On Tue, Jan 29, 2008 at 06:28:05PM -0600, Jack Steiner wrote: > On Tue, Jan 29, 2008 at 04:20:50PM -0800, Christoph Lameter wrote: > > On Wed, 30 Jan 2008, Andrea Arcangeli wrote: > > > > > > invalidate_range after populate allows access to memory for which ptes > > > > were zapped and the refcount was released. > > > > > > The last refcount is released by the invalidate_range itself. > > > > That is true for your implementation and to address Robin's issues. Jack: > > Is that true for the GRU? > > I'm not sure I understand the question. The GRU never (currently) takes > a reference on a page. It has no mechanism for tracking pages that > were exported to the external TLBs.
If you don't have a pin, then things like invalidate_range in remap_file_pages can't be safe as writes through the external TLBs can keep going on pages in the freelist. For you to be safe w/o a page-pin, you need to return in the direction of invalidate_page inside ptep_clear_flush (or anyway before page_cache_release/__free_page/put_page...). You're generally not safe with any invalidate_range that may run after the page pointed by the pte has been freed (or can be freed by the VM anytime because of being unpinned cache). ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ kvm-devel mailing list kvm-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/kvm-devel
