David Vrabel <david.vrabel@xxxxxxxxxx> writes: > On 07/01/16 17:23, Vitaly Kuznetsov wrote: >> >> - Changes since 'v1': >> Add 'online' parameter to add_memory_resource() as it is being used by >> xen ballon driver and it adds "empty" memory pages [David Vrabel]. >> (I don't completely understand what prevents manual onlining in this >> case as we still have all newly added blocks in sysfs ... this is the >> discussion point.) > (there is a discussion with Daniel on the same topic in a parallel thread) > I'm not sure what you're not understanding here? > > Memory added by the Xen balloon driver (whether populated with real > memory or not) does need to be onlined by udev or similar. Yes, same as all other memory hotplug mechanisms (hyper-v's balloon driver and acpi memory hotplug). My patch adds an option to make this happen automatically. Xen driver is currently excluded because of a deadlock. If this deadlock is the only problem we can easily change taking the lock to checking that the lock was taken (and taking in case it wasn't) or something similar and everything is going to work. From briefly looking at the code it seems to me it's going to work. What I wasn't sure about is 'empty pages' you were mentioning. In case there are some pages we can't online there should be a protection mechanism actively preventing them from going online (similar to hv_online_page() in Hyper-V driver) as this patch does nothing 'special' compared to udev onlining newly added blocks. -- Vitaly -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
