On Wed, Oct 24, 2018 at 07:13:50PM -0700, Joel Fernandes wrote:

On Wed, Oct 24, 2018 at 10:57:33PM +1100, Balbir Singh wrote:
[...]

quoted

quoted

quoted

+		pmd_t pmd;
+
+		new_ptl = pmd_lockptr(mm, new_pmd);

Looks like this is largely inspired by move_huge_pmd(), I guess a lot of
the code applies, why not just reuse as much as possible? The same comments
w.r.t mmap_sem helping protect against lock order issues applies as well.

I thought about this and when I looked into it, it seemed there are subtle
differences that make such sharing not worth it (or not possible).

Could you elaborate on them?

Thanks,
Balbir Singh.