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Thu, 06 Jan 2022 14:14:06 -0800 (PST) Received: from LeoBras.redhat.com ([2804:431:c7f1:cc01:fae1:7982:b010:d91]) by smtp.gmail.com with ESMTPSA id c15sm2098831uaj.13.2022.01.06.14.14.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 06 Jan 2022 14:14:06 -0800 (PST) From: Leonardo Bras To: =?utf-8?q?Daniel_P=2E_Berrang=C3=A9?= , Juan Quintela , "Dr. David Alan Gilbert" , Eric Blake , Markus Armbruster , Peter Xu Subject: [PATCH v7 1/5] QIOChannel: Add flags on io_writev and introduce io_flush callback Date: Thu, 6 Jan 2022 19:13:38 -0300 Message-Id: <20220106221341.8779-2-leobras@redhat.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220106221341.8779-1-leobras@redhat.com> References: <20220106221341.8779-1-leobras@redhat.com> MIME-Version: 1.0 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=leobras@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=170.10.129.124; envelope-from=leobras@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -31 X-Spam_score: -3.2 X-Spam_bar: --- X-Spam_report: (-3.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.372, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Leonardo Bras , qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Add flags to io_writev and introduce io_flush as optional callback to QIOChannelClass, allowing the implementation of zero copy writes by subclasses. How to use them: - Write data using qio_channel_writev(...,QIO_CHANNEL_WRITE_FLAG_ZERO_COPY), - Wait write completion with qio_channel_flush(). Notes: As some zero copy implementations work asynchronously, it's recommended to keep the write buffer untouched until the return of qio_channel_flush(), to avoid the risk of sending an updated buffer instead of the buffer state during write. As io_flush callback is optional, if a subclass does not implement it, then: - io_flush will return 0 without changing anything. Also, some functions like qio_channel_writev_full_all() were adapted to receive a flag parameter. That allows shared code between zero copy and non-zero copy writev, and also an easier implementation on new flags. Signed-off-by: Leonardo Bras --- include/io/channel.h | 67 +++++++++++++++++++++++++++++++++++--------- io/channel-buffer.c | 1 + io/channel-command.c | 1 + io/channel-file.c | 1 + io/channel-socket.c | 2 ++ io/channel-tls.c | 1 + io/channel-websock.c | 1 + io/channel.c | 51 +++++++++++++++++++++++---------- migration/rdma.c | 1 + 9 files changed, 98 insertions(+), 28 deletions(-) diff --git a/include/io/channel.h b/include/io/channel.h index 88988979f8..343766ce5b 100644 --- a/include/io/channel.h +++ b/include/io/channel.h @@ -32,12 +32,15 @@ OBJECT_DECLARE_TYPE(QIOChannel, QIOChannelClass, #define QIO_CHANNEL_ERR_BLOCK -2 +#define QIO_CHANNEL_WRITE_FLAG_ZERO_COPY 0x1 + typedef enum QIOChannelFeature QIOChannelFeature; enum QIOChannelFeature { QIO_CHANNEL_FEATURE_FD_PASS, QIO_CHANNEL_FEATURE_SHUTDOWN, QIO_CHANNEL_FEATURE_LISTEN, + QIO_CHANNEL_FEATURE_WRITE_ZERO_COPY, }; @@ -104,6 +107,7 @@ struct QIOChannelClass { size_t niov, int *fds, size_t nfds, + int flags, Error **errp); ssize_t (*io_readv)(QIOChannel *ioc, const struct iovec *iov, @@ -136,6 +140,8 @@ struct QIOChannelClass { IOHandler *io_read, IOHandler *io_write, void *opaque); + int (*io_flush)(QIOChannel *ioc, + Error **errp); }; /* General I/O handling functions */ @@ -222,12 +228,13 @@ ssize_t qio_channel_readv_full(QIOChannel *ioc, /** - * qio_channel_writev_full: + * qio_channel_writev_full_flags: * @ioc: the channel object * @iov: the array of memory regions to write data from * @niov: the length of the @iov array * @fds: an array of file handles to send * @nfds: number of file handles in @fds + * @flags: write flags (QIO_CHANNEL_WRITE_FLAG_*) * @errp: pointer to a NULL-initialized error object * * Write data to the IO channel, reading it from the @@ -255,12 +262,16 @@ ssize_t qio_channel_readv_full(QIOChannel *ioc, * or QIO_CHANNEL_ERR_BLOCK if no data is can be sent * and the channel is non-blocking */ -ssize_t qio_channel_writev_full(QIOChannel *ioc, - const struct iovec *iov, - size_t niov, - int *fds, - size_t nfds, - Error **errp); +ssize_t qio_channel_writev_full_flags(QIOChannel *ioc, + const struct iovec *iov, + size_t niov, + int *fds, + size_t nfds, + int flags, + Error **errp); + +#define qio_channel_writev_full(ioc, iov, niov, fds, nfds, errp) \ + qio_channel_writev_full_flags(ioc, iov, niov, fds, nfds, 0, errp) /** * qio_channel_readv_all_eof: @@ -831,12 +842,13 @@ int qio_channel_readv_full_all(QIOChannel *ioc, Error **errp); /** - * qio_channel_writev_full_all: + * qio_channel_writev_full_all_flags: * @ioc: the channel object * @iov: the array of memory regions to write data from * @niov: the length of the @iov array * @fds: an array of file handles to send * @nfds: number of file handles in @fds + * @flags: write flags (QIO_CHANNEL_WRITE_FLAG_*) * @errp: pointer to a NULL-initialized error object * * @@ -846,13 +858,42 @@ int qio_channel_readv_full_all(QIOChannel *ioc, * to be written, yielding from the current coroutine * if required. * + * If QIO_CHANNEL_WRITE_FLAG_ZERO_COPY is passed in flags, + * instead of waiting for all requested data to be written, + * this function will wait until it's all queued for writing. + * In this case, if the buffer gets changed between queueing and + * sending, the updated buffer will be sent. If this is not a + * desired behavior, it's suggested to call qio_channel_flush() + * before reusing the buffer. + * * Returns: 0 if all bytes were written, or -1 on error */ -int qio_channel_writev_full_all(QIOChannel *ioc, - const struct iovec *iov, - size_t niov, - int *fds, size_t nfds, - Error **errp); +int qio_channel_writev_full_all_flags(QIOChannel *ioc, + const struct iovec *iov, + size_t niov, + int *fds, size_t nfds, + int flags, Error **errp); +#define qio_channel_writev_full_all(ioc, iov, niov, fds, nfds, errp) \ + qio_channel_writev_full_all_flags(ioc, iov, niov, fds, nfds, 0, errp) + +/** + * qio_channel_flush: + * @ioc: the channel object + * @errp: pointer to a NULL-initialized error object + * + * Will block until every packet queued with + * qio_channel_writev_full_flags() + QIO_CHANNEL_WRITE_FLAG_ZERO_COPY + * is sent, or return in case of any error. + * + * If not implemented, acts as a no-op, and returns 0. + * + * Returns -1 if any error is found, + * 1 if every send failed to use zero copy. + * 0 otherwise. + */ + +int qio_channel_flush(QIOChannel *ioc, + Error **errp); #endif /* QIO_CHANNEL_H */ diff --git a/io/channel-buffer.c b/io/channel-buffer.c index baa4e2b089..bf52011be2 100644 --- a/io/channel-buffer.c +++ b/io/channel-buffer.c @@ -81,6 +81,7 @@ static ssize_t qio_channel_buffer_writev(QIOChannel *ioc, size_t niov, int *fds, size_t nfds, + int flags, Error **errp) { QIOChannelBuffer *bioc = QIO_CHANNEL_BUFFER(ioc); diff --git a/io/channel-command.c b/io/channel-command.c index b2a9e27138..5ff1691bad 100644 --- a/io/channel-command.c +++ b/io/channel-command.c @@ -258,6 +258,7 @@ static ssize_t qio_channel_command_writev(QIOChannel *ioc, size_t niov, int *fds, size_t nfds, + int flags, Error **errp) { QIOChannelCommand *cioc = QIO_CHANNEL_COMMAND(ioc); diff --git a/io/channel-file.c b/io/channel-file.c index c4bf799a80..348a48545e 100644 --- a/io/channel-file.c +++ b/io/channel-file.c @@ -114,6 +114,7 @@ static ssize_t qio_channel_file_writev(QIOChannel *ioc, size_t niov, int *fds, size_t nfds, + int flags, Error **errp) { QIOChannelFile *fioc = QIO_CHANNEL_FILE(ioc); diff --git