[PATCH v4 14/38] drm: kselftest for drm_mm and eviction

Chris Wilson
2016-12-22T08:36:17Z

Check that we add arbitrary blocks to the eviction scanner in order to
find the first minimal hole that matches our request.

v2: Refactor out some common eviction code for later

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
---
drivers/gpu/drm/selftests/drm_mm_selftests.h | 1 +
drivers/gpu/drm/selftests/test-drm_mm.c | 337 +++++++++++++++++++++++++++
2 files changed, 338 insertions(+)

diff --git a/drivers/gpu/drm/selftests/drm_mm_selftests.h b/drivers/gpu/drm/selftests/drm_mm_selftests.h
index a7a3763f8b20..a31b4458c7eb 100644
--- a/drivers/gpu/drm/selftests/drm_mm_selftests.h
+++ b/drivers/gpu/drm/selftests/drm_mm_selftests.h
@@ -15,3 +15,4 @@ selftest(insert_range, igt_insert_range)
selftest(align, igt_align)
selftest(align32, igt_align32)
selftest(align64, igt_align64)
+selftest(evict, igt_evict)
diff --git a/drivers/gpu/drm/selftests/test-drm_mm.c b/drivers/gpu/drm/selftests/test-drm_mm.c
index 53ba268e07d9..065e2c72845b 100644
--- a/drivers/gpu/drm/selftests/test-drm_mm.c
+++ b/drivers/gpu/drm/selftests/test-drm_mm.c
@@ -36,6 +36,10 @@ static const struct insert_mode {
[TOPDOWN] = { "top-down", DRM_MM_SEARCH_BELOW, DRM_MM_CREATE_TOP },
[BEST] = { "best", DRM_MM_SEARCH_BEST, DRM_MM_CREATE_DEFAULT },
{}
+}, evict_modes[] = {
+ { "default", DRM_MM_SEARCH_DEFAULT, DRM_MM_CREATE_DEFAULT },
+ { "top-down", DRM_MM_SEARCH_BELOW, DRM_MM_CREATE_TOP },
+ {}
};

static int igt_sanitycheck(void *ignored)
@@ -1110,6 +1114,339 @@ static int igt_align64(void *ignored)
return igt_align_pot(64);
}

