Re: [PATCH 3/3] hugetlb-allow-huge-page-mappings-to-be-created-without-reservations

[Andrew Morton <akpm@linux-foundation.org>]

On Wed, 28 May 2008 00:10:06 +0100 Andy Whitcroft <apw@shadowen.org> wrote:

> +		unsigned long idx = ((addr - vma->vm_start) >> HPAGE_SHIFT) +
> +				(vma->vm_pgoff >> (HPAGE_SHIFT - PAGE_SHIFT));
> +		return region_chg(&inode->i_mapping->private_list,
> +							idx, idx + 1);
> +
> +	} else {
> +		if (!is_vma_resv_set(vma, HPAGE_RESV_OWNER))
> +			return 1;
> +	}
> +
> +	return 0;
> +}
> +static void vma_commit_reservation(struct vm_area_struct *vma,
> +							unsigned long addr)
> +{
> +	struct address_space *mapping = vma->vm_file->f_mapping;
> +	struct inode *inode = mapping->host;
> +
> +	if (vma->vm_flags & VM_SHARED) {
> +		unsigned long idx = ((addr - vma->vm_start) >> HPAGE_SHIFT) +
> +				(vma->vm_pgoff >> (HPAGE_SHIFT - PAGE_SHIFT));
> +		region_add(&inode->i_mapping->private_list, idx, idx + 1);

There are a couple more users of the little helper function which I
suggested that Mel add.

They both use ulong too - I do think that pgoff_t has a little
documentary value.

I guess these changes impact the manpages, but the mmap manpage doesn't
seem to know about huge pages at all.

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