[patch] Add support for more than 256 zones

[patch] Add support for more than 256 zones

[Jay Lan]

This patch is to support more than 256 zones for large systems.
The changes is to add #ifdef CONFIG_IA64 to mm.h to give different
#define to ZONE_SHIFT.

Thanks,
  - jay lan


diff -urN a-2.5.75/include/linux/mm.h b-2.5.75/include/linux/mm.h
--- a-2.5.75/include/linux/mm.h     Thu Jul 10 13:04:45 2003
+++ b-2.5.75/include/linux/mm.h     Tue Aug 12 17:20:22 2003
@@ -323,7 +323,11 @@
   * sets it, so none of the operations on it need to be atomic.
   */
  #define NODE_SHIFT 4
+#ifdef CONFIG_IA64
+#define ZONE_SHIFT (BITS_PER_LONG - 10)
+#else
  #define ZONE_SHIFT (BITS_PER_LONG - 8)
+#endif

  struct zone;
  extern struct zone *zone_table[];



For patch to 2.4.21:

diff -urN a-2.4.21/include/linux/mm.h b-2.4.21/include/linux/mm.h
--- a-2.4.21/include/linux/mm.h     Fri Jun 13 07:51:38 2003
+++ b-2.4.21/include/linux/mm.h     Tue Aug 12 17:19:27 2003
@@ -321,7 +321,11 @@
   * sets it, so none of the operations on it need to be atomic.
   */
  #define NODE_SHIFT 4
+#ifdef CONFIG_IA64
+#define ZONE_SHIFT (BITS_PER_LONG - 10)
+#else
  #define ZONE_SHIFT (BITS_PER_LONG - 8)
+#endif

  struct zone_struct;
  extern struct zone_struct *zone_table[];

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Re: [patch] Add support for more than 256 zones

[Andrew Morton]

Jay Lan <jlan@sgi.com> wrote:
>
> This patch is to support more than 256 zones for large systems.
> The changes is to add #ifdef CONFIG_IA64 to mm.h to give different
> #define to ZONE_SHIFT.
> 
> Thanks,
>   - jay lan
> 
> 
> diff -urN a-2.5.75/include/linux/mm.h b-2.5.75/include/linux/mm.h
> --- a-2.5.75/include/linux/mm.h     Thu Jul 10 13:04:45 2003
> +++ b-2.5.75/include/linux/mm.h     Tue Aug 12 17:20:22 2003
> @@ -323,7 +323,11 @@
>    * sets it, so none of the operations on it need to be atomic.
>    */
>   #define NODE_SHIFT 4
> +#ifdef CONFIG_IA64
> +#define ZONE_SHIFT (BITS_PER_LONG - 10)
> +#else
>   #define ZONE_SHIFT (BITS_PER_LONG - 8)
> +#endif

Yes, this is good - it gives us five more page flags on 32-bit machines. 
Assuming that no 32 bit machiens will ever need more than three zones(?)

Please do it this way:

#ifndef ARCH_NR_ZONES_SHIFT
#define ARCH_NR_ZONES_SHIFT	3
#endif

#define ZONE_SHIFT (BITS_PER_LONG - ARCH_NR_ZONES_SHIFT)


and, in asm-ia64/page.h:

#define ARCH_NR_ZONES	10	/* 1024 zones */
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Re: [patch] Add support for more than 256 zones

[Martin J. Bligh]

> Yes, this is good - it gives us five more page flags on 32-bit machines. 
> Assuming that no 32 bit machiens will ever need more than three zones(?)

There has been talk already of a ZONE_DMA32 or whatever (first 4GB).
That'd be useful for quite a few things, so might be nice to leave
space for at least four zones ...

M.
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