[PATCH] nvmet: Use direct IO for writes

[Jens Axboe]

On 09/22/2016 07:57 AM, Christoph Hellwig wrote:
> On Wed, Sep 21, 2016 at 11:10:50AM -0700, Sagi Grimberg wrote:
>> We're designed to work with high-end devices where
>> direct IO makes perfect sense. We noticed that we
>> context switch by scheduling kblockd instead of going
>> directly to the device without REQ_SYNC for writes.
>
> This looks reasonable.  But I still wonder why we bother to inject delay
> for any fast blk-mq device (background: Sagi told me he is observing
> issues without this on a NVMe PCIe card backend)

Batching/merging. It's not like we're doing a calculated explicit delay,
it's just async running the queue.

-- 
Jens Axboe