experimental use of atomic functions

lib/hio-cmn.h

@@ -963,6 +963,14 @@ struct hio_cmgr_t
 	#endif
 #endif
 
+#if defined(__clang__) || (defined(__GNUC__) && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 7)))
+	#define HCL_ATOMIC_LOAD(dst) __atomic_load_n(dst, __ATOMIC_RELAXED)
+	#define HCL_ATOMIC_CMP_XCHG(dst,expected,desired) \
+		__atomic_compare_exchange_n(dst, expected, desired, 0, __ATOMIC_RELAXED, __ATOMIC_RELAXED)
+#else
+	#error NOT SUPPORTED
+#endif
+
 #if defined(HIO_HAVE_BUILTIN_EXPECT)
 #	define HIO_LIKELY(x) (__builtin_expect(!!(x),1))
 #	define HIO_UNLIKELY(x) (__builtin_expect(!!(x),0))

lib/http-cgi.c

@@ -48,6 +48,8 @@
 #define CGI_OVER_WRITE_TO_PEER    (1 << 3)
 #define CGI_OVER_ALL (CGI_OVER_READ_FROM_CLIENT | CGI_OVER_READ_FROM_PEER | CGI_OVER_WRITE_TO_CLIENT | CGI_OVER_WRITE_TO_PEER)
 
+/* ----------------------------------------------------------------------- */
+
 struct cgi_t
 {
 	HIO_SVC_HTTS_TASK_HEADER;
@@ -75,9 +77,45 @@ struct cgi_peer_xtn_t
 };
 typedef struct cgi_peer_xtn_t cgi_peer_xtn_t;
 
+/* ----------------------------------------------------------------------- */
+
 static void unbind_task_from_client (cgi_t* cgi, int rcdown);
 static void unbind_task_from_peer (cgi_t* cgi, int rcdown);
 
+/* ----------------------------------------------------------------------- */
+
+static int inc_ntask_cgis (hio_svc_htts_t* htts)
+{
+	int ok;
+	do
+	{
+		hio_oow_t ntask_cgis;
+		ntask_cgis = HCL_ATOMIC_LOAD(&htts->stat.ntask_cgis);
+		if (ntask_cgis >= htts->option.task_cgi_max)
+		{
+			hio_seterrbfmt (htts->hio, HIO_ENOCAPA, "too many cgi tasks");
+			return -1;
+		}
+		ok = HCL_ATOMIC_CMP_XCHG(&htts->stat.ntask_cgis, &ntask_cgis, ntask_cgis + 1);
+	}
+	while (!ok);
+	return 0;
+}
+
+static void dec_ntask_cgis (hio_svc_htts_t* htts)
+{
+	int ok;
+	do
+	{
+		hio_oow_t ntask_cgis;
+		ntask_cgis = HCL_ATOMIC_LOAD(&htts->stat.ntask_cgis);
+		ok = HCL_ATOMIC_CMP_XCHG(&htts->stat.ntask_cgis, &ntask_cgis, ntask_cgis - 1);
+	}
+	while (!ok);
+}
+
+/* ----------------------------------------------------------------------- */
+
 static void cgi_halt_participating_devices (cgi_t* cgi)
 {
 	HIO_DEBUG5 (cgi->htts->hio, "HTTS(%p) - cgi(t=%p,c=%p(%d),p=%p) Halting participating devices\n", cgi->htts, cgi, cgi->task_csck, (cgi->task_csck? cgi->task_csck->hnd: -1), cgi->peer);
@@ -192,7 +230,8 @@ static void cgi_on_kill (hio_svc_htts_task_t* task)
 	}
 
 	if (cgi->task_next) HIO_SVC_HTTS_TASKL_UNLINK_TASK (cgi); /* detach from the htts service only if it's attached */
-	cgi->htts->stat.ntask_cgis--;
+	dec_ntask_cgis (cgi->htts);
+
 	HIO_DEBUG5 (hio, "HTTS(%p) - cgi(t=%p,c=%p[%d],p=%p) - killed the task\n", cgi->htts, cgi, cgi->task_client, (cgi->task_csck? cgi->task_csck->hnd: -1), cgi->peer);
 }
 
@@ -939,16 +978,14 @@ int hio_svc_htts_docgi (hio_svc_htts_t* htts, hio_dev_sck_t* csck, hio_htre_t* r
 	HIO_ASSERT (hio, hio_htre_getcontentlen(req) == 0);
 	HIO_ASSERT (hio, cli->sck == csck);
 
