[EXT] Re: [PATCH 2/2] block: remove the per-bio/request write hint.

[Luca Porzio (lporzio)]

> Since there is a desire to remove the write hint information from struct bio, is
> there any other information the "system data characteristics" information
> can be derived from?
> How about e.g. deriving that information from request flags like REQ_SYNC,
> REQ_META and/or REQ_IDLE?

Bart,

I agree with all your analysis. The point is these flags (Sync, Meta and Idle) are 
really meant for latency management whereas here the problem is hot/cold separation.

At this moment I am not aware of any methodology we can use to map S/M/Idle flags
Into hot/cold meaning but I am open to talk and discuss :-)

> 
> Thanks,
> 
> Bart.

Cheers,
  Luca