Re: [PATCH v2] generic/233,270: unlimit the max locked memory size for io_uring

["Darrick J. Wong" <djwong@kernel.org>]

On Tue, Mar 30, 2021 at 08:59:42AM +0800, Zorro Lang wrote:
> The ltp/fsstress always fails on io_uring_queue_init() by returnning
> ENOMEM. Due to io_uring accounts memory it needs under the rlimit
> memlocked option, which can be quite low on some setups, especially
> on 64K pagesize machine. root isn't under this restriction, but
> regular users are. So only g/233 and g/270 which use $qa_user to run
> fsstress are failed.
> 
> To avoid this failure, set max locked memory to unlimited before doing
> fsstress, then restore it after test done.
> 
> Signed-off-by: Zorro Lang <zlang@redhat.com>
> ---
> 
> Hi,
> 
> V2 removed `ulimit -l $lmem`, due to each case runs in child process, won't
> affect other testing.
> 
> Thanks,
> Zorro
> 
>  tests/generic/233 | 6 ++++++
>  tests/generic/270 | 6 ++++++
>  2 files changed, 12 insertions(+)
> 
> diff --git a/tests/generic/233 b/tests/generic/233
> index 7eda5774..cc794c79 100755
> --- a/tests/generic/233
> +++ b/tests/generic/233
> @@ -43,6 +43,12 @@ _fsstress()
>  -f rename=10 -f fsync=2 -f write=15 -f dwrite=15 \
>  -n $count -d $out -p 7`
>  
> +	# io_uring accounts memory it needs under the rlimit memlocked option,
> +	# which can be quite low on some setups (especially 64K pagesize). root
> +	# isn't under this restriction, but regular users are. To avoid the
> +	# io_uring_queue_init fail on ENOMEM, set max locked memory to unlimited
> +	# temporarily.
> +	ulimit -l unlimited
>  	echo "fsstress $args" >> $seqres.full
>  	if ! su $qa_user -c "$FSSTRESS_PROG $args" | tee -a $seqres.full | _filter_num

/me kinda feels like this should be refactored into a common helper, but
somehow when I try to picture that in my head all I can see is a
screeching nightmare of bash goop so feel free to ignore me. :)

--D

>  	then
> diff --git a/tests/generic/270 b/tests/generic/270
> index 3d8656d4..e93940ef 100755
> --- a/tests/generic/270
> +++ b/tests/generic/270
> @@ -37,6 +37,12 @@ _workout()
>  	cp $FSSTRESS_PROG  $tmp.fsstress.bin
>  	$SETCAP_PROG cap_chown=epi  $tmp.fsstress.bin
>  
> +	# io_uring accounts memory it needs under the rlimit memlocked option,
> +	# which can be quite low on some setups (especially 64K pagesize). root
> +	# isn't under this restriction, but regular users are. To avoid the
> +	# io_uring_queue_init fail on ENOMEM, set max locked memory to unlimited
> +	# temporarily.
> +	ulimit -l unlimited
>  	(su $qa_user -c "$tmp.fsstress.bin $args" &) > /dev/null 2>&1
>  
>  	echo "Run dd writers in parallel"
> -- 
> 2.30.2
>