-	if (htts->stat.ntask_cgis >= htts->option.task_cgi_max)
-	{
-		hio_seterrbfmt (hio, HIO_ENOCAPA, "too many cgi tasks");
-		return -1;
-	}
-
+	if (inc_ntask_cgis(htts) <= -1) return -1;
 	cgi = (cgi_t*)hio_svc_htts_task_make(htts, HIO_SIZEOF(*cgi), cgi_on_kill, req, csck);
-	if (HIO_UNLIKELY(!cgi)) goto oops;
+	if (HIO_UNLIKELY(!cgi))
+	{
+		dec_ntask_cgis (htts);
+		goto oops;
+	}
 	HIO_SVC_HTTS_TASK_RCUP((hio_svc_htts_task_t*)cgi);
-	htts->stat.ntask_cgis++;
 
 	cgi->on_kill = on_kill;
 	cgi->options = options;

lib/http-svr.c

@@ -38,6 +38,38 @@ static int client_on_read (hio_dev_sck_t* sck, const void* buf, hio_iolen_t len,
 static int client_on_write (hio_dev_sck_t* sck, hio_iolen_t wrlen, void* wrctx, const hio_skad_t* dstaddr);
 static void client_on_disconnect (hio_dev_sck_t* sck);
 
+/* ------------------------------------------------------------------------ */
+
+static int inc_ntasks (hio_svc_htts_t* htts)
+{
+	int ok;
+	do
+	{
+		hio_oow_t ntasks;
+		ntasks = HCL_ATOMIC_LOAD(&htts->stat.ntasks);
+		if (ntasks >= htts->option.task_cgi_max)
+		{
+			hio_seterrbfmt (htts->hio, HIO_ENOCAPA, "too many tasks");
+			return -1;
+		}
+		ok = HCL_ATOMIC_CMP_XCHG(&htts->stat.ntasks, &ntasks, ntasks + 1);
+	}
+	while (!ok);
+	return 0;
+}
+
+static void dec_ntasks (hio_svc_htts_t* htts)
+{
+	int ok;
+	do
+	{
+		hio_oow_t ntasks;
+		ntasks = HCL_ATOMIC_LOAD(&htts->stat.ntasks);
+		ok = HCL_ATOMIC_CMP_XCHG(&htts->stat.ntasks, &ntasks, ntasks - 1);
+	}
+	while (!ok);
+}
+
 /* ------------------------------------------------------------------------ */
 static int client_htrd_peek_request (hio_htrd_t* htrd, hio_htre_t* req)
 {
@@ -805,10 +837,13 @@ hio_svc_htts_task_t* hio_svc_htts_task_make (hio_svc_htts_t* htts, hio_oow_t tas
 	qpath_len = hio_htre_getqpathlen(req);
 	qmth_len = hio_htre_getqmethodlen(req);
 
+	if (inc_ntasks(htts) <= -1) return HIO_NULL;
+
 	task = hio_callocmem(hio, task_size + qmth_len + 1 + qpath_len + 1);
 	if (HIO_UNLIKELY(!task))
 	{
 		HIO_DEBUG1 (hio, "HTTS(%p) - failed to allocate task\n", htts);
+		dec_ntasks (htts);
 		return HIO_NULL;
 	}
 
@@ -837,7 +872,6 @@ hio_svc_htts_task_t* hio_svc_htts_task_make (hio_svc_htts_t* htts, hio_oow_t tas
 	HIO_ASSERT (hio, csck->on_write == client_on_write);
 	HIO_ASSERT (hio, csck->on_disconnect == client_on_disconnect);
 
-	htts->stat.ntasks++;
 	HIO_DEBUG2 (hio, "HTTS(%p) - allocated task %p\n", htts, task);
 	return task;
 }
@@ -852,7 +886,7 @@ void hio_svc_htts_task_kill (hio_svc_htts_task_t* task)
 	if (task->task_on_kill) task->task_on_kill (task);
 	hio_freemem (hio, task);
 
-	htts->stat.ntasks--;
+	dec_ntasks (htts);
 	HIO_DEBUG2 (hio, "HTTS(%p) - destroyed task %p\n", htts, task);
 }
 

lib/thr.c

@@ -323,7 +323,7 @@ static int dev_thr_kill_master (hio_dev_t* dev, int force)
 		hio_freemem (hio, ti);
 	#else
 		/* schedule a resource destroyer */
-		hio_addcfmb (hio, ti, ready_to_free_thr_info, HIO_NULL);
+		hio_addcfmb (hio, (hio_cfmb_t*)ti, ready_to_free_thr_info, HIO_NULL);
 	#endif
 	}