+static void show_scan(const struct drm_mm *scan)
+{
+ pr_info("scan: hit [%llx, %llx], size=%lld, align=%d, color=%ld\n",
+ scan->scan_hit_start, scan->scan_hit_end,
+ scan->scan_size, scan->scan_alignment, scan->scan_color);
+}
+
+static void show_holes(const struct drm_mm *mm, int count)
+{
+ u64 hole_start, hole_end;
+ struct drm_mm_node *hole;
+
+ drm_mm_for_each_hole(hole, mm, hole_start, hole_end) {
+ struct drm_mm_node *next = list_next_entry(hole, node_list);
+ const char *node1 = NULL, *node2 = NULL;
+
+ if (hole->allocated)
+ node1 = kasprintf(GFP_KERNEL,
+ "[%llx + %lld, color=%ld], ",
+ hole->start, hole->size, hole->color);
+
+ if (next->allocated)
+ node2 = kasprintf(GFP_KERNEL,
+ ", [%llx + %lld, color=%ld]",
+ next->start, next->size, next->color);
+
+ pr_info("%sHole [%llx - %llx, size %lld]%s\n",
+ node1,
+ hole_start, hole_end, hole_end - hole_start,
+ node2);
+
+ kfree(node2);
+ kfree(node1);
+
+ if (!--count)
+ break;
+ }
+}
+
+struct evict_node {
+ struct drm_mm_node node;
+ struct list_head link;
+};
+
+static bool evict_nodes(struct drm_mm *mm,
+ struct evict_node *nodes,
+ unsigned int *order,
+ unsigned int count,
+ struct list_head *evict_list)
+{
+ struct evict_node *e, *en;
+ unsigned int i;
+
+ for (i = 0; i < count; i++) {
+ e = &nodes[order ? order[i] : i];
+ list_add(&e->link, evict_list);
+ if (drm_mm_scan_add_block(&e->node))
+ break;
+ }
+ list_for_each_entry_safe(e, en, evict_list, link) {
+ if (!drm_mm_scan_remove_block(&e->node))
+ list_del(&e->link);
+ }
+ if (list_empty(evict_list)) {
+ pr_err("Failed to find eviction: size=%lld [avail=%d], align=%d (color=%lu)\n",
+ mm->scan_size, count,
+ mm->scan_alignment,
+ mm->scan_color);
+ return false;
+ }
+
+ list_for_each_entry(e, evict_list, link)
+ drm_mm_remove_node(&e->node);
+
+ return true;
+}
+
+static bool evict_nothing(struct drm_mm *mm,
+ unsigned int total_size,
+ struct evict_node *nodes)
+{
+ LIST_HEAD(evict_list);
+ struct evict_node *e;
+ struct drm_mm_node *node;
+ unsigned int n;
+
+ drm_mm_init_scan(mm, 1, 0, 0);
+ for (n = 0; n < total_size; n++) {
+ e = &nodes[n];
+ list_add(&e->link, &evict_list);
+ drm_mm_scan_add_block(&e->node);
+ }
+ list_for_each_entry(e, &evict_list, link)
+ drm_mm_scan_remove_block(&e->node);
+
+ for (n = 0; n < total_size; n++) {
+ e = &nodes[n];
+
+ if (!drm_mm_node_allocated(&e->node)) {
+ pr_err("node[%d] no longer allocated!\n", n);
+ return false;
+ }
+
+ e->link.next = NULL;
+ }
+
+ drm_mm_for_each_node(node, mm) {
+ e = container_of(node, typeof(*e), node);
+ e->link.next = &e->link;
+ }
+
+ for (n = 0; n < total_size; n++) {
+ e = &nodes[n];
+
+ if (!e->link.next) {
+ pr_err("node[%d] no longer connected!\n", n);
+ return false;
+ }
+ }
+
+ return assert_continuous(mm, nodes[0].node.size);
+}
+
+static bool evict_everything(struct drm_mm *mm,
+ unsigned int total_size,
+ struct evict_node *nodes)
+{
+ LIST_HEAD(evict_list);
+ struct evict_node *e;
+ unsigned int n;
+ int err;
+
+ drm_mm_init_scan(mm, total_size, 0, 0);
+ for (n = 0; n < total_size; n++) {
+ e = &nodes[n];
+ list_add(&e->link, &evict_list);
+ drm_mm_scan_add_block(&e->node);
+ }
+ list_for_each_entry(e, &evict_list, link) {
+ if (!drm_mm_scan_remove_block(&e->node)) {
+ pr_err("Node %lld not marked for eviction!\n",
+ e->node.start);
+ list_del(&e->link);
+ }
+ }
+
+ list_for_each_entry(e, &evict_list, link)
+ drm_mm_remove_node(&e->node);
+
+ if (!assert_one_hole(mm, 0, total_size))
+ return false;
+
+ list_for_each_entry(e, &evict_list, link) {
+ err = drm_mm_reserve_node(mm, &e->node);
+ if (err) {
+ pr_err("Failed to reinsert node after eviction: start=%llx\n",
+ e->node.start);
+ return false;
+ }
+ }
+
+ return assert_continuous(mm, nodes[0].node.size);
+}
+
+static int evict_something(struct drm_mm *mm,
+ struct evict_node *nodes,
+ unsigned int *order,
+ unsigned int count,
+ unsigned int size,
