------- Comment From leona...@ibm.com 2019-01-04 06:12 EDT-------
I have tried the following test in order to reproduce the bug:
##
root@localhost:~# uname -a
Linux localhost 4.15.0-20-generic #21-Ubuntu SMP Tue Apr 24 06:14:44 UTC 2018
ppc64le ppc64le ppc64le GNU/Linux
root@localhost:~# cat /sys/kernel/mm/transparent_hugepage/enabled
[always] madvise never
##
dd if=/dev/urandom of=/dev/shm/img bs=2M count=2000
md5sum /dev/shm/img > test.md5
After the migration, i did:
md5sum -c test.md5
And the result was OK. (memory not corrupted).
I also modified the above test allocating chunks of 2M, this way:
for i in {0001..2000} ; do dd if=/dev/urandom of=/dev/shm/img_${i} bs=2M
count=1 ; done
md5sum /dev/shm/* > test.md5
After the migration, i did:
md5sum -c test.md5
And the result was OK for every file. (memory not corrupted).
Conclusion:
- I have found no difference between patched and unpatched kernel during the
tests.
- The memory after the migration seems fine, returning the same memory block
(tested with md5sum)
Is there any other suggestion about how to reproduce the bug?
Thanks!
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https://bugs.launchpad.net/bugs/1788098
Title:
Avoid migration issues with aligned 2MB THB
Status in The Ubuntu-power-systems project:
Incomplete
Status in linux package in Ubuntu:
In Progress
Status in qemu package in Ubuntu:
Invalid
Status in linux source package in Bionic:
In Progress
Status in linux source package in Cosmic:
In Progress
Bug description:
FYI: This blocks bug 1781526 - once this one here is resolved we can
go on with SRU considerations for 1781526
------- Comment From jhop...@us.ibm.com 2018-08-20 17:12 EDT-------
Hi, in some environments it was observed that this qemu patch to
enable THP made it more likely to hit guest migration issues, however
the following kernel patch resolves those migration issues:
https://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc.git/commit/?h=kvm-ppc-next&id=c066fafc595eef5ae3c83ae3a8305956b8c3ef15
KVM: PPC: Book3S HV: Use correct pagesize in kvm_unmap_radix()
Once merged upstream, it would be good to include that change as well
to avoid potential migration problems. Should I open a new bug for
that or is it better to track here?
Note Paelzer: I have not seen related migration issues myself, but it
seems reasonable and confirmed by IBM.
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