Re: [PATCH 09/10] memory-hotplug: enable memory hotplug to handle hugepage

["Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>]

Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> writes:

> +/* Returns true for head pages of in-use hugepages, otherwise returns false. */
> +bool is_hugepage_movable(struct page *hpage)
> +{
> +	struct page *page;
> +	struct hstate *h;
> +	bool ret = false;
> +
> +	VM_BUG_ON(!PageHuge(hpage));
> +	/*
> +	 * This function can be called for a tail page because memory hotplug
> +	 * scans movability of pages by pfn range of a memory block.
> +	 * Larger hugepages (1GB for x86_64) are larger than memory block, so
> +	 * the scan can start at the tail page of larger hugepages.
> +	 * 1GB hugepage is not movable now, so we return with false for now.
> +	 */
> +	if (PageTail(hpage))
> +		return false;
> +	h = page_hstate(hpage);
> +	spin_lock(&hugetlb_lock);
> +	list_for_each_entry(page, &h->hugepage_activelist, lru)
> +		if (page == hpage) {
> +			ret = true;
> +			break;
> +		}
> +	spin_unlock(&hugetlb_lock);
> +	return ret;
> +}
> +

May be is_hugepage_active() ?


-aneesh

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