+ unsigned int alignment,
+ const struct insert_mode *mode)
+{
+ LIST_HEAD(evict_list);
+ struct evict_node *e;
+ struct drm_mm_node tmp;
+ int err;
+
+ drm_mm_init_scan(mm, size, alignment, 0);
+ if (!evict_nodes(mm,
+ nodes, order, count,
+ &evict_list))
+ return -EINVAL;
+
+ memset(&tmp, 0, sizeof(tmp));
+ err = drm_mm_insert_node_generic(mm, &tmp, size, alignment, 0,
+ mode->search_flags,
+ mode->create_flags);
+ if (err) {
+ pr_err("Failed to insert into eviction hole: size=%d, align=%d\n",
+ size, alignment);
+ show_scan(mm);
+ show_holes(mm, 3);
+ return err;
+ }
+
+ if (!assert_node(&tmp, mm, size, alignment, 0) || tmp.hole_follows) {
+ pr_err("Inserted did not fill the eviction hole: size=%lld [%d], align=%d [rem=%lld], start=%llx, hole-follows?=%d\n",
+ tmp.size, size,
+ alignment, misalignment(&tmp, alignment),
+ tmp.start, tmp.hole_follows);
+ err = -EINVAL;
+ }
+
+ drm_mm_remove_node(&tmp);
+ if (err)
+ return err;
+
+ list_for_each_entry(e, &evict_list, link) {
+ err = drm_mm_reserve_node(mm, &e->node);
+ if (err) {
+ pr_err("Failed to reinsert node after eviction: start=%llx\n",
+ e->node.start);
+ return err;
+ }
+ }
+
+ if (!assert_continuous(mm, nodes[0].node.size)) {
+ pr_err("range is no longer continuous\n");
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static int igt_evict(void *ignored)
+{
+ DRM_RND_STATE(prng, random_seed);
+ const unsigned int size = 8192;
+ const struct insert_mode *mode;
+ struct drm_mm mm;
+ struct evict_node *nodes;
+ struct drm_mm_node *node, *next;
+ unsigned int *order, n;
+ int ret, err;
+
+ /* Here we populate a full drm_mm and then try and insert a new node
+ * by evicting other nodes in a random order. The drm_mm_scan should
+ * pick the first matching hole it finds from the random list. We
+ * repeat that for different allocation strategies, alignments and
+ * sizes to try and stress the hole finder.
+ */
+
+ ret = -ENOMEM;
+ nodes = vzalloc(size * sizeof(*nodes));
+ if (!nodes)
+ goto err;
+
+ order = drm_random_order(size, &prng);
+ if (!order)
+ goto err_nodes;
+
+ ret = -EINVAL;
+ drm_mm_init(&mm, 0, size);
+ for (n = 0; n < size; n++) {
+ err = drm_mm_insert_node(&mm, &nodes[n].node, 1, 0,
+ DRM_MM_SEARCH_DEFAULT);
+ if (err) {
+ pr_err("insert failed, step %d\n", n);
+ ret = err;
+ goto out;
+ }
+ }
+
+ /* First check that using the scanner doesn't break the mm */
+ if (!evict_nothing(&mm, size, nodes)) {
+ pr_err("evict_nothing() failed\n");
+ goto out;
+ }
+ if (!evict_everything(&mm, size, nodes)) {
+ pr_err("evict_everything() failed\n");
+ goto out;
+ }
+
+ for (mode = evict_modes; mode->name; mode++) {
+ for (n = 1; n <= size; n <<= 1) {
+ drm_random_reorder(order, size, &prng);
+ err = evict_something(&mm,
+ nodes, order, size,
+ n, 1,
+ mode);
+ if (err) {
+ pr_err("%s evict_something(size=%u) failed\n",
+ mode->name, n);
+ ret = err;
+ goto out;
+ }
+ }
+
+ for (n = 1; n < size; n <<= 1) {
+ drm_random_reorder(order, size, &prng);
+ err = evict_something(&mm,
+ nodes, order, size,
+ size/2, n,
+ mode);
+ if (err) {
+ pr_err("%s evict_something(size=%u, alignment=%u) failed\n",
+ mode->name, size/2, n);
+ ret = err;
+ goto out;
+ }
+ }
+
+ for_each_prime_number_from(n, 1, min(size, max_prime)) {
+ unsigned int nsize = (size - n + 1) / 2;
+
+ DRM_MM_BUG_ON(!nsize);
+
+ drm_random_reorder(order, size, &prng);
+ err = evict_something(&mm,
+ nodes, order, size,
+ nsize, n,
+ mode);
+ if (err) {
+ pr_err("%s evict_something(size=%u, alignment=%u) failed\n",
+ mode->name, nsize, n);
+ ret = err;
+ goto out;
+ }
+ }
+ }
+
+ ret = 0;
+out:
+ drm_mm_for_each_node_safe(node, next, &mm)
+ drm_mm_remove_node(node);
+ drm_mm_takedown(&mm);
+ kfree(order);
+err_nodes:
+ vfree(nodes);
+err:
+ return ret;
+}
+
#include "drm_selftest.c"

static int __init test_drm_mm_init(void)
--
2.11.0

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