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authorRickard Green <[email protected]>2011-10-09 00:03:14 +0200
committerRickard Green <[email protected]>2011-11-13 20:40:58 +0100
commitdcc7ecbf6af5420af2d5dbd0e97fc7a2e0e894a6 (patch)
tree36335364e0e2ece36709ae73bf57f1d1d1b4b211 /erts/emulator/sys/unix
parent933790021e5fa95e4e6242e3f2eb2fcf64666a57 (diff)
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Use generic lock-free queue for async threads
Queues used for communication between async threads and scheduler threads have been replaced with lock-free queues. Drivers using the driver_async functionality are not automatically locked to the system anymore, and can be unloaded as any dynamically linked in driver. Scheduling of ready async jobs is now also interleaved in between other jobs. Previously all ready async jobs was performed at once.
Diffstat (limited to 'erts/emulator/sys/unix')
-rw-r--r--erts/emulator/sys/unix/sys.c171
1 files changed, 15 insertions, 156 deletions
diff --git a/erts/emulator/sys/unix/sys.c b/erts/emulator/sys/unix/sys.c
index 8e8d4cce61..7f851e6007 100644
--- a/erts/emulator/sys/unix/sys.c
+++ b/erts/emulator/sys/unix/sys.c
@@ -128,7 +128,6 @@ static ErtsSysReportExit *report_exit_list;
static ErtsSysReportExit *report_exit_transit_list;
#endif
-extern int check_async_ready(void);
extern int driver_interrupt(int, int);
extern void do_break(void);
@@ -1125,31 +1124,6 @@ struct erl_drv_entry vanilla_driver_entry = {
stop_select
};
-#if defined(USE_THREADS) && !defined(ERTS_SMP)
-static int async_drv_init(void);
-static ErlDrvData async_drv_start(ErlDrvPort, char*, SysDriverOpts*);
-static void async_drv_stop(ErlDrvData);
-static void async_drv_input(ErlDrvData, ErlDrvEvent);
-
-/* INTERNAL use only */
-
-struct erl_drv_entry async_driver_entry = {
- async_drv_init,
- async_drv_start,
- async_drv_stop,
- NULL,
- async_drv_input,
- NULL,
- "async",
- NULL,
- NULL,
- NULL,
- NULL,
- NULL,
- NULL
-};
-#endif
-
/* Handle SIGCHLD signals. */
#if (defined(SIG_SIGSET) || defined(SIG_SIGNAL))
static RETSIGTYPE onchld(void)
@@ -2334,87 +2308,6 @@ static void stop_select(ErlDrvEvent fd, void* _)
close((int)fd);
}
-/*
-** Async opertation support
-*/
-#if defined(USE_THREADS) && !defined(ERTS_SMP)
-static void
-sys_async_ready_failed(int fd, int r, int err)
-{
- char buf[120];
- sprintf(buf, "sys_async_ready(): Fatal error: fd=%d, r=%d, errno=%d\n",
- fd, r, err);
- erts_silence_warn_unused_result(write(2, buf, strlen(buf)));
- abort();
-}
-
-/* called from threads !! */
-void sys_async_ready(int fd)
-{
- int r;
- while (1) {
- r = write(fd, "0", 1); /* signal main thread fd MUST be async_fd[1] */
- if (r == 1) {
- DEBUGF(("sys_async_ready(): r = 1\r\n"));
- break;
- }
- if (r < 0 && errno == EINTR) {
- DEBUGF(("sys_async_ready(): r = %d\r\n", r));
- continue;
- }
- sys_async_ready_failed(fd, r, errno);
- }
-}
-
-static int async_drv_init(void)
-{
- async_fd[0] = -1;
- async_fd[1] = -1;
- return 0;
-}
-
-static ErlDrvData async_drv_start(ErlDrvPort port_num,
- char* name, SysDriverOpts* opts)
-{
- if (async_fd[0] != -1)
- return ERL_DRV_ERROR_GENERAL;
- if (pipe(async_fd) < 0)
- return ERL_DRV_ERROR_GENERAL;
-
- DEBUGF(("async_drv_start: %d\r\n", port_num));
-
- SET_NONBLOCKING(async_fd[0]);
- driver_select(port_num, async_fd[0], ERL_DRV_READ, 1);
-
- if (init_async(async_fd[1]) < 0)
