Re: [RFC][PATCH] zone config patch set [2/2] CONFIG_ZONE_MOVABLE

[mel@skynet.ie (Mel Gorman)]

On (21/07/07 16:03), KAMEZAWA Hiroyuki didst pronounce:
> 
> Makes ZONE_MOVABLE as configurable
> 
> Based on "zone_ifdef_cleanup_by_renumbering.patch"
> 
> Signed-Off-By: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
> 
> 
> 
> ---
>  include/linux/gfp.h    |    3 ++-
>  include/linux/mmzone.h |   11 +++++++----
>  include/linux/vmstat.h |   13 +++++++++++--
>  mm/Kconfig             |   13 +++++++++++++
>  mm/page_alloc.c        |    6 ++++++
>  mm/vmstat.c            |    8 +++++++-
>  6 files changed, 46 insertions(+), 8 deletions(-)
> 
> Index: linux-2.6.22-rc6-mm1/include/linux/mmzone.h
> ===================================================================
> --- linux-2.6.22-rc6-mm1.orig/include/linux/mmzone.h
> +++ linux-2.6.22-rc6-mm1/include/linux/mmzone.h
> @@ -177,7 +177,9 @@ enum zone_type {
>  	 */
>  	ZONE_HIGHMEM,
>  #endif
> +#ifdef CONFIG_ZONE_MOVABLE
>  	ZONE_MOVABLE,
> +#endif
>  	MAX_NR_ZONES,
>  #ifndef CONFIG_ZONE_DMA
>  	ZONE_DMA,
> @@ -188,6 +190,9 @@ enum zone_type {
>  #ifndef CONFIG_HIGHMEM
>  	ZONE_HIGHMEM,
>  #endif
> +#ifndef CONFIG_ZONE_MOVABLE
> +	ZONE_MOVABLE,
> +#endif
>  	MAX_POSSIBLE_ZONES,
>  };
>  
> @@ -567,11 +572,9 @@ static inline int zone_idx_is(enum zone_
>  
>  static inline int zone_movable_is_highmem(void)
>  {
> -#if CONFIG_ARCH_POPULATES_NODE_MAP
> -	if (is_configured_zone(ZONE_HIGHMEM))
> -		return movable_zone == ZONE_HIGHMEM;
> -#endif
> -	return 0;
> +	return is_configured_zone(ZONE_HIGHMEM) &&
> +	       is_configured_zone(ZONE_MOVABLE) &&
> +		(movable_zone == ZONE_HIGHMEM);
>  }

I think this should remain inside the check for
CONFIG_ARCH_POPULATES_NODE_MAP . movable_zone is not defined if it is
not set. While this works with a cross-compiler for ARM (doesn't use
CONFIG_ARCH_POPULATES_NODE_MAP), it's because the optimiser is getting
rid of the references as opposed to the code being correct.

>  
>  static inline int is_highmem_idx(enum zone_type idx)
> Index: linux-2.6.22-rc6-mm1/include/linux/gfp.h
> ===================================================================
> --- linux-2.6.22-rc6-mm1.orig/include/linux/gfp.h
> +++ linux-2.6.22-rc6-mm1/include/linux/gfp.h
> @@ -122,7 +122,8 @@ static inline enum zone_type gfp_zone(gf
>  	if (is_configured_zone(ZONE_DMA32) && (flags & __GFP_DMA32))
>  		return ZONE_DMA32;
>  
> -	if ((flags & (__GFP_HIGHMEM | __GFP_MOVABLE)) ==
> +	if (is_configured_zone(ZONE_MOVABLE) &&
> +	    (flags & (__GFP_HIGHMEM | __GFP_MOVABLE)) ==
>  			(__GFP_HIGHMEM | __GFP_MOVABLE))
>  		return ZONE_MOVABLE;
>  
> Index: linux-2.6.22-rc6-mm1/mm/Kconfig
> ===================================================================
> --- linux-2.6.22-rc6-mm1.orig/mm/Kconfig
> +++ linux-2.6.22-rc6-mm1/mm/Kconfig
> @@ -112,6 +112,19 @@ config SPARSEMEM_EXTREME
>  	def_bool y
>  	depends on SPARSEMEM && !SPARSEMEM_STATIC
>  
> +
> +config ZONE_MOVABLE
> +	bool	"A zone for movable pages"
> +	depends on ARCH_POPULATES_NODE_MAP
> +	help
> +	  Allows creating a zone type only for movable pages, i.e page cache

e.g. instead of i.e. here

i.e. implies that only page cache and anonymous memory can use the zone.
e.g. implies that page cache and anonymous memory are just two types
that can use it.

> +	  and anonymous memory. Because movable pages are to end to be easily

Because movable pages are easily reclaimed .....

