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* [TRIVIAL PATCH] Ensure pfn_to_nid() is always defined for i386
@ 2003-12-22 19:44 Matthew Dobson
  2003-12-23  0:26 ` Martin J. Bligh
  0 siblings, 1 reply; 8+ messages in thread
From: Matthew Dobson @ 2003-12-22 19:44 UTC (permalink / raw)
  To: linux-kernel; +Cc: mbligh, Andrew Morton, Trivial Patch Monkey

[-- Attachment #1: Type: text/plain, Size: 248 bytes --]

pfn_to_nid() is defined for *almost* all configurations for i386.  There 
is a small bug in that for CONFIG_X86_PC it is not.  This just sets up a 
generic definition so that this function is always defined in a 
reasonable manner.

Cheers!

-Matt

[-- Attachment #2: pfn_to_nid_def.patch --]
[-- Type: text/plain, Size: 523 bytes --]

diff -Nurp --exclude-from=/home/mcd/.dontdiff linux-2.6.0-vanilla/include/asm-i386/mmzone.h linux-2.6.0-patched/include/asm-i386/mmzone.h
--- linux-2.6.0-vanilla/include/asm-i386/mmzone.h	Wed Dec 17 18:58:49 2003
+++ linux-2.6.0-patched/include/asm-i386/mmzone.h	Thu Dec 18 14:46:14 2003
@@ -123,6 +123,7 @@ static inline struct pglist_data *pfn_to
 #include <asm/srat.h>
 #elif CONFIG_X86_PC
 #define get_zholes_size(n) (0)
+#define pfn_to_nid(pfn)		(0)
 #else
 #define pfn_to_nid(pfn)		(0)
 #endif /* CONFIG_X86_NUMAQ */

^ permalink raw reply	[flat|nested] 8+ messages in thread

* Re: [TRIVIAL PATCH] Ensure pfn_to_nid() is always defined for i386
  2003-12-22 19:44 [TRIVIAL PATCH] Ensure pfn_to_nid() is always defined for i386 Matthew Dobson
@ 2003-12-23  0:26 ` Martin J. Bligh
  2004-01-05 21:35   ` Matthew Dobson
                     ` (3 more replies)
  0 siblings, 4 replies; 8+ messages in thread
From: Martin J. Bligh @ 2003-12-23  0:26 UTC (permalink / raw)
  To: colpatch, linux-kernel; +Cc: Andrew Morton, Trivial Patch Monkey

> pfn_to_nid() is defined for *almost* all configurations for i386.  
> There is a small bug in that for CONFIG_X86_PC it is not.  This 
> just sets up a generic definition so that this function is always 
> defined in a reasonable manner.

I'd prefer to fix the current ungodly mess in the current fashion ...
I know it's longer, but I'd prefer to clean it up more if we're 
going to touch it. This has been sitting in my tree for a while, 
waiting for the code freeze to slush out a bit.

M.


diff -purN -X /home/mbligh/.diff.exclude 276-per_node_rss/include/asm-i386/mmzone.h 278-pfn_to_nid/include/asm-i386/mmzone.h
--- 276-per_node_rss/include/asm-i386/mmzone.h	2003-10-01 11:48:22.000000000 -0700
+++ 278-pfn_to_nid/include/asm-i386/mmzone.h	2003-12-11 17:16:48.000000000 -0800
@@ -10,7 +10,49 @@
 
