Changeset b14ec5f for libcfa/src/concurrency/kernel_private.hfa

Timestamp:

Nov 19, 2021, 11:23:24 AM (9 months ago)

Author:

Thierry Delisle <tdelisle@…>

Branches:

enum, forall-pointer-decay, master, pthread-emulation

Children:

a633f6f

Parents:

34b8cb7 (diff), 84a6e70 (diff)
Note: this is a merge changeset, the changes displayed below correspond to the merge itself.
Use the (diff) links above to see all the changes relative to each parent.

Message:

Merge branch 'master' of plg.uwaterloo.ca:software/cfa/cfa-cc

File:

• libcfa/src/concurrency/kernel_private.hfa (modified) (1 diff)

libcfa/src/concurrency/kernel_private.hfa

@@ -282 +282 @@
 }
 
+static inline bool try_lock(__cluster_proc_list & this) {
+        /* paranoid */ verify( ! __preemption_enabled() );
+
+        // Start by locking the global RWlock so that we know no-one is
+        // adding/removing processors while we mess with the idle lock
+        ready_schedule_lock();
+
+        // Simple counting lock, acquired, acquired by incrementing the counter
+        // to an odd number
+        uint64_t l = this.lock;
+        if(
+                (0 == (l % 2))
+                && __atomic_compare_exchange_n(&this.lock, &l, l + 1, false, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST)
+        ) {
+                // success
+                /* paranoid */ verify( ! __preemption_enabled() );
+                return true;
+        }
+
+        // failed to lock
+        ready_schedule_unlock();
+
+        /* paranoid */ verify( ! __preemption_enabled() );
+        return false;
+}
+
 static inline void unlock(__cluster_proc_list & this) {
         /* paranoid */ verify( ! __preemption_enabled() );