2008-10-13 20:22:36

by Nathan Fontenot

Subject: [PATCH] release memory regions in PAGES_PER_SECTION chunks

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 <[email protected]>
Signed-off-by: Badari Pulavarty <[email protected]>

---

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;

2008-10-14 12:00:18

by Yasunori Goto

Subject: Re: [PATCH] release memory regions in PAGES_PER_SECTION chunks

Good catch.
Looks good to me.

Acked-by: Yasunori Goto <[email protected]>

> 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 <[email protected]>
> Signed-off-by: Badari Pulavarty <[email protected]>
>
> ---
>
> 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