On Thu, May 29, 2014 at 10:08:07AM -0700, Mario Smarduch wrote: > > >> So this needs to be cleared up given this is key to logging. > >> Cases this code handles during migration - > >> 1. huge page fault described above - write protect fault so you breakup > >> the huge page. > >> 2. All other faults - first time access, pte write protect you again wind up in > >> stage2_set_pte(). > >> > >> Am I missing something here? > >> > > > > no, I forgot about the fact that we can take the permission fault now. > > Hmm, ok, so either we need to use the original approach of always > > splitting up huge pages or we need to just follow the regular huge page > > path here and just mark all 512 4K pages dirty in the log, or handle it > > in stage2_set_pte(). > > > > I would say go with the most simple appraoch for now (which may be going > > back to splitting all pmd_huge() into regular pte's), and we can take a > > more careful look in the next patch iteration. > > > > Looking at the overall memslot update architecture and various > fail scenarios - user_mem_abort() appears to be the most > optimal and reliable place. First Write Protect huge pages after > memslots are committed and deal with rest in user_mem_abort(). > > Still need some feedback on the pud_huge() before revising for > next iteration? > Just assume it's not used for now, and that you don't have to consider it, and make that assumption clear in the commit message, so it doesn't block this work. I have a feeling we need to go through a few iterations here, so let's get that rolling. Thanks. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
