refactor: Break sched API functions out of the main daemon source

Signed-off-by: Kai Krakow <kai@kaishome.de>

daemon/gamemode-sched.c

@@ -0,0 +1,157 @@
+/*
+
+Copyright (c) 2017-2018, Feral Interactive
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+ * Redistributions of source code must retain the above copyright notice,
+   this list of conditions and the following disclaimer.
+ * Redistributions in binary form must reproduce the above copyright
+   notice, this list of conditions and the following disclaimer in the
+   documentation and/or other materials provided with the distribution.
+ * Neither the name of Feral Interactive nor the names of its contributors
+   may be used to endorse or promote products derived from this software
+   without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGE.
+
+ */
+
+#define _GNU_SOURCE
+
+#include "daemon_config.h"
+#include "gamemode.h"
+#include "logging.h"
+
+#include <errno.h>
+#include <sched.h>
+#include <string.h>
+#include <sys/resource.h>
+#include <sys/sysinfo.h>
+
+/**
+ * Priority to renice the process to.
+ */
+#define NICE_DEFAULT_PRIORITY -4
+
+/**
+ * Apply scheduling policies
+ *
+ * This tries to change the scheduler of the client to soft realtime mode
+ * available in some kernels as SCHED_ISO. It also tries to adjust the nice
+ * level. If some of each fail, ignore this and log a warning.
+ *
+ * We don't need to store the current values because when the client exits,
+ * everything will be good: Scheduling is only applied to the client and
+ * its children.
+ */
+void game_mode_apply_renice(const GameModeContext *self, const pid_t client)
+{
+	GameModeConfig *config = game_mode_config_from_context(self);
+
+	/*
+	 * read configuration "renice" (1..20)
+	 */
+	long int renice = 0;
+	config_get_renice_value(config, &renice);
+	if ((renice < 1) || (renice > 20)) {
+		LOG_ERROR("Invalid renice value '%ld' reset to default: %d.\n",
+		          renice,
+		          -NICE_DEFAULT_PRIORITY);
+		renice = NICE_DEFAULT_PRIORITY;
+	} else {
+		renice = -renice;
+	}
+
+	/*
+	 * don't adjust priority if it was already adjusted
+	 */
+	if (getpriority(PRIO_PROCESS, (id_t)client) != 0) {
+		LOG_ERROR("Refused to renice client [%d]: already reniced\n", client);
+	} else if (setpriority(PRIO_PROCESS, (id_t)client, (int)renice)) {
+		LOG_ERROR(
+		    "Failed to renice client [%d], ignoring error condition: %s\n"
+		    "    -- Your user may not have permission to do this. Please read the docs\n"
+		    "    -- to learn how to adjust the pam limits.\n",
+		    client,
+		    strerror(errno));
+	}
+}
+
+void game_mode_apply_scheduling(const GameModeContext *self, const pid_t client)
+{
+	GameModeConfig *config = game_mode_config_from_context(self);
+
+	/*
+	 * read configuration "softrealtime" (on, off, auto)
+	 */
+	char softrealtime[CONFIG_VALUE_MAX] = { 0 };
+	config_get_soft_realtime(config, softrealtime);
+
+	/*
+	 * Enable unconditionally or auto-detect soft realtime usage,
+	 * auto detection is based on observations where dual-core CPU suffered
+	 * priority inversion problems with the graphics driver thus running
+	 * slower as a result, so enable only with more than 3 cores.
+	 */
+	bool enable_softrealtime = (strcmp(softrealtime, "on") == 0) || (get_nprocs() > 3);
+
+	/*
+	 * Actually apply the scheduler policy if not explicitly turned off
+	 */
+	if (!(strcmp(softrealtime, "off") == 0) && (enable_softrealtime)) {
+		const struct sched_param p = { .sched_priority = 0 };
+		if (sched_setscheduler(client, SCHED_ISO | SCHED_RESET_ON_FORK, &p)) {
+			const char *additional_message = "";
+			switch (errno) {
+			case EPERM: {
+				static int once = 0;
+				if (once++)
+					break;
+				additional_message =
+				    "    -- The error indicates that you may be running a resource management\n"
+				    "    -- daemon managing your game launcher and it leaks lower scheduling\n"
+				    "    -- classes into the games. This is likely a bug in the management daemon\n"
+				    "    -- and not a bug in GameMode, it should be reported upstream.\n"
+				    "    -- If unsure, please also look here:\n"
+				    "    -- https://github.com/FeralInteractive/gamemode/issues/68\n";
+				break;
+			}
+			case EINVAL: {
+				static int once = 0;
+				if (once++)
+					break;
+				additional_message =
+				    "    -- The error indicates that your kernel may not support this. If you\n"
+				    "    -- don't know what SCHED_ISO means, you can safely ignore this. If you\n"
+				    "    -- expected it to work, ensure you're running a kernel with MuQSS or\n"
+				    "    -- PDS scheduler.\n"
+				    "    -- For further technical reading on the topic start here:\n"
+				    "    -- https://lwn.net/Articles/720227/\n";
+				break;
+			}
+			}
+			LOG_ERROR(
+			    "Failed setting client [%d] into SCHED_ISO mode, ignoring error condition: %s\n%s",
+			    client,
+			    strerror(errno),
+			    additional_message);
+		}
+	} else {
+		LOG_ERROR("Skipped setting client [%d] into SCHED_ISO mode: softrealtime setting is '%s'\n",
+		          client,
+		          softrealtime);
+	}
+}

