Changeset 4fc3343 for libcfa/src/concurrency/io

Timestamp:

Jan 18, 2021, 1:32:01 PM (4 years ago)

Author:

Thierry Delisle <tdelisle@…>

Branches:

ADT, arm-eh, ast-experimental, enum, forall-pointer-decay, jacob/cs343-translation, master, new-ast-unique-expr, pthread-emulation, qualifiedEnum

Children:

978e5eb, efdfdee

Parents:

78a8440

Message:

Fix race with memory reclamation of io_context.

File:

• libcfa/src/concurrency/io/setup.cfa (modified) (4 diffs)

libcfa/src/concurrency/io/setup.cfa

@@ -113 +113 @@
 
         static struct {
-                pthread_t       thrd;    // pthread handle to io poller thread
-                void *          stack;   // pthread stack for io poller thread
-                int             epollfd; // file descriptor to the epoll instance
-                volatile bool   run;     // Whether or not to continue
-                volatile size_t epoch;   // Epoch used for memory reclamation
+                      pthread_t  thrd;    // pthread handle to io poller thread
+                      void *     stack;   // pthread stack for io poller thread
+                      int        epollfd; // file descriptor to the epoll instance
+                volatile     bool run;     // Whether or not to continue
+                volatile     bool stopped; // Whether the poller has finished running
+                volatile uint64_t epoch;   // Epoch used for memory reclamation
         } iopoll;
 
@@ -130 +131 @@
                 __cfadbg_print_safe(io_core, "Kernel : Starting io poller thread\n" );
 
-                iopoll.run = true;
-                iopoll.stack = __create_pthread( &iopoll.thrd, iopoll_loop, 0p );
-                iopoll.epoch = 0;
+                iopoll.stack   = __create_pthread( &iopoll.thrd, iopoll_loop, 0p );
+                iopoll.run     = true;
+                iopoll.stopped = false;
+                iopoll.epoch   = 0;
         }
 
@@ -205 +207 @@
                         }
                 }
+
+                __atomic_store_n(&iopoll.stopped, true, __ATOMIC_SEQ_CST);
 
                 __cfadbg_print_safe(io_core, "Kernel : IO poller thread stopping\n" );
@@ -536 +540 @@
 
                 // Wait for the next epoch
-                while(curr == __atomic_load_n(&iopoll.epoch, __ATOMIC_RELAXED)) yield();
+                while(curr == iopoll.epoch && !iopoll.stopped) Pause();
         }