Changeset d95969a for libcfa/src/concurrency/io/setup.cfa

Timestamp:

Jan 25, 2021, 3:45:42 PM (5 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:

c292244

Parents:

b6a8b31 (diff), 7158202 (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/io/setup.cfa (modified) (8 diffs)

libcfa/src/concurrency/io/setup.cfa

@@ -42 +42 @@
         void ^?{}(io_context & this, bool cluster_context) {}
 
+        void register_fixed_files( io_context &, int *, unsigned ) {}
+        void register_fixed_files( cluster    &, int *, unsigned ) {}
+
 #else
         #include <errno.h>
@@ -110 +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
+                      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;
 
@@ -126 +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.stack   = __create_pthread( &iopoll.thrd, iopoll_loop, 0p );
+                iopoll.run     = true;
+                iopoll.stopped = false;
+                iopoll.epoch   = 0;
         }
 
@@ -171 +178 @@
                 while( iopoll.run ) {
                         __cfadbg_print_safe(io_core, "Kernel I/O - epoll : waiting on io_uring contexts\n");
+
+                        // increment the epoch to notify any deleters we are starting a new cycle
+                        __atomic_fetch_add(&iopoll.epoch, 1, __ATOMIC_SEQ_CST);
 
                         // Wait for events
@@ -197 +207 @@
                         }
                 }
+
+                __atomic_store_n(&iopoll.stopped, true, __ATOMIC_SEQ_CST);
 
                 __cfadbg_print_safe(io_core, "Kernel : IO poller thread stopping\n" );
@@ -493 +505 @@
 // I/O Context Sleep
 //=============================================================================================
-        #define IOEVENTS EPOLLIN | EPOLLONESHOT
-
         static inline void __ioctx_epoll_ctl($io_ctx_thread & ctx, int op, const char * error) {
                 struct epoll_event ev;
-                ev.events = IOEVENTS;
+                ev.events = EPOLLIN | EPOLLONESHOT;
                 ev.data.u64 = (__u64)&ctx;
                 int ret = epoll_ctl(iopoll.epollfd, op, ctx.ring->efd, &ev);
@@ -514 +524 @@
         }
 
+        void __ioctx_unregister($io_ctx_thread & ctx) {
+                // Read the current epoch so we know when to stop
+                size_t curr = __atomic_load_n(&iopoll.epoch, __ATOMIC_SEQ_CST);
+
+                // Remove the fd from the iopoller
+                __ioctx_epoll_ctl(ctx, EPOLL_CTL_DEL, "REMOVE");
+
+                // Notify the io poller thread of the shutdown
+                iopoll.run = false;
+                sigval val = { 1 };
+                pthread_sigqueue( iopoll.thrd, SIGUSR1, val );
+
+                // Make sure all this is done
+                __atomic_thread_fence(__ATOMIC_SEQ_CST);
+
+                // Wait for the next epoch
+                while(curr == iopoll.epoch && !iopoll.stopped) Pause();
+        }
+
 //=============================================================================================
 // I/O Context Misc Setup
@@ -520 +549 @@
                 int ret = syscall( __NR_io_uring_register, ctx.thrd.ring->fd, IORING_REGISTER_FILES, files, count );
                 if( ret < 0 ) {
-                        abort( "KERNEL ERROR: IO_URING SYSCALL - (%d) %s\n", (int)errno, strerror(errno) );
+                        abort( "KERNEL ERROR: IO_URING REGISTER - (%d) %s\n", (int)errno, strerror(errno) );
                 }