BLI: use explicit task isolation, no longer part of parallel operations

After looking into task isolation issues with Sergey, we couldn't find the
reason behind the deadlocks that we are getting in T87938 and a Sprite Fright
file involving motion blur renders.

There is no apparent place where we adding or waiting on tasks in a task group
from different isolation regions, which is what is known to cause problems. Yet
it still hangs. Either we do not understand some limitation of TBB isolation,
or there is a bug in TBB, but we could not figure it out.

Instead the idea is to use isolation only where we know we need it: when
holding a mutex lock and then doing some multithreaded operation within that
locked region. Three places where we do this now:
* Generated images
* Cached BVH tree building
* OpenVDB lazy grid loading

Compared to the more automatic approach previously used, there is the downside
that it is easy to miss places where we need isolation. Yet doing it more
automatically is also causing unexpected issue and bugs that we found no
solution for, so this seems better.

Patch implemented by Sergey and me.

Differential Revision: https://developer.blender.org/D11603

6 files changed, 6 insertions, 7 deletions

diff --git a/source/blender/editors/mesh/editmesh_undo.c b/source/blender/editors/mesh/editmesh_undo.c
index 274f4cdbb6c..112de68b52c 100644
--- a/source/blender/editors/mesh/editmesh_undo.c
+++ b/source/blender/editors/mesh/editmesh_undo.c
@@ -626,7 +626,7 @@ static void *undomesh_from_editmesh(UndoMesh *um, BMEditMesh *em, Key *key, Undo
 
 #  ifdef USE_ARRAY_STORE_THREAD
     if (um_arraystore.task_pool == NULL) {
-      um_arraystore.task_pool = BLI_task_pool_create_background(NULL, TASK_PRIORITY_LOW, true);
+      um_arraystore.task_pool = BLI_task_pool_create_background(NULL, TASK_PRIORITY_LOW);
     }
 
     struct UMArrayData *um_data = MEM_mallocN(sizeof(*um_data), __func__);
diff --git a/source/blender/editors/render/render_opengl.c b/source/blender/editors/render/render_opengl.c
index cfc07de3f6c..48f937fb4ec 100644
--- a/source/blender/editors/render/render_opengl.c
+++ b/source/blender/editors/render/render_opengl.c
@@ -859,7 +859,7 @@ static bool screen_opengl_render_init(bContext *C, wmOperator *op)
       oglrender->task_pool = BLI_task_pool_create_background_serial(oglrender, TASK_PRIORITY_LOW);
     }
     else {
-      oglrender->task_pool = BLI_task_pool_create(oglrender, TASK_PRIORITY_LOW, TASK_ISOLATION_ON);
+      oglrender->task_pool = BLI_task_pool_create(oglrender, TASK_PRIORITY_LOW);
     }
     oglrender->pool_ok = true;
     BLI_spin_init(&oglrender->reports_lock);
diff --git a/source/blender/editors/sculpt_paint/paint_image_proj.c b/source/blender/editors/sculpt_paint/paint_image_proj.c
index 41db79bc134..26f86c8eabb 100644
--- a/source/blender/editors/sculpt_paint/paint_image_proj.c
+++ b/source/blender/editors/sculpt_paint/paint_image_proj.c
@@ -5571,7 +5571,7 @@ static bool project_paint_op(void *state, const float lastpos[2], const float po
   }
 
   if (ps->thread_tot > 1) {
-    task_pool = BLI_task_pool_create_suspended(NULL, TASK_PRIORITY_HIGH, TASK_ISOLATION_ON);
+    task_pool = BLI_task_pool_create_suspended(NULL, TASK_PRIORITY_HIGH);
   }
 
   image_pool = BKE_image_pool_new();
diff --git a/source/blender/editors/space_clip/clip_editor.c b/source/blender/editors/space_clip/clip_editor.c
index 9aa6a993c13..2da13646a8b 100644
--- a/source/blender/editors/space_clip/clip_editor.c
+++ b/source/blender/editors/space_clip/clip_editor.c
@@ -904,7 +904,7 @@ static void start_prefetch_threads(MovieClip *clip,
   queue.do_update = do_update;
   queue.progress = progress;
 
-  TaskPool *task_pool = BLI_task_pool_create(&queue, TASK_PRIORITY_LOW, TASK_ISOLATION_ON);
+  TaskPool *task_pool = BLI_task_pool_create(&queue, TASK_PRIORITY_LOW);
   for (int i = 0; i < tot_thread; i++) {
     BLI_task_pool_push(task_pool, prefetch_task_func, clip, false, NULL);
   }
diff --git a/source/blender/editors/space_clip/clip_ops.c b/source/blender/editors/space_clip/clip_ops.c
index 369a6e7c944..f5e4c4d55d9 100644
--- a/source/blender/editors/space_clip/clip_ops.c
+++ b/source/blender/editors/space_clip/clip_ops.c
@@ -1429,7 +1429,7 @@ static void do_sequence_proxy(void *pjv,
   queue.do_update = do_update;
   queue.progress = progress;
 
-  TaskPool *task_pool = BLI_task_pool_create(&queue, TASK_PRIORITY_LOW, TASK_ISOLATION_ON);
+  TaskPool *task_pool = BLI_task_pool_create(&queue, TASK_PRIORITY_LOW);
   handles = MEM_callocN(sizeof(ProxyThread) * tot_thread, "proxy threaded handles");
   for (int i = 0; i < tot_thread; i++) {
     ProxyThread *handle = &handles[i];
diff --git a/source/blender/editors/space_file/filelist.c b/source/blender/editors/space_file/filelist.c
index 8ea44e5c3ee..37a32164cfc 100644
--- a/source/blender/editors/space_file/filelist.c
+++ b/source/blender/editors/space_file/filelist.c
@@ -1553,8 +1553,7 @@ static void filelist_cache_preview_freef(TaskPool *__restrict UNUSED(pool), void
 static void filelist_cache_preview_ensure_running(FileListEntryCache *cache)
 {
   if (!cache->previews_pool) {
-    cache->previews_pool = BLI_task_pool_create_background(
-        cache, TASK_PRIORITY_LOW, TASK_ISOLATION_ON);
+    cache->previews_pool = BLI_task_pool_create_background(cache, TASK_PRIORITY_LOW);
     cache->previews_done = BLI_thread_queue_init();
 
     IMB_thumb_locks_acquire();