binder: Eliminate a data copy in RPC transport operations
Switch RpcTransportRaw to use sendmsg() and recvmsg() over
iovecs to send data from multiple buffers to avoid having
to copy all data into a single large buffer.
Bug: 202878542
Test: atest binderRpcTest
Change-Id: I8ba7fa815040555503160ae41888a0b0efe9e5d2
diff --git a/libs/binder/RpcState.cpp b/libs/binder/RpcState.cpp
index 09b3d68..6286c9c 100644
--- a/libs/binder/RpcState.cpp
+++ b/libs/binder/RpcState.cpp
@@ -19,6 +19,7 @@
#include "RpcState.h"
#include <android-base/hex.h>
+#include <android-base/macros.h>
#include <android-base/scopeguard.h>
#include <binder/BpBinder.h>
#include <binder/IPCThreadState.h>
@@ -309,22 +310,18 @@
}
status_t RpcState::rpcSend(const sp<RpcSession::RpcConnection>& connection,
- const sp<RpcSession>& session, const char* what, const void* data,
- size_t size, const std::function<status_t()>& altPoll) {
- LOG_RPC_DETAIL("Sending %s on RpcTransport %p: %s", what, connection->rpcTransport.get(),
- android::base::HexString(data, size).c_str());
-
- if (size > std::numeric_limits<ssize_t>::max()) {
- ALOGE("Cannot send %s at size %zu (too big)", what, size);
- (void)session->shutdownAndWait(false);
- return BAD_VALUE;
+ const sp<RpcSession>& session, const char* what, iovec* iovs,
+ size_t niovs, const std::function<status_t()>& altPoll) {
+ for (size_t i = 0; i < niovs; i++) {
+ LOG_RPC_DETAIL("Sending %s on RpcTransport %p: %s", what, connection->rpcTransport.get(),
+ android::base::HexString(iovs[i].iov_base, iovs[i].iov_len).c_str());
}
if (status_t status =
connection->rpcTransport->interruptableWriteFully(session->mShutdownTrigger.get(),
- data, size, altPoll);
+ iovs, niovs, altPoll);
status != OK) {
- LOG_RPC_DETAIL("Failed to write %s (%zu bytes) on RpcTransport %p, error: %s", what, size,
+ LOG_RPC_DETAIL("Failed to write %s (%zu iovs) on RpcTransport %p, error: %s", what, niovs,
connection->rpcTransport.get(), statusToString(status).c_str());
(void)session->shutdownAndWait(false);
return status;
@@ -334,34 +331,30 @@
}
status_t RpcState::rpcRec(const sp<RpcSession::RpcConnection>& connection,
- const sp<RpcSession>& session, const char* what, void* data,
- size_t size) {
- if (size > std::numeric_limits<ssize_t>::max()) {
- ALOGE("Cannot rec %s at size %zu (too big)", what, size);
- (void)session->shutdownAndWait(false);
- return BAD_VALUE;
- }
-
+ const sp<RpcSession>& session, const char* what, iovec* iovs,
+ size_t niovs) {
if (status_t status =
connection->rpcTransport->interruptableReadFully(session->mShutdownTrigger.get(),
- data, size, {});
+ iovs, niovs, {});
status != OK) {
- LOG_RPC_DETAIL("Failed to read %s (%zu bytes) on RpcTransport %p, error: %s", what, size,
+ LOG_RPC_DETAIL("Failed to read %s (%zu iovs) on RpcTransport %p, error: %s", what, niovs,
connection->rpcTransport.get(), statusToString(status).c_str());
(void)session->shutdownAndWait(false);
return status;
}
- LOG_RPC_DETAIL("Received %s on RpcTransport %p: %s", what, connection->rpcTransport.get(),
- android::base::HexString(data, size).c_str());
+ for (size_t i = 0; i < niovs; i++) {
+ LOG_RPC_DETAIL("Received %s on RpcTransport %p: %s", what, connection->rpcTransport.get(),
+ android::base::HexString(iovs[i].iov_base, iovs[i].iov_len).c_str());
+ }
return OK;
}
status_t RpcState::readNewSessionResponse(const sp<RpcSession::RpcConnection>& connection,
const sp<RpcSession>& session, uint32_t* version) {
RpcNewSessionResponse response;
- if (status_t status =
- rpcRec(connection, session, "new session response", &response, sizeof(response));
+ iovec iov{&response, sizeof(response)};
+ if (status_t status = rpcRec(connection, session, "new session response", &iov, 1);
status != OK) {
return status;
}
@@ -374,14 +367,15 @@
RpcOutgoingConnectionInit init{
.msg = RPC_CONNECTION_INIT_OKAY,
};
- return rpcSend(connection, session, "connection init", &init, sizeof(init));
+ iovec iov{&init, sizeof(init)};
+ return rpcSend(connection, session, "connection init", &iov, 1);
}
status_t RpcState::readConnectionInit(const sp<RpcSession::RpcConnection>& connection,
const sp<RpcSession>& session) {
RpcOutgoingConnectionInit init;
- if (status_t status = rpcRec(connection, session, "connection init", &init, sizeof(init));
- status != OK)
+ iovec iov{&init, sizeof(init)};
+ if (status_t status = rpcRec(connection, session, "connection init", &iov, 1); status != OK)
return status;
static_assert(sizeof(init.msg) == sizeof(RPC_CONNECTION_INIT_OKAY));
@@ -514,17 +508,6 @@
.flags = flags,
.asyncNumber = asyncNumber,
};
- CommandData transactionData(sizeof(RpcWireHeader) + sizeof(RpcWireTransaction) +
- data.dataSize());
- if (!transactionData.valid()) {
- return NO_MEMORY;
- }
-
- memcpy(transactionData.data() + 0, &command, sizeof(RpcWireHeader));
- memcpy(transactionData.data() + sizeof(RpcWireHeader), &transaction,
- sizeof(RpcWireTransaction));
- memcpy(transactionData.data() + sizeof(RpcWireHeader) + sizeof(RpcWireTransaction), data.data(),
- data.dataSize());
constexpr size_t kWaitMaxUs = 1000000;
constexpr size_t kWaitLogUs = 10000;
@@ -550,8 +533,13 @@
return drainCommands(connection, session, CommandType::CONTROL_ONLY);
};
- if (status_t status = rpcSend(connection, session, "transaction", transactionData.data(),
- transactionData.size(), drainRefs);
+ iovec iovs[]{
+ {&command, sizeof(RpcWireHeader)},
+ {&transaction, sizeof(RpcWireTransaction)},
+ {const_cast<uint8_t*>(data.data()), data.dataSize()},
+ };
+ if (status_t status =
+ rpcSend(connection, session, "transaction", iovs, arraysize(iovs), drainRefs);
status != OK) {
// TODO(b/167966510): need to undo onBinderLeaving - we know the
// refcount isn't successfully transferred.
