[PATCH v3 03/37] drm/i915/region: support basic eviction

Matthew Auld
2019-08-09T22:26:09Z

Support basic eviction for regions.

Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Abdiel Janulgue <abdiel.janulgue@linux.intel.com>
---
.../gpu/drm/i915/gem/i915_gem_object_types.h | 7 ++
drivers/gpu/drm/i915/gem/i915_gem_region.c | 11 +++
drivers/gpu/drm/i915/gem/i915_gem_region.h | 1 +
drivers/gpu/drm/i915/i915_gem.c | 17 +++++
drivers/gpu/drm/i915/intel_memory_region.c | 73 +++++++++++++++++-
drivers/gpu/drm/i915/intel_memory_region.h | 5 ++
.../drm/i915/selftests/intel_memory_region.c | 76 +++++++++++++++++++
drivers/gpu/drm/i915/selftests/mock_region.c | 1 +
8 files changed, 187 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object_types.h b/drivers/gpu/drm/i915/gem/i915_gem_object_types.h
index a32066e66271..5e2fa37e9bc0 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_object_types.h
+++ b/drivers/gpu/drm/i915/gem/i915_gem_object_types.h
@@ -168,6 +168,13 @@ struct drm_i915_gem_object {
* List of memory region blocks allocated for this object.
*/
struct list_head blocks;
+ /**
+ * Element within memory_region->objects or
+ * memory_region->purgeable if the object is marked as
+ * DONTNEED. Access is protected by memory_region->obj_lock.
+ */
+ struct list_head region_link;
+ struct list_head tmp_link;

struct sg_table *pages;
void *mapping;
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_region.c b/drivers/gpu/drm/i915/gem/i915_gem_region.c
index 3cd1bf15e25b..be126e70c90f 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_region.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_region.c
@@ -102,6 +102,17 @@ void i915_gem_object_init_memory_region(struct drm_i915_gem_object *obj,
{
INIT_LIST_HEAD(&obj->mm.blocks);
obj->mm.region= mem;
+
+ mutex_lock(&mem->obj_lock);
+ list_add(&obj->mm.region_link, &mem->objects);
+ mutex_unlock(&mem->obj_lock);
+}
+
+void i915_gem_object_release_memory_region(struct drm_i915_gem_object *obj)
+{
+ mutex_lock(&obj->mm.region->obj_lock);
+ list_del(&obj->mm.region_link);
+ mutex_unlock(&obj->mm.region->obj_lock);
}

struct drm_i915_gem_object *
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_region.h b/drivers/gpu/drm/i915/gem/i915_gem_region.h
index da5a2ca1a0fb..ebddc86d78f7 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_region.h
+++ b/drivers/gpu/drm/i915/gem/i915_gem_region.h
@@ -18,6 +18,7 @@ void i915_gem_object_put_pages_buddy(struct drm_i915_gem_object *obj,

void i915_gem_object_init_memory_region(struct drm_i915_gem_object *obj,
struct intel_memory_region *mem);
+void i915_gem_object_release_memory_region(struct drm_i915_gem_object *obj);

struct drm_i915_gem_object *
i915_gem_object_create_region(struct intel_memory_region *mem,
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 6ff01a404346..8735dea74809 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -1105,6 +1105,23 @@ i915_gem_madvise_ioctl(struct drm_device *dev, void *data,
!i915_gem_object_has_pages(obj))
i915_gem_object_truncate(obj);

