Changeset 31d8e10 in mainline for kernel/generic/include

Timestamp:

2007-04-05T16:09:49Z (19 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

547fa39

Parents:

879585a3

Message:

Continue to de-oversynchronize the kernel.

• replace as→refcount with an atomic counter; accesses to this

reference counter are not to be done when the as→lock mutex is held;
this gets us rid of mutex_lock_active();

Remove the possibility of a deadlock between TLB shootdown and asidlock.

• get rid of mutex_lock_active() on as→lock
• when locking the asidlock spinlock, always do it conditionally and with

preemption disabled; in the unsuccessful case, enable interrupts and try again

• there should be no deadlock between TLB shootdown and the as→lock mutexes
• PLEASE REVIEW !!!

Add DEADLOCK_PROBE's to places where we have spinlock_trylock() loops.

Location:

kernel/generic/include

Files:

• mm/as.h (modified) (2 diffs)
• synch/mutex.h (modified) (1 diff)
• synch/spinlock.h (modified) (2 diffs)

kernel/generic/include/mm/as.h

@@ -102 +102 @@
                 asid_t asid;
                 
+                /** Number of references (i.e tasks that reference this as). */
+                atomic_t refcount;
+
                 mutex_t lock;
-                
-                /** Number of references (i.e tasks that reference this as). */
-                count_t refcount;
                 
                 /** B+tree of address space areas. */
@@ -148 +148 @@
         asid_t asid;
 
+        /** Number of references (i.e tasks that reference this as). */
+        atomic_t refcount;
+
         mutex_t lock;
-
-        /** Number of references (i.e tasks that reference this as). */
-        count_t refcount;
 
         /** B+tree of address space areas. */

kernel/generic/include/synch/mutex.h

@@ -45 +45 @@
 
 #define mutex_lock(mtx) \
-        _mutex_lock_timeout((mtx),SYNCH_NO_TIMEOUT,SYNCH_FLAGS_NONE)
+        _mutex_lock_timeout((mtx), SYNCH_NO_TIMEOUT, SYNCH_FLAGS_NONE)
 #define mutex_trylock(mtx) \
-        _mutex_lock_timeout((mtx),SYNCH_NO_TIMEOUT,SYNCH_FLAGS_NON_BLOCKING)
-#define mutex_lock_timeout(mtx,usec) \
-        _mutex_lock_timeout((mtx),(usec),SYNCH_FLAGS_NON_BLOCKING)
-#define mutex_lock_active(mtx) \
-        while (mutex_trylock((mtx)) != ESYNCH_OK_ATOMIC)
+        _mutex_lock_timeout((mtx), SYNCH_NO_TIMEOUT, SYNCH_FLAGS_NON_BLOCKING)
+#define mutex_lock_timeout(mtx, usec) \
+        _mutex_lock_timeout((mtx), (usec), SYNCH_FLAGS_NON_BLOCKING)
 
 extern void mutex_initialize(mutex_t *mtx);

kernel/generic/include/synch/spinlock.h

@@ -102 +102 @@
 }
 
+#ifdef CONFIG_DEBUG_SPINLOCK
+
+extern int printf(const char *, ...);
+
+#define DEADLOCK_THRESHOLD              100000000
+#define DEADLOCK_PROBE_INIT(pname)      count_t pname = 0
+#define DEADLOCK_PROBE(pname, value)                                    \
+        if ((pname)++ > (value)) {                                      \
+                (pname) = 0;                                            \
+                printf("Deadlock probe %s: exceeded threshold %d\n",    \
+                    "cpu%d: function=%s, line=%d\n",                    \
+                    #pname, (value), CPU->id, __FUNCTION__, __LINE__);  \
+        }
+#else
+#define DEADLOCK_PROBE_INIT(pname)
+#define DEADLOCK_PROBE(pname, value)
+#endif
+
 #else
 
@@ -114 +132 @@
 #define spinlock_unlock(x)              preemption_enable()
 
+#define DEADLOCK_PROBE_INIT(pname)
+#define DEADLOCK_PROBE(pname, value)
+
 #endif