- return ERL_DRV_ERROR_GENERAL;
- return (ErlDrvData)port_num;
-}
-
-static void async_drv_stop(ErlDrvData e)
-{
- int port_num = (int)(long)e;
-
- DEBUGF(("async_drv_stop: %d\r\n", port_num));
-
- exit_async();
-
- driver_select(port_num, async_fd[0], ERL_DRV_READ, 0);
-
- close(async_fd[0]);
- close(async_fd[1]);
- async_fd[0] = async_fd[1] = -1;
-}
-
-
-static void async_drv_input(ErlDrvData e, ErlDrvEvent fd)
-{
- char *buf[32];
- DEBUGF(("async_drv_input\r\n"));
- while (read((int) fd, (void *) buf, 32) > 0); /* fd MUST be async_fd[0] */
- check_async_ready(); /* invoke all async_ready */
-}
-#endif
void erts_do_break_handling(void)
{
@@ -2488,12 +2381,10 @@ erts_sys_putenv(char *buffer, int sep_ix)
}
int
-erts_sys_getenv(char *key, char *value, size_t *size)
+erts_sys_getenv__(char *key, char *value, size_t *size)
{
- char *orig_value;
int res;
- erts_smp_rwmtx_rlock(&environ_rwmtx);
- orig_value = getenv(key);
+ char *orig_value = getenv(key);
if (!orig_value)
res = -1;
else {
@@ -2508,6 +2399,15 @@ erts_sys_getenv(char *key, char *value, size_t *size)
res = 0;
}
}
+ return res;
+}
+
+int
+erts_sys_getenv(char *key, char *value, size_t *size)
+{
+ int res;
+ erts_smp_rwmtx_rlock(&environ_rwmtx);
+ res = erts_sys_getenv__(key, value, size);
erts_smp_rwmtx_runlock(&environ_rwmtx);
return res;
}
@@ -2519,31 +2419,6 @@ sys_init_io(void)
erts_alloc(ERTS_ALC_T_FD_TAB, max_files * sizeof(struct fd_data));
erts_smp_atomic_add_nob(&sys_misc_mem_sz,
max_files * sizeof(struct fd_data));
-
-#ifdef USE_THREADS
-#ifdef ERTS_SMP
- if (init_async(-1) < 0)
- erl_exit(1, "Failed to initialize async-threads\n");
-#else
- {
- /* This is speical stuff, starting a driver from the
- * system routines, but is a nice way of handling stuff
- * the erlang way
- */
- SysDriverOpts dopts;
- int ret;
-
- sys_memset((void*)&dopts, 0, sizeof(SysDriverOpts));
- add_driver_entry(&async_driver_entry);
- ret = erts_open_driver(NULL, NIL, "async", &dopts, NULL);
- DEBUGF(("open_driver = %d\n", ret));
- if (ret < 0)
- erl_exit(1, "Failed to open async driver\n");
- erts_port[ret].status |= ERTS_PORT_SFLG_IMMORTAL;
- }
-#endif
-#endif
-
}
#if (0) /* unused? */
@@ -2770,15 +2645,7 @@ initiate_report_exit_status(ErtsSysReportExit *rep, int status)
rep->next = report_exit_transit_list;
rep->status = status;
report_exit_transit_list = rep;
- /*
- * We need the scheduler thread to call check_children().
- * If the scheduler thread is sleeping in a poll with a
- * timeout, we need to wake the scheduler thread. We use the
- * functionality of the async driver to do this, instead of
- * implementing yet another driver doing the same thing. A
- * little bit ugly, but it works...
- */
- sys_async_ready(async_fd[1]);
+ erts_sys_schedule_interrupt(1);
}
static int check_children(void)
@@ -2865,19 +2732,11 @@ erl_sys_schedule(int runnable)
{
#ifdef ERTS_SMP
ERTS_CHK_IO(!runnable);
- ERTS_SMP_LC_ASSERT(!erts_thr_progress_is_blocking());
#else
- if (runnable) {
- ERTS_CHK_IO(0); /* Poll for I/O */
- check_async_ready(); /* Check async completions */
- } else {
- int wait_for_io = !check_async_ready();
- if (wait_for_io)
- wait_for_io = !check_children();
- ERTS_CHK_IO(wait_for_io);
- }
- (void) check_children();
+ ERTS_CHK_IO(runnable ? 0 : !check_children());
#endif
+ ERTS_SMP_LC_ASSERT(!erts_thr_progress_is_blocking());
+ (void) check_children();
}