On 05/02/14 at 10:31am, Vivek Goyal wrote:
On Fri, May 02, 2014 at 10:28:50AM -0400, Prarit Bhargava wrote:
> During debugging of another problem issues were noted with the kdump udev
> rules. The kdump service is restarted on memory add and remove events.
> These are the wrong events for these types of devices and result in an overly
> aggressive restarting of the kdump service.
>
> There are four udev events to consider, "add", "remove",
"online", and
> "offline". The remove event is a complete removal from the system --
neither
> the hardware nor the kernel know about the hardware; it has been physically
> removed. The add event is associated with hardware being physically added to
> the system. The kernel has some limited knowledge of the device, however,
> it is not avaiable for the kernel to use until it is brought online. Online
> events refer to the device being available for the kernel to use. Opposite
> to that is the offline event, which occurs when a device is no longer in
> use by the kernel.
>
> Note that in all four events the kernel *may* have some remaining information
> stored about the device.
>
> In the case of memory hotplug, kdump should be restarted when a memory module
> is onlined or offlined. This is because the memory is not in use by the
> kernel until the memory is onlined, and it is unused when the memory is
> offlined.
>
> Making these modifications results in smooth service on systems that do
> heavy memory onlining and offlining.
>
> Cc: Vivek Goyal <vgoyal(a)redhat.com>
> Signed-off-by: Prarit Bhargava <prarit(a)redhat.com>
> ---
Acked-by: Vivek Goyal <vgoyal(a)redhat.com>
Thanks. Pushed this one.