Merge pull request #144 from mdiluz/add-config-hotreloading

Add config hot-reloading
This commit is contained in:
Alex Smith 2019-05-24 08:58:43 +01:00 committed by GitHub
commit 3a2ebd1cdf
6 changed files with 279 additions and 57 deletions

View File

@ -37,11 +37,14 @@ POSSIBILITY OF SUCH DAMAGE.
/* Ben Hoyt's inih library */
#include "ini.h"
#include <dirent.h>
#include <linux/limits.h>
#include <pthread.h>
#include <pwd.h>
#include <stdio.h>
#include <string.h>
#include <sys/inotify.h>
#include <sys/stat.h>
#include <sys/types.h>
/* Name and possible location of the config file */
@ -59,6 +62,9 @@ POSSIBILITY OF SUCH DAMAGE.
return value; \
}
/* The number of current locations for config files */
#define CONFIG_NUM_LOCATIONS 4
/**
* The config holds various details as needed
* and a rwlock to allow config_reload to be called
@ -66,7 +72,7 @@ POSSIBILITY OF SUCH DAMAGE.
struct GameModeConfig {
pthread_rwlock_t rwlock;
int inotfd;
int inotwd;
int inotwd[CONFIG_NUM_LOCATIONS];
struct {
char whitelist[CONFIG_LIST_MAX][CONFIG_VALUE_MAX];
@ -342,7 +348,7 @@ static void load_config_files(GameModeConfig *self)
const char *path;
bool protected;
};
struct ConfigLocation locations[] = {
struct ConfigLocation locations[CONFIG_NUM_LOCATIONS] = {
{ "/usr/share/gamemode", true }, /* shipped default config */
{ "/etc", true }, /* administrator config */
{ config_location_home, false }, /* $XDG_CONFIG_HOME or $HOME/.config/ */
@ -350,11 +356,12 @@ static void load_config_files(GameModeConfig *self)
};
/* Load each file in order and overwrite values */
for (unsigned int i = 0; i < sizeof(locations) / sizeof(locations[0]); i++) {
for (unsigned int i = 0; i < CONFIG_NUM_LOCATIONS; i++) {
char *path = NULL;
if (locations[i].path && asprintf(&path, "%s/" CONFIG_NAME, locations[i].path) > 0) {
FILE *f = fopen(path, "r");
if (f) {
FILE *f = NULL;
DIR *d = NULL;
if ((f = fopen(path, "r"))) {
LOG_MSG("Loading config file [%s]\n", path);
load_protected = locations[i].protected;
int error = ini_parse_file(f, inih_handler, (void *)self);
@ -364,6 +371,24 @@ static void load_config_files(GameModeConfig *self)
LOG_MSG("Failed to parse config file - error on line %d!\n", error);
}
fclose(f);
/* Register for inotify */
/* Watch for modification, deletion, moves, or attribute changes */
uint32_t fileflags = IN_MODIFY | IN_DELETE_SELF | IN_MOVE_SELF | IN_ATTRIB;
if ((self->inotwd[i] = inotify_add_watch(self->inotfd, path, fileflags)) == -1) {
LOG_ERROR("Failed to watch %s, error: %s", path, strerror(errno));
}
} else if ((d = opendir(locations[i].path))) {
/* We didn't find a file, so we'll wait on the directory */
/* Notify if a file is created, or move to the directory, or if the directory itself
* is removed or moved away */
uint32_t dirflags = IN_CREATE | IN_MOVED_TO | IN_DELETE_SELF | IN_MOVE_SELF;
if ((self->inotwd[i] =
