[PATCH v2 03/37] drm/i915/region: support basic eviction

Matthew Auld
2019-06-27T20:56:40Z

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/i915_gem.c | 16 ++++
drivers/gpu/drm/i915/intel_memory_region.c | 89 ++++++++++++++++++-
drivers/gpu/drm/i915/intel_memory_region.h | 10 +++
.../drm/i915/selftests/intel_memory_region.c | 73 +++++++++++++++
drivers/gpu/drm/i915/selftests/mock_region.c | 1 +
6 files changed, 192 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 8d760e852c4b..87000fc24ab3 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_object_types.h
+++ b/drivers/gpu/drm/i915/gem/i915_gem_object_types.h
@@ -72,6 +72,13 @@ 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 eviction_link;

struct {
/**
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index db3744b0bc80..85677ae89849 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -1122,6 +1122,22 @@ i915_gem_madvise_ioctl(struct drm_device *dev, void *data,
!i915_gem_object_has_pages(obj))
i915_gem_object_truncate(obj);

+ if (obj->memory_region) {
+ mutex_lock(&obj->memory_region->obj_lock);
+
+ switch (obj->mm.madv) {
+ case I915_MADV_WILLNEED:
+ list_move(&obj->region_link, &obj->memory_region->objects);
+ break;
+ default:
+ list_move(&obj->region_link,
+ &obj->memory_region->purgeable);
+ break;
+ }
+
+ mutex_unlock(&obj->memory_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 4c89853a7769..721b47e46492 100644
--- a/drivers/gpu/drm/i915/intel_memory_region.c
+++ b/drivers/gpu/drm/i915/intel_memory_region.c
@@ -6,6 +6,56 @@
#include "intel_memory_region.h"
#include "i915_drv.h"

+int i915_memory_region_evict(struct intel_memory_region *mem,
+ resource_size_t target)
+{
+ struct drm_i915_gem_object *obj, *on;
+ resource_size_t found;
+ LIST_HEAD(purgeable);
+ int err;
+
+ err = 0;
+ found = 0;
+
+ mutex_lock(&mem->obj_lock);
+
+ list_for_each_entry(obj, &mem->purgeable, region_link) {
+ if (!i915_gem_object_has_pages(obj))
+ continue;
+
+ if (READ_ONCE(obj->pin_global))
+ continue;
+
+ if (atomic_read(&obj->bind_count))
+ continue;
+
+ list_add(&obj->eviction_link, &purgeable);
+
+ found += obj->base.size;
+ if (found >= target)
+ goto found;
+ }
+
+ err = -ENOSPC;
+found:
+ list_for_each_entry_safe(obj, on, &purgeable, eviction_link) {
+ if (!err) {
+ __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;
+ mutex_unlock(&obj->mm.lock);
+ }
+
+ list_del(&obj->eviction_link);
+ }
+
+ mutex_unlock(&mem->obj_lock);
+
+ return err;
+}
+
static void
memory_region_free_pages(struct drm_i915_gem_object *obj,
struct sg_table *pages)
@@ -70,7 +120,8 @@ i915_memory_region_get_pages_buddy(struct drm_i915_gem_object *obj)
unsigned int order;
u64 block_size;
u64 offset;
-
+ bool retry = true;
+retry:
order = fls(n_pages) - 1;
GEM_BUG_ON(order > mem->mm.max_order);

@@ -79,9 +130,24 @@ i915_memory_region_get_pages_buddy(struct drm_i915_gem_object *obj)
if (!IS_ERR(block))
break;

- /* XXX: some kind of eviction pass, local to the device */
- if (!order--)
- goto err_free_blocks;
+ if (!order--) {
+ resource_size_t target;
+ int err;
+
+ if (!retry)
+ goto err_free_blocks;
+
+ target = n_pages * mem->mm.min_size;
+
+ mutex_unlock(&mem->mm_lock);
+ err = i915_memory_region_evict(mem, target);
+ mutex_lock(&mem->mm_lock);
+ if (err)
+ goto err_free_blocks;
+
+ retry = false;
+ goto retry;
+ }
} while (1);

n_pages -= BIT(order);
@@ -136,6 +202,13 @@ void i915_memory_region_release_buddy(struct intel_memory_region *mem)
i915_buddy_fini(&mem->mm);
}

+void i915_gem_object_release_memory_region(struct drm_i915_gem_object *obj)
+{
+ mutex_lock(&obj->memory_region->obj_lock);
+ list_del(&obj->region_link);
+ mutex_unlock(&obj->memory_region->obj_lock);
+}
+
struct drm_i915_gem_object *
i915_gem_object_create_region(struct intel_memory_region *mem,
resource_size_t size,
@@ -164,6 +237,10 @@ i915_gem_object_create_region(struct intel_memory_region *mem,
INIT_LIST_HEAD(&obj->blocks);
obj->memory_region = mem;

+ mutex_lock(&mem->obj_lock);
+ list_add(&obj->region_link, &mem->objects);
+ mutex_unlock(&mem->obj_lock);
+
return obj;
}

@@ -188,6 +265,10 @@ 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 8d4736bdde50..bee0c022d295 100644
--- a/drivers/gpu/drm/i915/intel_memory_region.h
+++ b/drivers/gpu/drm/i915/intel_memory_region.h
@@ -80,8 +80,16 @@ 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 i915_memory_region_evict(struct intel_memory_region *mem,
+ resource_size_t target);
+
int i915_memory_region_init_buddy(struct intel_memory_region *mem);
void i915_memory_region_release_buddy(struct intel_memory_region *mem);

@@ -89,6 +97,8 @@ int i915_memory_region_get_pages_buddy(struct drm_i915_gem_object *obj);
void i915_memory_region_put_pages_buddy(struct drm_i915_gem_object *obj,
struct sg_table *pages);

+void i915_gem_object_release_memory_region(struct drm_i915_gem_object *obj);
+
struct intel_memory_region *
intel_memory_region_create(struct drm_i915_private *i915,
resource_size_t start,
diff --git a/drivers/gpu/drm/i915/selftests/intel_memory_region.c b/drivers/gpu/drm/i915/selftests/intel_memory_region.c
index c3b160cfd713..ece499869747 100644
--- a/drivers/gpu/drm/i915/selftests/intel_memory_region.c
+++ b/drivers/gpu/drm/i915/selftests/intel_memory_region.c
@@ -76,10 +76,83 @@ 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->region_link, &obj->memory_region->purgeable);
+}
+
+static int igt_mock_evict(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.min_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);
+
+ err = i915_gem_object_pin_pages(obj);
+ if (err) {
+ pr_err("failed to evict 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_evict),
};
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 cb942a461e9d..80eafdc54927 100644
--- a/drivers/gpu/drm/i915/selftests/mock_region.c
+++ b/drivers/gpu/drm/i915/selftests/mock_region.c
@@ -8,6 +8,7 @@
static const struct drm_i915_gem_object_ops mock_region_obj_ops = {
.get_pages = i915_memory_region_get_pages_buddy,
.put_pages = i915_memory_region_put_pages_buddy,
+ .release = i915_gem_object_release_memory_region,
};

static struct drm_i915_gem_object *
--
2.20.1