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Session-Subsystem(#318): investigation of locking sanity (ongoing...)

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Found an inconsistency and a deadlock!
See proc-dispatcher.cpp, the lambda embedded into the start() operation!
This commit is contained in:
Fischlurch 2017-01-04 01:44:35 +01:00
parent 34686713d4
commit 77303ad007
8 changed files with 126 additions and 91 deletions
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8
src/common/subsys.hpp
View file

@ -95,9 +95,11 @@ namespace lumiera {
virtual bool shouldStart (lumiera::Option&) =0;
/** how to start up this subsystem. Failure to start up
* usually terminates the whole application. When this subsystem
* ceases to work, it must assure to activate the given signal.
/** attempt to bring up this subsystem up. On return, the
* subsystem must be operational, according to checkRunningState().
* Failure to start up usually terminates the whole application.
* When this subsystem ceases to work, it must ensure to activate
* the given callback signal.
* @param options may be influencing the operation mode
* @param termination to be signalled by the subsystem.
* @warning termination must be signalled reliably.

2
src/common/subsystem-runner.hpp
View file

@ -170,7 +170,7 @@ namespace lumiera {
throw error::Logic("Subsystem "+string(*susy)+" failed to start");
}
if (!and_all (susy->getPrerequisites(), isRunning() ))
if (not and_all (susy->getPrerequisites(), isRunning() ))
{
susy->triggerShutdown();
throw error::State("Unable to start all prerequisites of Subsystem "+string(*susy));

24
src/proc/control/proc-dispatcher.cpp
View file

@ -128,6 +128,14 @@ namespace control {
public:
/** start the session loop thread
* @param notification callback to invoke on thread termination
* @remark _in theory_ this ctor could block, since it waits for the thread
* actually to get operational and it waits for the SessionCommand interface
* to be opened. The latter _should not_ run into any obstacles, because
* in case it does, the main application thread is deadlocked on startup.
* Such might happen indirectly, when something depends on "the Session"
*/
DispatcherLoop (Subsys::SigTerm notification)
: ThreadJoinable("Lumiera Session"
, bind (&DispatcherLoop::runSessionThread, this, notification))
@ -315,7 +323,14 @@ namespace control {
/** */
/** starting the ProcDispatcher means to start the session subsystem.
* @return `false` when _starting_ failed since it is already running...
* @remark this function implements the start operation for the »session subsystem«.
* More specifically, this operation starts a new thread to perform the
* _session loop,_ which means to perform commands and trigger the builder.
* It might block temporarily for synchronisation with this new thread and
* while opening the SessionCommand facade.
*/
bool
ProcDispatcher::start (Subsys::SigTerm termNotification)
{
@ -326,7 +341,7 @@ namespace control {
new DispatcherLoop (
[=] (string* problemMessage)
{
runningLoop_.reset();
runningLoop_.reset(); //////////////////////TODO: (1) Race in ProcDispatcher (2) Deadlock because the Thread attempts to reap itself
termNotification(problemMessage);
}));
@ -336,7 +351,10 @@ namespace control {
}
/** */
/** whether the »session subsystem« is operational.
* @return `true` if the session loop thread has been fully
* started and is not (yet) completely terminated.
*/
bool
ProcDispatcher::isRunning()
{

