On 15/06/15 21:35, Ingo Molnar wrote: > > * David Vrabel <david.vrabel@xxxxxxxxxx> wrote: > >> On 15/06/15 10:05, Ian Campbell wrote: >>> On Sat, 2015-06-13 at 11:49 +0200, Ingo Molnar wrote: > >>>> xen_mm_pin_all()/unpin_all() are used to implement full guest instance >>>> suspend/restore. It's a stop-all method that needs to iterate through all >>>> allocated pgds in the system to fix them up for Xen's use. >>>> >>>> This code uses pgd_list, probably because it was an easy interface. >>>> >>>> But we want to remove the pgd_list, so convert the code over to walk all >>>> tasks in the system. This is an equivalent method. >> >> It is not equivalent because pgd_alloc() now populates entries in pgds that are >> not visible to xen_mm_pin_all() (note how the original code adds the pgd to the >> pgd_list in pgd_ctor() before calling pgd_prepopulate_pmd()). These newly >> allocated page tables won't be correctly converted on suspend/resume and the new >> process will die after resume. > > So how should the Xen logic be fixed for the new scheme? I can't say I can see > through the paravirt complexity here. Actually, since we freeze_processes() before trying to pin page tables, I think it should be ok as-is. I'll put the patch through some tests. David -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>