Flushing the cachelines for an object is slow, can be as much as 100ms
for a large framebuffer. We currently do this under the struct_mutex BKL
on execution or on pageflip. But now with the ability to add fences to
obj->resv for both flips and execbuf (and we naturally wait on the fence
before CPU access), we can move the clflush operation to a workqueue and
signal a fence for completion, thereby doing the work asynchronously and
not blocking the driver or its clients.
Suggested-by: Akash Goel <akash.goel@xxxxxxxxx>
Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx>
Cc: Matthew Auld <matthew.auld@xxxxxxxxx>
---
drivers/gpu/drm/i915/Makefile | 1 +
drivers/gpu/drm/i915/i915_drv.h | 8 +-
drivers/gpu/drm/i915/i915_gem.c | 66 ++--------
drivers/gpu/drm/i915/i915_gem_clflush.c | 192 +++++++++++++++++++++++++++++
drivers/gpu/drm/i915/i915_gem_execbuffer.c | 8 +-
drivers/gpu/drm/i915/intel_display.c | 49 ++++----
6 files changed, 238 insertions(+), 86 deletions(-)
create mode 100644 drivers/gpu/drm/i915/i915_gem_clflush.c
diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
index 1490d8622234..b1b580337c7a 100644
--- a/drivers/gpu/drm/i915/Makefile
+++ b/drivers/gpu/drm/i915/Makefile
@@ -29,6 +29,7 @@ i915-$(CONFIG_DEBUG_FS) += i915_debugfs.o intel_pipe_crc.o
# GEM code
i915-y += i915_cmd_parser.o \
i915_gem_batch_pool.o \
+ i915_gem_clflush.o \
i915_gem_context.o \
i915_gem_dmabuf.o \
i915_gem_evict.o \
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 4e7046df1b5e..de00768667b0 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -3389,7 +3389,13 @@ int i915_gem_reset_prepare(struct drm_i915_private *dev_priv);
void i915_gem_reset(struct drm_i915_private *dev_priv);
void i915_gem_reset_finish(struct drm_i915_private *dev_priv);
void i915_gem_set_wedged(struct drm_i915_private *dev_priv);
-void i915_gem_clflush_object(struct drm_i915_gem_object *obj, bool force);
+
+void i915_gem_clflush_init(struct drm_i915_private *i915);
+void i915_gem_clflush_object(struct drm_i915_gem_object *obj,
+ unsigned int flags);
+#define I915_CLFLUSH_FORCE BIT(0)
+#define I915_CLFLUSH_SYNC BIT(1)
+
void i915_gem_init_mmio(struct drm_i915_private *i915);
int __must_check i915_gem_init(struct drm_i915_private *dev_priv);
int __must_check i915_gem_init_hw(struct drm_i915_private *dev_priv);
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 9d382f110b5c..c8525d30b025 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -1621,23 +1621,17 @@ i915_gem_sw_finish_ioctl(struct drm_device *dev, void *data,
{
struct drm_i915_gem_sw_finish *args = data;
struct drm_i915_gem_object *obj;
- int err = 0;
obj = i915_gem_object_lookup(file, args->handle);
if (!obj)
return -ENOENT;
/* Pinned buffers may be scanout, so flush the cache */
- if (READ_ONCE(obj->pin_display)) {
- err = i915_mutex_lock_interruptible(dev);
- if (!err) {
- i915_gem_object_flush_cpu_write_domain(obj);
- mutex_unlock(&dev->struct_mutex);
- }
- }
+ if (READ_ONCE(obj->pin_display))
+ i915_gem_clflush_object(obj, I915_CLFLUSH_FORCE);
i915_gem_object_put(obj);
- return err;
+ return 0;
}
/**
@@ -3148,46 +3142,6 @@ int i915_gem_wait_for_idle(struct drm_i915_private *i915, unsigned int flags)
return 0;
}
-void i915_gem_clflush_object(struct drm_i915_gem_object *obj,
- bool force)
-{
- /* If we don't have a page list set up, then we're not pinned
- * to GPU, and we can ignore the cache flush because it'll happen
- * again at bind time.
- */
- if (!obj->mm.pages) {
- GEM_BUG_ON(obj->base.write_domain != I915_GEM_DOMAIN_CPU);
- return;
- }
-
- /*
- * Stolen memory is always coherent with the GPU as it is explicitly
- * marked as wc by the system, or the system is cache-coherent.
