On Thu, 2012-11-08 at 19:04 +0800, Wen Congyang wrote: > The memory device can be removed by 2 ways: > 1. send eject request by SCI > 2. echo 1 >/sys/bus/pci/devices/PNP0C80:XX/eject > > This 2 events may happen at the same time, so we may touch > acpi_memory_device.res_list at the same time. This patch > introduce a lock to protect this list.
Hi Wen, This race condition is not unique in memory hot-remove as the sysfs eject interface is created for all objects with _EJ0. For CPU hot-remove, I addressed this race condition by making the notify handler to run the hot-remove operation on kacpi_hotplug_wq by calling acpi_os_hotplug_execute(). This serializes the hot-remove operations among the two events since the sysfs eject also runs on kacpi_hotplug_wq. This way is much simpler and is easy to maintain, although it does not allow both operations to run simultaneously (which I do not think we need). Can it be used for memory hot-remove as well? Thanks, -Toshi -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
