On Tue, Sep 30, 2014 at 12:03:06PM -0400, Rik van Riel wrote: > > What kind of CPU is the problematic machine? There was some > > question about just how architectural the whole "TLB entry causing > > a page fault gets invalidated automatically" really is. > > Intel people told me at the time that the guarantee was architectural. > I don't know whether other x86 manufacturers know this... > > Doing a local tlb flush from ptep_set_access_flags seems appropriate, > if that is indeed the issue. > > On the other hand, do_wp_page does not seem to do a tlb flush when > the old page is reused, so CPUs do get rid of inappropriate TLB > entries. We would have noticed do_wp_page not working right :) The puzzling thing is we've had that code change for two years without issue. This isn't a new machine, so why would it only be showing up bad effects now ?
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