On 6/9/21 11:45 AM, Max Gurtovoy wrote: > > On 6/9/2021 2:04 AM, Sagi Grimberg wrote: >> >>>> On 5/25/21 7:22 PM, Max Gurtovoy wrote: >>>>> On 5/25/2021 6:54 PM, Sagi Grimberg wrote: >>>>>>> Since the Linux iser initiator default max I/O size set to 512KB and >>>>>>> since there is no handshake procedure for this size in iser >>>>>>> protocol, >>>>>>> set the default max IO size of the target to 512KB as well. >>>>>>> >>>>>>> For changing the default values, there is a module parameter for >>>>>>> both >>>>>>> drivers. >>>>>> Is this solving a bug? >>>>> No. Only OOB for some old connect-IB devices. >>>>> >>>>> I think it's reasonable to align initiator and target defaults anyway. >>>>> >>>>> >>>> Actually, this patch is solving a bug when trying iser over >>>> Connect-IB, We see >>>> the following failure when trying to do discovery: >>> >>> You can work around this using the ib_isert sg_tablesize module param >>> and set it to 128. >>> >>> So it's more OOB behavior than a bug. >>> >>> Anyway, This is good practice to be able to establish connections >>> also for old devices without WAs and we also aligning to the sg_table >>> size in the initiator side. >>> >>> Jason/Sagi, >>> >>> can you comment on this patch for 5.14 ? >> >> Actually, if this is the case, why not have a fallback when creating the >> QP? Seems more reasonable to have the exception for the old devices >> rather than having those mandate the common denominator no? > > We first wanted to support 16MiB for isert but then we get a report from > Chelsio that it will dramatically reduce the total amount of connections > the can support. > > So we created a module param and reduced the default to 1MiB. Now we > have similar issue with Connect-IB so reducing it to 512KiB (same as the > default for Linux iser initiator) seems reasonable. > > Users that would like larger sg_table will use the module param. > > I would avoid doing fallbacks for that and maintain a code that might be > dead in a year or two. > > Well, from the distro's point of view this code is not going to be dead any time soon..., And the current user experience is very bad, Could you guys please decide on a way to fix this issue? Thanks, Kamal
