[LTP] [PATCH 2/4] memcg_process_stress: allocate memory not in the signal handler

[Cyril Hrubis]

Hi!
> -static void sigusr_handler(int __attribute__ ((unused)) signo)
> +static void alloc_memory(void)
>  {
>  	int i;
>  	int pagesize;
>  
>  	pagesize = sysconf(_SC_PAGE_SIZE);
>  
> -	nr_page = ceil((double)memsize / pagesize);
> +	nr_page = memsize / pagesize;

This will cause to allocate one less page than the previous code in case
that memsize % pagesize != 0.

ceil((double)memsize/pagesize) == (memsize + pagesize - 1)/pagesize

In case that you want to avoid floating point.

>  	pages = calloc(nr_page, sizeof(char *));
>  	if (pages == NULL)
> @@ -62,7 +54,18 @@ static void sigusr_handler(int __attribute__ ((unused)) signo)
>  		if (pages[i] == MAP_FAILED)
>  			err(1, "mmap");
>  	}
> +}
>  
> +static void touch_memory(void)
> +{
> +	int i;
> +
> +	for (i = 0; i < nr_page; i++)
> +		pages[i][0] = 0xef;
> +}
> +
> +static void sigusr_handler(int __attribute__ ((unused)) signo)
> +{
>  	flag_ready = 1;
>  }
>  
> @@ -76,6 +79,7 @@ int main(int argc, char *argv[])
>  	char *end;
>  	struct sigaction sigint_action;
>  	struct sigaction sigusr_action;
> +	int allocated = 0;
>  
>  	if (argc != 3)
>  		errx(1, "wrong argument num");
> @@ -102,8 +106,14 @@ int main(int argc, char *argv[])
>  	while (!flag_exit) {
>  		sleep(interval);
>  
> -		if (flag_ready)
> +		if (flag_ready) {
> +			if (!allocated) {
> +				alloc_memory();
> +				allocated = 1;
> +			}
> +
>  			touch_memory();
> +		}
>  	}


We can do even better if we change the sleep() for pause().

>  	return 0;

Otherwise it looks good.

-- 
Cyril Hrubis
chrubis@suse.cz