Re: [PATCH v5 2/5] page_alloc: add movable_memmap kernel parameter

[Andrew Morton]

On Mon, 14 Jan 2013 17:15:22 +0800
Tang Chen <tangchen@xxxxxxxxxxxxxx> wrote:

> This patch adds functions to parse movablecore_map boot option. Since the
> option could be specified more then once, all the maps will be stored in
> the global variable movablecore_map.map array.
> 
> And also, we keep the array in monotonic increasing order by start_pfn.
> And merge all overlapped ranges.
> 
> ...
>
> +#define MOVABLECORE_MAP_MAX MAX_NUMNODES
> +struct movablecore_entry {
> +	unsigned long start_pfn;    /* start pfn of memory segment */
> +	unsigned long end_pfn;      /* end pfn of memory segment */

It is important to tell readers whether an "end" is inclusive or
exclusive.  ie: does it point at the last byte, or one beyond it?

By reading the code I see it is exclusive, so...

--- a/include/linux/mm.h~page_alloc-add-movable_memmap-kernel-parameter-fix
+++ a/include/linux/mm.h
@@ -1362,7 +1362,7 @@ extern void sparse_memory_present_with_a
 #define MOVABLECORE_MAP_MAX MAX_NUMNODES
 struct movablecore_entry {
 	unsigned long start_pfn;    /* start pfn of memory segment */
-	unsigned long end_pfn;      /* end pfn of memory segment */
+	unsigned long end_pfn;      /* end pfn of memory segment (exclusive) */
 };
 
 struct movablecore_map {

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