a/io/channel-socket.c b/io/channel-socket.c index 606ec97cf7..bfbd64787e 100644 --- a/io/channel-socket.c +++ b/io/channel-socket.c @@ -525,6 +525,7 @@ static ssize_t qio_channel_socket_writev(QIOChannel *ioc, size_t niov, int *fds, size_t nfds, + int flags, Error **errp) { QIOChannelSocket *sioc = QIO_CHANNEL_SOCKET(ioc); @@ -620,6 +621,7 @@ static ssize_t qio_channel_socket_writev(QIOChannel *ioc, size_t niov, int *fds, size_t nfds, + int flags, Error **errp) { QIOChannelSocket *sioc = QIO_CHANNEL_SOCKET(ioc); diff --git a/io/channel-tls.c b/io/channel-tls.c index 2ae1b92fc0..4ce890a538 100644 --- a/io/channel-tls.c +++ b/io/channel-tls.c @@ -301,6 +301,7 @@ static ssize_t qio_channel_tls_writev(QIOChannel *ioc, size_t niov, int *fds, size_t nfds, + int flags, Error **errp) { QIOChannelTLS *tioc = QIO_CHANNEL_TLS(ioc); diff --git a/io/channel-websock.c b/io/channel-websock.c index 70889bb54d..035dd6075b 100644 --- a/io/channel-websock.c +++ b/io/channel-websock.c @@ -1127,6 +1127,7 @@ static ssize_t qio_channel_websock_writev(QIOChannel *ioc, size_t niov, int *fds, size_t nfds, + int flags, Error **errp) { QIOChannelWebsock *wioc = QIO_CHANNEL_WEBSOCK(ioc); diff --git a/io/channel.c b/io/channel.c index e8b019dc36..904855e16e 100644 --- a/io/channel.c +++ b/io/channel.c @@ -67,12 +67,13 @@ ssize_t qio_channel_readv_full(QIOChannel *ioc, } -ssize_t qio_channel_writev_full(QIOChannel *ioc, - const struct iovec *iov, - size_t niov, - int *fds, - size_t nfds, - Error **errp) +ssize_t qio_channel_writev_full_flags(QIOChannel *ioc, + const struct iovec *iov, + size_t niov, + int *fds, + size_t nfds, + int flags, + Error **errp) { QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc); @@ -83,7 +84,7 @@ ssize_t qio_channel_writev_full(QIOChannel *ioc, return -1; } - return klass->io_writev(ioc, iov, niov, fds, nfds, errp); + return klass->io_writev(ioc, iov, niov, fds, nfds, flags, errp); } @@ -217,14 +218,15 @@ int qio_channel_writev_all(QIOChannel *ioc, size_t niov, Error **errp) { - return qio_channel_writev_full_all(ioc, iov, niov, NULL, 0, errp); + return qio_channel_writev_full_all_flags(ioc, iov, niov, NULL, 0, 0, + errp); } -int qio_channel_writev_full_all(QIOChannel *ioc, - const struct iovec *iov, - size_t niov, - int *fds, size_t nfds, - Error **errp) +int qio_channel_writev_full_all_flags(QIOChannel *ioc, + const struct iovec *iov, + size_t niov, + int *fds, size_t nfds, + int flags, Error **errp) { int ret = -1; struct iovec *local_iov = g_new(struct iovec, niov); @@ -235,10 +237,16 @@ int qio_channel_writev_full_all(QIOChannel *ioc, iov, niov, 0, iov_size(iov, niov)); + if (flags & QIO_CHANNEL_WRITE_FLAG_ZERO_COPY) { + assert(fds == NULL && nfds == 0); + } + while (nlocal_iov > 0) { ssize_t len; - len = qio_channel_writev_full(ioc, local_iov, nlocal_iov, fds, nfds, - errp); + + len = qio_channel_writev_full_flags(ioc, local_iov, nlocal_iov, fds, + nfds, flags, errp); + if (len == QIO_CHANNEL_ERR_BLOCK) { if (qemu_in_coroutine()) { qio_channel_yield(ioc, G_IO_OUT); @@ -473,6 +481,19 @@ off_t qio_channel_io_seek(QIOChannel *ioc, return klass->io_seek(ioc, offset, whence, errp); } +int qio_channel_flush(QIOChannel *ioc, + Error **errp) +{ + QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc); + + if (!klass->io_flush || + !qio_channel_has_feature(ioc, QIO_CHANNEL_FEATURE_WRITE_ZERO_COPY)) { + return 0; + } + + return klass->io_flush(ioc, errp); +} + static void qio_channel_restart_read(void *opaque) { diff --git a/migration/rdma.c b/migration/rdma.c index f5d3bbe7e9..54acd2000e 100644 --- a/migration/rdma.c +++ b/migration/rdma.c @@ -2833,6 +2833,7 @@ static ssize_t qio_channel_rdma_writev(QIOChannel *ioc, size_t niov, int *fds, size_t nfds, + int flags, Error **errp) { QIOChannelRDMA *rioc = QIO_CHANNEL_RDMA(ioc);