linux-kernel - Re: [PATCH v6 08/10] mm, vma: use percpu sheaves for vm_area

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Message-ID: <195d00ab-5429-48ff-b5dd-a45b26cd9ea9@lucifer.local>
Date: Tue, 2 Sep 2025 12:13:41 +0100
From: Lorenzo Stoakes <lorenzo.stoakes@...cle.com>
To: Vlastimil Babka <vbabka@...e.cz>
Cc: Suren Baghdasaryan <surenb@...gle.com>,
        "Liam R. Howlett" <Liam.Howlett@...cle.com>,
        Christoph Lameter <cl@...two.org>,
        David Rientjes <rientjes@...gle.com>,
        Roman Gushchin <roman.gushchin@...ux.dev>,
        Harry Yoo <harry.yoo@...cle.com>, Uladzislau Rezki <urezki@...il.com>,
        linux-mm@...ck.org, linux-kernel@...r.kernel.org, rcu@...r.kernel.org,
        maple-tree@...ts.infradead.org
Subject: Re: [PATCH v6 08/10] mm, vma: use percpu sheaves for vm_area_struct
 cache

On Wed, Aug 27, 2025 at 10:26:40AM +0200, Vlastimil Babka wrote:
> Create the vm_area_struct cache with percpu sheaves of size 32 to
> improve its performance.
>
> Reviewed-by: Suren Baghdasaryan <surenb@...gle.com>
> Signed-off-by: Vlastimil Babka <vbabka@...e.cz>
> ---
>  mm/vma_init.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/mm/vma_init.c b/mm/vma_init.c
> index 8e53c7943561e7324e7992946b4065dec1149b82..52c6b55fac4519e0da39ca75ad018e14449d1d95 100644
> --- a/mm/vma_init.c
> +++ b/mm/vma_init.c
> @@ -16,6 +16,7 @@ void __init vma_state_init(void)
>  	struct kmem_cache_args args = {
>  		.use_freeptr_offset = true,
>  		.freeptr_offset = offsetof(struct vm_area_struct, vm_freeptr),
> +		.sheaf_capacity = 32,

This breaks the VMA tests.

Please also update tools/testing/vma/vma_internal.h to add this field
(probably actually at the commit that adds the field in mainline :P)

I do wish we could have these tests be run by a bot :/ seems today I am
that bot :)

>  	};
>
>  	vm_area_cachep = kmem_cache_create("vm_area_struct",
>
> --
> 2.51.0
>
>
>