29
src/proc/control/proc-dispatcher.hpp
View file

@ -23,10 +23,29 @@
/** @file proc-dispatcher.hpp
** Dispatch and execute mutation operations on the High-level model.
** //TODO
** The ProcDispatcher is the application facility to back and support working
** on the Session. While the session itself is just a data structure, _operating_
** the session means to process commands changing that data structure and it means
** to evaluate the _session model_ and _build_ a render nodes network in accordance
** to that model's meaning. This _operation aspect_ of the session thus has a lifecycle
** and this is what we call the "session subsystem" within the application. When this is
** running, the SessionCommand facade is opened, accepting commands to work on the session.
** Such commands are passed through a dispatch queue to ensure consistent session state
** and to force strictly sequential processing of commands. Moreover, the ProcDispatcher's
** responsibility is to care for triggering the Builder after any changes induced by those
** commands. The Builder is guaranteed to run _eventually_, yet with some leeway.
**
** Talking of state, independent of the lifecycle running state, the ProcDispatcher can be
** _activated or deactivated_. In active state, commands are dequeued and processed, while
** in inactive state commands are just accepted and queued, assuming the SessionCommand
** interface is currently opened. This activation state is controlled by the session
** datastructure itself, more precisely the SessionManager. A session can be stored,
** closed, reset and loaded with existing content from persistent storage, and only
** when the data structure is complete and consistent, processing can be enabled.
**
** @see Command
** @see Session
** @see proc-dispatcher.cpp for details of operational semantics
**
*/
@ -54,7 +73,13 @@ namespace control {
/**
* @todo Type-comment
* Guard to manage processing commands working on the session.
* A static application facility, actually backing and implementing
* the »session subsystem«. Embedded within the implementation of this
* class is the _»session loop thread«_ to perform any session mutation
* commands and to operate the Builder, which translates the session
* contents into a render nodes network. Also embedded herein is
* the implementation of proc::control::SessionCommandService
*/
class ProcDispatcher
: public lib::Sync<>

5
src/proc/facade.cpp
View file

@ -47,8 +47,9 @@ namespace proc {
{
operator string() const { return "Session"; }
/** @remarks there is no need explicitly to start the session core,
* since it will usually be pulled up as prerequisite */
/** @remarks there is no need explicitly to start the session,
* since it is passive, waiting for invocations and will be
* pulled up as prerequisite of other subsystems. */
bool
shouldStart (Option&) override
{

8
src/proc/facade.hpp
View file

@ -56,14 +56,14 @@ namespace proc {
struct Facade
{
/** provide a descriptor for lumiera::AppState,
* wired accordingly to allow main to bring up
* a editing session, possibly by loading an
* existing session from storage. */
* wired accordingly to allow `main()` to boot
* the support infrastructure for loading of
* and working on the editing session. */
static lumiera::Subsys& getSessionDescriptor();
/** provide a descriptor for lumiera::AppState,
* wired accordingly to allow main to bring up
* wired accordingly to allow `main()` to bring up
* the render / playback coordination and
* output management subsystem. */
static lumiera::Subsys& getPlayOutDescriptor();

4
tests/core/proc/control/dispatcher-looper-test.cpp
View file

@ -167,8 +167,8 @@ namespace test {
CHECK (looper.shallLoop());
setup.has_commands_in_queue = false;
looper.markStateProcessed();
looper.markStateProcessed();
looper.markStateProcessed(); // after command processing
looper.markStateProcessed(); // after builder run
CHECK (not looper.requireAction());
CHECK (not looper.isWorking());

