drm/radeon: validate relocations in the order determined by userspace v3

Userspace should set the first 4 bits of drm_radeon_cs_reloc::flags to
a number from 0 to 15. The higher the number, the higher the priority,
which means a buffer with a higher number will be validated sooner.

The old behavior is preserved: Buffers used for write are prioritized over
read-only buffers if the userspace doesn't set the number.

v2: add buffers to buckets directly, then concatenate them
v3: use a stable sort

Signed-off-by: Marek Olšák <marek.olsak@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>

diff --git a/drivers/gpu/drm/radeon/radeon.h b/drivers/gpu/drm/radeon/radeon.h
index 7bb8fd9..efad567 100644 (file)
--- a/drivers/gpu/drm/radeon/radeon.h
+++ b/drivers/gpu/drm/radeon/radeon.h
@@ -483,7 +483,6 @@ struct radeon_bo_list {
        struct ttm_validate_buffer tv;
        struct radeon_bo        *bo;
        uint64_t                gpu_offset;
-       bool                    written;
        unsigned                domain;
        unsigned                alt_domain;
        u32                     tiling_flags;

diff --git a/drivers/gpu/drm/radeon/radeon_cs.c b/drivers/gpu/drm/radeon/radeon_cs.c
index d49a3f7..07e1651 100644 (file)
--- a/drivers/gpu/drm/radeon/radeon_cs.c
+++ b/drivers/gpu/drm/radeon/radeon_cs.c
@@ -31,10 +31,52 @@
 #include "radeon.h"
 #include "radeon_trace.h"
 
+#define RADEON_CS_MAX_PRIORITY         32u
+#define RADEON_CS_NUM_BUCKETS          (RADEON_CS_MAX_PRIORITY + 1)
+
+/* This is based on the bucket sort with O(n) time complexity.
+ * An item with priority "i" is added to bucket[i]. The lists are then
+ * concatenated in descending order.
+ */
+struct radeon_cs_buckets {
+       struct list_head bucket[RADEON_CS_NUM_BUCKETS];
+};
+
+static void radeon_cs_buckets_init(struct radeon_cs_buckets *b)
+{
+       unsigned i;
+
+       for (i = 0; i < RADEON_CS_NUM_BUCKETS; i++)
+               INIT_LIST_HEAD(&b->bucket[i]);
+}
+
+static void radeon_cs_buckets_add(struct radeon_cs_buckets *b,
+                                 struct list_head *item, unsigned priority)
+{
+       /* Since buffers which appear sooner in the relocation list are
+        * likely to be used more often than buffers which appear later
+        * in the list, the sort mustn't change the ordering of buffers
+        * with the same priority, i.e. it must be stable.
+        */
+       list_add_tail(item, &b->bucket[min(priority, RADEON_CS_MAX_PRIORITY)]);
+}
+
+static void radeon_cs_buckets_get_list(struct radeon_cs_buckets *b,
+                                      struct list_head *out_list)
+{
+       unsigned i;
+
+       /* Connect the sorted buckets in the output list. */
+       for (i = 0; i < RADEON_CS_NUM_BUCKETS; i++) {
+               list_splice(&b->bucket[i], out_list);
+       }
+}
+
 static int radeon_cs_parser_relocs(struct radeon_cs_parser *p)
 {
        struct drm_device *ddev = p->rdev->ddev;
        struct radeon_cs_chunk *chunk;
+       struct radeon_cs_buckets buckets;
        unsigned i, j;
        bool duplicate;
 
