Re: [PATCH -next v4 1/3] selftests/memory-hotplug: Add checking after online or offline

[zhaogongyi <zhaogongyi@huawei.com>]

Hi,

We can not get the EBUSY from " echo 0 > /sys/devices/system/memory/memoryxxx/online", maybe, redirect the error ouput to /dev/null is suitable when calling offline_memory_expect_success():

# sh mem-on-off-test.sh -a
mem-on-off-test.sh: illegal option -- a
Test scope: 2% hotplug memory
         online all hot-pluggable memory in offline state:
                 SKIPPED - no hot-pluggable memory in offline state
         offline 2% hot-pluggable memory in online state
         trying to offline 4 out of 192 memory block(s):
online->offline memory0
online->offline memory10
online->offline memory100
online->offline memory101
online->offline memory102
online->offline memory103
online->offline memory104
online->offline memory105
online->offline memory106
online->offline memory107
online->offline memory108
online->offline memory109
online->offline memory11
online->offline memory110
online->offline memory111
online->offline memory112
online->offline memory113
online->offline memory114
online->offline memory115
online->offline memory116
online->offline memory117
online->offline memory118
online->offline memory119
online->offline memory12
online->offline memory120
online->offline memory121
online->offline memory122
online->offline memory123
online->offline memory124
         online all hot-pluggable memory in offline state:
offline->online memory121
offline->online memory122
offline->online memory123
offline->online memory124
         Test with memory notifier error injection
# echo $?
0

Thanks!
Gongyi


> 
> 
> >> Reviewed-by: David Hildenbrand <david@redhat.com>
> >>
> >>
> >> I am questioning the stability of the offlining test, though.
> >> Offlining a random memory block can fail easily, because
> >> "->removable" is not
> >> expressive:
> >>
> >> # tools/testing/selftests/memory-hotplug/mem-on-off-test.sh
> >> Test scope: 2% hotplug memory
> >>            online all hot-pluggable memory in offline state:
> >>                    SKIPPED - no hot-pluggable memory in offline state
> >>            offline 2% hot-pluggable memory in online state
> >>            trying to offline 2 out of 96 memory block(s):
> >> online->offline memory0
> >> tools/testing/selftests/memory-hotplug/mem-on-off-test.sh: line 78: echo:
> >> write error: Invalid argument offline_memory_expect_success 0:
> >> unexpected fail
> >> online->offline memory10
> >> online->offline memory11
> >>
> >>
> >> I guess this test will almost always fail nowadays.
> >
> > Offline some memory node maybe failed as expected, but the error message
> is a bit annoying.
> 
> Ah, I see it now. We try offlining two and fail offlining the first one.
> Can we silence that warning in that case somehow?
> 
> --
> Thanks,
> 
> David / dhildenb