Re: [PATCH] ext4: rralloc - (former rotalloc) improved round-robin allocation policy

[Theodore Tso]

On Mon, Mar 02, 2026 at 09:04:44PM +0100, Mario Lohajner wrote:
> RRALLOC spreads allocation starting points across block groups to avoid
> repeated concentration under parallel load.

There are already other ways in which we spread allocations across
block groups.  You need to tell explain a specific workload where this
actually makes a difference.

Also note that in most use cases, files are written once, and read
multiple times.  So spreading blocks across different block groups is
can often be actively harmful.

> In high-concurrency testing, performance is consistently comparable to
> or occasionally better than the regular allocator. No regressions have
> been observed across tested configurations.

No regressions, and only "occasionally better" not enough of a justifiation.

What is your real life workload which is motivating your efforts?

     	     	       		      	 - Ted