- * Similarly, we only access struct pages through the CPU cache, so
- * anything not backed by physical memory we consider to be always
- * coherent and not need clflushing.
- */
- if (!i915_gem_object_has_struct_page(obj))
- return;
-
- /* If the GPU is snooping the contents of the CPU cache,
- * we do not need to manually clear the CPU cache lines. However,
- * the caches are only snooped when the render cache is
- * flushed/invalidated. As we always have to emit invalidations
- * and flushes when moving into and out of the RENDER domain, correct
- * snooping behaviour occurs naturally as the result of our domain
- * tracking.
- */
- if (!force && cpu_cache_is_coherent(obj->base.dev, obj->cache_level)) {
- obj->cache_dirty = true;
- return;
- }
-
- trace_i915_gem_object_clflush(obj);
- drm_clflush_sg(obj->mm.pages);
- obj->cache_dirty = false;
-}
-
/** Flushes the GTT write domain for the object if it's dirty. */
static void
i915_gem_object_flush_gtt_write_domain(struct drm_i915_gem_object *obj)
@@ -3231,8 +3185,7 @@ i915_gem_object_flush_cpu_write_domain(struct drm_i915_gem_object *obj)
if (obj->base.write_domain != I915_GEM_DOMAIN_CPU)
return;
- i915_gem_clflush_object(obj, obj->pin_display);
- intel_fb_obj_flush(obj, false, ORIGIN_CPU);
+ i915_gem_clflush_object(obj, I915_CLFLUSH_SYNC);
obj->base.write_domain = 0;
trace_i915_gem_object_change_domain(obj,
@@ -3603,10 +3556,8 @@ i915_gem_object_pin_to_display_plane(struct drm_i915_gem_object *obj,
vma->display_alignment = max_t(u64, vma->display_alignment, alignment);
/* Treat this as an end-of-frame, like intel_user_framebuffer_dirty() */
- if (obj->cache_dirty || obj->base.write_domain == I915_GEM_DOMAIN_CPU) {
- i915_gem_clflush_object(obj, true);
- intel_fb_obj_flush(obj, false, ORIGIN_DIRTYFB);
- }
+ if (obj->cache_dirty || obj->base.write_domain == I915_GEM_DOMAIN_CPU)
+ i915_gem_clflush_object(obj, I915_CLFLUSH_FORCE);
old_write_domain = obj->base.write_domain;
old_read_domains = obj->base.read_domains;
@@ -3680,8 +3631,7 @@ i915_gem_object_set_to_cpu_domain(struct drm_i915_gem_object *obj, bool write)
/* Flush the CPU cache if it's still invalid. */
if ((obj->base.read_domains & I915_GEM_DOMAIN_CPU) == 0) {
- i915_gem_clflush_object(obj, false);
-
+ i915_gem_clflush_object(obj, I915_CLFLUSH_SYNC);
obj->base.read_domains |= I915_GEM_DOMAIN_CPU;
}
@@ -4553,6 +4503,8 @@ int i915_gem_init(struct drm_i915_private *dev_priv)
mutex_lock(&dev_priv->drm.struct_mutex);
+ i915_gem_clflush_init(dev_priv);
+
if (!i915.enable_execlists) {
dev_priv->gt.resume = intel_legacy_submission_resume;
dev_priv->gt.cleanup_engine = intel_engine_cleanup;
diff --git a/drivers/gpu/drm/i915/i915_gem_clflush.c b/drivers/gpu/drm/i915/i915_gem_clflush.c
new file mode 100644
index 000000000000..83293705cf2b
--- /dev/null
+++ b/drivers/gpu/drm/i915/i915_gem_clflush.c
@@ -0,0 +1,192 @@
+/*
+ * Copyright © 2016 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 "i915_drv.h"
+#include "intel_frontbuffer.h"
+
