Re: [PATCH v4 06/22] slab: add sheaves to most caches

Breno Leitao
2026-01-26T13:59:56Z

On Fri, Jan 23, 2026 at 07:52:44AM +0100, Vlastimil Babka wrote:
> In the first step to replace cpu (partial) slabs with sheaves, enable
> sheaves for almost all caches. Treat args->sheaf_capacity as a minimum,
> and calculate sheaf capacity with a formula that roughly follows the
> formula for number of objects in cpu partial slabs in set_cpu_partial().
>
> This should achieve roughly similar contention on the barn spin lock as
> there's currently for node list_lock without sheaves, to make
> benchmarking results comparable. It can be further tuned later.
>
> Don't enable sheaves for bootstrap caches as that wouldn't work. In
> order to recognize them by SLAB_NO_OBJ_EXT, make sure the flag exists
> even for !CONFIG_SLAB_OBJ_EXT.
>
> This limitation will be lifted for kmalloc caches after the necessary
> bootstrapping changes.
>
> Also do not enable sheaves for SLAB_NOLEAKTRACE caches to avoid
> recursion with kmemleak tracking (thanks to Breno Leitao).
>
> Reviewed-by: Suren Baghdasaryan <surenb@google.com>
> Reviewed-by: Harry Yoo <harry.yoo@oracle.com>
> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>

Tested-by: Breno Leitao <leitao@debian.org>