daemon/gamemode.c

@@ -41,13 +41,9 @@ POSSIBILITY OF SUCH DAMAGE.
 
 #include <ctype.h>
 #include <fcntl.h>
-#include <linux/sched.h>
 #include <pthread.h>
-#include <sched.h>
 #include <signal.h>
 #include <stdatomic.h>
-#include <sys/resource.h>
-#include <sys/sysinfo.h>
 #include <systemd/sd-daemon.h>
 
 /* SCHED_ISO may not be defined as it is a reserved value not yet
@@ -57,10 +53,6 @@ POSSIBILITY OF SUCH DAMAGE.
 #define SCHED_ISO 4
 #endif
 
-/* Priority to renice the process to.
- */
-#define NICE_DEFAULT_PRIORITY -4
-
 /**
  * The GameModeClient encapsulates the remote connection, providing a list
  * form to contain the pid and credentials.
@@ -167,109 +159,6 @@ void game_mode_context_destroy(GameModeContext *self)
 	pthread_rwlock_destroy(&self->rwlock);
 }
 
-/**
- * Apply scheduling policies
- *
- * This tries to change the scheduler of the client to soft realtime mode
- * available in some kernels as SCHED_ISO. It also tries to adjust the nice
- * level. If some of each fail, ignore this and log a warning.
- *
- * We don't need to store the current values because when the client exits,
- * everything will be good: Scheduling is only applied to the client and
- * its children.
- */
-static void game_mode_apply_scheduler(GameModeContext *self, pid_t client)
-{
-	/*
-	 * read configuration "renice" (1..20)
-	 */
-	long int renice = 0;
-	config_get_renice_value(self->config, &renice);
-	if ((renice < 1) || (renice > 20)) {
-		LOG_ERROR("Invalid renice value '%ld' reset to default: %d.\n",
-		          renice,
-		          -NICE_DEFAULT_PRIORITY);
-		renice = NICE_DEFAULT_PRIORITY;
-	} else {
-		renice = -renice;
-	}
-
-	/*
-	 * don't adjust priority if it was already adjusted
-	 */
-	if (getpriority(PRIO_PROCESS, (id_t)client) != 0) {
-		LOG_ERROR("Refused to renice client [%d]: already reniced\n", client);
-	} else if (setpriority(PRIO_PROCESS, (id_t)client, (int)renice)) {
-		LOG_ERROR(
-		    "Failed to renice client [%d], ignoring error condition: %s\n"
-		    "    -- Your user may not have permission to do this. Please read the docs\n"
-		    "    -- to learn how to adjust the pam limits.\n",
-		    client,
-		    strerror(errno));
-	}
-
-	/*
-	 * read configuration "softrealtime" (on, off, auto)
-	 */
-	char softrealtime[CONFIG_VALUE_MAX] = { 0 };
-	config_get_soft_realtime(self->config, softrealtime);
-
-	/*
-	 * Enable unconditionally or auto-detect soft realtime usage,
-	 * auto detection is based on observations where dual-core CPU suffered
-	 * priority inversion problems with the graphics driver thus running
-	 * slower as a result, so enable only with more than 3 cores.
-	 */
-	bool enable_softrealtime = (strcmp(softrealtime, "on") == 0) || (get_nprocs() > 3);
-
-	/*
-	 * Actually apply the scheduler policy if not explicitly turned off