@@ -584,8 +572,8 @@
const sp<RpcSession>& session, Parcel* reply) {
RpcWireHeader command;
while (true) {
- if (status_t status = rpcRec(connection, session, "command header (for reply)", &command,
- sizeof(command));
+ iovec iov{&command, sizeof(command)};
+ if (status_t status = rpcRec(connection, session, "command header (for reply)", &iov, 1);
status != OK)
return status;
@@ -599,8 +587,8 @@
CommandData data(command.bodySize);
if (!data.valid()) return NO_MEMORY;
- if (status_t status = rpcRec(connection, session, "reply body", data.data(), command.bodySize);
- status != OK)
+ iovec iov{data.data(), command.bodySize};
+ if (status_t status = rpcRec(connection, session, "reply body", &iov, 1); status != OK)
return status;
if (command.bodySize < sizeof(RpcWireReply)) {
@@ -653,11 +641,8 @@
.command = RPC_COMMAND_DEC_STRONG,
.bodySize = sizeof(RpcDecStrong),
};
- if (status_t status = rpcSend(connection, session, "dec ref header", &cmd, sizeof(cmd));
- status != OK)
- return status;
-
- return rpcSend(connection, session, "dec ref body", &body, sizeof(body));
+ iovec iovs[]{{&cmd, sizeof(cmd)}, {&body, sizeof(body)}};
+ return rpcSend(connection, session, "dec ref", iovs, arraysize(iovs));
}
status_t RpcState::getAndExecuteCommand(const sp<RpcSession::RpcConnection>& connection,
@@ -665,8 +650,8 @@
LOG_RPC_DETAIL("getAndExecuteCommand on RpcTransport %p", connection->rpcTransport.get());
RpcWireHeader command;
- if (status_t status = rpcRec(connection, session, "command header (for server)", &command,
- sizeof(command));
+ iovec iov{&command, sizeof(command)};
+ if (status_t status = rpcRec(connection, session, "command header (for server)", &iov, 1);
status != OK)
return status;
@@ -726,9 +711,8 @@
if (!transactionData.valid()) {
return NO_MEMORY;
}
- if (status_t status = rpcRec(connection, session, "transaction body", transactionData.data(),
- transactionData.size());
- status != OK)
+ iovec iov{transactionData.data(), transactionData.size()};
+ if (status_t status = rpcRec(connection, session, "transaction body", &iov, 1); status != OK)
return status;
return processTransactInternal(connection, session, std::move(transactionData));
@@ -965,16 +949,12 @@
.status = replyStatus,
};
- CommandData replyData(sizeof(RpcWireHeader) + sizeof(RpcWireReply) + reply.dataSize());
- if (!replyData.valid()) {
- return NO_MEMORY;
- }
- memcpy(replyData.data() + 0, &cmdReply, sizeof(RpcWireHeader));
- memcpy(replyData.data() + sizeof(RpcWireHeader), &rpcReply, sizeof(RpcWireReply));
- memcpy(replyData.data() + sizeof(RpcWireHeader) + sizeof(RpcWireReply), reply.data(),
- reply.dataSize());
-
- return rpcSend(connection, session, "reply", replyData.data(), replyData.size());
+ iovec iovs[]{
+ {&cmdReply, sizeof(RpcWireHeader)},
+ {&rpcReply, sizeof(RpcWireReply)},
+ {const_cast<uint8_t*>(reply.data()), reply.dataSize()},
+ };
+ return rpcSend(connection, session, "reply", iovs, arraysize(iovs));
}
status_t RpcState::processDecStrong(const sp<RpcSession::RpcConnection>& connection,
@@ -985,9 +965,8 @@
if (!commandData.valid()) {
return NO_MEMORY;
}
- if (status_t status =
- rpcRec(connection, session, "dec ref body", commandData.data(), commandData.size());
- status != OK)
+ iovec iov{commandData.data(), commandData.size()};
+ if (status_t status = rpcRec(connection, session, "dec ref body", &iov, 1); status != OK)
return status;
if (command.bodySize != sizeof(RpcDecStrong)) {