ARM cacheflush syscall with range that spans multiple vma

[Russell King - ARM Linux]

On Sun, Jun 09, 2013 at 05:05:24PM -0700, John Reiser wrote:
> Why does the ARM cacheflush syscall stop after the lowest vma
> which intersects the user-requested range?  The range could
> span more than one vma having contiguous addresses, such as
> two files MAP_SHARED into adjacent pages; or even a region
> that contains holes (pages not present.)

Because you're not supposed to use it on large ranges because it's
an expensive operation.