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[#2647] Respect IOV_MAX when call writev in native transport

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Motivation:

epoll transport fails on gathering write of more then 1024 buffers. As linux supports max. 1024 iov entries when calling writev(...) the epoll transport throws an exception.

Thanks again to @blucas to provide me with a reproducer and so helped me to understand what the issue is.

Modifications:

Make sure we break down the writes if to many buffers are uses for gathering writes.

Result:

Gathering writes work with any number of buffers
This commit is contained in:
Norman Maurer 2014-07-09 12:18:48 +02:00
parent ac8ac59148
commit fb22d34925
4 changed files with 151 additions and 87 deletions
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24
testsuite/src/test/java/io/netty/testsuite/transport/socket/SocketGatheringWriteTest.java
View File

@ -46,7 +46,7 @@ public class SocketGatheringWriteTest extends AbstractSocketTest {
}
public void testGatheringWrite(ServerBootstrap sb, Bootstrap cb) throws Throwable {
testGatheringWrite0(sb, cb, false, true);
testGatheringWrite0(sb, cb, data, false, true);
}
@Test(timeout = 30000)
@ -55,7 +55,7 @@ public class SocketGatheringWriteTest extends AbstractSocketTest {
}
public void testGatheringWriteNotAutoRead(ServerBootstrap sb, Bootstrap cb) throws Throwable {
testGatheringWrite0(sb, cb, false, false);
testGatheringWrite0(sb, cb, data, false, false);
}
@Test(timeout = 30000)
@ -64,7 +64,7 @@ public class SocketGatheringWriteTest extends AbstractSocketTest {
}
public void testGatheringWriteWithCompositeNotAutoRead(ServerBootstrap sb, Bootstrap cb) throws Throwable {
testGatheringWrite0(sb, cb, true, false);
testGatheringWrite0(sb, cb, data, true, false);
}
@Test(timeout = 30000)
@ -73,11 +73,23 @@ public class SocketGatheringWriteTest extends AbstractSocketTest {
}
public void testGatheringWriteWithComposite(ServerBootstrap sb, Bootstrap cb) throws Throwable {
testGatheringWrite0(sb, cb, true, true);
testGatheringWrite0(sb, cb, data, true, true);
}
// Test for https://github.com/netty/netty/issues/2647
@Test(timeout = 30000)
public void testGatheringWriteBig() throws Throwable {
run();
}
public void testGatheringWriteBig(ServerBootstrap sb, Bootstrap cb) throws Throwable {
byte[] bigData = new byte[1024 * 1024 * 50];
random.nextBytes(bigData);
testGatheringWrite0(sb, cb, bigData, false, true);
}
private static void testGatheringWrite0(
ServerBootstrap sb, Bootstrap cb, boolean composite, boolean autoRead) throws Throwable {
ServerBootstrap sb, Bootstrap cb, byte[] data, boolean composite, boolean autoRead) throws Throwable {
final TestHandler sh = new TestHandler(autoRead);
final TestHandler ch = new TestHandler(autoRead);
@ -88,7 +100,7 @@ public class SocketGatheringWriteTest extends AbstractSocketTest {
Channel cc = cb.connect().sync().channel();
for (int i = 0; i < data.length;) {
int length = Math.min(random.nextInt(1024 * 64), data.length - i);
int length = Math.min(random.nextInt(1024 * 8), data.length - i);
ByteBuf buf = Unpooled.wrappedBuffer(data, i, length);
if (composite && i % 2 == 0) {
int split = buf.readableBytes() / 2;

