drm/msm: Add _NO_SHARE flag

Buffers that are not shared between contexts can share a single resv
object.  This way drm_gpuvm will not track them as external objects, and
submit-time validating overhead will be O(1) for all N non-shared BOs,
instead of O(n).

Signed-off-by: Rob Clark <robdclark@chromium.org>
Signed-off-by: Rob Clark <robin.clark@oss.qualcomm.com>
Tested-by: Antonino Maniscalco <antomani103@gmail.com>
Reviewed-by: Antonino Maniscalco <antomani103@gmail.com>
Patchwork: https://patchwork.freedesktop.org/patch/661497/

diff --git a/drivers/gpu/drm/msm/msm_drv.h b/drivers/gpu/drm/msm/msm_drv.h
index 0fe3c9a24baac6c38af2080d8b10bc8f317ea331..9b1ccb2b18f6ddf8afb9dc3d9728bc57a6343a1e 100644 (file)
--- a/drivers/gpu/drm/msm/msm_drv.h
+++ b/drivers/gpu/drm/msm/msm_drv.h
@@ -269,6 +269,7 @@ int msm_gem_prime_vmap(struct drm_gem_object *obj, struct iosys_map *map);
 void msm_gem_prime_vunmap(struct drm_gem_object *obj, struct iosys_map *map);
 struct drm_gem_object *msm_gem_prime_import_sg_table(struct drm_device *dev,
                struct dma_buf_attachment *attach, struct sg_table *sg);
+struct dma_buf *msm_gem_prime_export(struct drm_gem_object *obj, int flags);
 int msm_gem_prime_pin(struct drm_gem_object *obj);
 void msm_gem_prime_unpin(struct drm_gem_object *obj);
 

diff --git a/drivers/gpu/drm/msm/msm_gem.c b/drivers/gpu/drm/msm/msm_gem.c
index d16d3012434aaaa8ed860d26d1c01a21b328aa84..100d159d52e20e01d3898257afa540802637fcbd 100644 (file)
--- a/drivers/gpu/drm/msm/msm_gem.c
+++ b/drivers/gpu/drm/msm/msm_gem.c
@@ -546,6 +546,9 @@ static int get_and_pin_iova_range_locked(struct drm_gem_object *obj,
 
        msm_gem_assert_locked(obj);
 
+       if (to_msm_bo(obj)->flags & MSM_BO_NO_SHARE)
+               return -EINVAL;
+
        vma = get_vma_locked(obj, vm, range_start, range_end);
        if (IS_ERR(vma))
                return PTR_ERR(vma);
@@ -1076,6 +1079,14 @@ static void msm_gem_free_object(struct drm_gem_object *obj)
                put_pages(obj);
        }
 
+       if (msm_obj->flags & MSM_BO_NO_SHARE) {
+               struct drm_gem_object *r_obj =
+                       container_of(obj->resv, struct drm_gem_object, _resv);
+
+               /* Drop reference we hold to shared resv obj: */
+               drm_gem_object_put(r_obj);
+       }
+
        drm_gem_object_release(obj);
 
        kfree(msm_obj->metadata);
@@ -1108,6 +1119,15 @@ int msm_gem_new_handle(struct drm_device *dev, struct drm_file *file,
        if (name)
                msm_gem_object_set_name(obj, "%s", name);
 
+       if (flags & MSM_BO_NO_SHARE) {
+               struct msm_context *ctx = file->driver_priv;
+               struct drm_gem_object *r_obj = drm_gpuvm_resv_obj(ctx->vm);
+
+               drm_gem_object_get(r_obj);
+
+               obj->resv = r_obj->resv;
+       }
+
        ret = drm_gem_handle_create(file, obj, handle);
 
