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Re: [PATCH 5/5] kern: make struct kmem_cache fit into two cache lines
From: |
Samuel Thibault |
Subject: |
Re: [PATCH 5/5] kern: make struct kmem_cache fit into two cache lines |
Date: |
Thu, 2 Jan 2014 23:48:49 +0100 |
User-agent: |
Mutt/1.5.21+34 (58baf7c9f32f) (2010-12-30) |
Justus Winter, le Thu 02 Jan 2014 20:02:46 +0100, a écrit :
> Previously, the size of struct kmem_cache was 136 bytes, just eight
> bytes larger than 128 bytes, which is typically two cache lines on
> today's CPUs.
>
> By reducing the size of the name field which holds a human-readable
> description by eight bytes to 24 bytes, the struct kmem_cache can be
> made fit into two cache lines. This change should not affect the
> usefulness of this field. For reference, the length of the largest
> hard-coded name is 17.
>
> * kern/slab.h (KMEM_CACHE_NAME_SIZE): Define to 24.
Ack.
> ---
> kern/slab.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/kern/slab.h b/kern/slab.h
> index b842fb7..a4219c4 100644
> --- a/kern/slab.h
> +++ b/kern/slab.h
> @@ -149,7 +149,7 @@ typedef void (*kmem_slab_free_fn_t)(vm_offset_t,
> vm_size_t);
> /*
> * Cache name buffer size.
> */
> -#define KMEM_CACHE_NAME_SIZE 32
> +#define KMEM_CACHE_NAME_SIZE 24
>
> /*
> * Cache of objects.
> --
> 1.8.5.2
>
--
Samuel
AUTHOR
FvwmM4 is the result of a random bit mutation on a hard
disk, presumably a result of a cosmic-ray or some such
thing.
(extrait de la page de man de FvwmM4)
- [PATCH 1/5] vm: remove NS32000-specific padding from struct vm_page, Justus Winter, 2014/01/02
- [PATCH 3/5] vm: reduce the size of struct vm_page, Justus Winter, 2014/01/02
- [PATCH 4/5] kern: reduce the size of struct task, Justus Winter, 2014/01/02
- [PATCH 2/5] vm: merge the two bit fields in struct vm_page, Justus Winter, 2014/01/02
- [PATCH 5/5] kern: make struct kmem_cache fit into two cache lines, Justus Winter, 2014/01/02
- Re: [PATCH 1/5] vm: remove NS32000-specific padding from struct vm_page, Samuel Thibault, 2014/01/02