Re: [LTP] [PATCH v2] cpuset_memory_spread: set lowerlimit according to pagesize

[Richard Palethorpe <rpalethorpe@suse.de>]

Hello,

Hongchen Zhang <zhanghongchen@loongson.cn> writes:

> When I test the cpuset_memory_spread case,this case FAIL too often.
> After dig into the code, I find out that the fowlloing things trigger
> the FAIL:
> 1) random events,the probability is very small and can be ignored
> 2) get_meminfo which before send signal to test_pid
> 3) account_memsinfo before result_check
>
> About 2) and 3), we can increase the value of lowerlimit to keep
> the result as SUCCESS.
>
> After discussing with Richard, we all agree to use the following
> formula to calculate the lowerlimit:
> lowerlimit(kb) = pagesize(byte) * 512 / 1024
>
> Signed-off-by: Hongchen Zhang <zhanghongchen@loongson.cn>
> ---
>  .../cpuset_memory_spread_testset.sh                    | 10 +++++++++-
>  1 file changed, 9 insertions(+), 1 deletion(-)
>
> diff --git
> a/testcases/kernel/controllers/cpuset/cpuset_memory_spread_test/cpuset_memory_spread_testset.sh
> b/testcases/kernel/controllers/cpuset/cpuset_memory_spread_test/cpuset_memory_spread_testset.sh
> index e2767ef05..f7230a4ea 100755
> --- a/testcases/kernel/controllers/cpuset/cpuset_memory_spread_test/cpuset_memory_spread_testset.sh
> +++ b/testcases/kernel/controllers/cpuset/cpuset_memory_spread_test/cpuset_memory_spread_testset.sh
> @@ -38,7 +38,15 @@ nr_mems=$N_NODES
>  # on which it is running. The other nodes' slab space has littler change.(less
>  # than 1000 kb).
>  upperlimit=10000
> -lowerlimit=2000
> +
> +# set lowerlimit according to pagesize
> +# pagesize(bytes)  | lowerlimit(kb)
> +# ------------------------------------
> +#  4096            | 2048
> +#  16384           | 8192
> +
> +PAGE_SIZE=`tst_getconf PAGESIZE`
> +lowerlimit=$((PAGE_SIZE * 512 / 1024))
>  
>  cpus_all="$(seq -s, 0 $((nr_cpus-1)))"
>  mems_all="$(seq -s, 0 $((nr_mems-1)))"
>
> base-commit: 020f3985a5ca86c8bbece27eef8fb0315a10463e

If we don't set the upperlimit what happens if we have 64Kb pages and
the lowerlimit > upperlimit?

-- 
Thank you,
Richard.

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