-	 */
-	if (!(strcmp(softrealtime, "off") == 0) && (enable_softrealtime)) {
-		const struct sched_param p = { .sched_priority = 0 };
-		if (sched_setscheduler(client, SCHED_ISO | SCHED_RESET_ON_FORK, &p)) {
-			const char *additional_message = "";
-			switch (errno) {
-			case EPERM: {
-				static int once = 0;
-				if (once++)
-					break;
-				additional_message =
-				    "    -- The error indicates that you may be running a resource management\n"
-				    "    -- daemon managing your game launcher and it leaks lower scheduling\n"
-				    "    -- classes into the games. This is likely a bug in the management daemon\n"
-				    "    -- and not a bug in GameMode, it should be reported upstream.\n"
-				    "    -- If unsure, please also look here:\n"
-				    "    -- https://github.com/FeralInteractive/gamemode/issues/68\n";
-				break;
-			}
-			case EINVAL: {
-				static int once = 0;
-				if (once++)
-					break;
-				additional_message =
-				    "    -- The error indicates that your kernel may not support this. If you\n"
-				    "    -- don't know what SCHED_ISO means, you can safely ignore this. If you\n"
-				    "    -- expected it to work, ensure you're running a kernel with MuQSS or\n"
-				    "    -- PDS scheduler.\n"
-				    "    -- For further technical reading on the topic start here:\n"
-				    "    -- https://lwn.net/Articles/720227/\n";
-				break;
-			}
-			}
-			LOG_ERROR(
-			    "Failed setting client [%d] into SCHED_ISO mode, ignoring error condition: %s\n%s",
-			    client,
-			    strerror(errno),
-			    additional_message);
-		}
-	} else {
-		LOG_ERROR("Skipped setting client [%d] into SCHED_ISO mode: softrealtime setting is '%s'\n",
-		          client,
-		          softrealtime);
-	}
-}
-
 /**
  * Apply io priorities
  *
@@ -539,7 +428,8 @@ bool game_mode_context_register(GameModeContext *self, pid_t client)
 	}
 
 	/* Apply scheduler policies */
-	game_mode_apply_scheduler(self, client);
+	game_mode_apply_renice(self, client);
+	game_mode_apply_scheduling(self, client);
 
 	/* Apply io priorities */
 	game_mode_apply_ioprio(self, client);

daemon/gamemode.h

@@ -110,3 +110,10 @@ char *game_mode_lookup_user_home(void);
  */
 procfd_t game_mode_open_proc(const pid_t pid);
 int game_mode_close_proc(const procfd_t procfd);
+
+/** gamemode-sched.c
+ * Provides internal API functions specific to adjusting process
+ * scheduling.
+ */
+void game_mode_apply_renice(const GameModeContext *self, const pid_t client);
+void game_mode_apply_scheduling(const GameModeContext *self, const pid_t client);

daemon/meson.build

@@ -20,6 +20,7 @@ daemon_sources = [
     'gamemode.c',
     'gamemode-env.c',
     'gamemode-proc.c',
+    'gamemode-sched.c',
     'daemonize.c',
     'dbus_messaging.c',
     'governors.c',