Re: [PATCH v3 07/11] mm: vmalloc: Offload free_vmap_area_lock lock

Dave Chinner
2024-01-11T09:02:20Z

On Tue, Jan 02, 2024 at 07:46:29PM +0100, Uladzislau Rezki (Sony) wrote:
> Concurrent access to a global vmap space is a bottle-neck.
> We can simulate a high contention by running a vmalloc test
> suite.
>
> To address it, introduce an effective vmap node logic. Each
> node behaves as independent entity. When a node is accessed
> it serves a request directly(if possible) from its pool.
>
> This model has a size based pool for requests, i.e. pools are
> serialized and populated based on object size and real demand.
> A maximum object size that pool can handle is set to 256 pages.
>
> This technique reduces a pressure on the global vmap lock.
>
> Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>

Why not use a llist for this? That gets rid of the need for a
new pool_lock altogether...

Cheers,

Dave.
--
Dave Chinner
david@fromorbit.com