[PATCH v3] prime_mmap_coherency: Add return error tests for prime sync ioctl

[Chris Wilson]

On Fri, Mar 18, 2016 at 03:08:56PM -0300, Tiago Vignatti wrote:
> This patch adds ioctl-errors subtest to be used for exercising prime sync ioctl
> errors.
> 
> The subtest constantly interrupts via signals a function doing concurrent blit
> to stress out the right usage of prime_sync_*, making sure these ioctl errors
> are handled accordingly. Important to note that in case of failure (e.g. in a
> case where the ioctl wouldn't try again in a return error) this test does not
> reliably catch the problem with 100% of accuracy.
> 
> v2: fix prime sync direction when reading mmap'ed file.
> v3: change the upper bound using time rather than loops
>  
> Cc: Chris Wilson <chris at chris-wilson.co.uk>
> Signed-off-by: Tiago Vignatti <tiago.vignatti at intel.com>
> ---
> +static void test_ioctl_errors(void)
> +{
> +	int ncpus = sysconf(_SC_NPROCESSORS_ONLN);
> +
> +	igt_fork_signal_helper();
> +	for (int num_children = 1; num_children <= 8 *ncpus; num_children <<= 1) {

Hmm, that's a lot of buffers....

I'm going to stick a couple of intel_require_memmory and
intel_check_memory() here.

Wait that's no moon. Oops, give me back my swap!

> +		igt_fork(child, num_children) {
> +			struct timespec start = {};
> +			while (igt_nsec_elapsed(&start) <= num_children)

igt_nsec_elapsed().... Barely any time at all!

Presumed you wanted seconds, fixed the memleak and pushed.
Thanks,
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre