Add support for setting thread stack size

When running the isc_quota unit test with less than usual amount of
RAM (e.g. in a CI for architectures with 32 bits of address space),
the pthread_create() function fails with the "Resource temporarily
unavailable (11):" error code.

Add functions to get and set the thread stack size (if requested),
and use these to set the thread stack size to smaller value in the
isc_quota unit test.

lib/isc/include/isc/thread.h

@@ -52,3 +52,8 @@ void
 isc_thread_setname(isc_thread_t thread, const char *name);
 
 #define isc_thread_self (uintptr_t)pthread_self
+
+size_t
+isc_thread_getstacksize(void);
+void
+isc_thread_setstacksize(size_t stacksize);

lib/isc/os.c

@@ -20,6 +20,7 @@
 #include <isc/uv.h>
 
 #include "os_p.h"
+#include "thread_p.h"
 
 static unsigned int isc__os_ncpus = 0;
 static unsigned long isc__os_cacheline = ISC_OS_CACHELINE_SIZE;
@@ -201,9 +202,16 @@ isc__os_initialize(void) {
 		isc__os_cacheline = s;
 	}
 #endif
+
+	pthread_attr_init(&isc__thread_attr);
+
+	size_t stacksize = isc_thread_getstacksize();
+	if (stacksize != 0 && stacksize < THREAD_MINSTACKSIZE) {
+		isc_thread_setstacksize(THREAD_MINSTACKSIZE);
+	}
 }
 
 void
 isc__os_shutdown(void) {
-	/* empty, but defined for completeness */;
+	pthread_attr_destroy(&isc__thread_attr);
 }

lib/isc/thread.c

@@ -40,12 +40,10 @@
 
 #include "thread_p.h"
 
-#ifndef THREAD_MINSTACKSIZE
-#define THREAD_MINSTACKSIZE (1024U * 1024)
-#endif /* ifndef THREAD_MINSTACKSIZE */
-
 static struct call_rcu_data *isc__thread_call_rcu_data = NULL;
 
+pthread_attr_t isc__thread_attr;
+
 /*
  * We can't use isc_mem API here, because it's called too early and the
  * memory debugging flags can be changed later causing mismatch between flags
@@ -126,28 +124,9 @@ isc_thread_main(isc_threadfunc_t func, void *arg) {
 
 void
 isc_thread_create(isc_threadfunc_t func, void *arg, isc_thread_t *thread) {
-	int ret;
-	pthread_attr_t attr;
-
-	pthread_attr_init(&attr);
-
-#if defined(HAVE_PTHREAD_ATTR_GETSTACKSIZE) && \
-	defined(HAVE_PTHREAD_ATTR_SETSTACKSIZE)
-	size_t stacksize;
-	ret = pthread_attr_getstacksize(&attr, &stacksize);
-	PTHREADS_RUNTIME_CHECK(pthread_attr_getstacksize, ret);
-
-	if (stacksize < THREAD_MINSTACKSIZE) {
-		ret = pthread_attr_setstacksize(&attr, THREAD_MINSTACKSIZE);
-		PTHREADS_RUNTIME_CHECK(pthread_attr_setstacksize, ret);
-	}
-#endif /* if defined(HAVE_PTHREAD_ATTR_GETSTACKSIZE) && \
-	* defined(HAVE_PTHREAD_ATTR_SETSTACKSIZE) */
-
-	ret = pthread_create(thread, &attr, thread_run, thread_wrap(func, arg));
+	int ret = pthread_create(thread, &isc__thread_attr, thread_run,
+				 thread_wrap(func, arg));
 	PTHREADS_RUNTIME_CHECK(pthread_create, ret);
-
-	pthread_attr_destroy(&attr);
 }
 
 void
@@ -188,6 +167,26 @@ isc_thread_yield(void) {
 #endif /* if defined(HAVE_SCHED_YIELD) */
 }
 
+size_t
+isc_thread_getstacksize(void) {
+	size_t stacksize = 0;
+
+#if HAVE_PTHREAD_ATTR_GETSTACKSIZE
+	int ret = pthread_attr_getstacksize(&isc__thread_attr, &stacksize);
+	PTHREADS_RUNTIME_CHECK(pthread_attr_getstacksize, ret);
+#endif /* HAVE_PTHREAD_ATTR_GETSTACKSIZE */
+
+	return stacksize;
+}
+
+void
+isc_thread_setstacksize(size_t stacksize ISC_ATTR_UNUSED) {
+#if HAVE_PTHREAD_ATTR_SETSTACKSIZE
+	int ret = pthread_attr_setstacksize(&isc__thread_attr, stacksize);
+	PTHREADS_RUNTIME_CHECK(pthread_attr_setstacksize, ret);
+#endif /* HAVE_PTHREAD_ATTR_SETSTACKSIZE */
+}
+
 void
 isc__thread_initialize(void) {
 	isc__thread_call_rcu_data = create_call_rcu_data(0, -1);

lib/isc/thread_p.h

@@ -17,6 +17,12 @@
 
 /*! \file */
 
+#ifndef THREAD_MINSTACKSIZE
+#define THREAD_MINSTACKSIZE (1U * 1024 * 1024)
+#endif /* ifndef THREAD_MINSTACKSIZE */
+
+extern pthread_attr_t isc__thread_attr;
+
 void
 isc__thread_initialize(void);
 

tests/isc/mem_test.c

@@ -37,6 +37,7 @@
 #include <isc/util.h>
 
 #include "mem_p.h"
+#include "thread_p.h"
 
 #include <tests/isc.h>
 
@@ -516,6 +517,8 @@ ISC_RUN_TEST_IMPL(isc_mem_benchmark) {
 	isc_time_t ts1, ts2;
 	double t;
 
+	isc_thread_setstacksize(THREAD_MINSTACKSIZE);
+
 	atomic_init(&mem_size, ITEM_SIZE);
 
 	ts1 = isc_time_now();

tests/isc/mutex_test.c

@@ -36,6 +36,8 @@
 #include <isc/time.h>
 #include <isc/util.h>
 
+#include "thread_p.h"
+
 #include <tests/isc.h>
 
 static unsigned int loops = 100;
@@ -124,6 +126,8 @@ ISC_RUN_TEST_IMPL(isc_mutex_benchmark) {
 	size_t cont;
 	int r;
 
+	isc_thread_setstacksize(THREAD_MINSTACKSIZE);
+
 	memset(threads, 0, sizeof(*threads) * workers);
 
 	expected_counter = ITERS * workers * loops *

tests/isc/quota_test.c

@@ -32,6 +32,8 @@
 #include <isc/util.h>
 #include <isc/uv.h>
 
+#include "thread_p.h"
+
 #include <tests/isc.h>
 
 isc_quota_t quota;
@@ -268,9 +270,10 @@ quota_thread(void *qtip) {
 }
 
 ISC_RUN_TEST_IMPL(isc_quota_callback_mt) {
-	UNUSED(state);
 	int i;
 
+	isc_thread_setstacksize(THREAD_MINSTACKSIZE);
+
 	isc_quota_init(&quota, 100);
 	static qthreadinfo_t qtis[10];
 	isc_thread_t threads[10];

tests/isc/rwlock_test.c

@@ -37,6 +37,8 @@
 #include <isc/time.h>
 #include <isc/util.h>
 
+#include "thread_p.h"
+
 #include <tests/isc.h>
 
 static unsigned int loops = 100;
@@ -255,6 +257,8 @@ isc__rwlock_benchmark(isc_thread_t *threads, unsigned int nthreads,
 	int dc;
 	size_t cont;
 
+	isc_thread_setstacksize(THREAD_MINSTACKSIZE);
+
 	expected_counter = ITERS * nthreads * loops *
 			   ((CNT_MAX - CNT_MIN) / DC + 1);
 

tests/isc/spinlock_test.c

@@ -42,6 +42,8 @@
 #include <isc/time.h>
 #include <isc/util.h>
 
+#include "thread_p.h"
+
 #include <tests/isc.h>
 
 static unsigned int loops = 100;
@@ -133,6 +135,8 @@ ISC_RUN_TEST_IMPL(isc_spinlock_benchmark) {
 	int dc;
 	size_t cont;
 
+	isc_thread_setstacksize(THREAD_MINSTACKSIZE);
+
 	memset(threads, 0, sizeof(*threads) * workers);
 
 	expected_counter = ITERS * workers * loops *