Messages in this thread |  | | Date | Tue, 8 Jan 2013 20:23:46 -0800 (PST) | From | Hugh Dickins <> | Subject | Re: oops in copy_page_rep() |
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On Tue, 8 Jan 2013, Andrea Arcangeli wrote: > > Looking at this, one thing that isn't clear is where the page_count is > checked in migrate_misplaced_transhuge_page. Ok that it's unable to > migrate anon transhuge COW shared pages so it doesn't need to mess > with rmap (the mapcount check makes it safe), but it shouldn't be > allowed to migrate memory that has gup direct-IO in flight (and that > can only be detected with a page_count vs mapcount check). Real > migrate does page_freeze_refs to be safe. Mel comments?
Yes, I protested to Mel about that before the holidays, and he quickly provided a patch, now in akpm's tree; but checking it again today, I believe it's still not quite right yet - see other mail.
Hugh
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