GLES ProgramCache listens to memory pressure

gpu/command_buffer/service/memory_program_cache.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "gpu/command_buffer/service/memory_program_cache.h"
 
 #include <stddef.h>
 
 #include "base/base64.h"
+#include "base/bind.h"
 #include "base/callback.h"
 #include "base/command_line.h"
+#include "base/metrics/histogram_functions.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/sha1.h"
 #include "base/strings/string_number_conversions.h"
 #include "gpu/command_buffer/common/activity_flags.h"
 #include "gpu/command_buffer/common/constants.h"
 #include "gpu/command_buffer/service/disk_cache_proto.pb.h"
 #include "gpu/command_buffer/service/gl_utils.h"
 #include "gpu/command_buffer/service/gles2_cmd_decoder.h"
 #include "gpu/command_buffer/service/gpu_preferences.h"
 #include "gpu/command_buffer/service/shader_manager.h"
@@ skipping 191 matching lines @@
     size_t max_cache_size_bytes,
     bool disable_gpu_shader_disk_cache,
     bool disable_program_caching_for_transform_feedback,
     GpuProcessActivityFlags* activity_flags)
     : max_size_bytes_(max_cache_size_bytes),
       disable_gpu_shader_disk_cache_(disable_gpu_shader_disk_cache),
       disable_program_caching_for_transform_feedback_(
           disable_program_caching_for_transform_feedback),
       curr_size_bytes_(0),
       store_(ProgramMRUCache::NO_AUTO_EVICT),
-      activity_flags_(activity_flags) {}
+      activity_flags_(activity_flags),
+      memory_pressure_listener_(
+          base::Bind(&MemoryProgramCache::HandleMemoryPressure,
+                     base::Unretained(this))) {}
 
 MemoryProgramCache::~MemoryProgramCache() {}
 
 void MemoryProgramCache::ClearBackend() {
   store_.Clear();
   DCHECK_EQ(0U, curr_size_bytes_);
 }
 
 ProgramCache::ProgramLoadResult MemoryProgramCache::LoadLinkedProgram(
     GLuint program,
@@ skipping 230 matching lines @@
             fragment_attribs, fragment_uniforms, fragment_varyings,
             fragment_output_variables, fragment_interface_blocks, this));
 
     UMA_HISTOGRAM_COUNTS("GPU.ProgramCache.MemorySizeAfterKb",
                          curr_size_bytes_ / 1024);
   } else {
     LOG(ERROR) << "Failed to parse proto file.";
   }
 }
 
+void MemoryProgramCache::HandleMemoryPressure(
+    base::MemoryPressureListener::MemoryPressureLevel memory_pressure_level) {
+  // Set a low limit on cache size for MEMORY_PRESSURE_LEVEL_MODERATE.
+  size_t limit = max_size_bytes_ / 4;
+  if (memory_pressure_level ==
+      base::MemoryPressureListener::MEMORY_PRESSURE_LEVEL_CRITICAL) {
+    limit = 0;
+  }
+  if (curr_size_bytes_ <= limit)
+    return;
+  size_t initial_size = curr_size_bytes_;
+  while (curr_size_bytes_ > limit && !store_.empty())
+    store_.Erase(store_.rbegin());
+  base::UmaHistogramCounts100000("GPU.ProgramCache.MemoryReleasedOnPressure",

[Ilya Sherman, 2017/06/08 01:11:38]

Optional nit: It's slightly more efficient to use the macro version,
UMA_HISTOGRAM_COUNTS_100000, when the histogram name is a constant.

[ssid, 2017/06/08 01:18:44]

Ah yes. Thanks! I should remember when to use the macros.

+                                 (initial_size - curr_size_bytes_) / 1024);
+}
+
 MemoryProgramCache::ProgramCacheValue::ProgramCacheValue(
     GLsizei length,
     GLenum format,
     const char* data,
     const std::string& program_hash,
     const char* shader_0_hash,
     const AttributeMap& attrib_map_0,
     const UniformMap& uniform_map_0,
     const VaryingMap& varying_map_0,
     const OutputVariableList& output_variable_list_0,
@@ skipping 26 matching lines @@
   program_cache_->LinkedProgramCacheSuccess(program_hash);
 }
 
 MemoryProgramCache::ProgramCacheValue::~ProgramCacheValue() {
   program_cache_->curr_size_bytes_ -= length_;
   program_cache_->Evict(program_hash_);
 }
 
 }  // namespace gles2
 }  // namespace gpu