On 05/29/2014 10:57 AM, Christoffer Dall wrote: > 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. > Ok thanks I'm on it now. - Mario -- 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