+ if (obj->mm.region) {
+ mutex_lock(&obj->mm.region->obj_lock);
+
+ switch (obj->mm.madv) {
+ case I915_MADV_WILLNEED:
+ list_move(&obj->mm.region_link,
+ &obj->mm.region->objects);
+ break;
+ default:
+ list_move(&obj->mm.region_link,
+ &obj->mm.region->purgeable);
+ break;
+ }
+
+ mutex_unlock(&obj->mm.region->obj_lock);
+ }
+
args->retained = obj->mm.madv != __I915_MADV_PURGED;
mutex_unlock(&obj->mm.lock);

diff --git a/drivers/gpu/drm/i915/intel_memory_region.c b/drivers/gpu/drm/i915/intel_memory_region.c
index ef12e462acb8..3a3caaadea1f 100644
--- a/drivers/gpu/drm/i915/intel_memory_region.c
+++ b/drivers/gpu/drm/i915/intel_memory_region.c
@@ -12,6 +12,51 @@ const u32 intel_region_map[] = {
[INTEL_MEMORY_STOLEN] = BIT(INTEL_STOLEN + INTEL_MEMORY_TYPE_SHIFT) | BIT(0),
};

+static int
+intel_memory_region_evict(struct intel_memory_region *mem,
+ resource_size_t target,
+ unsigned int flags)
+{
+ struct drm_i915_gem_object *obj;
+ resource_size_t found;
+ int err;
+
+ err = 0;
+ found = 0;
+
+ mutex_lock(&mem->obj_lock);
+ list_for_each_entry(obj, &mem->purgeable, mm.region_link) {
+ if (!i915_gem_object_has_pages(obj))
+ continue;
+
+ if (READ_ONCE(obj->pin_global))
+ continue;
+
+ if (atomic_read(&obj->bind_count))
+ continue;
+
+ mutex_unlock(&mem->obj_lock);
+
+ __i915_gem_object_put_pages(obj, I915_MM_SHRINKER);
+
+ mutex_lock_nested(&obj->mm.lock, I915_MM_SHRINKER);
+ if (!i915_gem_object_has_pages(obj)) {
+ obj->mm.madv = __I915_MADV_PURGED;
+ found += obj->base.size;
+ }
+ mutex_unlock(&obj->mm.lock);
+
+ if (found >= target)
+ return 0;
+
+ mutex_lock(&mem->obj_lock);
+ }
+
+ err = -ENOSPC;
+ mutex_unlock(&mem->obj_lock);
+ return err;
+}
+
static u64
intel_memory_region_free_pages(struct intel_memory_region *mem,
struct list_head *blocks)
@@ -63,7 +108,8 @@ __intel_memory_region_get_pages_buddy(struct intel_memory_region *mem,
do {
struct i915_buddy_block *block;
unsigned int order;
-
+ bool retry = true;
+retry:
order = fls(n_pages) - 1;
GEM_BUG_ON(order > mem->mm.max_order);

@@ -72,9 +118,24 @@ __intel_memory_region_get_pages_buddy(struct intel_memory_region *mem,
if (!IS_ERR(block))
break;

- /* XXX: some kind of eviction pass, local to the device */
- if (flags & I915_ALLOC_CONTIGUOUS || !order--)
- goto err_free_blocks;
+ if (flags & I915_ALLOC_CONTIGUOUS || !order--) {
+ resource_size_t target;
+ int err;
+
+ if (!retry)
+ goto err_free_blocks;
+
+ target = n_pages * mem->mm.chunk_size;
+
+ mutex_unlock(&mem->mm_lock);
+ err = intel_memory_region_evict(mem, target, 0);
+ mutex_lock(&mem->mm_lock);
+ if (err)
+ goto err_free_blocks;
+
+ retry = false;
+ goto retry;
+ }
} while (1);

n_pages -= BIT(order);
@@ -147,6 +208,10 @@ intel_memory_region_create(struct drm_i915_private *i915,
mem->min_page_size = min_page_size;
mem->ops = ops;