137
wiki/thinkPad.ichthyo.mm
View file

@ -330,8 +330,7 @@
meint: zwei gekoppelte Statusvariable
</p>
</body>
</html>
</richcontent>
</html></richcontent>
</node>
<node CREATED="1481767706906" ID="ID_815807707" MODIFIED="1481767710581" TEXT="bekomme dort Zustand"/>
<node CREATED="1481767720576" ID="ID_714877064" MODIFIED="1481767729611" TEXT="mu&#xdf; dort Locking verwenden"/>
@ -358,8 +357,7 @@
oder mu&#223; PImpl als Interface exponieren
</p>
</body>
</html>
</richcontent>
</html></richcontent>
</node>
<node CREATED="1481767831105" ID="ID_1351930491" MODIFIED="1481768989667" TEXT="fragiler Lebenszyklus">
<richcontent TYPE="NOTE"><html>
@ -371,8 +369,7 @@
meint: zwei gekoppelte Statusvariable
</p>
</body>
</html>
</richcontent>
</html></richcontent>
</node>
</node>
</node>
@ -463,8 +460,7 @@
<i>ist nicht</i>&#160;&quot;die Session
</p>
</body>
</html>
</richcontent>
</html></richcontent>
<icon BUILTIN="yes"/>
</node>
<node CREATED="1482464332981" ID="ID_1523357281" MODIFIED="1482464350688" TEXT="Session Subsystem == Session Dispatcher Loop Thread">
@ -487,8 +483,7 @@
das Lock sorgt hier f&#252;r konsistenten Zustand und Sichtbarkeit (memory barrier)
</p>
</body>
</html>
</richcontent>
</html></richcontent>
</node>
<node CREATED="1481684394544" ID="ID_1314197501" MODIFIED="1481684422640" TEXT="Back-End">
<richcontent TYPE="NOTE"><html>
@ -500,12 +495,23 @@
Lock ist hier das Dispatcher-Lock
</p>
</body>
</html>
</richcontent>
</html></richcontent>
</node>
</node>
<node CREATED="1481599468712" ID="ID_1273965744" MODIFIED="1481599482440" TEXT="Vorsicht beim Anhalten (Deadlock-Gefahr)">
<icon BUILTIN="messagebox_warning"/>
<node CREATED="1483477519974" ID="ID_1731425552" MODIFIED="1483477535864" TEXT="Term-Signal k&#xf6;nnte blocken">
<icon BUILTIN="help"/>
</node>
<node BACKGROUND_COLOR="#eee5c3" COLOR="#990000" CREATED="1483484052785" ID="ID_667055412" MODIFIED="1483484091053" TEXT="Race beim runningLoop_.reset()">
<icon BUILTIN="flag-yellow"/>
</node>
<node CREATED="1483490316758" ID="ID_1734989824" MODIFIED="1483490376306" TEXT="nur das Term-Signal kann DispatcherLoop deleten">
<icon BUILTIN="idea"/>
</node>
<node BACKGROUND_COLOR="#fdfdcf" COLOR="#ff0000" CREATED="1483490459499" ID="ID_1006586365" MODIFIED="1483490478840" TEXT="Thread will sich selbst reapen ==&gt; Deadlock">
<icon BUILTIN="flag-pink"/>
</node>
</node>
<node CREATED="1482464502542" ID="ID_284397306" MODIFIED="1482464609118" TEXT="Vorsicht beim Schlie&#xdf;en der Session">
<arrowlink COLOR="#5a97df" DESTINATION="ID_1378897740" ENDARROW="Default" ENDINCLINATION="9540;0;" ID="Arrow_ID_1446486242" STARTARROW="None" STARTINCLINATION="9540;0;"/>
@ -532,8 +538,7 @@
...wenn jemand zugreift
</p>
</body>
</html>
</richcontent>
</html></richcontent>
</node>
<node CREATED="1481599603757" ID="ID_812618450" MODIFIED="1481599612320" TEXT="Operation auf dem SessionManager"/>
<node CREATED="1481599612812" ID="ID_1970476027" MODIFIED="1481599618598" TEXT="der ist Singleton"/>
