Mesa (marge_bot_batch_merge_job): util/primconvert: map only index buffer part that is needed

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Module: Mesa
Branch: marge_bot_batch_merge_job
Commit: aba2d879d4604a089dcf5b1d2eb23f7102fa56f4
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=aba2d879d4604a089dcf5b1d2eb23f7102fa56f4

Author: Gert Wollny <gert.wollny at collabora.com>
Date:   Wed Jan  5 15:17:36 2022 +0100

util/primconvert: map only index buffer part that is needed

By putting vertex store and indices all in one buffer the larger part
of the shared buffer might actually only be vertex data we are not
interested in. Hence only map the part of the buffer that contains the
index data for the currently active draw command.

This helps drivers where a mapping operation is expensive, like e.g. virgl.

v2: - add comment about ranged buffer mapping (Pierre-Eric)
    - keep passing direct_draws[i].start to direct_draw_func, it looks
      like the "start" parameter is properly set in
      util_prim_restart_convert_to_direct

v3: Fix ws error (Mike)

Related: #5825

Fixes: f9d12bf50e9c09a5896d9419f82d9f510982bc5d
   vbo/dlist: use a single buffer object

Signed-off-by: Gert Wollny <gert.wollny at collabora.com>
Reviewed-By: Mike Blumenkrantz <michael.blumenkrantz at gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/14423>

---

 src/util/indices/u_primconvert.c | 27 +++++++++++++++++----------
 1 file changed, 17 insertions(+), 10 deletions(-)

diff --git a/src/util/indices/u_primconvert.c b/src/util/indices/u_primconvert.c
index 11586ad76f2..ede86e4cd2a 100644
--- a/src/util/indices/u_primconvert.c
+++ b/src/util/indices/u_primconvert.c
@@ -121,13 +121,13 @@ primconvert_init_draw(struct primconvert_context *pc,
    unsigned total_index_count = draws->count;
    void *rewrite_buffer = NULL;
 
-   const struct pipe_draw_start_count_bias *draw = &draws[0];
+   struct pipe_draw_start_count_bias draw = draws[0];
 
    /* Filter out degenerate primitives, u_upload_alloc() will assert
     * on size==0 so just bail:
     */
    if (!info->primitive_restart &&
-       !u_trim_pipe_prim(info->mode, (unsigned*)&draw->count))
+       !u_trim_pipe_prim(info->mode, (unsigned*)&draw.count))
       return false;
 
    util_draw_init_info(new_info);
@@ -141,14 +141,21 @@ primconvert_init_draw(struct primconvert_context *pc,
    if (info->index_size) {
       enum pipe_prim_type mode = new_info->mode = u_index_prim_type_convert(pc->cfg.primtypes_mask, info->mode, true);
       unsigned index_size = info->index_size;
+      unsigned offset = draw.start * info->index_size;
+
       new_info->index_size = u_index_size_convert(info->index_size);
 
       src = info->has_user_indices ? info->index.user : NULL;
       if (!src) {
-         src = pipe_buffer_map(pc->pipe, info->index.resource,
-                               PIPE_MAP_READ, &src_transfer);
+         /* Map the index range we're interested in (not the whole buffer) */
+         src = pipe_buffer_map_range(pc->pipe, info->index.resource,
+                                     offset,
+                                     draw.count * info->index_size,
+                                     PIPE_MAP_READ, &src_transfer);
+         offset = 0;
+         draw.start = 0;
       }
-      const void *restart_src = (const uint8_t *)src + draw->start * info->index_size;
+      const void *restart_src = (const uint8_t *)src  + offset;
 
       /* if the resulting primitive type is not supported by the driver for primitive restart,
        * or if the original primitive type was not supported by the driver,
@@ -160,7 +167,7 @@ primconvert_init_draw(struct primconvert_context *pc,
          /* step 1: rewrite draw to not use primitive primitive restart;
           *         this pre-filters degenerate primitives
           */
-         direct_draws = util_prim_restart_convert_to_direct(restart_src, info, draw, &num_direct_draws,
+         direct_draws = util_prim_restart_convert_to_direct(restart_src, info, &draw, &num_direct_draws,
                                                             &new_info->min_index, &new_info->max_index, &total_index_count);
          new_info->primitive_restart = false;
          /* step 2: get a translator function which does nothing but handle any index size conversions
@@ -200,7 +207,7 @@ primconvert_init_draw(struct primconvert_context *pc,
       unsigned index_size;
 
       u_index_generator(pc->cfg.primtypes_mask,
-                        info->mode, draw->start, draw->count,
+                        info->mode, draw.start, draw.count,
                         pc->api_pv, pc->api_pv,
                         &mode, &index_size, &new_draw->count,
                         &gen_func);
@@ -212,7 +219,7 @@ primconvert_init_draw(struct primconvert_context *pc,
    u_upload_alloc(pc->pipe->stream_uploader, 0, new_info->index_size * new_draw->count, 4,
                   &ib_offset, &new_info->index.resource, &dst);
    new_draw->start = ib_offset / new_info->index_size;
-   new_draw->index_bias = info->index_size ? draw->index_bias : 0;
+   new_draw->index_bias = info->index_size ? draw.index_bias : 0;
 
    if (info->index_size) {
       if (num_direct_draws) {
@@ -238,7 +245,7 @@ primconvert_init_draw(struct primconvert_context *pc,
          /* step 7: set the final index count, which is the converted total index count from the original draw rewrite */
          new_draw->count = u_index_count_converted_indices(pc->cfg.primtypes_mask, true, info->mode, total_index_count);
       } else
-         trans_func(src, draw->start, draw->count, new_draw->count, info->restart_index, dst);
+         trans_func(src, draw.start, draw.count, new_draw->count, info->restart_index, dst);
 
       if (pc->cfg.fixed_prim_restart && new_info->primitive_restart) {
          new_info->restart_index = (1ull << (new_info->index_size * 8)) - 1;
@@ -249,7 +256,7 @@ primconvert_init_draw(struct primconvert_context *pc,
       }
    }
    else {
-      gen_func(draw->start, new_draw->count, dst);
+      gen_func(draw.start, new_draw->count, dst);
    }
 
    if (src_transfer)