 #ifdef CONFIG_DISCONTIGMEM
 
+#ifdef CONFIG_NUMA
+	#ifdef CONFIG_X86_NUMAQ
+		#include <asm/numaq.h>
+	#else	/* summit or generic arch */
+		#include <asm/srat.h>
+	#endif
+#else /* !CONFIG_NUMA */
+	#define get_memcfg_numa get_memcfg_numa_flat
+	#define get_zholes_size(n) (0)
+#endif /* CONFIG_NUMA */
+
 extern struct pglist_data *node_data[];
+#define NODE_DATA(nid)		(node_data[nid])
+
+/*
+ * generic node memory support, the following assumptions apply:
+ *
+ * 1) memory comes in 256Mb contigious chunks which are either present or not
+ * 2) we will not have more than 64Gb in total
+ *
+ * for now assume that 64Gb is max amount of RAM for whole system
+ *    64Gb / 4096bytes/page = 16777216 pages
+ */
+#define MAX_NR_PAGES 16777216
+#define MAX_ELEMENTS 256
+#define PAGES_PER_ELEMENT (MAX_NR_PAGES/MAX_ELEMENTS)
+
+extern u8 physnode_map[];
+
+static inline int pfn_to_nid(unsigned long pfn)
+{
+#ifdef CONFIG_NUMA
+	return(physnode_map[(pfn) / PAGES_PER_ELEMENT]);
+#else
+	return 0;
+#endif
+}
+
+static inline struct pglist_data *pfn_to_pgdat(unsigned long pfn)
+{
+	return(NODE_DATA(pfn_to_nid(pfn)));
+}
+
 
 /*
  * Following are macros that are specific to this numa platform.
@@ -43,11 +85,6 @@ extern struct pglist_data *node_data[];
  */
 #define kvaddr_to_nid(kaddr)	pfn_to_nid(__pa(kaddr) >> PAGE_SHIFT)
 
-/*
- * Return a pointer to the node data for node n.
- */
-#define NODE_DATA(nid)		(node_data[nid])
-
 #define node_mem_map(nid)	(NODE_DATA(nid)->node_mem_map)
 #define node_start_pfn(nid)	(NODE_DATA(nid)->node_start_pfn)
 #define node_end_pfn(nid)						\
@@ -93,40 +130,6 @@ extern struct pglist_data *node_data[];
  */ 
 #define pfn_valid(pfn)          ((pfn) < num_physpages)
 
-/*
- * generic node memory support, the following assumptions apply:
- *
- * 1) memory comes in 256Mb contigious chunks which are either present or not
- * 2) we will not have more than 64Gb in total
- *
- * for now assume that 64Gb is max amount of RAM for whole system
- *    64Gb / 4096bytes/page = 16777216 pages
- */
-#define MAX_NR_PAGES 16777216
-#define MAX_ELEMENTS 256
-#define PAGES_PER_ELEMENT (MAX_NR_PAGES/MAX_ELEMENTS)
-
-extern u8 physnode_map[];
-
-static inline int pfn_to_nid(unsigned long pfn)
-{
-	return(physnode_map[(pfn) / PAGES_PER_ELEMENT]);
-}
-static inline struct pglist_data *pfn_to_pgdat(unsigned long pfn)
-{
-	return(NODE_DATA(pfn_to_nid(pfn)));
-}
-
-#ifdef CONFIG_X86_NUMAQ
-#include <asm/numaq.h>
-#elif CONFIG_ACPI_SRAT
-#include <asm/srat.h>
-#elif CONFIG_X86_PC
-#define get_zholes_size(n) (0)
-#else
-#define pfn_to_nid(pfn)		(0)
-#endif /* CONFIG_X86_NUMAQ */
-
 extern int get_memcfg_numa_flat(void );
 /*
  * This allows any one NUMA architecture to be compiled
diff -purN -X /home/mbligh/.diff.exclude 276-per_node_rss/include/linux/mmzone.h 278-pfn_to_nid/include/linux/mmzone.h
--- 276-per_node_rss/include/linux/mmzone.h	2003-10-14 15:50:34.000000000 -0700
+++ 278-pfn_to_nid/include/linux/mmzone.h	2003-12-11 17:16:48.000000000 -0800
@@ -303,7 +303,7 @@ extern struct pglist_data contig_page_da
 #define NODE_DATA(nid)		(&contig_page_data)
 #define NODE_MEM_MAP(nid)	mem_map
 #define MAX_NODES_SHIFT		0
-
+#define pfn_to_nid(pfn)		(0)
 #else /* CONFIG_DISCONTIGMEM */
 