@ -558,8 +563,7 @@
</li>
</ul>
</body>
</html>
</richcontent>
</html></richcontent>
<icon BUILTIN="yes"/>
</node>
</node>
@ -586,8 +590,7 @@
<i>bevor</i>&#160;die Dispatcher-loop angehalten wird
</p>
</body>
</html>
</richcontent>
</html></richcontent>
<icon BUILTIN="button_ok"/>
<node CREATED="1481778397600" ID="ID_1997192349" MODIFIED="1481778409498" TEXT="bereits wenn Anhalten signalisiert wird"/>
<node CREATED="1481778409942" ID="ID_100284739" MODIFIED="1481778419113" TEXT="zur Sicherheit nochmal im dtor"/>
@ -604,8 +607,7 @@
<icon BUILTIN="idea"/>
</node>
</node>
<node CREATED="1482464658193" HGAP="-19" ID="ID_726798260" MODIFIED="1482464708932" TEXT="Ausgestaltung" VSHIFT="24">
<icon BUILTIN="pencil"/>
<node CREATED="1482464658193" HGAP="-14" ID="ID_726798260" MODIFIED="1482711954690" TEXT="Ausgestaltung" VSHIFT="29">
<node CREATED="1482465840843" ID="ID_818984499" MODIFIED="1482465853543" TEXT="Entwurf">
<icon BUILTIN="stop-sign"/>
<node CREATED="1482464676366" FOLDED="true" ID="ID_1064506750" MODIFIED="1482464760237" TEXT="bekommt Nachrichten vom UI-Bus">
@ -638,8 +640,7 @@
wenn in der UI ein InvocationTrail angelegt wird.
</p>
</body>
</html>
</richcontent>
</html></richcontent>
</node>
<node CREATED="1482466104359" ID="ID_235553653" MODIFIED="1482466115902" TEXT="speichert aber eigentlich nur die Cmd-ID">
<icon BUILTIN="idea"/>
@ -658,8 +659,7 @@
<i>kann offen bleiben</i>
</p>
</body>
</html>
</richcontent>
</html></richcontent>
<node CREATED="1482466246933" ID="ID_870716233" MODIFIED="1482466256655" TEXT="h&#xe4;ngt von der Verwendung ab"/>
<node CREATED="1482466257027" ID="ID_1491453181" MODIFIED="1482466260134" TEXT="von InvocationTrail"/>
<node CREATED="1482466260627" ID="ID_1708185529" MODIFIED="1482466265989" TEXT="wie Commands im UI gebunden werden"/>
@ -676,8 +676,7 @@
reine ID-Wirtschaft <i>w&#228;re m&#246;glich</i>
</p>
</body>
</html>
</richcontent>
</html></richcontent>
<icon BUILTIN="idea"/>
</node>
<node CREATED="1482466285359" ID="ID_1077952925" MODIFIED="1482466316309" TEXT="Zugriff auf proc::control::Command is OK">
@ -11177,7 +11176,11 @@
</node>
<node CREATED="1481777397542" ID="ID_1147135932" MODIFIED="1481778447806" TEXT="DispatcherLoop stirbt"/>
<node CREATED="1481777410972" ID="ID_457965735" MODIFIED="1481777418982" TEXT="sigTerm"/>
<node CREATED="1481778453137" ID="ID_1895977623" MODIFIED="1481778465907" TEXT="bewirkt reapen des LoopThread"/>
<node CREATED="1481778453137" ID="ID_1895977623" MODIFIED="1481778465907" TEXT="bewirkt reapen des LoopThread">
<node BACKGROUND_COLOR="#eee5c3" COLOR="#990000" CREATED="1482712050992" ID="ID_336551514" MODIFIED="1482712065548" TEXT="wie genau">
<icon BUILTIN="help"/>
</node>
</node>
</node>
</node>
</node>
@ -11186,7 +11189,11 @@
<icon BUILTIN="button_ok"/>
<node CREATED="1481826329819" ID="ID_1238318698" MODIFIED="1481826431105" TEXT="enqueue commands concurrently">
<node CREATED="1481827297122" ID="ID_860095678" MODIFIED="1481827311268" TEXT="FIFO for regular commands"/>
