Re: [patch 2/9] Store max number of objects in the page struct.

[Christoph Lameter]

Reviewed-by: Christoph Lameter <clameter@xxxxxxx>

On Thu, 20 Mar 2008, Zhang, Yanmin wrote:

> On Wed, 2008-03-19 at 10:49 -0700, Christoph Lameter wrote:
> > On Wed, 19 Mar 2008, Zhang, Yanmin wrote:
> > 
> > > > +	if ((PAGE_SIZE << min_order) / size > 65535)
> > > > +		return get_order(size * 65535) - 1;
> > > Is it better to define something like USHORT_MAX to replace 65535?
> > 
> > Yes. Do we have something like that?
> 
> I couldn't find such definition in include/linux/kernel.h.
> 
> 
> But glibc defines USHRT_MAX file include/limits.h:
> 
> /* Minimum and maximum values a `signed short int' can hold.  */
> #  define SHRT_MIN      (-32768)
> #  define SHRT_MAX      32767
> 
> /* Maximum value an `unsigned short int' can hold.  (Minimum is 0.)  */
> #  define USHRT_MAX     65535
> 
> 
> How about below patch against 2.6.25-rc6?
> 
> ---
> 
> Add definitions of USHRT_MAX and others into kernel. ipc uses it and
> slub implementation might also use it.
> 
> The patch is against 2.6.25-rc6.
> 
> Signed-off-by: Zhang Yanmin <yanmin.zhang@xxxxxxxxx>
> 
> ---
> 
> --- linux-2.6.25-rc6/include/linux/kernel.h	2008-03-20 04:25:46.000000000 +0800
> +++ linux-2.6.25-rc6_work/include/linux/kernel.h	2008-03-20 04:17:45.000000000 +0800
> @@ -20,6 +20,9 @@
>  extern const char linux_banner[];
>  extern const char linux_proc_banner[];
>  
> +#define USHRT_MAX	((u16)(~0U))
> +#define SHRT_MAX	((s16)(USHRT_MAX>>1))
> +#define SHRT_MIN	(-SHRT_MAX - 1)
>  #define INT_MAX		((int)(~0U>>1))
>  #define INT_MIN		(-INT_MAX - 1)
>  #define UINT_MAX	(~0U)
> --- linux-2.6.25-rc6/ipc/util.h	2008-03-20 04:25:46.000000000 +0800
> +++ linux-2.6.25-rc6_work/ipc/util.h	2008-03-20 04:22:07.000000000 +0800
> @@ -12,7 +12,6 @@
>  
>  #include <linux/err.h>
>  
> -#define USHRT_MAX 0xffff
>  #define SEQ_MULTIPLIER	(IPCMNI)
>  
>  void sem_init (void);
> 
> 
> 
> 
> 
> 
> 
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