Re: [PATCH v2] Support for write stream IDs

[Peter Zijlstra <peterz@infradead.org>]

On Tue, May 05, 2015 at 06:09:18PM -0400, Martin K. Petersen wrote:
> >>>>> "Jens" == Jens Axboe <axboe@fb.com> writes:
> 
> Jens> I'm not trying to make a shortcut. I deliberately do not want to
> Jens> make ID generation/assignment part of the kernel. There's no
> Jens> reason that can't exist outside of the kernel, in a libstreamid or
> Jens> similar.
> 
> That just perpetuates the broken model, though. Why wouldn't we want to
> have stream ids readily available inside the kernel to tag journals,
> filesystem metadata, data migration, who knows what?

> The only sensible solution is for the kernel to manage the stream
> IDs. And for them to be plentiful. The storage device is free to ignore
> them, do LRU or whatever it pleases to manage them if it has an internal
> limit on number of open streams, etc.

I agree; one of the primary tasks of an operating system kernel is
arbitrage and control of hardware resources.