discardable_memory: Using mojo IPC to replace Chrome IPC

components/discardable_memory/service/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 "components/discardable_memory/service/discardable_shared_memory_manager.h"
 
 #include <algorithm>
 #include <utility>
 
 #include "base/atomic_sequence_num.h"
@@ skipping 11 matching lines @@
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/stringprintf.h"
 #include "base/sys_info.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "base/trace_event/memory_allocator_dump.h"
 #include "base/trace_event/memory_dump_manager.h"
 #include "base/trace_event/process_memory_dump.h"
 #include "base/trace_event/trace_event.h"
 #include "build/build_config.h"
 #include "components/discardable_memory/common/discardable_shared_memory_heap.h"
+#include "mojo/public/cpp/bindings/strong_binding.h"
+#include "mojo/public/cpp/system/platform_handle.h"
 
 #if defined(OS_LINUX)
 #include "base/files/file_path.h"
 #include "base/files/file_util.h"
 #include "base/metrics/histogram_macros.h"
 #endif
 
 namespace discardable_memory {
 namespace {
 
 const char kSingleProcess[] = "single-process";
 
 const int kInvalidUniqueClientID = -1;
 
 const uint64_t kBrowserTracingProcessId = std::numeric_limits<uint64_t>::max();
 
 uint64_t ClientProcessUniqueIdToTracingProcessId(int client_id) {
   // TODO(penghuang): Move this function to right place.
   // https://crbug.com/661257
   if (base::CommandLine::ForCurrentProcess()->HasSwitch(kSingleProcess))
     return kBrowserTracingProcessId;
   // The hash value is incremented so that the tracing id is never equal to
   // MemoryDumpManager::kInvalidTracingProcessId.
   return static_cast<uint64_t>(base::Hash(
              reinterpret_cast<const char*>(&client_id), sizeof(client_id))) +
          1;
 }
 
+// mojom::DiscardableSharedMemoryManager implementation. It contains the
+// |client_id_| which is not visible to client. We associate allocations with a
+// given mojo instance, so if the instance is closed, we can release the
+// allocations associated with that instance.
+class MojoDiscardableSharedMemoryManagerImpl
+    : public mojom::DiscardableSharedMemoryManager {
+ public:
+  MojoDiscardableSharedMemoryManagerImpl(
+      int32_t client_id,
+      ::discardable_memory::DiscardableSharedMemoryManager* manager)
+      : client_id_(client_id), manager_(manager) {}
+
+  ~MojoDiscardableSharedMemoryManagerImpl() override {
+    // Remove this client from the |manager_|, so all allocated discardable
+    // memory belong to this client will be released.
+    manager_->ClientRemoved(client_id_);
+  }
+
+  // mojom::DiscardableSharedMemoryManager overrides:
+  void AllocateLockedDiscardableSharedMemory(
+      uint32_t size,
+      int32_t id,
+      const AllocateLockedDiscardableSharedMemoryCallback& callback) override {
+    base::SharedMemoryHandle handle;
+    manager_->AllocateLockedDiscardableSharedMemoryForClient(client_id_, size,
+                                                             id, &handle);
+    mojo::ScopedSharedBufferHandle memory =
+        mojo::WrapSharedMemoryHandle(handle, size, false /* read_only */);
+    return callback.Run(std::move(memory));
+  }
+
+  void DeletedDiscardableSharedMemory(int32_t id) override {
+    manager_->ClientDeletedDiscardableSharedMemory(id, client_id_);
+  }
+
+ private:
+  const int32_t client_id_;
+  ::discardable_memory::DiscardableSharedMemoryManager* const manager_;
+
+  DISALLOW_COPY_AND_ASSIGN(MojoDiscardableSharedMemoryManagerImpl);
+};
+
 class DiscardableMemoryImpl : public base::DiscardableMemory {
  public:
   DiscardableMemoryImpl(
       std::unique_ptr<base::DiscardableSharedMemory> shared_memory,
       const base::Closure& deleted_callback)
       : shared_memory_(std::move(shared_memory)),
         deleted_callback_(deleted_callback),
         is_locked_(true) {}
 
   ~DiscardableMemoryImpl() override {
@@ skipping 103 matching lines @@
 
 }  // namespace
 
 DiscardableSharedMemoryManager::MemorySegment::MemorySegment(
     std::unique_ptr<base::DiscardableSharedMemory> memory)
     : memory_(std::move(memory)) {}
 
