Messages in this thread | | | From | WANG Cong <> | Subject | Re: [PATCH v2] kdump: Add udev events for memory online/offline | Date | Mon, 14 Nov 2011 02:37:06 +0000 (UTC) |
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On Mon, 31 Oct 2011 14:21:46 +0100, Michael Holzheu wrote:
> On Fri, 2011-10-28 at 15:46 -0700, Andrew Morton wrote: >> On Thu, 27 Oct 2011 11:32:45 +0200 > > [snip] > >> I think a safer place from which to send the uevent is >> memory_block_change_state() or even memory_block_action(). Because if >> either of those functions later gets new callers, those callers might >> forget to send the uevent? > > Ok fine. I put the code into memory_block_change_state(). This also has > the advantage that we are serialized by "mem->state_mutex". Not sure if > we need that, but for CPU hotplug the udev events are also serialized > with a lock. See "drivers/base/cpu.c" -> cpu_hotplug_driver_lock() > > Do you think the following patch is acceptable?
Yes.
> --- > From: Michael Holzheu <holzheu@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@linux.vnet.ibm.com>
Acked-by: WANG Cong <xiyou.wangcong@gmail.com>
Thanks.
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