<node CREATED="1481827312024" ID="ID_850193431" MODIFIED="1481827318187" TEXT="LIFO for priority requests"/>
<node CREATED="1481827312024" ID="ID_850193431" MODIFIED="1481827318187" TEXT="LIFO for priority requests">
<node CREATED="1482712100745" ID="ID_1387300775" MODIFIED="1482712106824" TEXT="vorerst nicht implementiert">
<icon BUILTIN="yes"/>
</node>
</node>
</node>
<node CREATED="1481826431861" ID="ID_328583048" MODIFIED="1481826440935" TEXT="process sequentially"/>
<node CREATED="1481826441884" ID="ID_952327020" MODIFIED="1481826446791" TEXT="until queue is empty"/>
@ -11230,8 +11237,7 @@
Guard beim Zugang &#252;ber das Interface
</p>
</body>
</html>
</richcontent>
</html></richcontent>
</node>
<node CREATED="1481918074269" ID="ID_1984339005" MODIFIED="1481918091136">
<richcontent TYPE="NODE"><html>
@ -11243,8 +11249,7 @@
<i>nur sie</i>&#160;ist atomar
</p>
</body>
</html>
</richcontent>
</html></richcontent>
<icon BUILTIN="messagebox_warning"/>
</node>
</node>
@ -11259,8 +11264,7 @@
<b>nur ein Thread</b>&#160;f&#252;r Commands und Builder
</p>
</body>
</html>
</richcontent>
</html></richcontent>
<arrowlink COLOR="#171ccb" DESTINATION="ID_1214851922" ENDARROW="Default" ENDINCLINATION="53;-5;" ID="Arrow_ID_1745317422" STARTARROW="None" STARTINCLINATION="42;2;"/>
<icon BUILTIN="messagebox_warning"/>
<node CREATED="1481918174199" ID="ID_364234189" MODIFIED="1481918180762" TEXT="essentiell f&#xfc;r Konsitenz der Session"/>
@ -11300,8 +11304,7 @@
Ticket <font color="#e90426">#1054</font>
</p>
</body>
</html>
</richcontent>
</html></richcontent>
<icon BUILTIN="bell"/>
<node CREATED="1482197270202" ID="ID_221875120" MODIFIED="1482197288634" TEXT="neues API auf unserem Thread-Wrapper schaffen">
<icon BUILTIN="yes"/>
@ -11348,8 +11351,7 @@
OO rocks!
</p>
</body>
</html>
</richcontent>
</html></richcontent>
<icon BUILTIN="info"/>
</node>
</node>
@ -11362,8 +11364,8 @@
<node CREATED="1481828624042" ID="ID_1970372601" MODIFIED="1481828635748" TEXT="Looper f&#xfc;r Schleifen-Logik"/>
<node CREATED="1481828639584" ID="ID_1344182776" MODIFIED="1481828648402" TEXT="CommandQueue"/>
</node>
<node CREATED="1481778549940" HGAP="50" ID="ID_676848252" MODIFIED="1482464798892" TEXT="DispatcherLoop" VSHIFT="1">
<icon BUILTIN="pencil"/>
<node CREATED="1481778549940" HGAP="50" ID="ID_676848252" MODIFIED="1482712315146" TEXT="DispatcherLoop" VSHIFT="1">
<icon BUILTIN="button_ok"/>
<node CREATED="1481778741546" ID="ID_684867533" MODIFIED="1481778755694" TEXT="&#xf6;ffnet Session-Interface">
<icon BUILTIN="button_ok"/>
</node>
@ -11387,42 +11389,33 @@
<arrowlink COLOR="#5242a4" DESTINATION="ID_1311208726" ENDARROW="Default" ENDINCLINATION="2;-45;" ID="Arrow_ID_313252247" STARTARROW="None" STARTINCLINATION="-186;-13;"/>
<icon BUILTIN="button_ok"/>
</node>
<node CREATED="1481831642376" ID="ID_1301681872" MODIFIED="1481831650435" TEXT="Checkpoint bieten">
<node CREATED="1482365008444" ID="ID_1520027430" MODIFIED="1482365011517" TEXT="wirklich">
