Re: mmu_notifier: invalidate_range for move_page_tables

[Christoph Lameter]

On Thu, 31 Jan 2008, Robin Holt wrote:

> On Thu, Jan 31, 2008 at 05:57:25PM -0800, Christoph Lameter wrote:
> > Move page tables also needs to invalidate the external references
> > and hold new references off while moving page table entries.
> 
> I must admit to not having spent any time thinking about this, but aren't
> we moving the entries from one set of page tables to the other, leaving
> the pte_t entries unchanged.  I guess I should go look, but could you
> provide a quick pointer in the proper direction as to why we need to
> recall externals when the before and after look of these page tables
> will have the same information for the TLBs.

remap changes the address of pages in a process. The pages appear at 
another address. Thus the external pte will have the wrong information if 
not invalidated.

Do a

man mremap


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