Changes between Version 14 and Version 15 of kernel_synchro

Timestamp:

Sep 11, 2020, 4:41:26 PM (4 years ago)

Author:

alain

Comment:

--

kernel_synchro

@@ -54 +54 @@
 == F) Locks debug  ==
 
-Each busylock (remote or local) contains a "type" field defining the specific resource protected by this lock, that is a non-zero value defined at lock initialization.
+Each local or remote busylock contains a <type> field defining the specific resource protected by this lock, that is a non-zero value defined at lock initialization.
+ * if the ''busylock'' is directly used to protect access to a shared kernel structure, this type field defines the type of the protected structure. 
+ * if the ''busylock'' is used to protect concurrent access to an higher level lock (queuelock or rwlock), the <type> field define the type of the structure protected by the higher level lock.
+The exiting lock types are defined in the <kernel_config.h> file.
 
-When the DEBUG_BUSYLOCK parameter is set to a non-zero value (in the kernel_config.h file), two optional debug mechanism are activated, thanks to conditional compilation.
+=== F.1 busylock debug ===
+
+When the DEBUG_BUSYLOCK parameter is set to a non-zero value in the <kernel_config.h> file, two debug mechanism are activated, thanks to conditional compilation.
 
 1. Each thread contains - besides the ''busylocks'' counter - an optional ''busylocks_root'' field, that is the root of an embedded xlist of (local or remote) busylocks hold by a given thread at a given time. This list is implemented by an optional ''xlist'' field in the busy lock descriptor. It  is dynamically updated by the ''busylock_acquire()'' and ''busylock_release()'' functions. The set of taken busylocks is printed in the error message, when the scheduler detects that a descheduling thread is holding one or several busylocks. This list can also be printed through the ''idbg'' interactive debugger, for any thread identified by its (pid,trdid).
 
-2. Moreover, when DEBUG_BUSYLOCK  is set,  all busylock_acquire() / busylock_release() made by the thread, identified by the DEBUG_BUSYLOCK_PID and DEBUG_BUSYLOCK_TRDID parameters are traced on kernel TXT0.  
+2. Moreover, when DEBUG_BUSYLOCK  is set,  all busylock_acquire() / busylock_release() made by the thread, identified by the DEBUG_BUSYLOCK_PID and DEBUG_BUSYLOCK_TRDID parameters (defined in the kernel_config.h file) are traced on kernel TXT0.  
 
+=== F.2 higher level lock debug ===
 
- 
+When the DEBUG_QUEUELOCK parameter is set,  all ''queuelock_acquire() / queuelock_release()'' made by any thread on a given ''queuelock''  identified by  its (cxy,ptr) are traced on the kernel TXT0 terminal. The DEBUG_QUEUELOCK, DEBUG_QUEUELOCK_CXY (cluster identifier) and DEBUG_QUEUELOCK_PTR (queuelock local pointer) parameters are defined in the <kernel_config.h> file.
+
+When the DEBUG_RWLOCK parameter is set,  all ''rwlock_acquire() / rwlock_release()'' made by any thread on a given ''rwlock''  identified by  its (cxy,ptr) are traced on the kernel TXT0 terminal. The DEBUG_RWLOCK, DEBUG_RWLOCK_CXY (cluster identifier) and DEBUG_RWLOCK_PTR (rwlock local pointer) parameters are defined in the <kernel_config.h> file.