From: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Date: Fri, 13 Jan 2012 01:20:14 +0000 (-0800)
Subject: kdump: add missing RAM resource in crash_shrink_memory()
X-Git-Tag: v3.3-rc1~81^2~20
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=6480e5a0923756b500634d9777ec4189492fbbfe;p=pandora-kernel.git

kdump: add missing RAM resource in crash_shrink_memory()

When shrinking crashkernel memory using /sys/kernel/kexec_crash_size for
the newly added memory no RAM resource is created at the moment.

Example:

  $ cat /proc/iomem
  00000000-bfffffff : System RAM
    00000000-005b7ac3 : Kernel code
    005b7ac4-009743bf : Kernel data
    009bb000-00a85c33 : Kernel bss
  c0000000-cfffffff : Crash kernel
  d0000000-ffffffff : System RAM

  $ echo 0 > /sys/kernel/kexec_crash_size
  $ cat /proc/iomem
  00000000-bfffffff : System RAM
    00000000-005b7ac3 : Kernel code
    005b7ac4-009743bf : Kernel data
    009bb000-00a85c33 : Kernel bss
                                   <<-- here is System RAM missing
  d0000000-ffffffff : System RAM

One result of this bug is that the memory chunk can never be set offline
using memory hotplug.  With this patch I insert a new "System RAM"
resource for the released memory.  Then the upper example looks like the
following:

  $ echo 0 > /sys/kernel/kexec_crash_size
  $ cat /proc/iomem
  00000000-bfffffff : System RAM
    00000000-005b7ac3 : Kernel code
    005b7ac4-009743bf : Kernel data
    009bb000-00a85c33 : Kernel bss
  c0000000-cfffffff : System RAM   <<-- new rescoure
  d0000000-ffffffff : System RAM

And now I can set chunk c0000000-cfffffff offline.

Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

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