Re: [PATCH -next v3 1/3] selftests/memory-hotplug: Add checking after online or offline

From: David Hildenbrand <david@redhat.com>
To: Zhao Gongyi <zhaogongyi@huawei.com>,
	linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-mm@kvack.org, linux-kselftest@vger.kernel.org
Cc: akinobu.mita@gmail.com, corbet@lwn.net, osalvador@suse.de,
	shuah@kernel.org
Subject: Re: [PATCH -next v3 1/3] selftests/memory-hotplug: Add checking after online or offline
Date: Mon, 26 Sep 2022 15:27:07 +0200	[thread overview]
Message-ID: <a889576f-0178-b44f-16b0-fdeafbe01035@redhat.com> (raw)
In-Reply-To: <20220926130341.253039-2-zhaogongyi@huawei.com>

On 26.09.22 15:03, Zhao Gongyi wrote:
> Add checking for online_memory_expect_success()/
> offline_memory_expect_success()/offline_memory_expect_fail(), or
> the test would exit 0 although the functions return 1.
> 
> Signed-off-by: Zhao Gongyi <zhaogongyi@huawei.com>
> ---
>   .../selftests/memory-hotplug/mem-on-off-test.sh   | 15 ++++++++++++---
>   1 file changed, 12 insertions(+), 3 deletions(-)
> 
> diff --git a/tools/testing/selftests/memory-hotplug/mem-on-off-test.sh b/tools/testing/selftests/memory-hotplug/mem-on-off-test.sh
> index 46a97f318f58..3edda1f13f7b 100755
> --- a/tools/testing/selftests/memory-hotplug/mem-on-off-test.sh
> +++ b/tools/testing/selftests/memory-hotplug/mem-on-off-test.sh
> @@ -266,7 +266,10 @@ done
>   #
>   echo $error > $NOTIFIER_ERR_INJECT_DIR/actions/MEM_GOING_ONLINE/error
>   for memory in `hotpluggable_offline_memory`; do
> -	online_memory_expect_fail $memory
> +	online_memory_expect_fail $memory || {
> +		echo "online memory $memory: unexpected success"

The functions themself already print an error, isn't it sufficient to 
set retval=1?

> +		retval=1
> +	}
>   done
> 
>   #
> @@ -274,7 +277,10 @@ done
>   #
>   echo 0 > $NOTIFIER_ERR_INJECT_DIR/actions/MEM_GOING_ONLINE/error
>   for memory in `hotpluggable_offline_memory`; do
> -	online_memory_expect_success $memory
> +	online_memory_expect_success $memory || {
> +		echo "online memory $memory: unexpected fail"
> +		retval=1
> +	}
>   done
> 
>   #
> @@ -283,7 +289,10 @@ done
>   echo $error > $NOTIFIER_ERR_INJECT_DIR/actions/MEM_GOING_OFFLINE/error
>   for memory in `hotpluggable_online_memory`; do
>   	if [ $((RANDOM % 100)) -lt $ratio ]; then
> -		offline_memory_expect_fail $memory
> +		offline_memory_expect_fail $memory || {
> +			echo "offline memory $memory: unexpected success"
> +			retval=1
> +		}

These functions return 0 if the result is as expected and 1 if the 
result is unexpected.

... but wouldn't we evaluate the right hand side only if the result is 
"0" -- expected? I might be wrong.

Wouldn't it be simpler do it as in "Online all hot-pluggable memory again"

if ! online_memory_expect_success $memory; then
	retval=1
fi

(similarly adjusting the function name)

-- 
Thanks,

David / dhildenb