Messages in this thread | | | Date | Tue, 22 Mar 2005 17:33:22 +1100 | From | Nick Piggin <> | Subject | Re: [PATCH 1/5] freepgt: free_pgtables use vma list |
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Hugh Dickins wrote: > On Mon, 21 Mar 2005, David S. Miller wrote: > >>On Tue, 22 Mar 2005 15:14:54 +1100 >>Nick Piggin <nickpiggin@yahoo.com.au> wrote: >> >> >>>Question, Dave: flush_tlb_pgtables after Hugh's patch is also >>>possibly not being called with enough range to cover all page >>>tables that have been freed. > > > Good question from Nick. > > >>>For example, you may have a single page (start,end) address range >>>to free, but if this is enclosed by a large enough (floor,ceiling) >>>then it may free an entire pgd entry. >>> >>>I assume the intention of the API would be to provide the full >>>pgd width in that case? >> >>It just wants the range of page tables liberated. I guess >>essentially PMD_SIZE is the granularity. > > > I _think_ that answer means that my current code is fine in this respect. > But I'm not entirely convinced. Since sparc64 is the only architecture > which implements a flush_tlb_pgtables which actually uses start,end, > we do need to suit your needs there - informed reassurance welcome! >
But Hugh I think you may still be freeing pgd (PGDIR_SIZE) regions that you don't quite cover with flush_tlb_pgtables?
I would have thought you'd need something like this:
if (!tlb_is_full_mm(tlb)) { /* This is the full range of page tables we could possibly free */ start = max(start & PGDIR_SIZE, (floor + PMD_SIZE - 1) & PMD_SIZE); end = min((end + PGDIR_SIZE - 1) & PGDIR_SIZE, ceiling & PMD_SIZE); flush_tlb_pgtables(tlb->mm, start, end); }
But I'll have to go away and look at it more...
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