        /* drop reference from allocate - handle holds it now */
@@ -1140,6 +1160,7 @@ static const struct drm_gem_object_funcs msm_gem_object_funcs = {
        .free = msm_gem_free_object,
        .open = msm_gem_open,
        .close = msm_gem_close,
+       .export = msm_gem_prime_export,
        .pin = msm_gem_prime_pin,
        .unpin = msm_gem_prime_unpin,
        .get_sg_table = msm_gem_prime_get_sg_table,

diff --git a/drivers/gpu/drm/msm/msm_gem_prime.c b/drivers/gpu/drm/msm/msm_gem_prime.c
index 2e37913d5a6a5e5bfa774b70dfce5615612022ec..4d93f2daeeaa0356db38757fd5f2b670a365c220 100644 (file)
--- a/drivers/gpu/drm/msm/msm_gem_prime.c
+++ b/drivers/gpu/drm/msm/msm_gem_prime.c
@@ -16,6 +16,9 @@ struct sg_table *msm_gem_prime_get_sg_table(struct drm_gem_object *obj)
        struct msm_gem_object *msm_obj = to_msm_bo(obj);
        int npages = obj->size >> PAGE_SHIFT;
 
+       if (msm_obj->flags & MSM_BO_NO_SHARE)
+               return ERR_PTR(-EINVAL);
+
        if (WARN_ON(!msm_obj->pages))  /* should have already pinned! */
                return ERR_PTR(-ENOMEM);
 
@@ -45,6 +48,15 @@ struct drm_gem_object *msm_gem_prime_import_sg_table(struct drm_device *dev,
        return msm_gem_import(dev, attach->dmabuf, sg);
 }
 
+
+struct dma_buf *msm_gem_prime_export(struct drm_gem_object *obj, int flags)
+{
+       if (to_msm_bo(obj)->flags & MSM_BO_NO_SHARE)
+               return ERR_PTR(-EPERM);
+
+       return drm_gem_prime_export(obj, flags);
+}
+
 int msm_gem_prime_pin(struct drm_gem_object *obj)
 {
        struct page **pages;
@@ -53,6 +65,9 @@ int msm_gem_prime_pin(struct drm_gem_object *obj)
        if (drm_gem_is_imported(obj))
                return 0;
 
+       if (to_msm_bo(obj)->flags & MSM_BO_NO_SHARE)
+               return -EINVAL;
+
        pages = msm_gem_pin_pages_locked(obj);
        if (IS_ERR(pages))
                ret = PTR_ERR(pages);

diff --git a/include/uapi/drm/msm_drm.h b/include/uapi/drm/msm_drm.h
index b974f5a24dbcff9b6c00dedb5391677327f557fe..1bccc347945cf0c9a6f5b13b2e8fbf49efd95276 100644 (file)
--- a/include/uapi/drm/msm_drm.h
+++ b/include/uapi/drm/msm_drm.h
@@ -140,6 +140,19 @@ struct drm_msm_param {
 
 #define MSM_BO_SCANOUT       0x00000001     /* scanout capable */
 #define MSM_BO_GPU_READONLY  0x00000002
+/* Private buffers do not need to be explicitly listed in the SUBMIT
+ * ioctl, unless referenced by a drm_msm_gem_submit_cmd.  Private
+ * buffers may NOT be imported/exported or used for scanout (or any
+ * other situation where buffers can be indefinitely pinned, but
+ * cases other than scanout are all kernel owned BOs which are not
+ * visible to userspace).
+ *
+ * In exchange for those constraints, all private BOs associated with
+ * a single context (drm_file) share a single dma_resv, and if there
+ * has been no eviction since the last submit, there are no per-BO
+ * bookeeping to do, significantly cutting the SUBMIT overhead.
+ */
+#define MSM_BO_NO_SHARE      0x00000004
 #define MSM_BO_CACHE_MASK    0x000f0000
 /* cache modes */
 #define MSM_BO_CACHED        0x00010000
@@ -149,6 +162,7 @@ struct drm_msm_param {
 
 #define MSM_BO_FLAGS         (MSM_BO_SCANOUT | \
                               MSM_BO_GPU_READONLY | \
+                              MSM_BO_NO_SHARE | \
                               MSM_BO_CACHE_MASK)
 
 struct drm_msm_gem_new {