 #include <asm/mmzone.h>


^ permalink raw reply	[flat|nested] 8+ messages in thread

* Re: [TRIVIAL PATCH] Ensure pfn_to_nid() is always defined for i386
  2003-12-23  0:26 ` Martin J. Bligh
@ 2004-01-05 21:35   ` Matthew Dobson
  2004-01-05 22:53   ` Mike Fedyk
                     ` (2 subsequent siblings)
  3 siblings, 0 replies; 8+ messages in thread
From: Matthew Dobson @ 2004-01-05 21:35 UTC (permalink / raw)
  To: Martin J. Bligh; +Cc: linux-kernel, Andrew Morton, Trivial Patch Monkey

Ok... This looks good to me.  It's definitely longer than my 1 line fix, 
but it's also more correct long-term solution.

Cheers!

-Matt

Martin J. Bligh wrote:
>>pfn_to_nid() is defined for *almost* all configurations for i386.  
>>There is a small bug in that for CONFIG_X86_PC it is not.  This 
>>just sets up a generic definition so that this function is always 
>>defined in a reasonable manner.
> 
> 
> I'd prefer to fix the current ungodly mess in the current fashion ...
> I know it's longer, but I'd prefer to clean it up more if we're 
> going to touch it. This has been sitting in my tree for a while, 
> waiting for the code freeze to slush out a bit.
> 
> M.
> 
> 
> diff -purN -X /home/mbligh/.diff.exclude 276-per_node_rss/include/asm-i386/mmzone.h 278-pfn_to_nid/include/asm-i386/mmzone.h
> --- 276-per_node_rss/include/asm-i386/mmzone.h	2003-10-01 11:48:22.000000000 -0700
> +++ 278-pfn_to_nid/include/asm-i386/mmzone.h	2003-12-11 17:16:48.000000000 -0800
> @@ -10,7 +10,49 @@
>  
>  #ifdef CONFIG_DISCONTIGMEM
>  
> +#ifdef CONFIG_NUMA
> +	#ifdef CONFIG_X86_NUMAQ
> +		#include <asm/numaq.h>
> +	#else	/* summit or generic arch */
> +		#include <asm/srat.h>
> +	#endif
> +#else /* !CONFIG_NUMA */
> +	#define get_memcfg_numa get_memcfg_numa_flat
> +	#define get_zholes_size(n) (0)
> +#endif /* CONFIG_NUMA */
> +
>  extern struct pglist_data *node_data[];
> +#define NODE_DATA(nid)		(node_data[nid])
> +
> +/*
> + * generic node memory support, the following assumptions apply:
> + *
> + * 1) memory comes in 256Mb contigious chunks which are either present or not
> + * 2) we will not have more than 64Gb in total
> + *
> + * for now assume that 64Gb is max amount of RAM for whole system
> + *    64Gb / 4096bytes/page = 16777216 pages
> + */
> +#define MAX_NR_PAGES 16777216
> +#define MAX_ELEMENTS 256
> +#define PAGES_PER_ELEMENT (MAX_NR_PAGES/MAX_ELEMENTS)
> +
> +extern u8 physnode_map[];
> +
> +static inline int pfn_to_nid(unsigned long pfn)
> +{
> +#ifdef CONFIG_NUMA
> +	return(physnode_map[(pfn) / PAGES_PER_ELEMENT]);
> +#else
> +	return 0;
> +#endif
> +}
> +
> +static inline struct pglist_data *pfn_to_pgdat(unsigned long pfn)
> +{
> +	return(NODE_DATA(pfn_to_nid(pfn)));
> +}
> +
>  
>  /*
>   * Following are macros that are specific to this numa platform.
> @@ -43,11 +85,6 @@ extern struct pglist_data *node_data[];
>   */
>  #define kvaddr_to_nid(kaddr)	pfn_to_nid(__pa(kaddr) >> PAGE_SHIFT)
>  
> -/*
> - * Return a pointer to the node data for node n.
> - */
> -#define NODE_DATA(nid)		(node_data[nid])
> -
>  #define node_mem_map(nid)	(NODE_DATA(nid)->node_mem_map)
>  #define node_start_pfn(nid)	(NODE_DATA(nid)->node_start_pfn)
>  #define node_end_pfn(nid)						\
> @@ -93,40 +130,6 @@ extern struct pglist_data *node_data[];
>   */ 
>  #define pfn_valid(pfn)          ((pfn) < num_physpages)
>  
> -/*
> - * generic node memory support, the following assumptions apply:
> - *
> - * 1) memory comes in 256Mb contigious chunks which are either present or not
> - * 2) we will not have more than 64Gb in total
> - *
> - * for now assume that 64Gb is max amount of RAM for whole system
> - *    64Gb / 4096bytes/page = 16777216 pages
> - */
> -#define MAX_NR_PAGES 16777216
> -#define MAX_ELEMENTS 256
> -#define PAGES_PER_ELEMENT (MAX_NR_PAGES/MAX_ELEMENTS)
> -
> -extern u8 physnode_map[];
> -
> -static inline int pfn_to_nid(unsigned long pfn)
> -{
> -	return(physnode_map[(pfn) / PAGES_PER_ELEMENT]);
> -}
> -static inline struct pglist_data *pfn_to_pgdat(unsigned long pfn)
> -{
> -	return(NODE_DATA(pfn_to_nid(pfn)));
> -}
> -
> -#ifdef CONFIG_X86_NUMAQ
> -#include <asm/numaq.h>
> -#elif CONFIG_ACPI_SRAT
> -#include <asm/srat.h>
> -#elif CONFIG_X86_PC
> -#define get_zholes_size(n) (0)
> -#else
> -#define pfn_to_nid(pfn)		(0)
> -#endif /* CONFIG_X86_NUMAQ */
> -
>  extern int get_memcfg_numa_flat(void );
>  /*
>   * This allows any one NUMA architecture to be compiled
> diff -purN -X /home/mbligh/.diff.exclude 276-per_node_rss/include/linux/mmzone.h 278-pfn_to_nid/include/linux/mmzone.h
> --- 276-per_node_rss/include/linux/mmzone.h	2003-10-14 15:50:34.000000000 -0700
> +++ 278-pfn_to_nid/include/linux/mmzone.h	2003-12-11 17:16:48.000000000 -0800
> @@ -303,7 +303,7 @@ extern struct pglist_data contig_page_da
>  #define NODE_DATA(nid)		(&contig_page_data)
>  #define NODE_MEM_MAP(nid)	mem_map
>  #define MAX_NODES_SHIFT		0
> -
> +#define pfn_to_nid(pfn)		(0)
>  #else /* CONFIG_DISCONTIGMEM */
>  
>  #include <asm/mmzone.h>
> 
> 



