Revert "[wasm] Reduce job priority once baseline compilation finishes"

This reverts commit cf9a28b6.

Reason for revert: TSAN failures: https://ci.chromium.org/p/v8/builders/ci/V8%20Linux64%20TSAN/34374?

Original change's description:
> [wasm] Reduce job priority once baseline compilation finishes
>
> This Cl changes the priority of baseline compilation from kUserVisible
> to kUserBlocking. Once baseline compilation finishes, the priority is
> reduced to kUserVisible. The reason for using kUserBlocking is that
> thereby TurboFan compilation cannot block Liftoff compilation anymore.
> Additionally, kUserBlocking is quite appropriate, as the initial
> compilation does block a whole section of a web app from execution.
>
> R=​clemensb@chromium.org
>
> Bug: v8:11088
> Change-Id: Ifde42d20f36d4c0a5122b0008311ccdffbb60e48
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2519559
> Commit-Queue: Andreas Haas <ahaas@chromium.org>
> Reviewed-by: Clemens Backes <clemensb@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#71404}

TBR=ahaas@chromium.org,clemensb@chromium.org

Change-Id: I9a975c4c43189015491b08d3a98de991d8167daf
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: v8:11088
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2560200Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/master@{#71409}

src/wasm/module-compiler.cc

@@ -595,10 +595,9 @@ class CompilationStateImpl {
 
   void WaitForCompilationEvent(CompilationEvent event);
 
-  void ReduceCompilationPriority() {
-    if (current_compile_job_ && current_compile_job_->UpdatePriorityEnabled()) {
-      current_compile_job_->UpdatePriority(TaskPriority::kUserVisible);
-    }
+  void SetHighPriority() {
+    base::MutexGuard guard(&mutex_);
+    has_priority_ = true;
   }
 
   bool failed() const {
@@ -676,6 +675,8 @@ class CompilationStateImpl {
   //////////////////////////////////////////////////////////////////////////////
   // Protected by {mutex_}:
 
+  bool has_priority_ = false;
+
   std::shared_ptr<JobHandle> current_compile_job_;
 
   // Features detected to be used in this module. Features can be detected
@@ -798,6 +799,8 @@ void CompilationState::WaitForTopTierFinished() {
   top_tier_finished_semaphore->Wait();
 }
 
+void CompilationState::SetHighPriority() { Impl(this)->SetHighPriority(); }
+
 void CompilationState::InitializeAfterDeserialization() {
   Impl(this)->InitializeCompilationProgressAfterDeserialization();
 }
@@ -1635,6 +1638,8 @@ std::shared_ptr<NativeModule> CompileToNativeModule(
   native_module = isolate->wasm_engine()->NewNativeModule(
       isolate, enabled, module, code_size_estimate);
   native_module->SetWireBytes(std::move(wire_bytes_copy));
+  // Sync compilation is user blocking, so we increase the priority.
+  native_module->compilation_state()->SetHighPriority();
 
   v8::metrics::Recorder::ContextId context_id =
       isolate->GetOrRegisterRecorderContextId(isolate->native_context());
@@ -2714,13 +2719,7 @@ CompilationStateImpl::CompilationStateImpl(
                         ? CompileMode::kTiering
                         : CompileMode::kRegular),
       async_counters_(std::move(async_counters)),
-      compilation_unit_queues_(native_module->num_functions()) {
-  AddCallback([&](CompilationEvent event) {
-    if (event == CompilationEvent::kFinishedBaselineCompilation) {
-      ReduceCompilationPriority();
-    }
-  });
-}
+      compilation_unit_queues_(native_module->num_functions()) {}
 
 void CompilationStateImpl::CancelCompilation() {
   // No more callbacks after abort.
@@ -3242,9 +3241,15 @@ void CompilationStateImpl::ScheduleCompileJobForNewUnits() {
     std::unique_ptr<JobTask> new_compile_job =
         std::make_unique<BackgroundCompileJob>(native_module_weak_,
                                                async_counters_);
+    // TODO(wasm): Lower priority for TurboFan-only jobs.
     new_job_handle = V8::GetCurrentPlatform()->PostJob(
-        TaskPriority::kUserBlocking, std::move(new_compile_job));
+        has_priority_ ? TaskPriority::kUserBlocking
+                      : TaskPriority::kUserVisible,
+        std::move(new_compile_job));
     current_compile_job_ = new_job_handle;
+    // Reset the priority. Later uses of the compilation state, e.g. for
+    // debugging, should compile with the default priority again.
+    has_priority_ = false;
   }
 
   if (new_job_handle) {
@@ -3367,7 +3372,7 @@ void CompileJsToWasmWrappers(Isolate* isolate, const WasmModule* module,
   auto job = std::make_unique<CompileJSToWasmWrapperJob>(
       &queue, &compilation_units, max_concurrency);
   auto job_handle = V8::GetCurrentPlatform()->PostJob(
-      TaskPriority::kUserBlocking, std::move(job));
+      TaskPriority::kUserVisible, std::move(job));
 
   // Wait for completion, while contributing to the work.
   job_handle->Join();