Changeset 5b03a72 in mainline for kernel/generic/include

Timestamp:

2012-07-29T17:53:48Z (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:

f0fcb04

Parents:

8e3ed06

Message:

rcu: Switched from using THREAD→nesting_cnt to CPU→nesting_cnt as the main nesting count variable. RCU no longer has to mess with pointers to the corrent nesting_cnt (and gets rid of one level of indirection when accessing the nesting count in reader sections).

Location:

kernel/generic/include/synch

Files:

• rcu.h (modified) (2 diffs)
• rcu_types.h (modified) (2 diffs)

kernel/generic/include/synch/rcu.h

@@ -181 +181 @@
 
         /* Record a QS if not in a reader critical section. */
-        if (0 == *CPU->rcu.pnesting_cnt)
+        if (0 == CPU->rcu.nesting_cnt)
                 _rcu_record_qs();
 
-        ++(*CPU->rcu.pnesting_cnt);
+        ++CPU->rcu.nesting_cnt;
 
         preemption_enable();
@@ -195 +195 @@
         preemption_disable();
         
-        if (0 == --(*CPU->rcu.pnesting_cnt)) {
+        if (0 == --CPU->rcu.nesting_cnt) {
                 _rcu_record_qs();
                 

kernel/generic/include/synch/rcu_types.h

@@ -61 +61 @@
         rcu_gp_t last_seen_gp;
         
-        /** Pointer to the currently used nesting count (THREAD's or CPU's). */
-        size_t *pnesting_cnt;
-        /** Temporary nesting count if THREAD is NULL, eg in scheduler(). */
-        size_t tmp_nesting_cnt;
+        /** The number of times an RCU reader section is nested on this cpu. 
+         * 
+         * If positive, it is definitely executing reader code. If zero, 
+         * the thread might already be executing reader code thanks to
+         * cpu instruction reordering.
+         */
+        size_t nesting_cnt;
 
         /** Callbacks to invoke once the current grace period ends, ie cur_cbs_gp.
@@ -128 +131 @@
 /** RCU related per-thread data. */
 typedef struct rcu_thread_data {
-        /** The number of times an RCU reader section is nested. 
-         * 
-         * If positive, it is definitely executing reader code. If zero, 
-         * the thread might already be executing reader code thanks to
-         * cpu instruction reordering.
+        /** 
+         * Nesting count of the thread's RCU read sections when the thread 
+         * is not running.
          */
         size_t nesting_cnt;