content: Use at most 128MB of discardable memory on Android.

content/common/host_discardable_shared_memory_manager.cc

 // Copyright 2014 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 "content/common/host_discardable_shared_memory_manager.h"
 
 #include <algorithm>
 
 #include "base/atomic_sequence_num.h"
 #include "base/bind.h"
@@ skipping 50 matching lines @@
   scoped_ptr<base::DiscardableSharedMemory> shared_memory_;
   const base::Closure deleted_callback_;
   bool is_locked_;
 
   DISALLOW_COPY_AND_ASSIGN(DiscardableMemoryImpl);
 };
 
 base::LazyInstance<HostDiscardableSharedMemoryManager>
     g_discardable_shared_memory_manager = LAZY_INSTANCE_INITIALIZER;
 
+#if defined(OS_ANDROID)
+// Limits the number of FDs used to 32, assuming a 4MB allocation size.
+const int64_t kMaxDefaultMemoryLimit = 128 * 1024 * 1024;
+#else
 const int64_t kMaxDefaultMemoryLimit = 512 * 1024 * 1024;
+#endif
 
 const int kEnforceMemoryPolicyDelayMs = 1000;
 
 // Global atomic to generate unique discardable shared memory IDs.
 base::StaticAtomicSequenceNumber g_next_discardable_shared_memory_id;
 
 }  // namespace
 
 HostDiscardableSharedMemoryManager::MemorySegment::MemorySegment(
     scoped_ptr<base::DiscardableSharedMemory> memory)
     : memory_(memory.Pass()) {
 }
 
 HostDiscardableSharedMemoryManager::MemorySegment::~MemorySegment() {
 }
 
 HostDiscardableSharedMemoryManager::HostDiscardableSharedMemoryManager()
     : memory_limit_(
           // Allow 25% of physical memory to be used for discardable memory.
           std::min(base::SysInfo::AmountOfPhysicalMemory() / 4,
-                   kMaxDefaultMemoryLimit)),
+                   base::SysInfo::IsLowEndDevice()
+                       ?
+                       // Use 1/8th of discardable memory on low-end devices.
+                       kMaxDefaultMemoryLimit / 8
+                       : kMaxDefaultMemoryLimit)),
       bytes_allocated_(0),
       memory_pressure_listener_(new base::MemoryPressureListener(
           base::Bind(&HostDiscardableSharedMemoryManager::OnMemoryPressure,
                      base::Unretained(this)))),
       enforce_memory_policy_pending_(false),
       weak_ptr_factory_(this) {
   DCHECK_NE(memory_limit_, 0u);
 }
 
 HostDiscardableSharedMemoryManager::~HostDiscardableSharedMemoryManager() {
@@ skipping 288 matching lines @@
 
   enforce_memory_policy_pending_ = true;
   base::ThreadTaskRunnerHandle::Get()->PostDelayedTask(
       FROM_HERE,
       base::Bind(&HostDiscardableSharedMemoryManager::EnforceMemoryPolicy,
                  weak_ptr_factory_.GetWeakPtr()),
       base::TimeDelta::FromMilliseconds(kEnforceMemoryPolicyDelayMs));
 }
 
 }  // namespace content