^ permalink raw reply	[flat|nested] 8+ messages in thread

* Re: [TRIVIAL PATCH] Ensure pfn_to_nid() is always defined for i386
  2003-12-23  0:26 ` Martin J. Bligh
  2004-01-05 21:35   ` Matthew Dobson
@ 2004-01-05 22:53   ` Mike Fedyk
  2004-01-05 23:15     ` Martin J. Bligh
  2004-03-29 15:45     ` Martin J. Bligh
  2004-03-29 15:45   ` Matthew Dobson
  2004-03-29 15:45   ` Mike Fedyk
  3 siblings, 2 replies; 8+ messages in thread
From: Mike Fedyk @ 2004-01-05 22:53 UTC (permalink / raw)
  To: Martin J. Bligh; +Cc: colpatch, linux-kernel, Andrew Morton

On Mon, Dec 22, 2003 at 04:26:40PM -0800, Martin J. Bligh wrote:
> + * for now assume that 64Gb is max amount of RAM for whole system
> + *    64Gb / 4096bytes/page = 16777216 pages
> + */
> +#define MAX_NR_PAGES 16777216
> +#define MAX_ELEMENTS 256
> +#define PAGES_PER_ELEMENT (MAX_NR_PAGES/MAX_ELEMENTS)

Why not do the calculation in the define, and use PAGE_SIZE?

