On Wed, 2013-02-20 at 23:29 +0100, Rafael J. Wysocki wrote: > On Wednesday, February 20, 2013 02:50:12 PM Toshi Kani wrote: > > On Wed, 2013-02-20 at 11:42 +0100, Vasilis Liaskovitis wrote: > > > Hi Yasuaki, > > > > > > On Wed, Feb 20, 2013 at 12:35:48PM +0900, Yasuaki Ishimatsu wrote: > > > > Hi Vasilis, > > > > > > > > 2013/02/20 3:11, Vasilis Liaskovitis wrote: > > > > >Hi, > > > > > > > > > >On Sun, Feb 17, 2013 at 04:27:18PM +0100, Rafael J. Wysocki wrote: > > > > >>From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> > > > > >> > > > > >>Make the ACPI memory hotplug driver use struct acpi_scan_handler > > > > >>for representing the object used to set up ACPI memory hotplug > > > > >>functionality and to remove hotplug memory ranges and data > > > > >>structures used by the driver before unregistering ACPI device > > > > >>nodes representing memory. Register the new struct acpi_scan_handler > > > > >>object with the help of acpi_scan_add_handler_with_hotplug() to allow > > > > >>user space to manipulate the attributes of the memory hotplug > > > > >>profile. > > > > > > > > > >Let's consider an example where we want acpi memory device ejection to be safely > > > > >handled by userspace. We do the following: > > > > > > > > > >echo 0 > /sys/firmware/acpi/hotplug/memory/autoeject > > > > >echo 1 > /sys/firmware/acpi/hotplug/memory/uevents > > > > > > > > > >We succesfully hotplug acpi device: > > > > >/sys/devices/LNXSYSTM:00/LNXSYSBUS:00/PNP0C80:00 > > > > >and its corresponding memblocks /sys/devices/system/memory/memoryXX are > > > > >also successfully onlined. > > > > > > > > > >On an eject request, since uevents == 1, the kernel will emit KOBJ_OFFLINE for: > > > > >/sys/devices/LNXSYSTM:00/LNXSYSBUS:00/PNP0C80:00 > > > > > > > > > >Can userspace know which memblocks in /sys/devices/system/memory/memoryXX/ > > > > >correspond to the acpi device /sys/devices/LNXSYSTM:00/LNXSYSBUS:00/PNP0C80:00 ? > > > > >This will be needed so that userspace tries to offline the memblocks (and only > > > > >if successful, issue the eject operation on the acpi device). As far as I see, > > > > >we don't create any sysfs links or files for this scenario - can userspace get > > > > >this info somehow? > > > > > > > > > > > > > >/sys/devices/system/memory/memoryXX/phys_device needs to be properly implemented > > > > >for this to work I think, see Documentation/ABI/testing/sysfs-memory > > > > > > > > > >The following test patch works toward that direction. Let me know if it's of > > > > >interest or if there are better ideas /comments. > > > > > > > > How about use ../PNP0C80:00/physical_node/resources file? > > > > In my system, the file shows following information. > > > > > > > > $ cat /sys/bus/acpi/devices/PNP0C80\:00/physical_node/resources > > > > state = active > > > > mem 0x0-0x80000000 > > > > mem 0x100000000-0x800000000 > > > > > > > > It means PNP0C80:00's memory ranges are "0x0-0x7fffffff" and > > > > "0x100000000-0x7ffffffff". In x86 architecture, memory section size is > > > > 128MiB. So, if these memory range is divided by 128MiB, you can > > > > calculate memory section number as follow: > > > > > > > > 0x0-0x7fffffff => 0x0-0x10 > > > > 0x100000000-0x7ffffffff => 0x20-0xff > > > > > > > > But there is one problem. The problem is that resources file of added memory > > > > is not created. If the problem is fixed, I think you can use the way. > > > > > > thanks for your suggestion. Is this resources file a property of the > > > physical_node or of each acpi devices? > > > > > > If it's a node specific file could there be a chance that adjacent memory > > > ranges get merged? We 'd like these to not get merged. > > > > > > I will look more into this property. I don't see it currently in my system > > > (probably because initial memory is not backed by acpi devices in my > > > seabios/virtual machine). > > > > I have been thinking about this issue as well. In case of CPUs, we have > > a sysdev link that links LNXCPU:%d to its system/cpu/cpu%d file. > > > > /sys/bus/acpi/devices/LNXCPU:02 > ll sysdev > > lrwxrwxrwx. 1 root root 0 Feb 8 13:52 sysdev -> ../../system/cpu/cpu2 > > > > So, one possible approach is to create a sysdev directory under > > PNP0C080:%d, and then create links to associated system/cpu/memory%d > > files underneath. What do you think? > > I need to think about that a bit more, quite frankly. > > I probably would prefer links to be created directly from under PNP0C080:%d > to system/cpu/memory%d (in analogy with PCI and other devices having ACPI > companions). > > One of the problems here is that the whole /sys/bus/acpi/ stuff is kind of > confusing, because it makes people think that there's an "ACPI bus", while > there's no such thing. For this reason, it should go away and the > /sys/devices/LNXSYSTM:00/ directory should be moved somewhere under > /sys/firmware/acpi/. Of course, that's long-term, but this means I'd prefer > not to add more stuff under /sys/devices/LNXSYSTM:00/ that may potentially > cause that to be more difficult to do in the future. I see. I think PCI creates files under PNP0A08:%d/physical_node. Either way, we need to do something in this space. I will think about a bit more as well. Thanks, -Toshi -- 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
