[LTP] [RFC PATCH] read_all: give more time to wait children finish read action

[Xiao Yang <yangx.jy@cn.fujitsu.com>]

On 2018/04/07 17:09, Li Wang wrote:
> 1. 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, so we get the following worker
> stalled messges in test.
Hi Li,

I got the same message on RHEL6.9Alpha as well, and this patch looks good to me.

Thanks,
Xiao Yang.

>   # uname -rm
>     4.16.0-rc7 ppc64
>   # ./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
>
> 2. The sched_work() push action in a infinite loop, here I propose to let
> it in limited times.
>
> Signed-off-by: Li Wang<liwang@redhat.com>
> ---
>   testcases/kernel/fs/read_all/read_all.c | 10 +++++++---
>   1 file changed, 7 insertions(+), 3 deletions(-)
>
> diff --git a/testcases/kernel/fs/read_all/read_all.c b/testcases/kernel/fs/read_all/read_all.c
> index b7ed540..ab206e7 100644
> --- a/testcases/kernel/fs/read_all/read_all.c
> +++ b/testcases/kernel/fs/read_all/read_all.c
> @@ -280,6 +280,7 @@ static void stop_workers(void)
>   						workers[i].pid);
>   					break;
>   				}
> +				usleep(100);
>   			}
>   		}
>   	}
> @@ -306,9 +307,12 @@ static void sched_work(const char *path)
>   		if (pushed)
>   			break;
>
> -		if (++push_attempts>  worker_count) {
> -			usleep(100);
> -			push_attempts = 0;
> +		usleep(100);
> +		if (++push_attempts>  0xffff) {
> +			tst_brk(TBROK,
> +				"Attempts %d times but still failed to push %s",
> +				push_attempts, path);
> +			break;
>   		}
>   	}
>   }