@@ -53,8 +95,12 @@ static int radeon_cs_parser_relocs(struct radeon_cs_parser *p)
        if (p->relocs == NULL) {
                return -ENOMEM;
        }
+
+       radeon_cs_buckets_init(&buckets);
+
        for (i = 0; i < p->nrelocs; i++) {
                struct drm_radeon_cs_reloc *r;
+               unsigned priority;
 
                duplicate = false;
                r = (struct drm_radeon_cs_reloc *)&chunk->kdata[i*4];
@@ -80,7 +126,14 @@ static int radeon_cs_parser_relocs(struct radeon_cs_parser *p)
                p->relocs_ptr[i] = &p->relocs[i];
                p->relocs[i].robj = gem_to_radeon_bo(p->relocs[i].gobj);
                p->relocs[i].lobj.bo = p->relocs[i].robj;
-               p->relocs[i].lobj.written = !!r->write_domain;
+
+               /* The userspace buffer priorities are from 0 to 15. A higher
+                * number means the buffer is more important.
+                * Also, the buffers used for write have a higher priority than
+                * the buffers used for read only, which doubles the range
+                * to 0 to 31. 32 is reserved for the kernel driver.
+                */
+               priority = (r->flags & 0xf) * 2 + !!r->write_domain;
 
                /* the first reloc of an UVD job is the msg and that must be in
                   VRAM, also but everything into VRAM on AGP cards to avoid
@@ -94,6 +147,8 @@ static int radeon_cs_parser_relocs(struct radeon_cs_parser *p)
                        p->relocs[i].lobj.alt_domain =
                                RADEON_GEM_DOMAIN_VRAM;
 
+                       /* prioritize this over any other relocation */
+                       priority = RADEON_CS_MAX_PRIORITY;
                } else {
                        uint32_t domain = r->write_domain ?
                                r->write_domain : r->read_domains;
@@ -107,9 +162,12 @@ static int radeon_cs_parser_relocs(struct radeon_cs_parser *p)
                p->relocs[i].lobj.tv.bo = &p->relocs[i].robj->tbo;
                p->relocs[i].handle = r->handle;
 
-               radeon_bo_list_add_object(&p->relocs[i].lobj,
-                                         &p->validated);
+               radeon_cs_buckets_add(&buckets, &p->relocs[i].lobj.tv.head,
+                                     priority);
        }
+
+       radeon_cs_buckets_get_list(&buckets, &p->validated);
+
        return radeon_bo_list_validate(&p->ticket, &p->validated, p->ring);
 }
 

diff --git a/drivers/gpu/drm/radeon/radeon_object.c b/drivers/gpu/drm/radeon/radeon_object.c
index 282d6a2..8399fe0 100644 (file)
--- a/drivers/gpu/drm/radeon/radeon_object.c
+++ b/drivers/gpu/drm/radeon/radeon_object.c
@@ -366,16 +366,6 @@ void radeon_bo_fini(struct radeon_device *rdev)
        arch_phys_wc_del(rdev->mc.vram_mtrr);
 }
 
-void radeon_bo_list_add_object(struct radeon_bo_list *lobj,
-                               struct list_head *head)
-{
-       if (lobj->written) {
-               list_add(&lobj->tv.head, head);
-       } else {
-               list_add_tail(&lobj->tv.head, head);
-       }
-}
-
 int radeon_bo_list_validate(struct ww_acquire_ctx *ticket,
                            struct list_head *head, int ring)
 {

diff --git a/drivers/gpu/drm/radeon/radeon_object.h b/drivers/gpu/drm/radeon/radeon_object.h
index a9a8c11..6c3ca9e 100644 (file)
--- a/drivers/gpu/drm/radeon/radeon_object.h
+++ b/drivers/gpu/drm/radeon/radeon_object.h
@@ -138,8 +138,6 @@ extern int radeon_bo_evict_vram(struct radeon_device *rdev);
 extern void radeon_bo_force_delete(struct radeon_device *rdev);
 extern int radeon_bo_init(struct radeon_device *rdev);
 extern void radeon_bo_fini(struct radeon_device *rdev);
-extern void radeon_bo_list_add_object(struct radeon_bo_list *lobj,
-                               struct list_head *head);
 extern int radeon_bo_list_validate(struct ww_acquire_ctx *ticket,
                                   struct list_head *head, int ring);
 extern int radeon_bo_fbdev_mmap(struct radeon_bo *bo,