On Thu, 27 Oct 2011 11:32:45 +0200
Michael Holzheu <holzheu at linux.vnet.ibm.com> wrote:
> From: Michael Holzheu <holzheu at linux.vnet.ibm.com>
>
> Currently no udev events for memory hotplug "online" and "offline" are
> generated:
>
> # udevadm monitor
> # echo offline > /sys/devices/system/memory/memory4/state
> ==> No event
>
> When kdump is loaded, kexec detects the current memory configuration and
> stores it in the pre-allocated ELF core header. Therefore, for kdump it is
> necessary to reload the kdump kernel with kexec when the memory
> configuration changes (e.g. for online/offline hotplug memory).
>
> In order to do this automatically, udev rules should be used. This kernel
> patch adds udev events for "online" and "offline". Together with this kernel
> patch, the following udev rules for online/offline have to be added to
> "/etc/udev/rules.d/98-kexec.rules":
>
> SUBSYSTEM=="memory", ACTION=="online", PROGRAM="/etc/init.d/kdump restart"
> SUBSYSTEM=="memory", ACTION=="offline", PROGRAM="/etc/init.d/kdump restart"
>
> Signed-off-by: Michael Holzheu <holzheu at linux.vnet.ibm.com>
> ---
> drivers/base/memory.c | 10 +++++++---
> 1 file changed, 7 insertions(+), 3 deletions(-)
>
> --- a/drivers/base/memory.c
> +++ b/drivers/base/memory.c
> @@ -310,11 +310,15 @@ store_mem_state(struct sys_device *dev,
>
> mem = container_of(dev, struct memory_block, sysdev);
>
> - if (!strncmp(buf, "online", min((int)count, 6)))
> + if (!strncmp(buf, "online", min((int)count, 6))) {
> ret = memory_block_change_state(mem, MEM_ONLINE, MEM_OFFLINE);
> - else if(!strncmp(buf, "offline", min((int)count, 7)))
> + if (ret == 0)
> + kobject_uevent(&dev->kobj, KOBJ_ONLINE);
> + } else if (!strncmp(buf, "offline", min((int)count, 7))) {
> ret = memory_block_change_state(mem, MEM_OFFLINE, MEM_ONLINE);
> -
> + if (ret == 0)
> + kobject_uevent(&dev->kobj, KOBJ_OFFLINE);
> + }
ot: what on earth is up with that min() thing which
Dave-who-doesn't-know-about-min_t added to the strncmp() calls?