+ mutex_init(&mem->obj_lock);
+ INIT_LIST_HEAD(&mem->objects);
+ INIT_LIST_HEAD(&mem->purgeable);
+
mutex_init(&mem->mm_lock);

if (ops->init) {
diff --git a/drivers/gpu/drm/i915/intel_memory_region.h b/drivers/gpu/drm/i915/intel_memory_region.h
index d299fed169e9..340411dcf86b 100644
--- a/drivers/gpu/drm/i915/intel_memory_region.h
+++ b/drivers/gpu/drm/i915/intel_memory_region.h
@@ -78,6 +78,11 @@ struct intel_memory_region {
unsigned int type;
unsigned int instance;
unsigned int id;
+
+ /* Protects access to objects and purgeable */
+ struct mutex obj_lock;
+ struct list_head objects;
+ struct list_head purgeable;
};

int intel_memory_region_init_buddy(struct intel_memory_region *mem);
diff --git a/drivers/gpu/drm/i915/selftests/intel_memory_region.c b/drivers/gpu/drm/i915/selftests/intel_memory_region.c
index 84daa92bf92c..2f13e4c1d999 100644
--- a/drivers/gpu/drm/i915/selftests/intel_memory_region.c
+++ b/drivers/gpu/drm/i915/selftests/intel_memory_region.c
@@ -79,10 +79,86 @@ static int igt_mock_fill(void *arg)
return err;
}

+static void igt_mark_evictable(struct drm_i915_gem_object *obj)
+{
+ i915_gem_object_unpin_pages(obj);
+ obj->mm.madv = I915_MADV_DONTNEED;
+ list_move(&obj->mm.region_link, &obj->mm.region->purgeable);
+}
+
+static int igt_mock_shrink(void *arg)
+{
+ struct intel_memory_region *mem = arg;
+ struct drm_i915_gem_object *obj;
+ unsigned long n_objects;
+ LIST_HEAD(objects);
+ resource_size_t target;
+ resource_size_t total;
+ int err = 0;
+
+ target = mem->mm.chunk_size;
+ total = resource_size(&mem->region);
+ n_objects = total / target;
+
+ while (n_objects--) {
+ obj = i915_gem_object_create_region(mem,
+ target,
+ 0);
+ if (IS_ERR(obj)) {
+ err = PTR_ERR(obj);
+ goto err_close_objects;
+ }
+
+ list_add(&obj->st_link, &objects);
+
+ err = i915_gem_object_pin_pages(obj);
+ if (err)
+ goto err_close_objects;
+
+ /*
+ * Make half of the region evictable, though do so in a
+ * horribly fragmented fashion.
+ */
+ if (n_objects % 2)
+ igt_mark_evictable(obj);
+ }
+
+ while (target <= total / 2) {
+ obj = i915_gem_object_create_region(mem, target, 0);
+ if (IS_ERR(obj)) {
+ err = PTR_ERR(obj);
+ goto err_close_objects;
+ }
+
+ list_add(&obj->st_link, &objects);
+
+ /* Provoke the shrinker to start violently swinging its axe! */
+ err = i915_gem_object_pin_pages(obj);
+ if (err) {
+ pr_err("failed to shrink for target=%pa", &target);
+ goto err_close_objects;
+ }
+
+ /* Again, half of the region should remain evictable */
+ igt_mark_evictable(obj);
+
+ target <<= 1;
+ }
+
+err_close_objects:
+ close_objects(&objects);
+
+ if (err == -ENOMEM)
+ err = 0;
+
+ return err;
+}
+
int intel_memory_region_mock_selftests(void)
{
static const struct i915_subtest tests[] = {
SUBTEST(igt_mock_fill),
+ SUBTEST(igt_mock_shrink),
};
struct intel_memory_region *mem;
struct drm_i915_private *i915;
diff --git a/drivers/gpu/drm/i915/selftests/mock_region.c b/drivers/gpu/drm/i915/selftests/mock_region.c
index fbde890385c7..cc97250dca62 100644
--- a/drivers/gpu/drm/i915/selftests/mock_region.c
+++ b/drivers/gpu/drm/i915/selftests/mock_region.c
@@ -11,6 +11,7 @@
static const struct drm_i915_gem_object_ops mock_region_obj_ops = {
.get_pages = i915_gem_object_get_pages_buddy,
.put_pages = i915_gem_object_put_pages_buddy,
+ .release = i915_gem_object_release_memory_region,
};

static struct drm_i915_gem_object *