If PAGE_SIZE isn't 4k will it break the rest of this code, or will the
calculations make sence with larger PAGE_SIZE?

Might as well make it easier to go in the direction of variable PAGE_SIZE
instead of keeping the assumption.

^ permalink raw reply	[flat|nested] 8+ messages in thread

* Re: [TRIVIAL PATCH] Ensure pfn_to_nid() is always defined for i386
  2004-01-05 22:53   ` Mike Fedyk
@ 2004-01-05 23:15     ` Martin J. Bligh
  2004-03-29 15:45     ` Martin J. Bligh
  1 sibling, 0 replies; 8+ messages in thread
From: Martin J. Bligh @ 2004-01-05 23:15 UTC (permalink / raw)
  To: Mike Fedyk; +Cc: colpatch, linux-kernel, Andrew Morton

>> + * for now assume that 64Gb is max amount of RAM for whole system
>> + *    64Gb / 4096bytes/page = 16777216 pages
>> + */
>> +#define MAX_NR_PAGES 16777216
>> +#define MAX_ELEMENTS 256
>> +#define PAGES_PER_ELEMENT (MAX_NR_PAGES/MAX_ELEMENTS)
> 
> Why not do the calculation in the define, and use PAGE_SIZE?
> 
> If PAGE_SIZE isn't 4k will it break the rest of this code, or will the
> calculations make sence with larger PAGE_SIZE?
> 
> Might as well make it easier to go in the direction of variable PAGE_SIZE
> instead of keeping the assumption.

The patch is just moving the code, not changing it ;-)
But yes, that value could probably be derived instead of hardcoded.
Separate patch though.

M.


^ permalink raw reply	[flat|nested] 8+ messages in thread

* Re: [TRIVIAL PATCH] Ensure pfn_to_nid() is always defined for i386
  2003-12-23  0:26 ` Martin J. Bligh
  2004-01-05 21:35   ` Matthew Dobson
  2004-01-05 22:53   ` Mike Fedyk
@ 2004-03-29 15:45   ` Matthew Dobson
  2004-03-29 15:45   ` Mike Fedyk
  3 siblings, 0 replies; 8+ messages in thread
From: Matthew Dobson @ 2004-03-29 15:45 UTC (permalink / raw)
  To: Administrator; +Cc: linux-kernel, Andrew Morton, Trivial Patch Monkey

Ok... This looks good to me.  It's definitely longer than my 1 line fix, 
but it's also more correct long-term solution.

Cheers!

