svn commit: r300556 - in head: sys/kern tests/sys/aio
John Baldwin
jhb at FreeBSD.org
Tue May 24 03:13:28 UTC 2016
Author: jhb
Date: Tue May 24 03:13:27 2016
New Revision: 300556
URL: https://svnweb.freebsd.org/changeset/base/300556
Log:
Don't prematurely return short completions on blocking sockets.
Always requeue an AIO job at the head of the socket buffer's queue if
sosend() or soreceive() returns EWOULDBLOCK on a blocking socket.
Previously, requests were only requeued if they returned EWOULDBLOCK
and completed no data. Now after a partial completion on a blocking
socket the request is queued and the remaining request is retried when
the socket is ready. This allows writes larger than the currently
available space on a blocking socket to fully complete. Reads on a
blocking socket that satifsy the low watermark can still return a short
read (same as read()).
In order to track previously completed data, the internal 'status'
field of the AIO job is used to store the amount of previously
computed data.
Non-blocking sockets continue to return short completions for both
reads and writes.
Add a test for a "large" AIO write on a blocking socket that writes
twice the socket buffer size to a UNIX domain socket.
Sponsored by: Chelsio Communications
Modified:
head/sys/kern/sys_socket.c
head/tests/sys/aio/aio_test.c
Modified: head/sys/kern/sys_socket.c
==============================================================================
--- head/sys/kern/sys_socket.c Tue May 24 03:08:32 2016 (r300555)
+++ head/sys/kern/sys_socket.c Tue May 24 03:13:27 2016 (r300556)
@@ -556,7 +556,7 @@ soaio_process_job(struct socket *so, str
struct file *fp;
struct uio uio;
struct iovec iov;
- size_t cnt;
+ size_t cnt, done;
int error, flags;
SOCKBUF_UNLOCK(sb);
@@ -567,8 +567,9 @@ retry:
td_savedcred = td->td_ucred;
td->td_ucred = job->cred;
- cnt = job->uaiocb.aio_nbytes;
- iov.iov_base = (void *)(uintptr_t)job->uaiocb.aio_buf;
+ done = job->uaiocb._aiocb_private.status;
+ cnt = job->uaiocb.aio_nbytes - done;
+ iov.iov_base = (void *)((uintptr_t)job->uaiocb.aio_buf + done);
iov.iov_len = cnt;
uio.uio_iov = &iov;
uio.uio_iovcnt = 1;
@@ -602,42 +603,52 @@ retry:
}
}
- cnt -= uio.uio_resid;
+ done += cnt - uio.uio_resid;
+ job->uaiocb._aiocb_private.status = done;
td->td_ucred = td_savedcred;
- if (cnt != 0 && (error == ERESTART || error == EINTR ||
- error == EWOULDBLOCK))
- error = 0;
if (error == EWOULDBLOCK) {
/*
- * A read() or write() on the socket raced with this
- * request. If the socket is now ready, try again.
- * If it is not, place this request at the head of the
+ * The request was either partially completed or not
+ * completed at all due to racing with a read() or
+ * write() on the socket. If the socket is
+ * non-blocking, return with any partial completion.
+ * If the socket is blocking or if no progress has
+ * been made, requeue this request at the head of the
* queue to try again when the socket is ready.
