Re: [PATCH 2/4] acpi,memory-hotplug : rename remove_memory() to offline_memory()

From: KOSAKI Motohiro
Date: Thu Oct 04 2012 - 17:37:24 EST


On Wed, Oct 3, 2012 at 6:02 AM, Yasuaki Ishimatsu
<isimatu.yasuaki@xxxxxxxxxxxxxx> wrote:
> From: Yasuaki Ishimatsu <isimatu.yasuaki@xxxxxxxxxxxxxx>
>
> add_memory() hot adds a physical memory. But remove_memory does not
> hot remove a phsical memory. It only offlines memory. The name
> confuse us.
>
> So the patch renames remove_memory() to offline_memory(). We will
> use rename_memory() for hot removing memory.
>
> CC: David Rientjes <rientjes@xxxxxxxxxx>
> CC: Jiang Liu <liuj97@xxxxxxxxx>
> CC: Len Brown <len.brown@xxxxxxxxx>
> CC: Christoph Lameter <cl@xxxxxxxxx>
> Cc: Minchan Kim <minchan.kim@xxxxxxxxx>
> CC: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> CC: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
> Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@xxxxxxxxxxxxxx>
> Signed-off-by: Wen Congyang <wency@xxxxxxxxxxxxxx>
> ---
> drivers/acpi/acpi_memhotplug.c | 2 +-
> include/linux/memory_hotplug.h | 2 +-
> mm/memory_hotplug.c | 6 +++---
> 3 files changed, 5 insertions(+), 5 deletions(-)

Probably, the better way is to just remove remove_memory() and use
offline_pages().

btw, current remove_memory() pfn calculation is just buggy.


> int remove_memory(u64 start, u64 size)
> {
> unsigned long start_pfn, end_pfn;
>
> start_pfn = PFN_DOWN(start);
> end_pfn = start_pfn + PFN_DOWN(size);

It should be:

start_pfn = PFN_DOWN(start);
end_pfn = PFN_UP(start + size)

or

start_pfn = PFN_UP(start);
end_pfn = PFN_DOWN(start + size)
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