On 2/2/2016 10:14 AM, Zhang, Helin wrote: > >> -----Original Message----- >> From: Qiu, Michael >> Sent: Tuesday, February 2, 2016 10:07 AM >> To: Lu, Wenzhuo; dev at dpdk.org >> Cc: Zhou, Danny; Liu, Yong; Liang, Cunming; Zhang, Helin >> Subject: Re: [PATCH v2] ixgbe: Fix disable interrupt twice >> >> [+cc helin] >> >> On 2/2/2016 9:03 AM, Lu, Wenzhuo wrote: >>> Hi Michael, >>> >>>> -----Original Message----- >>>> From: Qiu, Michael >>>> Sent: Monday, February 1, 2016 4:05 PM >>>> To: Lu, Wenzhuo; dev at dpdk.org >>>> Cc: Zhou, Danny; Liu, Yong; Liang, Cunming >>>> Subject: Re: [PATCH v2] ixgbe: Fix disable interrupt twice >>>> >>>> On 1/29/2016 4:07 PM, Lu, Wenzhuo wrote: >>>>> Hi Michael, >>>>> >>>>>> -----Original Message----- >>>>>> From: Qiu, Michael >>>>>> Sent: Friday, January 29, 2016 1:58 PM >>>>>> To: dev at dpdk.org >>>>>> Cc: Zhou, Danny; Liu, Yong; Liang, Cunming; Lu, Wenzhuo; Qiu, >>>>>> Michael >>>>>> Subject: [PATCH v2] ixgbe: Fix disable interrupt twice >>>>>> >>>>>> Currently, ixgbe vf and pf will disable interrupt twice in stop >>>>>> stage and uninit stage. It will cause an error: >>>>>> >>>>>> testpmd> quit >>>>>> >>>>>> Shutting down port 0... >>>>>> Stopping ports... >>>>>> Done >>>>>> Closing ports... >>>>>> EAL: Error disabling MSI-X interrupts for fd 26 >>>>>> Done >>>>>> >>>>>> Becasue the interrupt already been disabled in stop stage. >>>>>> Since it is enabled in init stage, better remove from stop stage. >>>>> I'm afraid it?s not a good idea to just remove the intr_disable from >> dev_stop. >>>>> I think dev_stop have the chance to be used independently with >>>>> dev_unint. In >>>> this scenario, we still need intr_disable, right? >>>>> Maybe what we need is some check before we disable the intr:) >>>> Yes, indeed we need some check in disable intr, but it need >>>> additional fields in "struct rte_intr_handle", and it's much saft to >>>> do so, but as I check i40e/fm10k code, only ixgbe disable it in dev_stop(). >>> I found fm10k doesn?t enable intr in dev_start. So, I think it's OK. But >>> i40e >> enables intr in dev_start. >>> To my opinion, it's more like i40e misses the intr_disable in dev_stop. >> I don't think i40e miss it, because it not the right please to disable >> interrupt. >> because all interrupts are enabled in init stage. >> >> Actually, ixgbe enable the interrupt in init stage, but in dev_start, it >> disable it >> first and re-enable, so it just the same with doing nothing about interrupt. >> >> Just think below: >> >> 1. start the port.(interrupt already enabled in init stage, disable --> >> re-enable) >> 2. stop the port.(disable interrupt) >> 3. start port again(Try to disable, but failed, already disabled) >> >> Would you think the code has issue? > [Zhang, Helin] in ixgbe PMD, it can be seen that uninit() calls dev_close(), > which calls dev_stop(). So I think the disabling can be done only in > dev_stop(). > All others can make use of dev_stop to disable the interrupt.
As I said, if it is in dev_stop, it will has issue when dev_start --> dev_stop --> dev_start, this also could applied in i40e and fm10k. If you want to put it in dev_stop, better to remove enable interrupts in init stage, and only put it in dev_start. Thanks, Michael > Regards, > Helin > >> Thanks, >> Michael >> >>> Maybe we can follow fm10k's style. >>> >>>> On other hand, if we remove it in dev_stop, any side effect? In ixgbe >>>> start, it will always disable it first and then re-enable it, so it's safe. >>> I think you mean we can disable intr anyway even if it has been disabled. >> Actually, we couldn't, DPDK call VFIO ioctl to kernel to disable interrupts, >> and >> if we try disable twice, it will return and error. >> That's why I mean we need a flag to show the interrupts stats. If it already >> disabled, we do not need call in to kernel. just return and give a warning >> message. >> >> Thanks, >> Michael >> >>> Sounds more like why we don't >>> need this patch :) >>> >>>> Thanks, >>>> Michael >
