Re: [PATCH gnumach 1/2] ipc: tune size of cached kernel message buffers

[Samuel Thibault]

Justus Winter, le Tue 16 Dec 2014 15:09:46 +0100, a écrit :
> The previous limit was 256 bytes.  That seems a little crummy by
> todays standards, and we are frequently sending bigger packets
> (e.g. every RPC containing a string_t on Hurd).
> 
> Use the page size for IKM_SAVED_KMSG_SIZE to make sure the page is
> pinned to a single processor.

Ack.

> * ipc/ipc_kmsg.h (IKM_SAVED_KMSG_SIZE): Define to `PAGE_SIZE'.
> ---
>  ipc/ipc_kmsg.h | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/ipc/ipc_kmsg.h b/ipc/ipc_kmsg.h
> index 07695fb..f06857a 100644
> --- a/ipc/ipc_kmsg.h
> +++ b/ipc/ipc_kmsg.h
> @@ -92,9 +92,12 @@ extern ipc_kmsg_t  ipc_kmsg_cache[NCPUS];
>  /*
>   *   The size of the kernel message buffers that will be cached.
>   *   IKM_SAVED_KMSG_SIZE includes overhead; IKM_SAVED_MSG_SIZE doesn't.
> + *
> + *   We use the page size for IKM_SAVED_KMSG_SIZE to make sure the
> + *   page is pinned to a single processor.
>   */
>  
> -#define      IKM_SAVED_KMSG_SIZE     ((vm_size_t) 256)
> +#define      IKM_SAVED_KMSG_SIZE     PAGE_SIZE
>  #define      IKM_SAVED_MSG_SIZE      ikm_less_overhead(IKM_SAVED_KMSG_SIZE)
>  
>  #define      ikm_alloc(size)                                                 
> \
> -- 
> 2.1.3
> 

-- 
Samuel
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