Re: [LTP] [PATCH/RFC] mtest01: add option to limit max swap usage

[Caspar Zhang <caspar@casparzhang.com>]

On 03/14/2012 12:27 AM, Jan Stancek wrote:
> On large machines (with dozens of gigabytes of swap)
> it can take significant time until it completes,
> unless you specify "-p" parameter to set percent of total
> memory to use. It is difficult to find value, that would fit
> all setups. If the value is low, it won't exercise
> conditions when memory is low. If the value is high it turns
> into stress test, which can be swapping memory for hours.
> 
> This patch adds new option '-s', which stops test if swap
> usage goes beyoned <s> MBytes. By default it is 0 - no limit.
> 
> For example:
>      mtest01 -p 95 -w -s 4096
> will keep allocating memory until 95% of total memory is used,
> or swap usage is > 4GB.
> 
> This parameter is meant to be used in sanity tests, so that
> malloc is exercised in situations with high/low memory
> until system resorts to swapping, but ends when swap usage
> is high enough.
> 
> Signed-off-by: Jan Stancek <jstancek@redhat.com>
> ---
>   testcases/kernel/mem/mtest01/mtest01.c |   17 +++++++++++++++--
>   1 files changed, 15 insertions(+), 2 deletions(-)

I wish to see a better mtest01.c with libltp and good format, but it's a
tough work, hmmm...

The patch itself looks good.

Reviewed-by: Caspar Zhang <caspar@casparzhang.com>

> 
> 
> 
> 
> 0001-mtest01-add-option-to-limit-max-swap-usage.patch
> 
> 
> diff --git a/testcases/kernel/mem/mtest01/mtest01.c b/testcases/kernel/mem/mtest01/mtest01.c
> index dc960a8..54bda70 100644
> --- a/testcases/kernel/mem/mtest01/mtest01.c
> +++ b/testcases/kernel/mem/mtest01/mtest01.c
> @@ -67,6 +67,7 @@ int main(int argc, char* argv[])
>  	unsigned long long original_maxbytes, maxbytes = 0;
>  	unsigned long long pre_mem = 0, post_mem = 0;
>  	unsigned long long total_ram, total_free, D, C;
> +	unsigned long long used_swap, swap_max = 0;
>  	int chunksize = 1024*1024; /* one meg at a time by default */
>  	struct sysinfo sstats;
>  	int i, pid_cntr;
> @@ -78,7 +79,7 @@ int main(int argc, char* argv[])
>  	sigemptyset(&act.sa_mask);
>  	sigaction(SIGRTMIN,  &act, 0);
>  	
> -	while ((c = getopt(argc, argv, "c:b:p:wvh")) != -1) {
> +	while ((c = getopt(argc, argv, "c:b:p:s:wvh")) != -1) {
>  		switch(c) {
>  		case 'c':
>  			chunksize = atoi(optarg);
> @@ -105,6 +106,10 @@ int main(int argc, char* argv[])
>  				    "ERROR: -p option cannot be greater than "
>  				    "99");
>  			break;
> +		case 's':
> +			swap_max = atoi(optarg);
> +			swap_max = swap_max * 1024 * 1024;
> +			break;
>  		case 'w':
>  			dowrite = 1;
>  			break;
> @@ -116,7 +121,8 @@ int main(int argc, char* argv[])
>  			printf("usage: %s [-c <bytes>] [-b <bytes>|-p <percent>] [-v]\n", argv[0]);
>  			printf("\t-c <num>\tsize of chunk in bytes to malloc on each pass\n");
>  			printf("\t-b <bytes>\tmaximum number of bytes to allocate before stopping\n");
> -			printf("\t-p <bytes>\tpercent of total memory used at which the program stops\n");
> +			printf("\t-p <percent>\tpercent of total memory used at which the program stops\n");
> +			printf("\t-s <MBytes>\tstop when used swap is higher than <s> MB, default: 0 - no limit\n");
>  			printf("\t-w\t\twrite to the memory after allocating\n");
>  			printf("\t-v\t\tverbose\n");
>  			printf("\t-h\t\tdisplay usage\n");
> @@ -262,6 +268,13 @@ int main(int argc, char* argv[])
>  				sysinfo(&sstats);
>  				post_mem = (unsigned long long)sstats.mem_unit * sstats.freeram;
>  				post_mem = post_mem + (unsigned long long)sstats.mem_unit * sstats.freeswap;
> +
> +				used_swap = sstats.mem_unit * (sstats.totalswap - sstats.freeswap);
> +				if (swap_max > 0 && used_swap > swap_max) {
> +					tst_resm(TINFO, "Reached max swap usage: %llu Mbytes > %llu MBytes",
> +							used_swap / 1024 / 1024, swap_max / 1024 / 1024);
> +					break;
> +				}
>  			}
>  		}
>  		while (pid_list[i] != 0) {
> 
> 
> 
> 
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