Merge "RPC Binder: increase transaction size" into main (412d19a0) · Commits · e / os / android_frameworks_native

libs/binder/Binder.cpp

+2 −3

Original line number	Diff line number	Diff line
		@@ -38,6 +38,7 @@
		#endif

		#include "BuildFlags.h"
		#include "Constants.h"
		#include "OS.h"
		#include "RpcState.h"

		@@ -70,8 +71,6 @@ constexpr bool kEnableRecording = true;
		constexpr bool kEnableRecording = false;
		#endif

		// Log any reply transactions for which the data exceeds this size
		#define LOG_REPLIES_OVER_SIZE (300 * 1024)
		// ---------------------------------------------------------------------------

		IBinder::IBinder()
		@@ -412,7 +411,7 @@ status_t BBinder::transact(
		// In case this is being transacted on in the same process.
		if (reply != nullptr) {
		reply->setDataPosition(0);
		if (reply->dataSize() > LOG_REPLIES_OVER_SIZE) {
		if (reply->dataSize() > binder::kLogTransactionsOverBytes) {
		ALOGW("Large reply transaction of %zu bytes, interface descriptor %s, code %d",
		reply->dataSize(), String8(getInterfaceDescriptor()).c_str(), code);
		}

libs/binder/BpBinder.cpp

+5 −5

Original line number	Diff line number	Diff line
		@@ -28,6 +28,7 @@
		#include <stdio.h>

		#include "BuildFlags.h"
		#include "Constants.h"
		#include "file.h"

		//#undef ALOGV
		@@ -63,9 +64,6 @@ std::atomic<uint32_t> BpBinder::sBinderProxyCountWarned(0);

		static constexpr uint32_t kBinderProxyCountWarnInterval = 5000;

		// Log any transactions for which the data exceeds this size
		#define LOG_TRANSACTIONS_OVER_SIZE (300 * 1024)

		enum {
		LIMIT_REACHED_MASK = 0x80000000, // A flag denoting that the limit has been reached
		WARNING_REACHED_MASK = 0x40000000, // A flag denoting that the warning has been reached
		@@ -403,9 +401,11 @@ status_t BpBinder::transact(

		status = IPCThreadState::self()->transact(binderHandle(), code, data, reply, flags);
		}
		if (data.dataSize() > LOG_TRANSACTIONS_OVER_SIZE) {

		if (data.dataSize() > binder::kLogTransactionsOverBytes) {
		RpcMutexUniqueLock _l(mLock);
		ALOGW("Large outgoing transaction of %zu bytes, interface descriptor %s, code %d",
		ALOGW("Large outgoing transaction of %zu bytes, interface descriptor %s, code %d was "
		"sent",
		data.dataSize(), String8(mDescriptorCache).c_str(), code);
		}

libs/binder/Constants.h

0 → 100644

+39 −0

Original line number	Diff line number	Diff line
		/*
		* Copyright (C) 2025 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.
		*/

		#pragma once

		namespace android::binder {

		/**
		* See also BINDER_VM_SIZE. In kernel binder, the sum of all transactions must be allocated in this
		* space. Large transactions are very error prone. In general, we should work to reduce this limit.
		* The same limit is used in RPC binder for consistency.
		*/
		constexpr size_t kLogTransactionsOverBytes = 300 * 1024;

		/**
		* See b/392575419 - this limit is chosen for a specific usecase, because RPC binder does not have
		* support for shared memory in the Android Baklava timeframe. This was 100 KB during and before
		* Android V.
		*
		* Keeping this low helps preserve overall system performance. Transactions of this size are far too
		* expensive to make multiple copies over binder or sockets, and they should be avoided if at all
		* possible and transition to shared memory.
		*/
		constexpr size_t kRpcTransactionLimitBytes = 600 * 1024;

		} // namespace android::binder

libs/binder/RpcState.cpp

+7 −4

Original line number	Diff line number	Diff line
		@@ -23,6 +23,7 @@
		#include <binder/IPCThreadState.h>
		#include <binder/RpcServer.h>

		#include "Constants.h"
		#include "Debug.h"
		#include "RpcWireFormat.h"
		#include "Utils.h"
		@@ -337,6 +338,8 @@ std::string RpcState::BinderNode::toString() const {
		}

		RpcState::CommandData::CommandData(size_t size) : mSize(size) {
		if (size == 0) return;

		// The maximum size for regular binder is 1MB for all concurrent
		// transactions. A very small proportion of transactions are even
		// larger than a page, but we need to avoid allocating too much
		@@ -348,11 +351,11 @@ RpcState::CommandData::CommandData(size_t size) : mSize(size) {
		// transaction (in some cases, additional fixed size amounts are added),
		// though for rough consistency, we should avoid cases where this data type
		// is used for multiple dynamic allocations for a single transaction.
		constexpr size_t kMaxTransactionAllocation = 100 * 1000;
		if (size == 0) return;
		if (size > kMaxTransactionAllocation) {
		ALOGW("Transaction requested too much data allocation %zu", size);
		if (size > binder::kRpcTransactionLimitBytes) {
		ALOGE("Transaction requested too much data allocation: %zu bytes, failing.", size);
		return;
		} else if (size > binder::kLogTransactionsOverBytes) {
		ALOGW("Transaction too large: inefficient and in danger of breaking: %zu bytes.", size);
		}
		mData.reset(new (std::nothrow) uint8_t[size]);
		}

libs/binder/tests/IBinderRpcTest.aidl

+2 −0

Original line number	Diff line number	Diff line
		@@ -34,6 +34,8 @@ interface IBinderRpcTest {
		void holdBinder(@nullable IBinder binder);
		@nullable IBinder getHeldBinder();

		byte[] repeatBytes(in byte[] bytes);

		// Idea is client creates its own instance of IBinderRpcTest and calls this,
		// and the server calls 'binder' with (calls - 1) passing itself as 'binder',
		// going back and forth until calls = 0