On pe, 2016-12-09 at 13:08 +0000, Chris Wilson wrote:
> Check that if we request top-down allocation with a particular alignment
> from drm_mm_insert_node() that the start of the node matches our
> request.
>
> Signed-off-by: Chris Wilson <ch...@chris-wilson.co.uk>
<SNIP>
> @@ -1038,6 +1038,98 @@ static int igt_topdown(void *ignored)
> return ret;
> }
>
> +static int igt_topdown_align(void *ignored)
> +{
> + struct drm_mm mm;
> + struct drm_mm_node tmp, resv;
> + int ret = -EINVAL;
> + int n, m, err;
> +
> + drm_mm_init(&mm, 0, ~0ull);
U64_MAX
> + memset(&tmp, 0, sizeof(tmp));
> + memset(&resv, 0, sizeof(resv));
> +
> + for (m = 0; m < 32; m++) {
> + u64 end = ~0ull;
> +
> + if (m) {
> + resv.size = BIT_ULL(m);
> + end -= resv.size;
> + resv.start = end;
> +
> + err = drm_mm_reserve_node(&mm, &resv);
> + if (err) {
> + pr_err("reservation of sentinel node failed\n");
> + ret = err;
> + goto out;
> + }
> + }
> +
> + for (n = 0; n < 63 - m; n++) {
> + u64 align = BIT_ULL(n);
> +
> + err = drm_mm_insert_node_generic(&mm, &tmp, 1, align, 0,
> + DRM_MM_SEARCH_BELOW,
> + DRM_MM_CREATE_TOP);
> + drm_mm_remove_node(&tmp);
> + if (err) {
> + pr_err("insert failed, ret=%d\n", err);
> + ret = err;
> + goto out;
> + }
Just drm_mm_remove_node(&tmp) here to avoid an unnecessary extra splat.
I think the tests should be valid code.
> +
> + if (tmp.start & (align - 1)) {
> + pr_err("insert alignment failed, aligment=%llx,
> start=%llx\n",
> + align, tmp.start);
> + goto out;
> + }
> +
> + if (tmp.start < end - align) {
> + pr_err("topdown insert failed, start=%llx,
> align=%llx, end=%llx\n",
> + tmp.start, align, end);
> + goto out;
> + }
> + }
> +
> + for_each_prime(n, min(8192ull, end - 1)) {
> + u64 rem;
> +
> + err = drm_mm_insert_node_generic(&mm, &tmp, n, 0, 0,
> + DRM_MM_SEARCH_BELOW,
> + DRM_MM_CREATE_TOP);
> + drm_mm_remove_node(&tmp);
> + if (err) {
> + pr_err("insert failed, ret=%d\n", err);
> + ret = err;
> + goto out;
> + }
Ditto.
In addition to those, I would use more meaningful variable names than m
& n.
Regards, Joonas
--
Joonas Lahtinen
Open Source Technology Center
Intel Corporation
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