Re: [PATCH v7 0/3] FDP and per-io hints

Jens Axboe
2024-10-03T22:15:00Z

On 10/3/24 6:54 AM, Christoph Hellwig wrote:
> For file: yes. The problem is when you have more files than buckets on
> the device or file systems. Typical enterprise SSDs support somewhere
> between 8 and 16 write streams, and there typically is more data than
> that. So trying to group it somehow is good idea as not all files can
> have their own bucket.
>
> Allowing this inside a file like done in this patch set on the other
> hand is pretty crazy.

I do agree that per-file hints are not ideal. In the spirit of making
some progress, how about we just retain per-io hints initially? We can
certainly make that work over dio. Yes buffered IO won't work initially,
but at least we're getting somewhere.

--
Jens Axboe