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Date:   Sat, 29 Sep 2018 13:28:12 +0300
From:   Mike Rapoport <rppt@linux.vnet.ibm.com>
To:     Peter Xu <peterx@redhat.com>
Cc:     linux-kernel@vger.kernel.org, Shuah Khan <shuah@kernel.org>,
        Jerome Glisse <jglisse@redhat.com>,
        Mike Kravetz <mike.kravetz@oracle.com>, linux-mm@kvack.org,
        Zi Yan <zi.yan@cs.rutgers.edu>,
        "Kirill A . Shutemov" <kirill@shutemov.name>,
        linux-kselftest@vger.kernel.org, Shaohua Li <shli@fb.com>,
        Andrea Arcangeli <aarcange@redhat.com>,
        "Dr . David Alan Gilbert" <dgilbert@redhat.com>,
        Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH 1/3] userfaultfd: selftest: cleanup help messages
References: <20180929084311.15600-1-peterx@redhat.com>
 <20180929084311.15600-2-peterx@redhat.com>
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On Sat, Sep 29, 2018 at 04:43:09PM +0800, Peter Xu wrote:
> Firstly, the help in the comment region is obsolete, now we support
> three parameters.  Since at it, change it and move it into the help
> message of the program.
> 
> Also, the help messages dumped here and there is obsolete too.  Use a
> single usage() helper.
> 
> Signed-off-by: Peter Xu <peterx@redhat.com>

Small comment below, otherwise

Acked-by: Mike Rapoport <rppt@linux.vnet.ibm.com>

> ---
>  tools/testing/selftests/vm/userfaultfd.c | 44 ++++++++++++++----------
>  1 file changed, 26 insertions(+), 18 deletions(-)
> 
> diff --git a/tools/testing/selftests/vm/userfaultfd.c b/tools/testing/selftests/vm/userfaultfd.c
> index 7b8171e3128a..2a84adaf8cf8 100644
> --- a/tools/testing/selftests/vm/userfaultfd.c
> +++ b/tools/testing/selftests/vm/userfaultfd.c
> @@ -34,18 +34,6 @@
>   * per-CPU threads 1 by triggering userfaults inside
>   * pthread_mutex_lock will also verify the atomicity of the memory
>   * transfer (UFFDIO_COPY).
> - *
> - * The program takes two parameters: the amounts of physical memory in
> - * megabytes (MiB) of the area and the number of bounces to execute.
> - *
> - * # 100MiB 99999 bounces
> - * ./userfaultfd 100 99999
> - *
> - * # 1GiB 99 bounces
> - * ./userfaultfd 1000 99
> - *
> - * # 10MiB-~6GiB 999 bounces, continue forever unless an error triggers
> - * while ./userfaultfd $[RANDOM % 6000 + 10] 999; do true; done
>   */
> 
>  #define _GNU_SOURCE
> @@ -115,6 +103,28 @@ pthread_attr_t attr;
>  				 ~(unsigned long)(sizeof(unsigned long long) \
>  						  -  1)))
> 
> +const char *examples =
> +    "# 100MiB 99999 bounces\n"
> +    "./userfaultfd anon 100 99999\n"
> +    "\n"
> +    "# 1GiB 99 bounces\n"
> +    "./userfaultfd anon 1000 99\n"
> +    "\n"
> +    "# 10MiB-~6GiB 999 bounces, continue forever unless an error triggers\n"
> +    "while ./userfaultfd anon $[RANDOM % 6000 + 10] 999; do true; done\n"
> +    "\n";

While at it, can you please update the examples to include other test
types?

> +
> +static void usage(void)
> +{
> +	fprintf(stderr, "\nUsage: ./userfaultfd <test type> <MiB> <bounces> "
> +		"[hugetlbfs_file]\n\n");
> +	fprintf(stderr, "Supported <test type>: anon, hugetlb, "
> +		"hugetlb_shared, shmem\n\n");
> +	fprintf(stderr, "Examples:\n\n");
> +	fprintf(stderr, examples);
> +	exit(1);
> +}
> +
>  static int anon_release_pages(char *rel_area)
>  {
>  	int ret = 0;
> @@ -1272,8 +1282,7 @@ static void sigalrm(int sig)
>  int main(int argc, char **argv)
>  {
>  	if (argc < 4)
> -		fprintf(stderr, "Usage: <test type> <MiB> <bounces> [hugetlbfs_file]\n"),
> -				exit(1);
> +		usage();
> 
>  	if (signal(SIGALRM, sigalrm) == SIG_ERR)
>  		fprintf(stderr, "failed to arm SIGALRM"), exit(1);
> @@ -1286,20 +1295,19 @@ int main(int argc, char **argv)
>  		nr_cpus;
>  	if (!nr_pages_per_cpu) {
>  		fprintf(stderr, "invalid MiB\n");
> -		fprintf(stderr, "Usage: <MiB> <bounces>\n"), exit(1);
> +		usage();
>  	}
> 
>  	bounces = atoi(argv[3]);
>  	if (bounces <= 0) {
>  		fprintf(stderr, "invalid bounces\n");
> -		fprintf(stderr, "Usage: <MiB> <bounces>\n"), exit(1);
> +		usage();
>  	}
>  	nr_pages = nr_pages_per_cpu * nr_cpus;
> 
>  	if (test_type == TEST_HUGETLB) {
>  		if (argc < 5)
> -			fprintf(stderr, "Usage: hugetlb <MiB> <bounces> <hugetlbfs_file>\n"),
> -				exit(1);
> +			usage();
>  		huge_fd = open(argv[4], O_CREAT | O_RDWR, 0755);
>  		if (huge_fd < 0) {
>  			fprintf(stderr, "Open of %s failed", argv[3]);
> -- 
> 2.17.1
> 

-- 
Sincerely yours,
Mike.