79
transport-native-epoll/src/main/c/io_netty_channel_epoll_Native.c
View File

@ -711,10 +711,18 @@ jlong writev0(JNIEnv * env, jclass clazz, jint fd, struct iovec iov[], jint leng
}
JNIEXPORT jlong JNICALL Java_io_netty_channel_epoll_Native_writev(JNIEnv * env, jclass clazz, jint fd, jobjectArray buffers, jint offset, jint length) {
struct iovec iov[length];
// Calculate maximal size of iov
//
// See https://github.com/netty/netty/issues/2647
int iovLen = IOV_MAX < length ? IOV_MAX : length;
struct iovec iov[iovLen];
jlong w = 0;
while (length > 0) {
int i;
int iovidx = 0;
for (i = offset; i < length; i++) {
int loop = IOV_MAX < length ? IOV_MAX : length;
int num = offset + loop;
for (i = offset; i < num; i++) {
jobject bufObj = (*env)->GetObjectArrayElement(env, buffers, i);
jint pos;
// Get the current position using the (*env)->GetIntField if possible and fallback
@ -747,38 +755,59 @@ JNIEXPORT jlong JNICALL Java_io_netty_channel_epoll_Native_writev(JNIEnv * env,
// See https://github.com/netty/netty/issues/2623
(*env)->DeleteLocalRef(env, bufObj);
}
jlong res = writev0(env, clazz, fd, iov, length);
jlong res = writev0(env, clazz, fd, iov, loop);
if (res <= 0) {
return res;
return res < 0 ? res : w;
}
w += res;
offset += loop;
length -= loop;
// update the position of the written buffers
int written = res;
int a;
for (a = 0; a < length; a++) {
for (a = 0; a < loop; a++) {
int len = iov[a].iov_len;
jobject bufObj = (*env)->GetObjectArrayElement(env, buffers, a + offset);
if (len >= written) {
if (len > written) {
incrementPosition(env, bufObj, written);
break;
} else {
incrementPosition(env, bufObj, len);
written -= len;
}
// Explicit delete local reference as otherwise the local references will only be released once the native method returns.
// Also there may be a lot of these and JNI specification only specify that 16 must be able to be created.
//
// See https://github.com/netty/netty/issues/2623
(*env)->DeleteLocalRef(env, bufObj);
// incomplete write which means the channel is not writable anymore. Return now!
return w;
} else {
incrementPosition(env, bufObj, len);
// Explicit delete local reference as otherwise the local references will only be released once the native method returns.
// Also there may be a lot of these and JNI specification only specify that 16 must be able to be created.
//
// See https://github.com/netty/netty/issues/2623
(*env)->DeleteLocalRef(env, bufObj);
written -= len;
}
return res;
}
}
return w;
}
JNIEXPORT jlong JNICALL Java_io_netty_channel_epoll_Native_writevAddresses(JNIEnv * env, jclass clazz, jint fd, jobjectArray addresses, jint offset, jint length) {
struct iovec iov[length];
// Calculate maximal size of iov
//
// See https://github.com/netty/netty/issues/2647
int iovLen = IOV_MAX < length ? IOV_MAX : length;
struct iovec iov[iovLen];
jlong w = 0;
while (length > 0) {
int i;
int iovidx = 0;
for (i = offset; i < length; i++) {
int loop = IOV_MAX < length ? IOV_MAX : length;
int num = offset + loop;
for (i = offset; i < num; i++) {
jobject addressEntry = (*env)->GetObjectArrayElement(env, addresses, i);
jint readerIndex = (*env)->GetIntField(env, addressEntry, readerIndexFieldId);
jint writerIndex = (*env)->GetIntField(env, addressEntry, writerIndexFieldId);
@ -795,10 +824,28 @@ JNIEXPORT jlong JNICALL Java_io_netty_channel_epoll_Native_writevAddresses(JNIEn
(*env)->DeleteLocalRef(env, addressEntry);
}
jlong res = writev0(env, clazz, fd, iov, length);
jlong res = writev0(env, clazz, fd, iov, loop);
if (res <= 0) {
return res;
return res < 0 ? res : w;
}
w += res;
offset += loop;
length -= loop;
// update the position of the written buffers
int written = res;
int a;
for (a = 0; a < loop; a++) {
int len = iov[a].iov_len;
if (len > written) {
// incomplete write which means the channel is not writable anymore. Return now!
return w;
}
written -= len;
}
}
return w;
}
jint read0(JNIEnv * env, jclass clazz, jint fd, void *buffer, jint pos, jint limit) {

8
transport-native-epoll/src/main/c/io_netty_channel_epoll_Native.h
View File

@ -14,7 +14,7 @@
* under the License.
*/
#include <jni.h>
#include <limits.h>
#define EPOLL_READ 0x01
#define EPOLL_WRITE 0x02
@ -27,6 +27,12 @@
#define SO_REUSEPORT 15
#endif /* SO_REUSEPORT */
// Define IOV_MAX if not found to limit the iov size on writev calls
// See https://github.com/netty/netty/issues/2647
#ifndef IOV_MAX
#define IOV_MAX 1024
#endif /* IOV_MAX */
jint Java_io_netty_channel_epoll_Native_eventFd(JNIEnv * env, jclass clazz);
void Java_io_netty_channel_epoll_Native_eventFdWrite(JNIEnv * env, jclass clazz, jint fd, jlong value);
void Java_io_netty_channel_epoll_Native_eventFdRead(JNIEnv * env, jclass clazz, jint fd);

1
transport-native-epoll/src/main/java/io/netty/channel/epoll/EpollSocketChannel.java
View File

@ -133,7 +133,6 @@ public final class EpollSocketChannel extends AbstractEpollChannel implements So
int nioBufferCnt = in.addressCount();
long expectedWrittenBytes = in.addressSize();
long localWrittenBytes = Native.writevAddresses(fd, nioBuffers, 0, nioBufferCnt);
if (localWrittenBytes < expectedWrittenBytes) {