On 03/25/2015 02:28 PM, Chris Wilson wrote:
On Wed, Mar 25, 2015 at 02:21:00PM +0000, Tvrtko Ursulin wrote:
From: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
This tests the new EXEC_OBJECT_PAD_TO_SIZE exec_object2 flag.
It uses the fact DRM allocation policy is set as ABI and allocates
space in order.
Ssh. That's not what I meant to say. I meant that the policy is not ABI,
and we abuse our internal knowledge to get a working test, as we do
elsewhere in igt.
Ah, OK. :)
That means that we should be able to easily get
two bos mapped at adjacent GTT addresses and then test that the
pad to size flag will move them apart.
+ /* Try to get two buffer object next to each other in GTT space. */
+ for (try = 0, idx = 0; try < max_tries;) {
+ eb_handles[0] = handles[0];
+ eb_handles[1] = loc_handles[idx];
+ eb_handles[2] = loc_handles[idx + 1];
+
+ igt_assert(exec(fd, eb_handles, (uint32_t[2]){0, 0},
+ offsets) == 0);
+
+ if (offsets[1] > offsets[0]) {
+ distance = offsets[1] - offsets[0];
+ if (distance == PAGE_SIZE)
+ neighbours = true;
+ pad_to_size[0] = ALIGN(distance + PAGE_SIZE, PAGE_SIZE);
+ } else {
+ distance = offsets[0] - offsets[1];
+ if (distance == PAGE_SIZE)
+ neighbours = true;
+ pad_to_size[1] = ALIGN(distance + PAGE_SIZE, PAGE_SIZE);
+ }
+
+ if (neighbours)
+ break;
What's important to make this trick work is to allocate new handles
every time. That way we fill up the GTT and thereby hope to skip over
the fragmented part.
It does do that!
Only perhaps I need to make sure they are kept bound so maybe keep them
mapped or something while trying new ones?
Regards,
Tvrtko
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