Subject: Re: [RFC v8 PATCH 04/20] memory-hotplug: offline and remove memory when removing the memory device

From: Andrew Morton <[email-masked]>
Date: Fri, 31 Aug 2012 13:55:14 -0700

On Tue, 28 Aug 2012 18:00:11 +0800
[email-masked] wrote:

> +int remove_memory(int nid, u64 start, u64 size)
> +{
> +	int ret = -EBUSY;
> +	lock_memory_hotplug();
> +	/*
> +	 * The memory might become online by other task, even if you offine it.
> +	 * So we check whether the cpu has been onlined or not.

I think you meant "memory", not "cpu".

Actually, "check whether any part of this memory range has been
onlined" would be better.  If that is accurate ;)

> +	 */
> +	if (!is_memblk_offline(start, size)) {
> +		pr_warn("memory removing [mem %#010llx-%#010llx] failed, "
> +			"because the memmory range is online\n",
> +			start, start + size);
> +		ret = -EAGAIN;
> +	}
> +
> +	unlock_memory_hotplug();
> +	return ret;
> +
> +}
> +EXPORT_SYMBOL_GPL(remove_memory);