Dexuan, > Regarding this patch, I'm not sure if it's a "workaround": if it's > incorrect to set a bigger-than-SHRT_MAX scsi_driver.can_queue value, > probably we should change scsi_driver.can_queue from "int" to "u16"? > BTW, I guess the "cmd_per_lun" should also be "u16" rather than > "short"? I agree that it would be nice to get all this cleaned up. Several, somewhat peculiar, 25-year old design choices. cmd_per_lun has traditionally been in the ballpark of low hundreds, can_queue typically in the low thousands. And the block layer currently caps at ~10K. Happy to take patches fixing this up, although I am a bit worried about how much churn it will generate. That said, I do think that cleaning this up is somewhat orthogonal to the issue with storvsc. I suspect that allowing a huge amount of concurrent outstanding commands is going to be detrimental to performance for most workloads. And from that perspective I think that the short->int fix, while valid given the type discrepancy, is just treating the symptom. Therefore I consider the short->int fix a workaround. And the proper fix involves looking closely at things are scaled in the storvsc case. Which I have noted that Michael is working on. -- Martin K. Petersen Oracle Linux Engineering
