On 09/08/2018 12:23 AM, Ming Lei wrote: > On Thu, Sep 06, 2018 at 10:19:27PM +0800, jianchao.wang wrote: >> >> >> On 09/06/2018 09:07 PM, Ming Lei wrote: >>> On Thu, Sep 06, 2018 at 09:28:46AM +0800, jianchao.wang wrote: >>>> Hi Ming >>>> >>>> On 09/06/2018 06:09 AM, Ming Lei wrote: >>>>> nvme_dev_add() still may call freeze & unfreeze queue, so your patch >>>>> can't avoid draining queue completely here. >>>> >>>> Yes, I know this. We still need to freeze queue when update nr_hw_queues. >>>> But we move forward a step at least. :) >>>> We don't need to drain request queue in normal case of nvme_reset_work. >>> >>> It is hard to say who is the normal case. In case of CPU hotplug, it is quite >>> easy to trigger updating nr_hw_queues. >>> >>>> >>>> As for updating nr_hw_queues, we could try some other method on it next. >>> >>> The thing is that draining queue may be inevitable inside reset work >>> function because of updating nr_hw_queues, that means the approach in >>> this patchset is just a partial solution >>> >>> Or it may not make sense to do that because we may never remove the draining >>> queue in the code path of updating nr_hw_queues. >>> >>> Given they belong to same issue, I suggest to solve them all. >> >> I still think if just prevent new IO, freeze queue is over-kill. >> >> With respect to update nr_hw_queues, we could try to take the bios down from the >> queued requests as the blk_steal_bios. Then re-issue these bios after updating the >> nr_hw_queues. > > It is always easier to say than done, :-) > > Please go ahead and post patches, and I am happy to review. > Yes, I'm trying it and will post it when complete. :) Thanks Jianchao > > Thanks, > Ming > > _______________________________________________ > Linux-nvme mailing list > Linux-nvme@xxxxxxxxxxxxxxxxxxx > https://urldefense.proofpoint.com/v2/url?u=http-3A__lists.infradead.org_mailman_listinfo_linux-2Dnvme&d=DwICAg&c=RoP1YumCXCgaWHvlZYR8PZh8Bv7qIrMUB65eapI_JnE&r=7WdAxUBeiTUTCy8v-7zXyr4qk7sx26ATvfo6QSTvZyQ&m=8v99qftJpifVTL4l7Od8_RT0UZCUN1aIotRsKWugz28&s=Z56o8mcARcWcRHe1yOr8Hu2a7djUCM6hKtrDTHuA9Qc&e= >
