and > IO_TLB_DEFAULT_SIZE configurable as flexible requirement about SW- > IOMMU. > > >>> On 05.03.15 at 04:53, <xiaoming.wang@xxxxxxxxx> wrote: > >> From: Konrad Rzeszutek Wilk [mailto:konrad.wilk@xxxxxxxxxx] > >> Sent: Thursday, March 5, 2015 3:43 AM On Tue, Mar 03, 2015 at > >> 04:11:09PM +0800, Wang Xiaoming wrote: > >> > @@ -101,13 +119,32 @@ setup_io_tlb_npages(char *str) { > >> > if (isdigit(*str)) { > >> > io_tlb_nslabs = simple_strtoul(str, &str, 0); > >> > - /* avoid tail segment of size < IO_TLB_SEGSIZE */ > >> > - io_tlb_nslabs = ALIGN(io_tlb_nslabs, IO_TLB_SEGSIZE); > >> > } > >> > if (*str == ',') > >> > ++str; > >> > - if (!strcmp(str, "force")) > >> > + if (!strncmp(str, "force", 5)) { > >> > swiotlb_force = 1; > >> > + str += 5; > >> > + } > >> > >> So the format is now: > >> > >> Format: { <int> | force | <int> | <int>} > >> > >> which means I can do > >> 32,22323,force > >> > >> Or > >> force,32 > >> > >> Or > >> 32,force > >> > > If I use Format: { <int>,force,<int>,<int>} 32,22323,force can't > > acceptable. > > There are three <int> here, if there are out of order, that will > > cause confuse. > > Only 32,force,32323 > > Or 32,,32323,2322 > > Or ,,323222,3232 > > Are available. > > You need to make sure that all previously valid variants are still usable, i.e. > force alone, a number alone, force,<number> and <number>,force. How > many variants you want to support with your additions is mostly up to you; > I'd recommend permitting force in any position. > I don't think it's suitable to accept that "force" in any position. If we defined Format: { <int>,force,<int>,<int>} "force" must be located in second position. And we add comment for each <int> also. Every position may be defined specifically. > Jan