 DiscardableSharedMemoryManager::MemorySegment::~MemorySegment() {}
 
 DiscardableSharedMemoryManager::DiscardableSharedMemoryManager()
-    : default_memory_limit_(GetDefaultMemoryLimit()),
+    : next_client_id_(1),
+      default_memory_limit_(GetDefaultMemoryLimit()),
       memory_limit_(default_memory_limit_),
       bytes_allocated_(0),
       memory_pressure_listener_(new base::MemoryPressureListener(
           base::Bind(&DiscardableSharedMemoryManager::OnMemoryPressure,
                      base::Unretained(this)))),
       // Current thread might not have a task runner in tests.
       enforce_memory_policy_task_runner_(base::ThreadTaskRunnerHandle::Get()),
       enforce_memory_policy_pending_(false),
       weak_ptr_factory_(this) {
   DCHECK_NE(memory_limit_, 0u);
   enforce_memory_policy_callback_ =
       base::Bind(&DiscardableSharedMemoryManager::EnforceMemoryPolicy,
                  weak_ptr_factory_.GetWeakPtr());
   base::trace_event::MemoryDumpManager::GetInstance()->RegisterDumpProvider(
       this, "DiscardableSharedMemoryManager",
       base::ThreadTaskRunnerHandle::Get());
   base::MemoryCoordinatorClientRegistry::GetInstance()->Register(this);
 }
 
 DiscardableSharedMemoryManager::~DiscardableSharedMemoryManager() {
   base::trace_event::MemoryDumpManager::GetInstance()->UnregisterDumpProvider(
       this);
 }
 
-DiscardableSharedMemoryManager* DiscardableSharedMemoryManager::current() {
+// static
+DiscardableSharedMemoryManager*
+DiscardableSharedMemoryManager::CreateInstance() {
+  DCHECK(g_discardable_shared_memory_manager == nullptr);
   return g_discardable_shared_memory_manager.Pointer();
 }
 
+// static
+DiscardableSharedMemoryManager* DiscardableSharedMemoryManager::GetInstance() {
+  DCHECK(!(g_discardable_shared_memory_manager == nullptr));
+  return g_discardable_shared_memory_manager.Pointer();
+}
+
+void DiscardableSharedMemoryManager::Bind(
+    mojom::DiscardableSharedMemoryManagerRequest request) {
+  mojo::MakeStrongBinding(
+      base::MakeUnique<MojoDiscardableSharedMemoryManagerImpl>(
+          next_client_id_++, this),
+      std::move(request));
+}
+
 std::unique_ptr<base::DiscardableMemory>
 DiscardableSharedMemoryManager::AllocateLockedDiscardableMemory(size_t size) {
   DCHECK_NE(size, 0u);
 
-  DiscardableSharedMemoryId new_id =
-      g_next_discardable_shared_memory_id.GetNext();
-  base::ProcessHandle current_process_handle = base::GetCurrentProcessHandle();
+  int32_t new_id = g_next_discardable_shared_memory_id.GetNext();
 
   // Note: Use DiscardableSharedMemoryHeap for in-process allocation
   // of discardable memory if the cost of each allocation is too high.
   base::SharedMemoryHandle handle;
-  AllocateLockedDiscardableSharedMemory(
-      current_process_handle, kInvalidUniqueClientID, size, new_id, &handle);
+  AllocateLockedDiscardableSharedMemory(kInvalidUniqueClientID, size, new_id,
+                                        &handle);
   std::unique_ptr<base::DiscardableSharedMemory> memory(
       new base::DiscardableSharedMemory(handle));
   if (!memory->Map(size))
     base::TerminateBecauseOutOfMemory(size);
   // Close file descriptor to avoid running out.
   memory->Close();
   return base::MakeUnique<DiscardableMemoryImpl>(
       std::move(memory),
       base::Bind(
           &DiscardableSharedMemoryManager::DeletedDiscardableSharedMemory,
@@ skipping 66 matching lines @@
                         static_cast<uint64_t>(resident_size));
       }
 #endif  // defined(COUNT_RESIDENT_BYTES_SUPPORTED)
     }
   }
   return true;
 }
 
