llvmpipe: keep context list and use to track resource usage.

Just check across all contexts if a resource is referenced.

Fixes: 6bbbe15a78 ("Reinstate: llvmpipe: allow vertex processing and fragment processing in parallel")
Acked-by: Mike Blumenkrantz <michael.blumenkrantz@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/17702>

src/gallium/drivers/llvmpipe/lp_context.c

@@ -57,8 +57,12 @@
 static void llvmpipe_destroy( struct pipe_context *pipe )
 {
    struct llvmpipe_context *llvmpipe = llvmpipe_context( pipe );
+   struct llvmpipe_screen *lp_screen = llvmpipe_screen(pipe->screen);
    uint i;
 
+   mtx_lock(&lp_screen->ctx_mutex);
+   list_del(&llvmpipe->list);
+   mtx_unlock(&lp_screen->ctx_mutex);
    lp_print_counters();
 
    if (llvmpipe->csctx) {
@@ -189,8 +193,9 @@ llvmpipe_create_context(struct pipe_screen *screen, void *priv,
                         unsigned flags)
 {
    struct llvmpipe_context *llvmpipe;
+   struct llvmpipe_screen *lp_screen = llvmpipe_screen(screen);
 
-   if (!llvmpipe_screen_late_init(llvmpipe_screen(screen)))
+   if (!llvmpipe_screen_late_init(lp_screen))
       return NULL;
 
    llvmpipe = align_malloc(sizeof(struct llvmpipe_context), 16);
@@ -258,7 +263,7 @@ llvmpipe_create_context(struct pipe_screen *screen, void *priv,
       goto fail;
 
    draw_set_disk_cache_callbacks(llvmpipe->draw,
-                                 llvmpipe_screen(screen),
+                                 lp_screen,
                                  lp_draw_disk_cache_find_shader,
                                  lp_draw_disk_cache_insert_shader);
 
@@ -311,6 +316,9 @@ llvmpipe_create_context(struct pipe_screen *screen, void *priv,
     */
    llvmpipe->dirty |= LP_NEW_SCISSOR;
 
+   mtx_lock(&lp_screen->ctx_mutex);
+   list_addtail(&llvmpipe->list, &lp_screen->ctx_list);
+   mtx_unlock(&lp_screen->ctx_mutex);
    return &llvmpipe->pipe;
 
  fail:

src/gallium/drivers/llvmpipe/lp_context.h

@@ -58,6 +58,7 @@ struct lp_velems_state;
 struct llvmpipe_context {
    struct pipe_context pipe;  /**< base class */
 
+   struct list_head list;
    /** Constant state objects */
    const struct pipe_blend_state *blend;
    struct pipe_sampler_state *samplers[PIPE_SHADER_TYPES][PIPE_MAX_SAMPLERS];

src/gallium/drivers/llvmpipe/lp_flush.c

@@ -111,10 +111,12 @@ llvmpipe_flush_resource(struct pipe_context *pipe,
                         boolean do_not_block,
                         const char *reason)
 {
-   unsigned referenced;
-
-   referenced = llvmpipe_is_resource_referenced(pipe, resource, level);
-
+   unsigned referenced = 0;
+   struct llvmpipe_screen *lp_screen = llvmpipe_screen(pipe->screen);
+   mtx_lock(&lp_screen->ctx_mutex);
+   list_for_each_entry(struct llvmpipe_context, ctx, &lp_screen->ctx_list, list)
+      referenced |= llvmpipe_is_resource_referenced((struct pipe_context *)ctx, resource, level);
+   mtx_unlock(&lp_screen->ctx_mutex);
    if ((referenced & LP_REFERENCED_FOR_WRITE) ||
        ((referenced & LP_REFERENCED_FOR_READ) && !read_only)) {
 

src/gallium/drivers/llvmpipe/lp_screen.c

@@ -1079,6 +1079,8 @@ llvmpipe_create_screen(struct sw_winsys *winsys)
 
    snprintf(screen->renderer_string, sizeof(screen->renderer_string), "llvmpipe (LLVM " MESA_LLVM_VERSION_STRING ", %u bits)", lp_native_vector_width );
 
+   list_inithead(&screen->ctx_list);
+   (void) mtx_init(&screen->ctx_mutex, mtx_plain);
    (void) mtx_init(&screen->cs_mutex, mtx_plain);
    (void) mtx_init(&screen->rast_mutex, mtx_plain);
 

src/gallium/drivers/llvmpipe/lp_screen.h

@@ -37,6 +37,7 @@
 #include "pipe/p_screen.h"
 #include "pipe/p_defines.h"
 #include "os/os_thread.h"
+#include "util/list.h"
 #include "gallivm/lp_bld.h"
 #include "gallivm/lp_bld_misc.h"
 
@@ -67,6 +68,9 @@ struct llvmpipe_screen
    mtx_t late_mutex;
    bool late_init_done;
 
+   mtx_t ctx_mutex;
+   struct list_head ctx_list;
+
    char renderer_string[100];
 
    struct disk_cache *disk_shader_cache;