[LTP] [PATCH v3 2/2] read_all: wait children I/O reading in limited time

[Richard Palethorpe <rpalethorpe@suse.de>]

Hello,

Li Wang writes:

> read_all reports some stalled messges in test:
>  # ./read_all -d /sys -q -r 10
>    tst_test.c:987: INFO: Timeout per run is 0h 05m 00s
>    read_all.c:280: BROK: Worker 26075 is stalled
>    read_all.c:280: WARN: Worker 26075 is stalled
>    read_all.c:280: WARN: Worker 26079 is stalled
>    read_all.c:280: WARN: Worker 26087 is stalled
>
> The reason is that some children are still working on the read
> I/O but parent trys to stopping them after visit_dir immediately.
> Although the stop_attemps is 65535, it still sometimes fails.
>
> Instead, we take use of TST_RETRY_FUNC maroc to loop the stop
> operation in limited seconds to wait children I/O.
>
> And, the sched_work push action in an infinite loop, here merge it
> into rep_sched_work with using TST_RETRY_FUNC macro.
>
> Signed-off-by: Li Wang <liwang@redhat.com>
> Cc: Richard Palethorpe <rpalethorpe@suse.de>
> Cc: Xiao Yang <yangx.jy@cn.fujitsu.com>
> Cc: Cyril Hrubis <chrubis@suse.cz>
> ---
>
> Notes:
>     Hi Cyril and Richard,
>     
>     The purpose of this patch is to replace the old one[1] to solve
>     the children I/O issue. Please could you consider to merge or
>     comment on the change of using new marco.
>     
>     [1] http://lists.linux.it/pipermail/ltp/2018-April/007704.html
>
>  testcases/kernel/fs/read_all/read_all.c | 45 +++++++--------------------------
>  1 file changed, 9 insertions(+), 36 deletions(-)
>
> diff --git a/testcases/kernel/fs/read_all/read_all.c b/testcases/kernel/fs/read_all/read_all.c
> index b7ed540..b420e37 100644
> --- a/testcases/kernel/fs/read_all/read_all.c
> +++ b/testcases/kernel/fs/read_all/read_all.c
> @@ -265,23 +265,14 @@ static void spawn_workers(void)
>  static void stop_workers(void)
>  {
>  	const char stop_code[1] = { '\0' };
> -	int i, stop_attempts;
> +	int i;
>  
>  	if (!workers)
>  		return;
>  
>  	for (i = 0; i < worker_count; i++) {
> -		stop_attempts = 0xffff;
> -		if (workers[i].q) {
> -			while (!queue_push(workers[i].q, stop_code)) {
> -				if (--stop_attempts < 0) {
> -					tst_brk(TBROK,
> -						"Worker %d is stalled",
> -						workers[i].pid);
> -					break;
> -				}
> -			}
> -		}
> +		if (workers[i].q)
> +			TST_RETRY_FUNC(queue_push(workers[i].q, stop_code), 1);
>  	}
>  
>  	for (i = 0; i < worker_count; i++) {
> @@ -292,33 +283,15 @@ static void stop_workers(void)
>  	}
>  }
>  
> -static void sched_work(const char *path)
> -{
> -	static int cur;
> -	int push_attempts = 0, pushed;
> -
> -	while (1) {
> -		pushed = queue_push(workers[cur].q, path);
> -
> -		if (++cur >= worker_count)
> -			cur = 0;
> -
> -		if (pushed)
> -			break;
> -
> -		if (++push_attempts > worker_count) {
> -			usleep(100);
> -			push_attempts = 0;
> -		}
> -	}
> -}
> -
>  static void rep_sched_work(const char *path, int rep)
>  {
> -	int i;
> +	int i, j;
>  
> -	for (i = 0; i < rep; i++)
> -		sched_work(path);
> +	for (i = j = 0; i < rep; i++, j++) {
> +		if (j >= worker_count)
> +			j = 0;
> +		TST_RETRY_FUNC(queue_push(workers[j].q, path), 1);
> +	}
>  }
>  
>  static void setup(void)

Patchset looks good to me!

-- 
Thank you,
Richard.