-Matt

Martin J. Bligh wrote:
>>pfn_to_nid() is defined for *almost* all configurations for i386.  
>>There is a small bug in that for CONFIG_X86_PC it is not.  This 
>>just sets up a generic definition so that this function is always 
>>defined in a reasonable manner.
> 
> 
> I'd prefer to fix the current ungodly mess in the current fashion ...
> I know it's longer, but I'd prefer to clean it up more if we're 
> going to touch it. This has been sitting in my tree for a while, 
> waiting for the code freeze to slush out a bit.
> 
> M.
> 
> 
> diff -purN -X /home/mbligh/.diff.exclude 276-per_node_rss/include/asm-i386/mmzone.h 278-pfn_to_nid/include/asm-i386/mmzone.h
> --- 276-per_node_rss/include/asm-i386/mmzone.h	2003-10-01 11:48:22.000000000 -0700
> +++ 278-pfn_to_nid/include/asm-i386/mmzone.h	2003-12-11 17:16:48.000000000 -0800
> @@ -10,7 +10,49 @@
>  
>  #ifdef CONFIG_DISCONTIGMEM
>  
> +#ifdef CONFIG_NUMA
> +	#ifdef CONFIG_X86_NUMAQ
> +		#include <asm/numaq.h>
> +	#else	/* summit or generic arch */
> +		#include <asm/srat.h>
> +	#endif
> +#else /* !CONFIG_NUMA */
> +	#define get_memcfg_numa get_memcfg_numa_flat
> +	#define get_zholes_size(n) (0)
> +#endif /* CONFIG_NUMA */
> +
>  extern struct pglist_data *node_data[];
> +#define NODE_DATA(nid)		(node_data[nid])
> +
> +/*
> + * generic node memory support, the following assumptions apply:
> + *
> + * 1) memory comes in 256Mb contigious chunks which are either present or not
> + * 2) we will not have more than 64Gb in total
> + *
> + * for now assume that 64Gb is max amount of RAM for whole system
> + *    64Gb / 4096bytes/page = 16777216 pages
> + */
> +#define MAX_NR_PAGES 16777216
> +#define MAX_ELEMENTS 256
> +#define PAGES_PER_ELEMENT (MAX_NR_PAGES/MAX_ELEMENTS)
> +
> +extern u8 physnode_map[];
> +
> +static inline int pfn_to_nid(unsigned long pfn)
> +{
> +#ifdef CONFIG_NUMA
> +	return(physnode_map[(pfn) / PAGES_PER_ELEMENT]);
> +#else
> +	return 0;
> +#endif
> +}
> +
> +static inline struct pglist_data *pfn_to_pgdat(unsigned long pfn)
> +{
> +	return(NODE_DATA(pfn_to_nid(pfn)));
> +}
> +
>  
>  /*
>   * Following are macros that are specific to this numa platform.
> @@ -43,11 +85,6 @@ extern struct pglist_data *node_data[];
>   */
>  #define kvaddr_to_nid(kaddr)	pfn_to_nid(__pa(kaddr) >> PAGE_SHIFT)
>  
> -/*
> - * Return a pointer to the node data for node n.
> - */
> -#define NODE_DATA(nid)		(node_data[nid])
> -
>  #define node_mem_map(nid)	(NODE_DATA(nid)->node_mem_map)
>  #define node_start_pfn(nid)	(NODE_DATA(nid)->node_start_pfn)
>  #define node_end_pfn(nid)						\
> @@ -93,40 +130,6 @@ extern struct pglist_data *node_data[];
>   */ 
>  #define pfn_valid(pfn)          ((pfn) < num_physpages)
>  
> -/*
> - * generic node memory support, the following assumptions apply:
> - *
> - * 1) memory comes in 256Mb contigious chunks which are either present or not
> - * 2) we will not have more than 64Gb in total
> - *
> - * for now assume that 64Gb is max amount of RAM for whole system
> - *    64Gb / 4096bytes/page = 16777216 pages
> - */
> -#define MAX_NR_PAGES 16777216
> -#define MAX_ELEMENTS 256
> -#define PAGES_PER_ELEMENT (MAX_NR_PAGES/MAX_ELEMENTS)
> -
> -extern u8 physnode_map[];
> -
> -static inline int pfn_to_nid(unsigned long pfn)
> -{
> -	return(physnode_map[(pfn) / PAGES_PER_ELEMENT]);
> -}
> -static inline struct pglist_data *pfn_to_pgdat(unsigned long pfn)
> -{
> -	return(NODE_DATA(pfn_to_nid(pfn)));
> -}
> -
> -#ifdef CONFIG_X86_NUMAQ
> -#include <asm/numaq.h>
> -#elif CONFIG_ACPI_SRAT
> -#include <asm/srat.h>
> -#elif CONFIG_X86_PC
> -#define get_zholes_size(n) (0)
> -#else
> -#define pfn_to_nid(pfn)		(0)
> -#endif /* CONFIG_X86_NUMAQ */
> -
>  extern int get_memcfg_numa_flat(void );
>  /*
>   * This allows any one NUMA architecture to be compiled
> diff -purN -X /home/mbligh/.diff.exclude 276-per_node_rss/include/linux/mmzone.h 278-pfn_to_nid/include/linux/mmzone.h
> --- 276-per_node_rss/include/linux/mmzone.h	2003-10-14 15:50:34.000000000 -0700
> +++ 278-pfn_to_nid/include/linux/mmzone.h	2003-12-11 17:16:48.000000000 -0800
> @@ -303,7 +303,7 @@ extern struct pglist_data contig_page_da
>  #define NODE_DATA(nid)		(&contig_page_data)
>  #define NODE_MEM_MAP(nid)	mem_map
>  #define MAX_NODES_SHIFT		0
> -
> +#define pfn_to_nid(pfn)		(0)
>  #else /* CONFIG_DISCONTIGMEM */
>  
>  #include <asm/mmzone.h>
> 
> 



