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

From: Andrew Morton
Date: Wed May 28 2008 - 21:53:26 EST


On Wed, 28 May 2008 00:10:06 +0100 Andy Whitcroft <apw@xxxxxxxxxxxx> 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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