Re: memory-hotplug : suppres "Trying to free nonexistent resource <XXXXXXXXXXXXXXXX-YYYYYYYYYYYYYYYY>" warning

[KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>]

CC to Dave Hanse.

Hello Dave,

I think following patch works both x86 and ppc. but I'm not ppc
expert. So I'm glad
if you double check it.

thank you.


<intentional full quote>

> When our x86 box calls __remove_pages(), release_mem_region() shows
> many warnings. And x86 box cannot unregister iomem_resource.
>
> "Trying to free nonexistent resource <XXXXXXXXXXXXXXXX-YYYYYYYYYYYYYYYY>"
>
> release_mem_region() has been changed as called in each PAGES_PER_SECTION
> chunk since applying a patch(de7f0cba96786c). Because powerpc registers
> iomem_resource in each PAGES_PER_SECTION chunk. But when I hot add memory
> on x86 box, iomem_resource is register in each _CRS not PAGES_PER_SECTION
> chunk. So x86 box unregisters iomem_resource.
>
> The patch fixes the problem.
>
> CC: David Rientjes <rientjes@google.com>
> CC: Jiang Liu <liuj97@gmail.com>
> CC: Len Brown <len.brown@intel.com>
> CC: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> CC: Paul Mackerras <paulus@samba.org>
> CC: Christoph Lameter <cl@linux.com>
> Cc: Minchan Kim <minchan.kim@gmail.com>
> CC: Andrew Morton <akpm@linux-foundation.org>
> CC: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
> CC: Wen Congyang <wency@cn.fujitsu.com>
> Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
> ---
>  arch/powerpc/platforms/pseries/hotplug-memory.c |   13 +++++++++----
>  mm/memory_hotplug.c                             |    4 ++--
>  2 files changed, 11 insertions(+), 6 deletions(-)
>
> Index: linux-3.6/arch/powerpc/platforms/pseries/hotplug-memory.c
> ===================================================================
> --- linux-3.6.orig/arch/powerpc/platforms/pseries/hotplug-memory.c      2012-10-04 14:22:59.833520792 +0900
> +++ linux-3.6/arch/powerpc/platforms/pseries/hotplug-memory.c   2012-10-04 14:23:05.150521411 +0900
> @@ -77,7 +77,8 @@ static int pseries_remove_memblock(unsig
>  {
>         unsigned long start, start_pfn;
>         struct zone *zone;
> -       int ret;
> +       int i, ret;
> +       int sections_to_remove;
>
>         start_pfn = base >> PAGE_SHIFT;
>
> @@ -97,9 +98,13 @@ static int pseries_remove_memblock(unsig
>          * to sysfs "state" file and we can't remove sysfs entries
>          * while writing to it. So we have to defer it to here.
>          */
> -       ret = __remove_pages(zone, start_pfn, memblock_size >> PAGE_SHIFT);
> -       if (ret)
> -               return ret;
> +       sections_to_remove = (memblock_size >> PAGE_SHIFT) / PAGES_PER_SECTION;
> +       for (i = 0; i < sections_to_remove; i++) {
> +               unsigned long pfn = start_pfn + i * PAGES_PER_SECTION;
> +               ret = __remove_pages(zone, start_pfn,  PAGES_PER_SECTION);
> +               if (ret)
> +                       return ret;
> +       }
>
>         /*
>          * Update memory regions for memory remove
> Index: linux-3.6/mm/memory_hotplug.c
> ===================================================================
> --- linux-3.6.orig/mm/memory_hotplug.c  2012-10-04 14:22:59.829520788 +0900
> +++ linux-3.6/mm/memory_hotplug.c       2012-10-04 14:23:25.860527278 +0900
> @@ -362,11 +362,11 @@ int __remove_pages(struct zone *zone, un
>         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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