<node CREATED="1481831642376" ID="ID_1301681872" MODIFIED="1482712297004" TEXT="Checkpoint bieten">
<icon BUILTIN="button_ok"/>
<node CREATED="1482365008444" ID="ID_1520027430" MODIFIED="1482712182562" TEXT="warum">
<icon BUILTIN="help"/>
</node>
<node CREATED="1482365012947" ID="ID_10844185" MODIFIED="1482365019558" TEXT="Konzept nicht klar"/>
<node CREATED="1482365020242" ID="ID_981800101" MODIFIED="1482365065006" TEXT="urspr&#xfc;nglich...">
<richcontent TYPE="NOTE"><html>
<head>
</head>
<body>
<p>
...meinte ich, so etwas wie den Sequence-Point von C++
</p>
<p>
also die Stelle, an der &quot;die Zahnr&#228;der ineinander greifen&quot;
</p>
</body>
</html>
</richcontent>
<node CREATED="1482365012947" ID="ID_10844185" MODIFIED="1482712196344" TEXT="um zuverl&#xe4;ssig anhalten zu k&#xf6;nnen"/>
<node CREATED="1482712199900" ID="ID_1990071363" MODIFIED="1482712291119" TEXT="Checkpoint == Zustand ausgeglichen">
<icon BUILTIN="idea"/>
</node>
<node CREATED="1482365070571" ID="ID_1387994688" MODIFIED="1482365108042" TEXT="Notwendigkeit zweifelhaft">
<richcontent TYPE="NOTE"><html>
<node CREATED="1482712212930" ID="ID_1065088226" MODIFIED="1482712286050" TEXT="das hei&#xdf;t">
<icon BUILTIN="info"/>
<node CREATED="1482712227048" ID="ID_172281578" MODIFIED="1482712234491" TEXT="keine schwebenden Zustands&#xe4;nderungen"/>
<node CREATED="1482712235016" ID="ID_943771142" MODIFIED="1482712249961" TEXT="Alle zustands-Relevanten &#xc4;nderungen sind ausgewertet"/>
<node CREATED="1482712250461" ID="ID_610930154" MODIFIED="1482712260744" TEXT="alle Pr&#xe4;dikate spiegeln den wirklichen Zustand wider"/>
<node CREATED="1482712261876" ID="ID_47966817" MODIFIED="1482712282765">
<richcontent TYPE="NODE"><html>
<head>
</head>
<body>
<p>
es scheint, als w&#252;rde ich eine Implementierung hinbekommen,
</p>
<p>
die (fast) nur auf logischen Zusammenh&#228;ngen beruht
Kontrollflu&#223; ist <i>nicht</i>&#160;in einer Arbeitsfunktion
</p>
</body>
</html>
</richcontent>
</html></richcontent>
<icon BUILTIN="messagebox_warning"/>
</node>
</node>
</node>
<node CREATED="1481831747042" ID="ID_134003952" MODIFIED="1481831788672" TEXT="sperrbar sein">
@ -11443,8 +11436,7 @@
</li>
</ul>
</body>
</html>
</richcontent>
</html></richcontent>
</node>
</node>
</node>
@ -11505,8 +11497,7 @@
<i>billig:</i>&#160;unsere Zeit-Lib nutzen
</p>
</body>
</html>
</richcontent>
</html></richcontent>
<icon BUILTIN="button_ok"/>
<node CREATED="1482430715396" ID="ID_1005651794" MODIFIED="1482430722896" TEXT="nicht besonders sch&#xf6;n">
<icon BUILTIN="smily_bad"/>
@ -11572,8 +11563,7 @@
generischer &#220;berlegungen implementiert
</p>
</body>
</html>
</richcontent>
</html></richcontent>
<icon BUILTIN="button_ok"/>
</node>
<node CREATED="1482202243253" ID="ID_1342399342" MODIFIED="1482202264229" TEXT="verh&#xe4;lt er sich dann richtig">
@ -12053,8 +12043,7 @@
Ticket <font color="#ba0c3f">#886</font>
</p>
</body>
</html>
</richcontent>
</html></richcontent>
</node>
</node>
</node>