[PATCH 11/55] drm/i915: Introduce an internal allocator for disposable private objects
Chris Wilson
chris at chris-wilson.co.uk
Mon Sep 19 10:36:25 UTC 2016
Quite a few of our objects used for internal hardware programming do not
benefit from being swappable or from being zero initialised. As such
they do not benefit from using a shmemfs backing storage and since they
are internal and never directly exposed to the user, we do not need to
worry about providing a filp. For these we can use an
drm_i915_gem_object wrapper around a sg_table of plain struct page. They
are not swapped backed and not automatically pinned. If they are reaped
by the shrinker, the pages are released and the contents discarded. For
the internal use case, this is fine as for example, ringbuffers are
pinned from being written by a request to be read by the hardware. Once
they are idle, they can be discarded entirely. As such they are a good
match for execlist ringbuffers and a small varierty of other internal
objects.
In the first iteration, this is limited to the scratch batch buffers we
use (for command parsing and state initialisation).
Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
drivers/gpu/drm/i915/Makefile | 1 +
drivers/gpu/drm/i915/i915_drv.h | 5 +
drivers/gpu/drm/i915/i915_gem_batch_pool.c | 28 ++---
drivers/gpu/drm/i915/i915_gem_internal.c | 156 +++++++++++++++++++++++++++
drivers/gpu/drm/i915/i915_gem_render_state.c | 2 +-
drivers/gpu/drm/i915/intel_engine_cs.c | 2 +-
drivers/gpu/drm/i915/intel_ringbuffer.c | 2 +-
7 files changed, 174 insertions(+), 22 deletions(-)
create mode 100644 drivers/gpu/drm/i915/i915_gem_internal.c
diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
index a998c2bce70a..b94a90f34d2d 100644
--- a/drivers/gpu/drm/i915/Makefile
+++ b/drivers/gpu/drm/i915/Makefile
@@ -35,6 +35,7 @@ i915-y += i915_cmd_parser.o \
i915_gem_execbuffer.o \
i915_gem_fence.o \
i915_gem_gtt.o \
+ i915_gem_internal.o \
i915_gem.o \
i915_gem_render_state.o \
i915_gem_request.o \
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 89eab85ab11c..6ef2068ed399 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -3522,6 +3522,11 @@ i915_gem_object_create_stolen_for_preallocated(struct drm_device *dev,
u32 gtt_offset,
u32 size);
+/* i915_gem_internal.c */
+struct drm_i915_gem_object *
+i915_gem_object_create_internal(struct drm_device *dev,
+ unsigned int size);
+
/* i915_gem_shrinker.c */
unsigned long i915_gem_shrink(struct drm_i915_private *dev_priv,
unsigned long target,
diff --git a/drivers/gpu/drm/i915/i915_gem_batch_pool.c b/drivers/gpu/drm/i915/i915_gem_batch_pool.c
index cb25cad3318c..3934c9103cf2 100644
--- a/drivers/gpu/drm/i915/i915_gem_batch_pool.c
+++ b/drivers/gpu/drm/i915/i915_gem_batch_pool.c
@@ -97,9 +97,9 @@ i915_gem_batch_pool_get(struct i915_gem_batch_pool *pool,
size_t size)
{
struct drm_i915_gem_object *obj = NULL;
- struct drm_i915_gem_object *tmp, *next;
+ struct drm_i915_gem_object *tmp;
struct list_head *list;
- int n;
+ int n, ret;
lockdep_assert_held(&pool->engine->i915->drm.struct_mutex);
@@ -112,19 +112,12 @@ i915_gem_batch_pool_get(struct i915_gem_batch_pool *pool,
n = ARRAY_SIZE(pool->cache_list) - 1;
list = &pool->cache_list[n];
- list_for_each_entry_safe(tmp, next, list, batch_pool_link) {
+ list_for_each_entry(tmp, list, batch_pool_link) {
/* The batches are strictly LRU ordered */
if (!i915_gem_active_is_idle(&tmp->last_read[pool->engine->id],