^ permalink raw reply	[flat|nested] 8+ messages in thread

* Re: [TRIVIAL PATCH] Ensure pfn_to_nid() is always defined for i386
  2003-12-23  0:26 ` Martin J. Bligh
                     ` (2 preceding siblings ...)
  2004-03-29 15:45   ` Matthew Dobson
@ 2004-03-29 15:45   ` Mike Fedyk
  3 siblings, 0 replies; 8+ messages in thread
From: Mike Fedyk @ 2004-03-29 15:45 UTC (permalink / raw)
  To: Administrator; +Cc: colpatch, linux-kernel, Andrew Morton

On Mon, Dec 22, 2003 at 04:26:40PM -0800, Martin J. Bligh wrote:
> + * for now assume that 64Gb is max amount of RAM for whole system
> + *    64Gb / 4096bytes/page = 16777216 pages
> + */
> +#define MAX_NR_PAGES 16777216
> +#define MAX_ELEMENTS 256
> +#define PAGES_PER_ELEMENT (MAX_NR_PAGES/MAX_ELEMENTS)

Why not do the calculation in the define, and use PAGE_SIZE?

If PAGE_SIZE isn't 4k will it break the rest of this code, or will the
calculations make sence with larger PAGE_SIZE?

Might as well make it easier to go in the direction of variable PAGE_SIZE
instead of keeping the assumption.

^ permalink raw reply	[flat|nested] 8+ messages in thread

* Re: [TRIVIAL PATCH] Ensure pfn_to_nid() is always defined for i386
  2004-01-05 22:53   ` Mike Fedyk
  2004-01-05 23:15     ` Martin J. Bligh
@ 2004-03-29 15:45     ` Martin J. Bligh
  1 sibling, 0 replies; 8+ messages in thread
From: Martin J. Bligh @ 2004-03-29 15:45 UTC (permalink / raw)
  To: Administrator; +Cc: colpatch, linux-kernel, Andrew Morton

>> + * for now assume that 64Gb is max amount of RAM for whole system
>> + *    64Gb / 4096bytes/page = 16777216 pages
>> + */
>> +#define MAX_NR_PAGES 16777216
>> +#define MAX_ELEMENTS 256
>> +#define PAGES_PER_ELEMENT (MAX_NR_PAGES/MAX_ELEMENTS)
> 
> Why not do the calculation in the define, and use PAGE_SIZE?
> 
> If PAGE_SIZE isn't 4k will it break the rest of this code, or will the
> calculations make sence with larger PAGE_SIZE?
> 
> Might as well make it easier to go in the direction of variable PAGE_SIZE
> instead of keeping the assumption.

The patch is just moving the code, not changing it ;-)
But yes, that value could probably be derived instead of hardcoded.
Separate patch though.

M.


^ permalink raw reply	[flat|nested] 8+ messages in thread

end of thread, other threads:[~2004-03-29 15:45 UTC | newest]

Thread overview: 8+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2003-12-22 19:44 [TRIVIAL PATCH] Ensure pfn_to_nid() is always defined for i386 Matthew Dobson
2003-12-23  0:26 ` Martin J. Bligh
2004-01-05 21:35   ` Matthew Dobson
2004-01-05 22:53   ` Mike Fedyk
2004-01-05 23:15     ` Martin J. Bligh
2004-03-29 15:45     ` Martin J. Bligh
2004-03-29 15:45   ` Matthew Dobson
2004-03-29 15:45   ` Mike Fedyk

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