+static DEFINE_SPINLOCK(clflush_lock);
+static u64 clflush_context;
+
+struct clflushf {
+ struct dma_fence dma;
+ struct i915_sw_fence wait;
+ struct work_struct work;
+ struct drm_i915_gem_object *obj;
+};
+
+static const char *i915_clflush_get_driver_name(struct dma_fence *fence)
+{
+ return "i915";
+}
+
+static const char *i915_clflush_get_timeline_name(struct dma_fence *fence)
+{
+ return "clflush";
+}
+
+static bool i915_clflush_enable_signaling(struct dma_fence *fence)
+{
+ return true;
+}
+
+static void i915_clflush_release(struct dma_fence *fence)
+{
+ struct clflushf *f = container_of(fence, typeof(*f), dma);
+
+ i915_sw_fence_fini(&f->wait);
+
+ BUILD_BUG_ON(offsetof(typeof(*f), dma));
+ dma_fence_free(&f->dma);
+}
+
+static const struct dma_fence_ops i915_clflush_ops = {
+ .get_driver_name = i915_clflush_get_driver_name,
+ .get_timeline_name = i915_clflush_get_timeline_name,
+ .enable_signaling = i915_clflush_enable_signaling,
+ .wait = dma_fence_default_wait,
+ .release = i915_clflush_release,
+};
+
+static bool cpu_cache_is_coherent(struct drm_device *dev,
+ enum i915_cache_level level)
+{
+ return HAS_LLC(to_i915(dev)) || level != I915_CACHE_NONE;
+}
+
+static void __i915_do_clflush(struct drm_i915_gem_object *obj)
+{
+ drm_clflush_sg(obj->mm.pages);
+ obj->cache_dirty = false;
+
+ intel_fb_obj_flush(obj, false, ORIGIN_CPU);
+}
+
+static void i915_clflush_work(struct work_struct *work)
+{
+ struct clflushf *f = container_of(work, typeof(*f), work);
+ struct drm_i915_gem_object *obj = f->obj;
+
+ if (i915_gem_object_pin_pages(obj)) {
+ obj->cache_dirty = true;
+ goto out;
+ }
+
+ __i915_do_clflush(obj);
+
+ i915_gem_object_unpin_pages(obj);
+
+out:
+ i915_gem_object_put(obj);
+
+ dma_fence_signal(&f->dma);
+ dma_fence_put(&f->dma);
+}
+
+static int __i915_sw_fence_call
+i915_clflush_notify(struct i915_sw_fence *fence,
+ enum i915_sw_fence_notify state)
+{
+ struct clflushf *f = container_of(fence, typeof(*f), wait);
+
+ switch (state) {
+ case FENCE_COMPLETE:
+ schedule_work(&f->work);
+ break;
+
+ case FENCE_FREE:
+ dma_fence_put(&f->dma);
+ break;
+ }
+
+ return NOTIFY_DONE;
+}
+
+void i915_gem_clflush_object(struct drm_i915_gem_object *obj,
+ unsigned int flags)
+{
+ struct clflushf *f;
+
+ /*
+ * Stolen memory is always coherent with the GPU as it is explicitly
+ * marked as wc by the system, or the system is cache-coherent.
+ * Similarly, we only access struct pages through the CPU cache, so
+ * anything not backed by physical memory we consider to be always
+ * coherent and not need clflushing.
+ */
+ if (!i915_gem_object_has_struct_page(obj))
+ return;
+
+ /* If the GPU is snooping the contents of the CPU cache,
+ * we do not need to manually clear the CPU cache lines. However,
+ * the caches are only snooped when the render cache is
+ * flushed/invalidated. As we always have to emit invalidations
+ * and flushes when moving into and out of the RENDER domain, correct
+ * snooping behaviour occurs naturally as the result of our domain
+ * tracking.