> +	  reclaimed and page migration technique can move them, your chance
> +	  for allocating big size memory will be better in this zone than

allocating contiguous memory such as huge pages will be better ....

> +  	  other zones.
> +	  To use this zone, please see "kernelcore=" or "movablecore=" in
> +	  Documentation/kernel-parameters.txt
> +
>  # eventually, we can have this option just 'select SPARSEMEM'
>  config MEMORY_HOTPLUG
>  	bool "Allow for memory hot-add"
> Index: linux-2.6.22-rc6-mm1/mm/page_alloc.c
> ===================================================================
> --- linux-2.6.22-rc6-mm1.orig/mm/page_alloc.c
> +++ linux-2.6.22-rc6-mm1/mm/page_alloc.c
> @@ -86,7 +86,9 @@ int sysctl_lowmem_reserve_ratio[MAX_NR_Z
>  #ifdef CONFIG_HIGHMEM
>  	 32,
>  #endif
> +#ifdef CONFIG_ZONE_MOVABLE
>  	 32,
> +#endif
>  };
>  
>  EXPORT_SYMBOL(totalram_pages);
> @@ -3883,6 +3885,10 @@ static int __init cmdline_parse_kernelco
>  	if (!p)
>  		return -EINVAL;
>  
> +	if (!is_configured_zone(ZONE_MOVABLE)) {
> +		printk ("ZONE_MOVABLE is not configured, kernelcore= is ignored.\n");
> +		return 0;
> +	}

This is a good check but bear in mind that in 2.6.23-rc1, this block of
code looks different and there is both cmdline_parse_kernelcore() and
cmdline_parse_movablecore().

>  	coremem = memparse(p, &p);
>  	required_kernelcore = coremem >> PAGE_SHIFT;
>  
> Index: linux-2.6.22-rc6-mm1/mm/vmstat.c
> ===================================================================
> --- linux-2.6.22-rc6-mm1.orig/mm/vmstat.c
> +++ linux-2.6.22-rc6-mm1/mm/vmstat.c
> @@ -694,8 +694,14 @@ const struct seq_operations pagetypeinfo
>  #define TEXT_FOR_HIGHMEM(xx)
>  #endif
>  
> +#ifdef CONFIG_ZONE_MOVABLE
> +#define TEXT_FOR_MOVABLE(xx) xx "_movable",
> +#else
> +#define TEXT_FOR_MOVABLE(xx)
> +#endif
> +
>  #define TEXTS_FOR_ZONES(xx) TEXT_FOR_DMA(xx) TEXT_FOR_DMA32(xx) xx "_normal", \
> -					TEXT_FOR_HIGHMEM(xx) xx "_movable",
> +					TEXT_FOR_HIGHMEM(xx) xx TEXT_FOR_MOVABLE(xx)
>  
>  static const char * const vmstat_text[] = {
>  	/* Zoned VM counters */
> Index: linux-2.6.22-rc6-mm1/include/linux/vmstat.h
> ===================================================================
> --- linux-2.6.22-rc6-mm1.orig/include/linux/vmstat.h
> +++ linux-2.6.22-rc6-mm1/include/linux/vmstat.h
> @@ -25,7 +25,14 @@
>  #define HIGHMEM_ZONE(xx)
>  #endif
>  
> -#define FOR_ALL_ZONES(xx) DMA_ZONE(xx) DMA32_ZONE(xx) xx##_NORMAL HIGHMEM_ZONE(xx) , xx##_MOVABLE
> +#ifdef CONFIG_ZONE_MOVABLE
> +#define MOVABLE_ZONE(xx) , xx##_MOVABLE
> +#else
> +#define MOVABLE_ZONE(xx)
> +#endif
> +
> +
> +#define FOR_ALL_ZONES(xx) DMA_ZONE(xx) DMA32_ZONE(xx) xx##_NORMAL HIGHMEM_ZONE(xx) MOVABLE_ZONE(xx)
>  
>  enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT,
>  		FOR_ALL_ZONES(PGALLOC),
> @@ -170,7 +177,9 @@ static inline unsigned long node_page_st
>  	if (is_configured_zone(ZONE_HIGHMEM))
>  		val += zone_page_state(&zones[ZONE_HIGHMEM], item);
>  
> -	val += zone_page_state(&zones[ZONE_MOVABLE], item);
> +	if (is_configured_zone(ZONE_MOVABLE))
> +		val += zone_page_state(&zones[ZONE_MOVABLE], item);
> +
>  	return val;
>  }
>  

-- 
-- 
Mel Gorman
Part-time Phd Student                          Linux Technology Center
University of Limerick                         IBM Dublin Software Lab

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