&tmp->base.dev->struct_mutex))
break;
- /* While we're looping, do some clean up */
- if (tmp->madv == __I915_MADV_PURGED) {
- list_del(&tmp->batch_pool_link);
- i915_gem_object_put(tmp);
- continue;
- }
-
if (tmp->base.size >= size) {
obj = tmp;
break;
@@ -132,19 +125,16 @@ i915_gem_batch_pool_get(struct i915_gem_batch_pool *pool,
}
if (obj == NULL) {
- int ret;
-
- obj = i915_gem_object_create(&pool->engine->i915->drm, size);
+ obj = i915_gem_object_create_internal(&pool->engine->i915->drm,
+ size);
if (IS_ERR(obj))
return obj;
-
- ret = i915_gem_object_get_pages(obj);
- if (ret)
- return ERR_PTR(ret);
-
- obj->madv = I915_MADV_DONTNEED;
}
+ ret = i915_gem_object_get_pages(obj);
+ if (ret)
+ return ERR_PTR(ret);
+
list_move_tail(&obj->batch_pool_link, list);
i915_gem_object_pin_pages(obj);
return obj;
diff --git a/drivers/gpu/drm/i915/i915_gem_internal.c b/drivers/gpu/drm/i915/i915_gem_internal.c
new file mode 100644
index 000000000000..4ea6d7e3fb3f
--- /dev/null
+++ b/drivers/gpu/drm/i915/i915_gem_internal.c
@@ -0,0 +1,156 @@
+/*
+ * Copyright © 2015 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ *
+ */
+
+#include <drm/drmP.h>
+#include <drm/i915_drm.h>
+#include "i915_drv.h"
+
+static void __i915_gem_object_free_pages(struct sg_table *st)
+{
+ struct sg_page_iter sg_iter;
+
+ for_each_sg_page(st->sgl, &sg_iter, st->nents, 0)
+ put_page(sg_page_iter_page(&sg_iter));
+
+ sg_free_table(st);
+ kfree(st);
+}
+
+static int i915_gem_object_get_pages_internal(struct drm_i915_gem_object *obj)
+{
+ const unsigned int npages = obj->base.size / PAGE_SIZE;
+ struct sg_table *st;
+ struct scatterlist *sg;
+ unsigned long last_pfn = 0; /* suppress gcc warning */
+ gfp_t gfp;
+ int i;
+
+ st = kmalloc(sizeof(*st), GFP_KERNEL);
+ if (!st)
+ return -ENOMEM;
+
+ if (sg_alloc_table(st, npages, GFP_KERNEL)) {
+ kfree(st);
+ return -ENOMEM;
+ }
+
+ sg = st->sgl;
+ st->nents = 0;
+
+ gfp = GFP_KERNEL | __GFP_HIGHMEM;
+ gfp |= __GFP_NORETRY | __GFP_NOWARN;
+ gfp &= ~(__GFP_IO | __GFP_RECLAIM);
+ for (i = 0; i < npages; i++) {
+ struct page *page;
+
+ page = alloc_page(gfp);
+ if (!page) {
+ i915_gem_shrink_all(to_i915(obj->base.dev));
+ page = alloc_page(GFP_KERNEL | __GFP_HIGHMEM);
+ if (!page)
+ goto err;
+ }
+
+#ifdef CONFIG_SWIOTLB
+ if (swiotlb_nr_tbl()) {
+ st->nents++;
+ sg_set_page(sg, page, PAGE_SIZE, 0);
+ sg = sg_next(sg);
+ continue;
+ }
+#endif
+ if (!i || page_to_pfn(page) != last_pfn + 1) {
+ if (i)
+ sg = sg_next(sg);
+ st->nents++;
+ sg_set_page(sg, page, PAGE_SIZE, 0);
+ } else {
+ sg->length += PAGE_SIZE;
+ }
+ last_pfn = page_to_pfn(page);
+ }
+#ifdef CONFIG_SWIOTLB
+ if (!swiotlb_nr_tbl())
+#endif
+ sg_mark_end(sg);
+ obj->pages = st;
+
+ if (i915_gem_gtt_prepare_object(obj)) {
+ obj->pages = NULL;
+ goto err;
+ }
+
+ obj->madv = I915_MADV_DONTNEED;
+ return 0;
+
+err:
+ sg_mark_end(sg);
+ __i915_gem_object_free_pages(st);
+ return -ENOMEM;
+}
+
+static void i915_gem_object_put_pages_internal(struct drm_i915_gem_object *obj)
+{
+ __i915_gem_object_free_pages(obj->pages);
+
+ obj->dirty = 0;
+ obj->madv = I915_MADV_WILLNEED;
+}
+
+static const struct drm_i915_gem_object_ops i915_gem_object_internal_ops = {
+ .flags = I915_GEM_OBJECT_HAS_STRUCT_PAGE,
+ .get_pages = i915_gem_object_get_pages_internal,
+ .put_pages = i915_gem_object_put_pages_internal,
+};
+
+/**
+ * Creates a new object that wraps some internal memory for private use.
