[B/F/H/I/Unstable][OEM-5.10/OEM-5.13][SRU][PATCH 0/1] ubunut_kernel_selftests: memory-hotplug: avoid spamming logs with dump_page()

[Po-Hsu Lin]

[Impact]
The memory-hotplug test has been intermittently timing out (or trashing the test
VM, see below) on Impish/Hirsute ppc64el and x86-64 for quite some time now.

While the offline memory test obey ratio limit, the same test with
error injection does not and tries to offline all the hotpluggable
memory, spamming system logs with hundreds of thousands of dump_page()
entries, slowing system down (to the point the test itself timesout and
gets terminated) and excessive fs occupation:

...
[ 9784.393354] page:c00c0000007d1b40 refcount:3 mapcount:0 mapping:c0000001fc03e950 index:0xe7b
[ 9784.393355] def_blk_aops
[ 9784.393356] flags: 0x3ffff800002062(referenced|active|workingset|private)
[ 9784.393358] raw: 003ffff800002062 c0000001b9343a68 c0000001b9343a68 c0000001fc03e950
[ 9784.393359] raw: 0000000000000e7b c000000006607b18 00000003ffffffff c00000000490d000
[ 9784.393359] page dumped because: migration failure
[ 9784.393360] page->mem_cgroup:c00000000490d000
[ 9784.393416] migrating pfn 1f46d failed ret:1
...

$ grep "page dumped because: migration failure" /var/log/kern.log | wc -l
2405558

$ ls -la /var/log/kern.log
-rw-r----- 1 syslog adm 2256109539 Jun 30 14:19 /var/log/kern.log

[Fix]
* 0c0f6299ba71fa selftests: memory-hotplug: avoid spamming logs with
  dump_page(), ratio limit hot-remove error test

[Test Plan]
Run the memory-hotplug test, this log spamming issue should not happen
again.

[Where problems could occur]
If this fix is incorrect we might be unable to catch some other issue.


Paolo Pisati (1):
  selftests: memory-hotplug: avoid spamming logs with dump_page(), ratio
    limit hot-remove error test

 tools/testing/selftests/memory-hotplug/mem-on-off-test.sh | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

-- 
2.7.4