*/
- SOCKBUF_LOCK(sb);
- empty_results++;
- if (soaio_ready(so, sb)) {
- empty_retries++;
- SOCKBUF_UNLOCK(sb);
- goto retry;
- }
-
- if (!aio_set_cancel_function(job, soo_aio_cancel)) {
- MPASS(cnt == 0);
- SOCKBUF_UNLOCK(sb);
- aio_cancel(job);
- SOCKBUF_LOCK(sb);
- } else {
- TAILQ_INSERT_HEAD(&sb->sb_aiojobq, job, list);
- }
- } else {
- if (error)
- aio_complete(job, -1, error);
- else
- aio_complete(job, cnt, 0);
+ MPASS(done != job->uaiocb.aio_nbytes);
SOCKBUF_LOCK(sb);
- }
+ if (done == 0 || !(so->so_state & SS_NBIO)) {
+ empty_results++;
+ if (soaio_ready(so, sb)) {
+ empty_retries++;
+ SOCKBUF_UNLOCK(sb);
+ goto retry;
+ }
+
+ if (!aio_set_cancel_function(job, soo_aio_cancel)) {
+ SOCKBUF_UNLOCK(sb);
+ if (done != 0)
+ aio_complete(job, done, 0);
+ else
+ aio_cancel(job);
+ SOCKBUF_LOCK(sb);
+ } else {
+ TAILQ_INSERT_HEAD(&sb->sb_aiojobq, job, list);
+ }
+ return;
+ }
+ SOCKBUF_UNLOCK(sb);
+ }
+ if (done != 0 && (error == ERESTART || error == EINTR ||
+ error == EWOULDBLOCK))
+ error = 0;
+ if (error)
+ aio_complete(job, -1, error);
+ else
+ aio_complete(job, done, 0);
+ SOCKBUF_LOCK(sb);
}
static void
@@ -758,6 +769,7 @@ soo_aio_queue(struct file *fp, struct ka
if (!aio_set_cancel_function(job, soo_aio_cancel))
panic("new job was cancelled");
TAILQ_INSERT_TAIL(&sb->sb_aiojobq, job, list);
+ job->uaiocb._aiocb_private.status = 0;
if (!(sb->sb_flags & SB_AIO_RUNNING)) {
if (soaio_ready(so, sb))
sowakeup_aio(so, sb);
Modified: head/tests/sys/aio/aio_test.c
==============================================================================
--- head/tests/sys/aio/aio_test.c Tue May 24 03:08:32 2016 (r300555)
+++ head/tests/sys/aio/aio_test.c Tue May 24 03:13:27 2016 (r300556)
@@ -781,6 +781,70 @@ ATF_TC_BODY(aio_socket_two_reads, tc)
close(s[0]);
}
+/*
+ * This test ensures that aio_write() on a blocking socket of a "large"
+ * buffer does not return a short completion.
+ */
+ATF_TC_WITHOUT_HEAD(aio_socket_blocking_short_write);
+ATF_TC_BODY(aio_socket_blocking_short_write, tc)
+{
+ struct aiocb iocb, *iocbp;
+ char *buffer[2];
+ ssize_t done;
+ int buffer_size, sb_size;
+ socklen_t len;
+ int s[2];
+
+ ATF_REQUIRE_KERNEL_MODULE("aio");
+
+ ATF_REQUIRE(socketpair(PF_UNIX, SOCK_STREAM, 0, s) != -1);
+
+ len = sizeof(sb_size);
+ ATF_REQUIRE(getsockopt(s[0], SOL_SOCKET, SO_RCVBUF, &sb_size, &len) !=
+ -1);
+ ATF_REQUIRE(len == sizeof(sb_size));
+ buffer_size = sb_size;
+
+ ATF_REQUIRE(getsockopt(s[1], SOL_SOCKET, SO_SNDBUF, &sb_size, &len) !=
+ -1);
+ ATF_REQUIRE(len == sizeof(sb_size));
+ if (sb_size > buffer_size)
+ buffer_size = sb_size;
+
+ /*
+ * Use twice the size of the MAX(receive buffer, send buffer)
+ * to ensure that the write is split up into multiple writes
+ * internally.
+ */
+ buffer_size *= 2;
+
+ buffer[0] = malloc(buffer_size);
+ ATF_REQUIRE(buffer[0] != NULL);
+ buffer[1] = malloc(buffer_size);
+ ATF_REQUIRE(buffer[1] != NULL);
+
+ srandomdev();
+ aio_fill_buffer(buffer[1], buffer_size, random());
+
+ memset(&iocb, 0, sizeof(iocb));
+ iocb.aio_fildes = s[1];
+ iocb.aio_buf = buffer[1];
+ iocb.aio_nbytes = buffer_size;
+ ATF_REQUIRE(aio_write(&iocb) == 0);
+
+ done = recv(s[0], buffer[0], buffer_size, MSG_WAITALL);
+ ATF_REQUIRE(done == buffer_size);
+
+ done = aio_waitcomplete(&iocbp, NULL);
+ ATF_REQUIRE(iocbp == &iocb);
+ ATF_REQUIRE(done == buffer_size);
+
+ ATF_REQUIRE(memcmp(buffer[0], buffer[1], buffer_size) == 0);
+
+ close(s[1]);
+ close(s[0]);
+}
+
ATF_TP_ADD_TCS(tp)
{
@@ -792,6 +856,7 @@ ATF_TP_ADD_TCS(tp)
ATF_TP_ADD_TC(tp, aio_md_test);
ATF_TP_ADD_TC(tp, aio_large_read_test);
ATF_TP_ADD_TC(tp, aio_socket_two_reads);
+ ATF_TP_ADD_TC(tp, aio_socket_blocking_short_write);
return (atf_no_error());
}
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