On 09/17/2019 07:32 PM, Jens Axboe wrote: > Regular io stats get merging stats for read/write/trim. Why do we need > something else for this? > > -- Jens Axboe Yes, but we don't have a mechanism through debug-fs to have such per request type information which makes debugging much easier. One such a scenario where we want to add a new request type and examine rq_merged not as a whole number, which is not covered by the io stats (since it only covers read/write/trim).