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== Comment: #0 - Ping Tian Han - 2016-04-07 23:04:30 ==
---Problem Description---
Because canonical  has fixed bug 137281 ( LP: #1560552 ) in 4.4.0-17-generic, the kernel now supports "nr_cpus=1". So we should update the "maxcpus=1" to "nr_cpus=1" in /etc/default/kdump-tools I think.
 
---uname output---
Linux thymelp2 4.4.0-17-generic #33-Ubuntu SMP Tue Mar 29 17:15:31 UTC 2016 ppc64le ppc64le ppc64le GNU/Linux
 
Userspace tool: kdump-tools  version 1:1.5.9-5 

== Comment: #2 - Hari Krishna Bathini - 2016-04-11 04:36:14 ==
(In reply to comment #1)
> Hari.
> 
> Would you please validate that nr_cpus is consistent across architectures
> and should become the new default?
> 
> Thanks.

Hi Kevin,

I know nr_cpus=1 is supported on x86 based on this patch
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=14cb6dcf0a023f5977461c94d8d5a163c937979b

About other architectures, I am not really sure.

But looking at the kdump-tools source package, it seems like other architectures
are using maxcpus=1 to boot kdump kernel unless there is architecture specific
overrides that are missing in the source. Canonical might be able to answer better.

If other aren't using or willing to use nr_cpus=1, we may need a patch
of this kind:

diff --git a/kdump-config b/kdump-config
index 0ff0e6f..aba300e 100755
--- a/kdump-config
+++ b/kdump-config
@@ -48,7 +48,11 @@ KDUMP_COREDIR=${KDUMP_COREDIR:=/var/crash}
 KDUMP_DUMP_DMESG=${KDUMP_DUMP_DMESG:=1}
 KDUMP_DIR="/var/lib/kdump"
 MAKEDUMP_ARGS=${MAKEDUMP_ARGS:="-c -d 31"}
-KDUMP_CMDLINE_APPEND=${KDUMP_CMDLINE_APPEND:="irqpoll maxcpus=1 nousb systemd.unit=kdump-tools.service"}
+if [ "$ARCH" = "ppc64le" ]; then
+       KDUMP_CMDLINE_APPEND=${KDUMP_CMDLINE_APPEND:="irqpoll nr_cpus=1 nousb systemd.unit=kdump-tools.service"}
+else
+       KDUMP_CMDLINE_APPEND=${KDUMP_CMDLINE_APPEND:="irqpoll maxcpus=1 nousb systemd.unit=kdump-tools.service"}
+fi
 KDUMP_KERNEL_HOOK="/etc/kernel/postinst.d/kdump-tools"
 [ -d $KDUMP_COREDIR ] || mkdir -p $KDUMP_COREDIR ;

== Comment: #4 - Kevin W. Rudd - 2016-04-11 11:08:16 ==
Mirroring to Canonical for their review and feedback.

** Affects: makedumpfile (Ubuntu)
     Importance: Undecided
     Assignee: Taco Screen team (taco-screen-team)
         Status: New


** Tags: architecture-ppc64le bot-comment bugnameltc-140174 severity-medium targetmilestone-inin---
-- 
ISST-LTE:pVM:thymelp2:ubuntu 16.04: change "maxcpus=1" to "nr_cpus=1" in kdump-tools
https://bugs.launchpad.net/bugs/1568952
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