+ */
+ if (!(flags & I915_CLFLUSH_FORCE) &&
+ cpu_cache_is_coherent(obj->base.dev, obj->cache_level)) {
+ obj->cache_dirty = true;
+ return;
+ }
+
+ trace_i915_gem_object_clflush(obj);
+
+ f = NULL;
+ if (!(flags & I915_CLFLUSH_SYNC))
+ f = kmalloc(sizeof(*f), GFP_KERNEL);
+ if (f) {
+ dma_fence_init(&f->dma,
+ &i915_clflush_ops,
+ &clflush_lock,
+ clflush_context,
+ 0);
+ i915_sw_fence_init(&f->wait, i915_clflush_notify);
+
+ f->obj = i915_gem_object_get(obj);
+ INIT_WORK(&f->work, i915_clflush_work);
+
+ dma_fence_get(&f->dma); /* 1 for fence, +1 for scheduled work */
+
+ i915_sw_fence_await_reservation(&f->wait,
+ obj->resv, NULL,
+ false, I915_FENCE_TIMEOUT,
+ GFP_KERNEL);
+
+ reservation_object_lock(obj->resv, NULL);
+ reservation_object_add_excl_fence(obj->resv, &f->dma);
+ reservation_object_unlock(obj->resv);
+
+ i915_sw_fence_commit(&f->wait);
+ } else if (obj->mm.pages) {
+ __i915_do_clflush(obj);
+ } else {
+ obj->cache_dirty = true;
+ }
+}
+
+void i915_gem_clflush_init(struct drm_i915_private *i915)
+{
+ clflush_context = dma_fence_context_alloc(1);
+}
diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
index da0846fe2ad6..341bbeb010da 100644
--- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
@@ -1114,13 +1114,15 @@ i915_gem_execbuffer_move_to_gpu(struct drm_i915_gem_request *req,
if (vma->exec_entry->flags & EXEC_OBJECT_ASYNC)
continue;
+ if (obj->base.write_domain & I915_GEM_DOMAIN_CPU) {
+ i915_gem_clflush_object(obj, 0);
+ obj->base.write_domain = 0;
+ }
+
ret = i915_gem_request_await_object
(req, obj, obj->base.pending_write_domain);
if (ret)
return ret;
-
- if (obj->base.write_domain & I915_GEM_DOMAIN_CPU)
- i915_gem_clflush_object(obj, false);
}
/* Unconditionally flush any chipset caches (for streaming writes). */
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index f6feb93d4bb1..f10feee58ffd 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -13189,6 +13189,29 @@ intel_prepare_plane_fb(struct drm_plane *plane,
struct drm_i915_gem_object *old_obj = intel_fb_obj(plane->state->fb);
int ret;
+ if (obj) {
+ if (plane->type == DRM_PLANE_TYPE_CURSOR &&
+ INTEL_INFO(dev_priv)->cursor_needs_physical) {
+ const int align = IS_I830(dev_priv) ? 16 * 1024 : 256;
+
+ ret = i915_gem_object_attach_phys(obj, align);
+ if (ret) {
+ DRM_DEBUG_KMS("failed to attach phys object\n");
+ return ret;
+ }
+ } else {
+ struct i915_vma *vma;
+
+ vma = intel_pin_and_fence_fb_obj(fb, new_state->rotation);
+ if (IS_ERR(vma)) {
+ DRM_DEBUG_KMS("failed to pin object\n");
+ return PTR_ERR(vma);
+ }
+
+ to_intel_plane_state(new_state)->vma = vma;
+ }
+ }
+
if (!obj && !old_obj)
return 0;
@@ -13241,26 +13264,6 @@ intel_prepare_plane_fb(struct drm_plane *plane,
i915_gem_object_wait_priority(obj, 0, I915_PRIORITY_DISPLAY);
}
- if (plane->type == DRM_PLANE_TYPE_CURSOR &&
- INTEL_INFO(dev_priv)->cursor_needs_physical) {
- int align = IS_I830(dev_priv) ? 16 * 1024 : 256;
- ret = i915_gem_object_attach_phys(obj, align);
- if (ret) {
- DRM_DEBUG_KMS("failed to attach phys object\n");
- return ret;
- }
- } else {
- struct i915_vma *vma;
-
- vma = intel_pin_and_fence_fb_obj(fb, new_state->rotation);
- if (IS_ERR(vma)) {
- DRM_DEBUG_KMS("failed to pin object\n");
- return PTR_ERR(vma);
- }
-
- to_intel_plane_state(new_state)->vma = vma;
- }
-
return 0;
}
@@ -14279,15 +14282,11 @@ static int intel_user_framebuffer_dirty(struct drm_framebuffer *fb,
struct drm_clip_rect *clips,
unsigned num_clips)
{
- struct drm_device *dev = fb->dev;
struct intel_framebuffer *intel_fb = to_intel_framebuffer(fb);
struct drm_i915_gem_object *obj = intel_fb->obj;
- mutex_lock(&dev->struct_mutex);
if (obj->pin_display && obj->cache_dirty)
- i915_gem_clflush_object(obj, true);
- intel_fb_obj_flush(obj, false, ORIGIN_DIRTYFB);
- mutex_unlock(&dev->struct_mutex);
+ i915_gem_clflush_object(obj, I915_CLFLUSH_FORCE);
return 0;
}
--
2.11.0
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