[code caching] Allow native code entries to take up to half the cache

- Adds new net::CacheType values so the JS code cache can be distinguished
  from the WASM code cache. GENERATED_BYTE_CODE_CACHE refers to Javascript,
  GENERATED_NATIVE_CODE_CACHE refers to WebAssembly.
- Changes SimpleBackendImpl::MaxFileSize to allow PNACL and WASM cache
  entries to take up to 1/2 of the cache. The previous limit was 1/8 of
  the cache.

This CL makes it possible for apps with large WASM modules (150 MB) to
benefit from code caching on desktop. The limit of 1/2 the cache size is
somewhat conservative. PNACL entries are also native code and can occupy
the entire cache (see BackEndImpl::MaxFileSize).

Bug: chromium:719172
Change-Id: Id177862f00c138034d43a5256d317928a48aa467
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1636648Reviewed-by: Maks Orlovich <morlovich@chromium.org>
Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Reviewed-by: Mythri Alle <mythria@chromium.org>
Commit-Queue: Bill Budge <bbudge@chromium.org>
Cr-Commit-Position: refs/heads/master@{#665925}

content/browser/code_cache/generated_code_cache.cc

@@ -312,9 +312,11 @@ void GeneratedCodeCache::CreateBackend() {
   // If the initialization of the existing cache fails, this call would delete
   // all the contents and recreates a new one.
   int rv = disk_cache::CreateCacheBackend(
-      net::GENERATED_CODE_CACHE, net::CACHE_BACKEND_SIMPLE, path_,
-      max_size_bytes_, true, nullptr, &shared_backend_ptr->data,
-      std::move(create_backend_complete));
+      cache_type_ == GeneratedCodeCache::CodeCacheType::kJavaScript
+          ? net::GENERATED_BYTE_CODE_CACHE
+          : net::GENERATED_NATIVE_CODE_CACHE,
+      net::CACHE_BACKEND_SIMPLE, path_, max_size_bytes_, true, nullptr,
+      &shared_backend_ptr->data, std::move(create_backend_complete));
   if (rv != net::ERR_IO_PENDING) {
     DidCreateBackend(shared_backend_ptr, rv);
   }

net/base/cache_type.h

@@ -9,14 +9,16 @@ namespace net {
 
 // The types of caches that can be created.
 enum CacheType {
-  DISK_CACHE,            // Disk is used as the backing storage.
-  MEMORY_CACHE,          // Data is stored only in memory.
-  MEDIA_CACHE,           // Optimized to handle media files.
-  APP_CACHE,             // Backing store for an AppCache.
-  SHADER_CACHE,          // Backing store for the GL shader cache.
-  PNACL_CACHE,           // Backing store the PNaCl translation cache
-  GENERATED_CODE_CACHE,  // Backing store for data (like code for JavaScript)
-                         // generated by renderer.
+  DISK_CACHE,                 // Disk is used as the backing storage.
+  MEMORY_CACHE,               // Data is stored only in memory.
+  MEDIA_CACHE,                // Optimized to handle media files.
+  APP_CACHE,                  // Backing store for an AppCache.
+  SHADER_CACHE,               // Backing store for the GL shader cache.
+  PNACL_CACHE,                // Backing store the PNaCl translation cache
+  GENERATED_BYTE_CODE_CACHE,  // Backing store for renderer generated data like
+                              // bytecode for JavaScript.
+  GENERATED_NATIVE_CODE_CACHE,  // Backing store for renderer generated data
+                                // like native code for WebAssembly.
 };
 
 // The types of disk cache backend, only used at backend instantiation.

net/disk_cache/blockfile/histogram_macros.h

@@ -102,7 +102,8 @@
       case net::PNACL_CACHE:                                         \
         CACHE_HISTOGRAM_##type(my_name.data(), sample);              \
         break;                                                       \
-      case net::GENERATED_CODE_CACHE:                                \
+      case net::GENERATED_BYTE_CODE_CACHE:                           \
+      case net::GENERATED_NATIVE_CODE_CACHE:                         \
         break;                                                       \
     }                                                                \
   }

