Changeset d4d36f9 in mainline for kernel/generic/include

Timestamp:

2012-07-30T05:23:06Z (13 years ago)

Author:

Adam Hraska <adam.hraska+hos@…>

Branches:

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

Children:

452e91b

Parents:

f0fcb04

Message:

rcu: Added another preemptible kernel rcu - A-RCU.

Location:

kernel/generic/include

Files:

• arch.h (modified) (2 diffs)
• synch/rcu.h (modified) (2 diffs)
• synch/rcu_types.h (modified) (6 diffs)

kernel/generic/include/arch.h

@@ -38 +38 @@
 #include <arch/arch.h>  /* arch_pre_main() */
 #include <arch/asm.h>   /* get_stack_base() */
+#include <config.h>
 
 
@@ -69 +70 @@
 typedef struct {
         size_t preemption;     /**< Preemption disabled counter and flag. */
+#ifdef RCU_PREEMPT_A
+        size_t rcu_nesting;    /**< RCU nesting count and flag. */
+#endif 
         struct thread *thread; /**< Current thread. */
         struct task *task;     /**< Current task. */

kernel/generic/include/synch/rcu.h

@@ -123 +123 @@
 extern void _rcu_synchronize(bool expedite);
 
+
+#ifdef RCU_PREEMPT_A
+
+#define RCU_CNT_INC       (1 << 1)
+#define RCU_WAS_PREEMPTED (1 << 0)
+
+/* Fwd. decl. because of inlining. */
+void _rcu_preempted_unlock(void);
+
+/** Delimits the start of an RCU reader critical section. 
+ * 
+ * Reader sections may be nested and are preemptable. You must not
+ * however block/sleep within reader sections.
+ */
+static inline void rcu_read_lock(void)
+{
+        THE->rcu_nesting += RCU_CNT_INC;
+}
+
+/** Delimits the end of an RCU reader critical section. */
+static inline void rcu_read_unlock(void)
+{
+        THE->rcu_nesting -= RCU_CNT_INC;
+        
+        if (RCU_WAS_PREEMPTED == THE->rcu_nesting) {
+                _rcu_preempted_unlock();
+        }
+}
+
+#elif defined(RCU_PREEMPT_PODZIMEK)
 
 /* Fwd decl. required by the inlined implementation. Not part of public API. */
@@ -210 +240 @@
         preemption_enable();
 }
-
-
 #endif
 
+#endif
+
 /** @}
  */

kernel/generic/include/synch/rcu_types.h

@@ -39 +39 @@
 #include <synch/semaphore.h>
 
+#if !defined(RCU_PREEMPT_PODZIMEK) && !defined(RCU_PREEMPT_A)
+#define RCU_PREEMPT_A
+//#error You must select an RCU algorithm.
+#endif
+
 
 /* Fwd decl. */
@@ -58 +63 @@
 /** RCU related per-cpu data. */
 typedef struct rcu_cpu_data {
-        /** The cpu recorded a quiescent state last time during this grace period */
+        /** The cpu recorded a quiescent state last time during this grace period.*/
         rcu_gp_t last_seen_gp;
+
+#ifdef RCU_PREEMPT_PODZIMEK
+        /** This cpu has not yet passed a quiescent state and it is delaying the
+         * detector. Once it reaches a QS it must sema_up(rcu.remaining_readers).
+         */
+        bool is_delaying_gp;
         
+        /** True if we should signal the detector that we exited a reader section.
+         * 
+         * Equal to (THREAD->rcu.was_preempted || CPU->rcu.is_delaying_gp).
+         */
+        bool signal_unlock;
+
         /** The number of times an RCU reader section is nested on this cpu. 
          * 
@@ -68 +85 @@
          */
         size_t nesting_cnt;
-
+#endif
+        
         /** Callbacks to invoke once the current grace period ends, ie cur_cbs_gp.
          * Accessed by the local reclaimer only.
@@ -102 +120 @@
         rcu_gp_t next_cbs_gp;
         
-        /** This cpu has not yet passed a quiescent state and it is delaying the
-         * detector. Once it reaches a QS it must sema_up(rcu.remaining_readers).
-         */
-        bool is_delaying_gp;
-        
-        /** True if we should signal the detector that we exited a reader section.
-         * 
-         * Equal to (THREAD->rcu.was_preempted || CPU->rcu.is_delaying_gp).
-         */
-        bool signal_unlock;
-        
         /** Positive if there are callbacks pending in arriving_cbs. */
         semaphore_t arrived_flag;
@@ -142 +149 @@
          */
         size_t nesting_cnt;
+
+#ifdef RCU_PREEMPT_PODZIMEK
         
         /** True if the thread was preempted in a reader section. 
@@ -151 +160 @@
          */
         bool was_preempted;
+#endif
+        
         /** Preempted threads link. Access with rcu.prempt_lock.*/
         link_t preempt_link;