[PATCH] release memory regions in PAGES_PER_SECTION chunks

[PATCH] release memory regions in PAGES_PER_SECTION chunks

[Nathan Fontenot]

During hotplug memory remove, memory regions should be released
on a PAGES_PER_SECTION size chunks.  This mirrors the code in
add_memory where resources are requested on a PAGES_PER_SECTION size.

Attempting to release the entire memory region fails because there is
not a single resource for the total number of pages being removed.
Instead the resources for the pages are split in PAGES_PER_SECTION
size chunks as requested during memory add.

Signed-off-by: Nathan Fontenot <nfont@austin.ibm.com>
Signed-off-by: Badari Pulavarty <pbadari@us.ibm.com>

---

Index: linux-2.6/mm/memory_hotplug.c
===================================================================
--- linux-2.6.orig/mm/memory_hotplug.c	2008-10-13 12:00:46.000000000 -0500
+++ linux-2.6/mm/memory_hotplug.c	2008-10-13 14:29:31.000000000 -0500
@@ -323,11 +323,11 @@
 	BUG_ON(phys_start_pfn & ~PAGE_SECTION_MASK);
 	BUG_ON(nr_pages % PAGES_PER_SECTION);
 
-	release_mem_region(phys_start_pfn << PAGE_SHIFT, nr_pages * PAGE_SIZE);
-
 	sections_to_remove = nr_pages / PAGES_PER_SECTION;
 	for (i = 0; i < sections_to_remove; i++) {
 		unsigned long pfn = phys_start_pfn + i*PAGES_PER_SECTION;
+		release_mem_region(pfn << PAGE_SHIFT,
+				   PAGES_PER_SECTION << PAGE_SHIFT);
 		ret = __remove_section(zone, __pfn_to_section(pfn));
 		if (ret)
 			break;

Re: [PATCH] release memory regions in PAGES_PER_SECTION chunks

[Yasunori Goto]

Good catch.
Looks good to me.

Acked-by: Yasunori Goto <y-goto@jp.fujitsu.com>

> During hotplug memory remove, memory regions should be released
> on a PAGES_PER_SECTION size chunks.  This mirrors the code in
> add_memory where resources are requested on a PAGES_PER_SECTION size.
> 
> Attempting to release the entire memory region fails because there is
> not a single resource for the total number of pages being removed.
> Instead the resources for the pages are split in PAGES_PER_SECTION
> size chunks as requested during memory add.
> 
> Signed-off-by: Nathan Fontenot <nfont@austin.ibm.com>
> Signed-off-by: Badari Pulavarty <pbadari@us.ibm.com>
> 
> ---
> 
> Index: linux-2.6/mm/memory_hotplug.c
> ===================================================================
> --- linux-2.6.orig/mm/memory_hotplug.c	2008-10-13 12:00:46.000000000 -0500
> +++ linux-2.6/mm/memory_hotplug.c	2008-10-13 14:29:31.000000000 -0500
> @@ -323,11 +323,11 @@
>  	BUG_ON(phys_start_pfn & ~PAGE_SECTION_MASK);
>  	BUG_ON(nr_pages % PAGES_PER_SECTION);
>  
> -	release_mem_region(phys_start_pfn << PAGE_SHIFT, nr_pages * PAGE_SIZE);
> -
>  	sections_to_remove = nr_pages / PAGES_PER_SECTION;
>  	for (i = 0; i < sections_to_remove; i++) {
>  		unsigned long pfn = phys_start_pfn + i*PAGES_PER_SECTION;
> +		release_mem_region(pfn << PAGE_SHIFT,
> +				   PAGES_PER_SECTION << PAGE_SHIFT);
>  		ret = __remove_section(zone, __pfn_to_section(pfn));
>  		if (ret)
>  			break;
> --
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-- 
Yasunori Goto