Bound time to delete cc::Resource

With OOP-D, we no longer have draw call pressure inducing flushes.
https://crbug.com/c/875319 suggests that there are cases where we
reuse tiles enough in the UI compositor that we never hit the
 unused_resources_.empty() condition in the EvictExpiredResource method.

This CL adds a deadline for the flush, so that we wait at most 1 second.

Bug: 875319
Cq-Include-Trybots: luci.chromium.try:android_optional_gpu_tests_rel;master.tryserver.blink:linux_trusty_blink_rel
Change-Id: Ifa8d516699be7ae1eff47db01f8be55a0aae92c8
Reviewed-on: https://chromium-review.googlesource.com/c/1284435
Commit-Queue: Jonathan Backer <backer@chromium.org>
Reviewed-by: Antoine Labour <piman@chromium.org>
Reviewed-by: Sunny Sachanandani <sunnyps@chromium.org>
Cr-Commit-Position: refs/heads/master@{#600387}

cc/resources/resource_pool.cc

@@ -67,6 +67,7 @@ bool ResourceMeetsSizeRequirements(const gfx::Size& requested_size,
 }  // namespace
 
 constexpr base::TimeDelta ResourcePool::kDefaultExpirationDelay;
+constexpr base::TimeDelta ResourcePool::kDefaultMaxFlushDelay;
 
 void ResourcePool::GpuBacking::InitOverlayCandidateAndTextureTarget(
     const viz::ResourceFormat format,
@@ -95,6 +96,7 @@ ResourcePool::ResourcePool(
       resource_expiration_delay_(expiration_delay),
       disallow_non_exact_reuse_(disallow_non_exact_reuse),
       tracing_id_(g_next_tracing_id.GetNext()),
+      flush_evicted_resources_deadline_(base::TimeTicks::Max()),
       weak_ptr_factory_(this) {
   base::trace_event::MemoryDumpManager::GetInstance()->RegisterDumpProvider(
       this, "cc::ResourcePool", task_runner_.get());
@@ -458,6 +460,10 @@ void ResourcePool::DeleteResource(std::unique_ptr<PoolResource> resource) {
       resource->size(), resource->format());
   total_memory_usage_bytes_ -= resource_bytes;
   --total_resource_count_;
+  if (flush_evicted_resources_deadline_ == base::TimeTicks::Max()) {
+    flush_evicted_resources_deadline_ =
+        base::TimeTicks::Now() + kDefaultMaxFlushDelay;
+  }
 }
 
 void ResourcePool::UpdateResourceContentIdAndInvalidation(
@@ -497,7 +503,9 @@ void ResourcePool::EvictExpiredResources() {
 
   EvictResourcesNotUsedSince(current_time - resource_expiration_delay_);
 
-  if (unused_resources_.empty()) {
+  if (unused_resources_.empty() ||
+      flush_evicted_resources_deadline_ < current_time) {
+    flush_evicted_resources_deadline_ = base::TimeTicks::Max();
     // If nothing is evictable, we have deleted one (and possibly more)
     // resources without any new activity. Flush to ensure these deletions are
     // processed.
@@ -510,9 +518,12 @@ void ResourcePool::EvictExpiredResources() {
   }
 
   // If we still have evictable resources, schedule a call to
-  // EvictExpiredResources at the time when the LRU buffer expires.
-  ScheduleEvictExpiredResourcesIn(GetUsageTimeForLRUResource() +
-                                  resource_expiration_delay_ - current_time);
+  // EvictExpiredResources for either (a) the time when the LRU buffer expires
+  // or (b) the deadline to explicitly flush previously evicted resources.
+  ScheduleEvictExpiredResourcesIn(
+      std::min(GetUsageTimeForLRUResource() + resource_expiration_delay_,
+               flush_evicted_resources_deadline_) -
+      current_time);
 }
 
 void ResourcePool::EvictResourcesNotUsedSince(base::TimeTicks time_limit) {

cc/resources/resource_pool.h

@@ -51,6 +51,9 @@ class CC_EXPORT ResourcePool : public base::trace_event::MemoryDumpProvider {
   // Delay before a resource is considered expired.
   static constexpr base::TimeDelta kDefaultExpirationDelay =
       base::TimeDelta::FromSeconds(5);
+  // Max delay before an evicted resource is flushed.
+  static constexpr base::TimeDelta kDefaultMaxFlushDelay =
+      base::TimeDelta::FromSeconds(1);
 
   // A base class to hold ownership of gpu backed PoolResources. Allows the
   // client to define destruction semantics.
@@ -391,6 +394,8 @@ class CC_EXPORT ResourcePool : public base::trace_event::MemoryDumpProvider {
 
   std::unique_ptr<base::MemoryPressureListener> memory_pressure_listener_;
 
+  base::TimeTicks flush_evicted_resources_deadline_;
+
   base::WeakPtrFactory<ResourcePool> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ResourcePool);