APPLIED[B/F/H]: [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()

[Kleber Souza]

On 27.08.21 07:02, Po-Hsu Lin wrote:
> [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(-)
> 

Applied to [bionic/focal/hirsute]:linux.

Thanks,
Kleber