On Thu, Aug 31, 2017 at 02:07:14PM +0100, Frediano Ziglio wrote: > Signed-off-by: Frediano Ziglio <fziglio@xxxxxxxxxx> > --- > .gitignore | 1 + > docs/Makefile.am | 6 ++-- > docs/spice_threading_model.txt | 73 ++++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 78 insertions(+), 2 deletions(-) > create mode 100644 docs/spice_threading_model.txt > > diff --git a/.gitignore b/.gitignore > index 25db761a..bf618932 100644 > --- a/.gitignore > +++ b/.gitignore > @@ -35,6 +35,7 @@ INSTALL > docs/manual/manual.chunked/ > docs/manual/manual.html > docs/spice_style.html > +docs/spice_threading_model.html > .dirstamp > .deps > .libs > diff --git a/docs/Makefile.am b/docs/Makefile.am > index 3dba2c3a..45667a60 100644 > --- a/docs/Makefile.am > +++ b/docs/Makefile.am > @@ -4,14 +4,16 @@ ASCIIDOC_FLAGS = -a icons -a toc > EXTRA_DIST = \ > spice_style.html \ > spice_style.txt \ > + spice_threading_model.html \ > + spice_threading_model.txt \ > $(NULL) > > if BUILD_MANUAL > SUBDIRS = manual > > -all-local: spice_style.html > +all-local: spice_style.html spice_threading_model.html > > -spice_style.html: spice_style.txt > +%.html: %.txt > $(AM_V_GEN) $(ASCIIDOC) -n $(ASCIIDOC_FLAGS) -o $@ $< > endif > > diff --git a/docs/spice_threading_model.txt b/docs/spice_threading_model.txt > new file mode 100644 > index 00000000..f88ead6d > --- /dev/null > +++ b/docs/spice_threading_model.txt > @@ -0,0 +1,73 @@ > +How does SPICE handle threading > +------------------------------- > + > +Lot of code run in a single thread. "Lots of code" > + > +Qemu usually calls SPICE from its main thread except on call backs to code > +already running in different threads. I think it's "callbacks", but not sure. > + > +Channels run mostly on a single thread except on creation and destruction which > +MUST be done in the main thread. I'd be a bit more explicit about "Channels" at least here: "Channels (RedChannel/RedChannelClient code) run mostly in a single thread..." (ok, you detail this a bit down the text) > +Lots of channels run in the main thread but currently CursorChannel and > +DisplayChannel can be run from within a thread created by RedWorker. "can be run" -> "are run"? > +Note that different CursorChannel/DisplayChannel (they differ by id) run in > +separate RedWorker threads (currently a single RedWorker thread run a pair "runs" > +of CursorChannel and DisplayChannel). > + > +RedChannelClient runs in the RedChannel thread. Creation is done in the same > +thread while destruction can happen in different threads. > + > +A RedClient instance groups the various RedChannelClient connected to > +the same remote SPICE client. > +These RedChannelClient instances can run in separate threads: > +MainChannelClient and most of the other RedChannelClient will be > +running in the main thread, while the CursorChannelClient and the > +DisplayChannelClient usually will be running from a different thread. > + > +Another important aspect of dealing with multiple threads are the dispatchers. > +Dispatchers are used to send messages/request from one thread to another. > +The main dispatcher is used to send requests to the main thread. > +The Qxl uses a dispatcher to send requests to the RedWorker which will forward > +to DisplayChannel/CursorChannel. For what it's worth, I would not call this an "important aspect", more of an uninteresting implementation detail :) I think I'd describe this as a way of ensuring a method is called in a different thread, either synchronously or asynchronously. It's more explicit than "sending requests" > + > +RedClient may call some RedChannelClient functions using some callbacks > +registered inside ClientCbs. Usually these callbacks are functions that do the > +job directly if the RedChannel is running in the main thread or they use a > +dispatcher to do the job in the right thread. Currently there are 3 callbacks: > +connect, disconnect and migrate. Connect and migrate are asynchronous (the job > +is done while the current thread is doing something else) while disconnect is > +synchronous (the main thread will wait for termination). > + > +Reference counting and ownership > +-------------------------------- > +-> pointer > + > +=> pointer with owning (mostly GObject ref counting) > + > +RedChannelClient::client -> RedClient > + > +RedClient::channels => RedChannelClient > + > +RedClient::mcc -> MainChannelClient > + > +RedChannelClient::channel => RedChannel > + > +RedChannel::clients -> RedChannelClient > + > +The RedClient represents a connection from a remote SPICE client, > +RedClient::channels corresponding to the connections for the individual > +channels. Their lifetime is tied to the TCP connection to this remote client. > +when a disconnection is detected, the corresponding RedChannelClient are "When" > +removed from RedClient::channels and Channel::clients (the main owner of I guess should be "RedChannel", but fairly obvious given all the surrounding text. > +RedChannelClient is RedClient). > +When MainChannelClient is disconnected all RedChannelClients connected to the > +same RedClient are automatically disconnected. "is disconnected, all RedChannelClients" > + > +Who owns RedClient? RedClient is released when the MainChannelClient attached > +to it is disconnected. In this case a request is scheduled in the main thread > +(even if MainChannelClient runs on the main thread too) and > +red_client_disconnect is called which calls red_client_destroy which uses > +g_object_unref to free the object. > + > +Where is freed the MainChannelClient? On disconnection like other channel I believe "Where is the MainChannelClient freed?" sounds better/is more correct Overall looks good! > +clients, currently before RedClient which will have a dangling pointer. > -- > 2.13.5 > > _______________________________________________ > Spice-devel mailing list > Spice-devel@xxxxxxxxxxxxxxxxxxxxx > https://lists.freedesktop.org/mailman/listinfo/spice-devel _______________________________________________ Spice-devel mailing list Spice-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/spice-devel