+ * This object is not backed by swappable storage, and as such its contents
+ * are volatile and only valid whilst pinned. If the object is reaped by the
+ * shrinker, its pages and data will be discarded. Equally, it is not a full
+ * GEM object and so not valid for access from userspace. This makes it useful
+ * for hardware interfaces like ringbuffers (which are pinned from the time
+ * the request is written to the time the hardware stops accessing it), but
+ * not for contexts (which need to be preserved when not active for later
+ * reuse).
+ */
+struct drm_i915_gem_object *
+i915_gem_object_create_internal(struct drm_device *dev,
+ unsigned int size)
+{
+ struct drm_i915_gem_object *obj;
+
+ obj = i915_gem_object_alloc(dev);
+ if (!obj)
+ return ERR_PTR(-ENOMEM);
+
+ drm_gem_private_object_init(dev, &obj->base, size);
+ i915_gem_object_init(obj, &i915_gem_object_internal_ops);
+
+ obj->base.write_domain = I915_GEM_DOMAIN_CPU;
+ obj->base.read_domains = I915_GEM_DOMAIN_CPU;
+ obj->cache_level = HAS_LLC(dev) ? I915_CACHE_LLC : I915_CACHE_NONE;
+
+ return obj;
+}
diff --git a/drivers/gpu/drm/i915/i915_gem_render_state.c b/drivers/gpu/drm/i915/i915_gem_render_state.c
index 055139343137..53175aac5cd0 100644
--- a/drivers/gpu/drm/i915/i915_gem_render_state.c
+++ b/drivers/gpu/drm/i915/i915_gem_render_state.c
@@ -187,7 +187,7 @@ int i915_gem_render_state_init(struct drm_i915_gem_request *req)
if (so.rodata->batch_items * 4 > 4096)
return -EINVAL;
- obj = i915_gem_object_create(&req->i915->drm, 4096);
+ obj = i915_gem_object_create_internal(&req->i915->drm, 4096);
if (IS_ERR(obj))
return PTR_ERR(obj);
diff --git a/drivers/gpu/drm/i915/intel_engine_cs.c b/drivers/gpu/drm/i915/intel_engine_cs.c
index e405f1080296..4d7318382c9e 100644
--- a/drivers/gpu/drm/i915/intel_engine_cs.c
+++ b/drivers/gpu/drm/i915/intel_engine_cs.c
@@ -254,7 +254,7 @@ int intel_engine_create_scratch(struct intel_engine_cs *engine, int size)
obj = i915_gem_object_create_stolen(&engine->i915->drm, size);
if (!obj)
- obj = i915_gem_object_create(&engine->i915->drm, size);
+ obj = i915_gem_object_create_internal(&engine->i915->drm, size);
if (IS_ERR(obj)) {
DRM_ERROR("Failed to allocate scratch page\n");
return PTR_ERR(obj);
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index 6530acd8be69..c1476262e701 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -1836,7 +1836,7 @@ static int init_status_page(struct intel_engine_cs *engine)
unsigned int flags;
int ret;
- obj = i915_gem_object_create(&engine->i915->drm, 4096);
+ obj = i915_gem_object_create_internal(&engine->i915->drm, 4096);
if (IS_ERR(obj)) {
DRM_ERROR("Failed to allocate status page\n");
return PTR_ERR(obj);
--
2.9.3
More information about the Intel-gfx-trybot
mailing list