inotify_add_watch(self->inotfd, locations[i].path, dirflags)) == -1) {
LOG_ERROR("Failed to watch %s, error: %s", path, strerror(errno));
}
closedir(d);
}
free(path);
}
@ -409,16 +434,104 @@ void config_init(GameModeConfig *self)
{
pthread_rwlock_init(&self->rwlock, NULL);
self->inotfd = inotify_init1(IN_NONBLOCK);
if (self->inotfd == -1)
LOG_ERROR(
"inotify_init failed: %s, gamemode will be able to watch config files for edits!\n",
strerror(errno));
for (unsigned int i = 0; i < CONFIG_NUM_LOCATIONS; i++) {
self->inotwd[i] = -1;
}
/* load the initial config */
load_config_files(self);
}
/*
* Destroy internal parts of config
*/
static void internal_destroy(GameModeConfig *self)
{
pthread_rwlock_destroy(&self->rwlock);
for (unsigned int i = 0; i < CONFIG_NUM_LOCATIONS; i++) {
if (self->inotwd[i] != -1) {
/* TODO: Error handle */
inotify_rm_watch(self->inotfd, self->inotwd[i]);
}
}
if (self->inotfd != -1)
close(self->inotfd);
}
/*
* Re-load the config file
*/
void config_reload(GameModeConfig *self)
{
load_config_files(self);
internal_destroy(self);
config_init(self);
}
/*
* Check if the config needs to be reloaded
*/
bool config_needs_reload(GameModeConfig *self)
{
bool need = false;
/* Take a read lock while we use the inotify fd */
pthread_rwlock_rdlock(&self->rwlock);
const size_t buflen = sizeof(struct inotify_event) + NAME_MAX + 1;
char buffer[buflen] __attribute__((aligned(__alignof__(struct inotify_event))));
ssize_t len = read(self->inotfd, buffer, buflen);
if (len == -1) {
/* EAGAIN is returned when there's nothing to read on a non-blocking fd */
if (errno != EAGAIN)
LOG_ERROR("Could not read inotify fd: %s\n", strerror(errno));
} else if (len > 0) {
/* Iterate over each event we've been given */
size_t i = 0;
while (i < (size_t)len) {
struct inotify_event *event = (struct inotify_event *)&buffer[i];
/* We have picked up an event and need to handle it */
if (event->mask & IN_ISDIR) {
/* If the event is a dir event we need to take a look */
if (event->mask & IN_DELETE_SELF || event->mask & IN_MOVE_SELF) {
/* The directory itself changed, trigger a reload */
need = true;
break;
} else if (event->mask & IN_CREATE || event->mask & IN_MOVED_TO) {
/* A new file has appeared, check the file name */
if (strncmp(basename(event->name), CONFIG_NAME, strlen(CONFIG_NAME)) == 0) {
/* This is a gamemode config file, trigger a reload */
need = true;
break;
}
}
} else {
/* When the event isn't a dir event - one of our files has been interacted with
* in some way, so let's reload regardless of the details
*/
need = true;
break;
}
i += sizeof(struct inotify_event) + event->len;
}
}
/* Return the read lock */
pthread_rwlock_unlock(&self->rwlock);
return need;
}
/*
@ -426,7 +539,7 @@ void config_reload(GameModeConfig *self)
*/
void config_destroy(GameModeConfig *self)
{
pthread_rwlock_destroy(&self->rwlock);
internal_destroy(self);
/* Finally, free the memory */
free(self);

