X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=blobdiff_plain;f=src%2Fcommon%2Fdefaults.cpp;fp=src%2Fcommon%2Fdefaults.cpp;h=5ecb435bb630af685be875ebf257fb6d6e46bd0b;hp=0000000000000000000000000000000000000000;hb=a6bc4ca9d659caf016ef932fcd944029737ac57c;hpb=97535efaa975ca52bf02c2d5e76351bfd2e3defa

diff --git a/src/common/defaults.cpp b/src/common/defaults.cpp
new file mode 100644
index 000000000..5ecb435bb
--- /dev/null
+++ b/src/common/defaults.cpp
@@ -0,0 +1,154 @@
+/*
+ * Copyright (C) 2012 Simon Marchi <simon.marchi@polymtl.ca>
+ *
+ * SPDX-License-Identifier: GPL-2.0-only
+ *
+ */
+
+#define _LGPL_SOURCE
+#include <stddef.h>
+#include <unistd.h>
+#include <stdbool.h>
+#include <sys/resource.h>
+#include <pthread.h>
+#include <algorithm>
+
+#include "defaults.h"
+#include "macros.h"
+#include "error.h"
+
+static int pthread_attr_init_done;
+static pthread_attr_t tattr;
+
+static size_t get_page_size(void)
+{
+	const long ret = sysconf(_SC_PAGE_SIZE);
+
+	if (ret < 0) {
+		/*
+		 * Fatal error since there is no safe way to recover from this.
+		 */
+		PERROR("Failed to get system page size using sysconf(_SC_PAGE_SIZE)");
+		abort();
+	}
+
+	return (size_t) ret;
+}
+
+size_t default_get_channel_subbuf_size(void)
+{
+	return std::max<size_t>(_DEFAULT_CHANNEL_SUBBUF_SIZE, get_page_size());
+}
+
+size_t default_get_metadata_subbuf_size(void)
+{
+	return std::max<size_t>(DEFAULT_METADATA_SUBBUF_SIZE, get_page_size());
+}
+
+size_t default_get_kernel_channel_subbuf_size(void)
+{
+	return std::max<size_t>(DEFAULT_KERNEL_CHANNEL_SUBBUF_SIZE, get_page_size());
+}
+
+size_t default_get_ust_pid_channel_subbuf_size(void)
+{
+	return std::max<size_t>(DEFAULT_UST_PID_CHANNEL_SUBBUF_SIZE, get_page_size());
+}
+
+size_t default_get_ust_uid_channel_subbuf_size(void)
+{
+	return std::max<size_t>(DEFAULT_UST_UID_CHANNEL_SUBBUF_SIZE, get_page_size());
+}
+
+pthread_attr_t *default_pthread_attr(void)
+{
+	if (pthread_attr_init_done) {
+		return &tattr;
+	}
+
+	WARN("Uninitialized pthread attributes, using libc defaults.");
+	return NULL;
+}
+
+static void __attribute__((constructor)) init_default_pthread_attr(void)
+{
+	int ret;
+	struct rlimit rlim;
+	size_t pthread_ss, system_ss, selected_ss;
+
+	ret = pthread_attr_init(&tattr);
+	if (ret) {
+		errno = ret;
+		PERROR("pthread_attr_init");
+		goto error;
+	}
+
+	/* Get system stack size limits. */
+	ret = getrlimit(RLIMIT_STACK, &rlim);
+	if (ret < 0) {
+		PERROR("getrlimit");
+		goto error_destroy;
+	}
+	DBG("Stack size limits: soft %lld, hard %lld bytes",
+			(long long) rlim.rlim_cur,
+			(long long) rlim.rlim_max);
+
+	/*
+	 * getrlimit() may return a stack size of "-1", meaning "unlimited".
+	 * In this case, we impose a known-good default minimum value which will
+	 * override the libc's default stack size if it is smaller.
+	 */
+	system_ss = rlim.rlim_cur != -1 ? rlim.rlim_cur :
+			DEFAULT_LTTNG_THREAD_STACK_SIZE;
+
+	/* Get pthread default thread stack size. */
+	ret = pthread_attr_getstacksize(&tattr, &pthread_ss);
+	if (ret < 0) {
+		PERROR("pthread_attr_getstacksize");
+		goto error_destroy;
+	}
+	DBG("Default pthread stack size is %zu bytes", pthread_ss);
+
+	selected_ss = std::max(pthread_ss, system_ss);
+	if (selected_ss < DEFAULT_LTTNG_THREAD_STACK_SIZE) {
+		DBG("Default stack size is too small, setting it to %zu bytes",
+			(size_t) DEFAULT_LTTNG_THREAD_STACK_SIZE);
+		selected_ss = DEFAULT_LTTNG_THREAD_STACK_SIZE;
+	}
+
+	if (rlim.rlim_max > 0 && selected_ss > rlim.rlim_max) {
+		WARN("Your system's stack size restrictions (%zu bytes) may be too low for the LTTng daemons to function properly, please set the stack size limit to at least %zu bytes to ensure reliable operation",
+			(size_t) rlim.rlim_max, (size_t) DEFAULT_LTTNG_THREAD_STACK_SIZE);
+		selected_ss = (size_t) rlim.rlim_max;
+	}
+
+	ret = pthread_attr_setstacksize(&tattr, selected_ss);
+	if (ret < 0) {
+		PERROR("pthread_attr_setstacksize");
+		goto error_destroy;
+	}
+	pthread_attr_init_done = 1;
+error:
+	return;
+error_destroy:
+	ret = pthread_attr_destroy(&tattr);
+	if (ret) {
+		errno = ret;
+		PERROR("pthread_attr_destroy");
+	}
+}
+
+static void __attribute__((destructor)) fini_default_pthread_attr(void)
+{
+	int ret;
+
+	if (!pthread_attr_init_done) {
+		return;
+	}
+
+	ret = pthread_attr_destroy(&tattr);
+	if (ret) {
+		errno = ret;
+		PERROR("pthread_attr_destroy");
+	}
+}