From: Simon Marchi <simon.marchi@polymtl.ca>
Date: Tue, 13 Nov 2012 19:28:42 +0000 (-0500)
Subject: Add default subbuf sizes getter functions
X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=f9f8d0f43862bb36c6c807eb5d7aa7175981d300;p=lttng-tools.git

Add default subbuf sizes getter functions

commit 8b3bd7a32e514aae56e718491a10f582b03140c3 upstream.

This patch adds functions to retrieve defaults subbuf sizes. It uses the
DEFAULT_*_SUBBUF_SIZE defines from defaults.h but also make sure that
the values are at least as big as the page size.

The functions are defined as static inline in defaults.h.

[ Edit by Christian Babeux: Resolved conflict in src/common/Makefile.am
  and src/common/defaults.h ]

Signed-off-by: Simon Marchi <simon.marchi@polymtl.ca>
Signed-off-by: David Goulet <dgoulet@efficios.com>
Signed-off-by: Christian Babeux <christian.babeux@efficios.com>
---

diff --git a/src/common/Makefile.am b/src/common/Makefile.am
index 5d79210b8..aec064c04 100644
--- a/src/common/Makefile.am
+++ b/src/common/Makefile.am
@@ -8,7 +8,7 @@ noinst_HEADERS = lttng-kernel.h defaults.h macros.h error.h
 
 noinst_LTLIBRARIES = libcommon.la
 
-libcommon_la_SOURCES = runas.c runas.h common.h
+libcommon_la_SOURCES = runas.c runas.h common.h defaults.c
 
 # Consumer library
 noinst_LTLIBRARIES += libconsumer.la
diff --git a/src/common/defaults.c b/src/common/defaults.c
new file mode 100644
index 000000000..ccdbaf499
--- /dev/null
+++ b/src/common/defaults.c
@@ -0,0 +1,49 @@
+/*
+ * Copyright (C) 2012 - Simon Marchi <simon.marchi@polymtl.ca>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License, version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 51
+ * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include <stddef.h>
+#include <unistd.h>
+
+#include "defaults.h"
+#include "macros.h"
+
+size_t default_channel_subbuf_size;
+size_t default_metadata_subbuf_size;
+size_t default_kernel_channel_subbuf_size;
+size_t default_ust_channel_subbuf_size;
+
+static void __attribute__((constructor)) init_defaults(void)
+{
+	/*
+	 * The libringbuffer won't accept subbuf sizes smaller than the page size.
+	 * If the default subbuf size is smaller, replace it by the page size.
+	 */
+	long page_size = sysconf(_SC_PAGESIZE);
+
+	if (page_size < 0) {
+		page_size = 0;
+	}
+
+	default_channel_subbuf_size =
+		max(DEFAULT_CHANNEL_SUBBUF_SIZE, page_size);
+	default_metadata_subbuf_size =
+		max(DEFAULT_METADATA_SUBBUF_SIZE, page_size);
+	default_kernel_channel_subbuf_size =
+		max(DEFAULT_KERNEL_CHANNEL_SUBBUF_SIZE, page_size);
+	default_ust_channel_subbuf_size =
+		max(DEFAULT_UST_CHANNEL_SUBBUF_SIZE, page_size);
+}
diff --git a/src/common/defaults.h b/src/common/defaults.h
index 5ee6562d9..a032ef444 100644
--- a/src/common/defaults.h
+++ b/src/common/defaults.h
@@ -117,4 +117,58 @@
  */
 #define DEFAULT_SEM_WAIT_TIMEOUT            30    /* in seconds */
 
+extern size_t default_channel_subbuf_size;
+extern size_t default_metadata_subbuf_size;
+extern size_t default_ust_channel_subbuf_size;
+extern size_t default_kernel_channel_subbuf_size;
+
+
+/*
+ * Returns the default subbuf size.
+ *
+ * This function depends on a value that is set at constructor time, so it is
+ * unsafe to call it from another constructor.
+ */
+static inline
+size_t default_get_channel_subbuf_size(void)
+{
+	return default_channel_subbuf_size;
+}
+
+/*
+ * Returns the default metadata subbuf size.
+ *
+ * This function depends on a value that is set at constructor time, so it is
+ * unsafe to call it from another constructor.
+ */
+static inline
+size_t default_get_metadata_subbuf_size(void)
+{
+	return default_metadata_subbuf_size;
+}
+
+/*
+ * Returns the default subbuf size for the kernel domain.
+ *
+ * This function depends on a value that is set at constructor time, so it is
+ * unsafe to call it from another constructor.
+ */
+static inline
+size_t default_get_kernel_channel_subbuf_size(void)
+{
+	return default_kernel_channel_subbuf_size;
+}
+
+/*
+ * Returns the default subbuf size for the UST domain.
+ *
+ * This function depends on a value that is set at constructor time, so it is
+ * unsafe to call it from another constructor.
+ */
+static inline
+size_t default_get_ust_channel_subbuf_size(void)
+{
+	return default_ust_channel_subbuf_size;
+}
+
 #endif /* _DEFAULTS_H */