net/disk_cache/disk_cache_fuzzer.cc

@@ -270,9 +270,13 @@ net::CacheType GetCacheTypeAndPrint(
       MAYBE_PRINT << "Cache type = PNACL_CACHE." << std::endl;
       return net::CacheType::PNACL_CACHE;
       break;
-    case disk_cache_fuzzer::FuzzCommands::GENERATED_CODE_CACHE:
-      MAYBE_PRINT << "Cache type = GENERATED_CODE_CACHE." << std::endl;
-      return net::CacheType::GENERATED_CODE_CACHE;
+    case disk_cache_fuzzer::FuzzCommands::GENERATED_BYTE_CODE_CACHE:
+      MAYBE_PRINT << "Cache type = GENERATED_BYTE_CODE_CACHE." << std::endl;
+      return net::CacheType::GENERATED_BYTE_CODE_CACHE;
+      break;
+    case disk_cache_fuzzer::FuzzCommands::GENERATED_NATIVE_CODE_CACHE:
+      MAYBE_PRINT << "Cache type = GENERATED_NATIVE_CODE_CACHE." << std::endl;
+      return net::CacheType::GENERATED_NATIVE_CODE_CACHE;
       break;
     case disk_cache_fuzzer::FuzzCommands::DISK_CACHE:
       MAYBE_PRINT << "Cache type = DISK_CACHE." << std::endl;

net/disk_cache/disk_cache_fuzzer.proto

@@ -28,8 +28,9 @@ message FuzzCommands {
     MEDIA_CACHE = 2;
     SHADER_CACHE = 3;
     PNACL_CACHE = 4;
-    GENERATED_CODE_CACHE = 5;
+    GENERATED_BYTE_CODE_CACHE = 5;
     DISK_CACHE = 6;
+    GENERATED_NATIVE_CODE_CACHE = 7;
   }
   required CacheType cache_type = 4;
 

net/disk_cache/simple/simple_backend_impl.cc

@@ -61,6 +61,10 @@ namespace {
 // Maximum fraction of the cache that one entry can consume.
 const int kMaxFileRatio = 8;
 
+// Native code entries can be large. Rather than increasing the overall cache
+// size, allow an individual entry to occupy up to half of the cache.
+const int kMaxNativeCodeFileRatio = 2;
+
 // Overrides the above.
 const int64_t kMinFileSizeLimit = 5 * 1024 * 1024;
 
@@ -247,7 +251,8 @@ SimpleBackendImpl::SimpleBackendImpl(
            base::TaskShutdownBehavior::BLOCK_SHUTDOWN})),
       orig_max_size_(max_bytes),
       entry_operations_mode_((cache_type == net::DISK_CACHE ||
-                              cache_type == net::GENERATED_CODE_CACHE)
+                              cache_type == net::GENERATED_BYTE_CODE_CACHE ||
+                              cache_type == net::GENERATED_NATIVE_CODE_CACHE)
                                  ? SimpleEntryImpl::OPTIMISTIC_OPERATIONS
                                  : SimpleEntryImpl::NON_OPTIMISTIC_OPERATIONS),
       net_log_(net_log) {
@@ -306,8 +311,11 @@ bool SimpleBackendImpl::SetMaxSize(int64_t max_bytes) {
 }
 
 int64_t SimpleBackendImpl::MaxFileSize() const {
+  uint64_t file_size_ratio = GetCacheType() == net::GENERATED_NATIVE_CODE_CACHE
+                                 ? kMaxNativeCodeFileRatio
+                                 : kMaxFileRatio;
   return std::max(
-      base::saturated_cast<int64_t>(index_->max_size() / kMaxFileRatio),
+      base::saturated_cast<int64_t>(index_->max_size() / file_size_ratio),
       kMinFileSizeLimit);
 }
 

net/disk_cache/simple/simple_histogram_macros.h

@@ -35,7 +35,8 @@
         SIMPLE_CACHE_THUNK(uma_type,                                        \
                            ("SimpleCache.Media." uma_name, ##__VA_ARGS__)); \
         break;                                                              \
-      case net::GENERATED_CODE_CACHE:                                       \
+      case net::GENERATED_BYTE_CODE_CACHE:                                  \
+      case net::GENERATED_NATIVE_CODE_CACHE:                                \
       case net::SHADER_CACHE:                                               \
         break;                                                              \
       default:                                                              \