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/*
* Copyright (C) 2019 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "src/tracing/internal/in_process_tracing_backend.h"
#include "perfetto/base/logging.h"
#include "perfetto/base/task_runner.h"
#include "perfetto/ext/base/paged_memory.h"
#include "perfetto/ext/tracing/core/shared_memory.h"
#include "perfetto/ext/tracing/core/tracing_service.h"
// TODO(primiano): When the in-process backend is used, we should never end up
// in a situation where the thread where the TracingService and Producer live
// writes a packet and hence can get into the GetNewChunk() stall.
// This would happen only if the API client code calls Trace() from one of the
// callbacks it receives (e.g. OnStart(), OnStop()). We should either cause a
// hard crash or ignore traces from that thread if that happens, because it
// will deadlock (the Service will never free up the SMB because won't ever get
// to run the task).
namespace perfetto {
namespace internal {
namespace {
class InProcessShm : public SharedMemory {
public:
explicit InProcessShm(size_t size);
~InProcessShm() override;
void* start() const override;
size_t size() const override;
private:
base::PagedMemory mem_;
};
class InProcessShmFactory : public SharedMemory::Factory {
public:
~InProcessShmFactory() override;
std::unique_ptr<SharedMemory> CreateSharedMemory(size_t) override;
};
InProcessShm::~InProcessShm() = default;
InProcessShm::InProcessShm(size_t size)
: mem_(base::PagedMemory::Allocate(size)) {}
void* InProcessShm::start() const {
return mem_.Get();
}
size_t InProcessShm::size() const {
return mem_.size();
}
InProcessShmFactory::~InProcessShmFactory() = default;
std::unique_ptr<SharedMemory> InProcessShmFactory::CreateSharedMemory(
size_t size) {
return std::unique_ptr<SharedMemory>(new InProcessShm(size));
}
} // namespace
// static
InProcessTracingBackend* InProcessTracingBackend::GetInstance() {
static auto* instance = new InProcessTracingBackend();
return instance;
}
InProcessTracingBackend::InProcessTracingBackend() {}
std::unique_ptr<ProducerEndpoint> InProcessTracingBackend::ConnectProducer(
const ConnectProducerArgs& args) {
PERFETTO_DCHECK(args.task_runner->RunsTasksOnCurrentThread());
// This should never happen as we can have at most one in-process backend.
if (service_)
PERFETTO_FATAL("InProcessTracingBackend initialized twice");
return GetOrCreateService(args.task_runner)
->ConnectProducer(args.producer, /*uid=*/0, args.producer_name,
args.shmem_size_hint_bytes,
/*in_process=*/true,
TracingService::ProducerSMBScrapingMode::kEnabled,
args.shmem_page_size_hint_bytes);
}
std::unique_ptr<ConsumerEndpoint> InProcessTracingBackend::ConnectConsumer(
const ConnectConsumerArgs& args) {
return GetOrCreateService(args.task_runner)
->ConnectConsumer(args.consumer, /*uid=*/0);
}
TracingService* InProcessTracingBackend::GetOrCreateService(
base::TaskRunner* task_runner) {
if (!service_) {
std::unique_ptr<InProcessShmFactory> shm(new InProcessShmFactory());
service_ = TracingService::CreateInstance(std::move(shm), task_runner);
service_->SetSMBScrapingEnabled(true);
}
return service_.get();
}
} // namespace internal
} // namespace perfetto