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Commit f5138e42211d4e8bfbd6ac5b3816348da1533433

Authored by Michael Holzheu
Committed by Linus Torvalds
1 parent 1f536b9e9f
Exists in master and in 6 other branches imx_3.10.17_1.0.1_ga, imx_3.10.53_1.1.0_ga, imx_3.14.28_1.0.0_ga, smarc-imx_3.10.53_1.1.0_ga, smarc-imx_3.14.28_1.0.0_ga, smarc-l5.0.0_1.0.0-ga

kdump: add udev events for memory online/offline 

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"

[sfr@canb.auug.org.au: fixups for class to subsystem conversion]
Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Dave Hansen <haveblue@us.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Showing 1 changed file with 14 additions and 3 deletions Side-by-side Diff

drivers/base/memory.c
Diff comments   View file @ f5138e4
... ... @@ -295,11 +295,22 @@
295 295  
296 296 ret = memory_block_action(mem->start_section_nr, to_state);
297 297  
298   - if (ret)
  298 + if (ret) {
299 299 mem->state = from_state_req;
300   - else
301   - mem->state = to_state;
  300 + goto out;
  301 + }
302 302  
  303 + mem->state = to_state;
  304 + switch (mem->state) {
  305 + case MEM_OFFLINE:
  306 + kobject_uevent(&mem->dev.kobj, KOBJ_OFFLINE);
  307 + break;
  308 + case MEM_ONLINE:
  309 + kobject_uevent(&mem->dev.kobj, KOBJ_ONLINE);
  310 + break;
  311 + default:
  312 + break;
  313 + }
303 314 out:
304 315 mutex_unlock(&mem->state_mutex);
305 316 return ret;