Re: [RFC][PATCH 1/3] contigous big page allocator

[KOSAKI Motohiro]

> 
> No big change since the previous version but divided into 3 patches.
> This patch is based onto mmotm-1008 and just works, IOW, mot tested in
> very-bad-situation.
> 
> What this wants to do: 
>   allocates a contiguous chunk of pages larger than MAX_ORDER.
>   for device drivers (camera? etc..)
>   My intention is not for allocating HUGEPAGE(> MAX_ORDER).
>   
> What this does:
>   allocates a contiguous chunk of page with page migration,
>   based on memory hotplug codes. (memory unplug is for isolating
>   a chunk of page from buddy allocator.)
> 
> Consideration:
>   Maybe more codes can be shared with other functions
>   (memory hotplug, compaction..)
> 
> Status:
>   Maybe still needs more updates, works on small test.
>   [1/3] ... move some codes from memory hotplug. (no functional changes)
>   [2/3] ... a code for searching contiguous pages.
>   [3/3] ... a code for allocating contig memory.
> 
> Thanks,
> -Kame
> ==
> 
> From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
> 
> Memory hotplug is a logic for making pages unused in the specified range
> of pfn. So, some of core logics can be used for other purpose as
> allocating a very large contigous memory block.
> 
> This patch moves some functions from mm/memory_hotplug.c to
> mm/page_isolation.c. This helps adding a function for large-alloc in
> page_isolation.c with memory-unplug technique.
> 
> 
> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
> ---
>  include/linux/page-isolation.h |    7 ++
>  mm/memory_hotplug.c            |  109 ---------------------------------------
>  mm/page_isolation.c            |  114 +++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 121 insertions(+), 109 deletions(-)
> 
> Index: mmotm-1008/include/linux/page-isolation.h
> ===================================================================
> --- mmotm-1008.orig/include/linux/page-isolation.h
> +++ mmotm-1008/include/linux/page-isolation.h
> @@ -33,5 +33,12 @@ test_pages_isolated(unsigned long start_
>  extern int set_migratetype_isolate(struct page *page);
>  extern void unset_migratetype_isolate(struct page *page);
>  
> +/*
> + * For migration.
> + */
> +
> +int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn);
> +int scan_lru_pages(unsigned long start, unsigned long end);

offtopic: scan_lru_pages() return type should be unsined long. it return
pfn.




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