Re: [PATCH 1/6] freepgt: free_pgtables use vma list

[Nick Piggin <nickpiggin@yahoo.com.au>]

Hugh Dickins wrote:

> And the range to sparc64's flush_tlb_pgtables?  It's less clear to me
> now that we need to do more than is done here - every PMD_SIZE ever
> occupied will be flushed, do we really have to flush every PGDIR_SIZE
> ever partially occupied?  A shame to complicate it unnecessarily.

It looks like sparc64 is the only user of this, so it is up to
you Dave.

I don't think I'd be able to decipher how sparc64 implements this.

I think Hugh and I interpreted your message different ways.

So, to make the question more concrete: if a pgd_t is freed due
to freeing the single pmd_t contained within it (which was the
only part of the pgd's address space that contained a valid mapping)
Then do you need the full PGDIR_SIZE width passed to
flush_tlb_pgtables, or just the PMD_SIZE'd start,end that covered
the freed pmd_t?