 void DiscardableSharedMemoryManager::
     AllocateLockedDiscardableSharedMemoryForClient(
-        base::ProcessHandle process_handle,
         int client_id,
         size_t size,
-        DiscardableSharedMemoryId id,
+        int32_t id,
         base::SharedMemoryHandle* shared_memory_handle) {
-  AllocateLockedDiscardableSharedMemory(process_handle, client_id, size, id,
+  AllocateLockedDiscardableSharedMemory(client_id, size, id,
                                         shared_memory_handle);
 }
 
 void DiscardableSharedMemoryManager::ClientDeletedDiscardableSharedMemory(
-    DiscardableSharedMemoryId id,
+    int32_t id,
     int client_id) {
   DeletedDiscardableSharedMemory(id, client_id);
 }
 
 void DiscardableSharedMemoryManager::ClientRemoved(int client_id) {
   base::AutoLock lock(lock_);
 
   auto it = clients_.find(client_id);
   if (it == clients_.end())
     return;
@@ skipping 41 matching lines @@
     case base::MemoryState::SUSPENDED:
     // Note that SUSPENDED never occurs in the main browser process so far.
     // Fall through.
     case base::MemoryState::UNKNOWN:
       NOTREACHED();
       break;
   }
 }
 
 void DiscardableSharedMemoryManager::AllocateLockedDiscardableSharedMemory(
-    base::ProcessHandle process_handle,
     int client_id,
     size_t size,
-    DiscardableSharedMemoryId id,
+    int32_t id,
     base::SharedMemoryHandle* shared_memory_handle) {
   base::AutoLock lock(lock_);
 
   // Make sure |id| is not already in use.
   MemorySegmentMap& client_segments = clients_[client_id];
   if (client_segments.find(id) != client_segments.end()) {
     LOG(ERROR) << "Invalid discardable shared memory ID";
     *shared_memory_handle = base::SharedMemory::NULLHandle();
     return;
   }
@@ skipping 12 matching lines @@
   if (bytes_allocated_ > limit)
     ReduceMemoryUsageUntilWithinLimit(limit);
 
   std::unique_ptr<base::DiscardableSharedMemory> memory(
       new base::DiscardableSharedMemory);
   if (!memory->CreateAndMap(size)) {
     *shared_memory_handle = base::SharedMemory::NULLHandle();
     return;
   }
 
-  if (!memory->ShareToProcess(process_handle, shared_memory_handle)) {
-    LOG(ERROR) << "Cannot share discardable memory segment";
-    *shared_memory_handle = base::SharedMemory::NULLHandle();
-    return;
-  }
-
-  // Close file descriptor to avoid running out.
-  memory->Close();
-
   base::CheckedNumeric<size_t> checked_bytes_allocated = bytes_allocated_;
   checked_bytes_allocated += memory->mapped_size();
   if (!checked_bytes_allocated.IsValid()) {
     *shared_memory_handle = base::SharedMemory::NULLHandle();
     return;
   }
 
   bytes_allocated_ = checked_bytes_allocated.ValueOrDie();
   BytesAllocatedChanged(bytes_allocated_);
 
+  *shared_memory_handle = base::SharedMemory::DuplicateHandle(memory->handle());
+  // Close file descriptor to avoid running out.
+  memory->Close();
+
   scoped_refptr<MemorySegment> segment(new MemorySegment(std::move(memory)));
   client_segments[id] = segment.get();
   segments_.push_back(segment.get());
   std::push_heap(segments_.begin(), segments_.end(), CompareMemoryUsageTime);
 
   if (bytes_allocated_ > memory_limit_)
     ScheduleEnforceMemoryPolicy();
 }
 
 void DiscardableSharedMemoryManager::DeletedDiscardableSharedMemory(
-    DiscardableSharedMemoryId id,
+    int32_t id,
     int client_id) {
   base::AutoLock lock(lock_);
 
   MemorySegmentMap& client_segments = clients_[client_id];
 
   MemorySegmentMap::iterator segment_it = client_segments.find(id);
   if (segment_it == client_segments.end()) {
     LOG(ERROR) << "Invalid discardable shared memory ID";
     return;
   }
@@ skipping 122 matching lines @@
     return;
 
   enforce_memory_policy_pending_ = true;
   DCHECK(enforce_memory_policy_task_runner_);
   enforce_memory_policy_task_runner_->PostDelayedTask(
       FROM_HERE, enforce_memory_policy_callback_,
       base::TimeDelta::FromMilliseconds(kEnforceMemoryPolicyDelayMs));
 }
 
 }  // namespace discardable_memory