Re: [PATCH v3 2/3] mm: add kmem_cache_create_rcu()

[Vlastimil Babka <vbabka@suse.cz>]

On 8/28/24 12:56, Christian Brauner wrote:
> When a kmem cache is created with SLAB_TYPESAFE_BY_RCU the free pointer
> must be located outside of the object because we don't know what part of
> the memory can safely be overwritten as it may be needed to prevent
> object recycling.
> 
> That has the consequence that SLAB_TYPESAFE_BY_RCU may end up adding a
> new cacheline. This is the case for e.g., struct file. After having it
> shrunk down by 40 bytes and having it fit in three cachelines we still
> have SLAB_TYPESAFE_BY_RCU adding a fourth cacheline because it needs to
> accommodate the free pointer.
> 
> Add a new kmem_cache_create_rcu() function that allows the caller to
> specify an offset where the free pointer is supposed to be placed.
> 
> Signed-off-by: Christian Brauner <brauner@kernel.org>

Reviewed-by: Vlastimil Babka <vbabka@suse.cz>

Thanks.