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@ -68,6 +68,11 @@ void config_init(GameModeConfig *self);
*/
void config_reload(GameModeConfig *self);
/*
* Check if the config has changed and will need a reload
*/
bool config_needs_reload(GameModeConfig *self);
/*
* Destroy a config
* Invalidates the config

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@ -206,24 +206,35 @@ void game_mode_client_count_changed(void)
NULL);
}
/**
* Handles the Refresh Config request
*/
static int method_refresh_config(sd_bus_message *m, void *userdata,
__attribute__((unused)) sd_bus_error *ret_error)
{
GameModeContext *context = userdata;
int status = game_mode_reload_config(context);
return sd_bus_reply_method_return(m, "i", status);
}
/**
* D-BUS vtable to dispatch virtual methods
*/
static const sd_bus_vtable gamemode_vtable[] = {
SD_BUS_VTABLE_START(0),
SD_BUS_PROPERTY("ClientCount", "i", property_get_client_count, 0,
SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE),
SD_BUS_METHOD("RegisterGame", "i", "i", method_register_game, SD_BUS_VTABLE_UNPRIVILEGED),
SD_BUS_METHOD("UnregisterGame", "i", "i", method_unregister_game, SD_BUS_VTABLE_UNPRIVILEGED),
SD_BUS_METHOD("QueryStatus", "i", "i", method_query_status, SD_BUS_VTABLE_UNPRIVILEGED),
SD_BUS_METHOD("RegisterGameByPID", "ii", "i", method_register_game_by_pid,
SD_BUS_VTABLE_UNPRIVILEGED),
SD_BUS_METHOD("UnregisterGameByPID", "ii", "i", method_unregister_game_by_pid,
SD_BUS_VTABLE_UNPRIVILEGED),
SD_BUS_METHOD("QueryStatusByPID", "ii", "i", method_query_status_by_pid,
SD_BUS_VTABLE_UNPRIVILEGED),
SD_BUS_VTABLE_END
};
static const sd_bus_vtable gamemode_vtable[] =
{ SD_BUS_VTABLE_START(0),
SD_BUS_PROPERTY("ClientCount", "i", property_get_client_count, 0,
SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE),
SD_BUS_METHOD("RegisterGame", "i", "i", method_register_game, SD_BUS_VTABLE_UNPRIVILEGED),
SD_BUS_METHOD("UnregisterGame", "i", "i", method_unregister_game, SD_BUS_VTABLE_UNPRIVILEGED),
SD_BUS_METHOD("QueryStatus", "i", "i", method_query_status, SD_BUS_VTABLE_UNPRIVILEGED),
SD_BUS_METHOD("RegisterGameByPID", "ii", "i", method_register_game_by_pid,
SD_BUS_VTABLE_UNPRIVILEGED),
SD_BUS_METHOD("UnregisterGameByPID", "ii", "i", method_unregister_game_by_pid,
SD_BUS_VTABLE_UNPRIVILEGED),
SD_BUS_METHOD("QueryStatusByPID", "ii", "i", method_query_status_by_pid,
SD_BUS_VTABLE_UNPRIVILEGED),
SD_BUS_METHOD("RefreshConfig", "", "i", method_refresh_config, SD_BUS_VTABLE_UNPRIVILEGED),
SD_BUS_VTABLE_END };
/**
* Main process loop for the daemon. Run until quitting has been requested.

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@ -99,6 +99,17 @@ static void game_mode_context_leave(GameModeContext *self);
static char *game_mode_context_find_exe(pid_t pid);
static void game_mode_execute_scripts(char scripts[CONFIG_LIST_MAX][CONFIG_VALUE_MAX], int timeout);
static void start_reaper_thread(GameModeContext *self)
{
pthread_mutex_init(&self->reaper.mutex, NULL);
pthread_cond_init(&self->reaper.condition, NULL);
self->reaper.running = true;
if (pthread_create(&self->reaper.thread, NULL, game_mode_context_reaper, self) != 0) {
FATAL_ERROR("Couldn't construct a new thread");
}
}
void game_mode_context_init(GameModeContext *self)
{
if (had_context_init) {
@ -120,14 +131,25 @@ void game_mode_context_init(GameModeContext *self)
game_mode_initialise_gpu(self->config, &self->target_gpu);
pthread_rwlock_init(&self->rwlock, NULL);
pthread_mutex_init(&self->reaper.mutex, NULL);
pthread_cond_init(&self->reaper.condition, NULL);
/* Get the reaper thread going */
self->reaper.running = true;
if (pthread_create(&self->reaper.thread, NULL, game_mode_context_reaper, self) != 0) {
FATAL_ERROR("Couldn't construct a new thread");
}
start_reaper_thread(self);
}
static void end_reaper_thread(GameModeContext *self)
{
self->reaper.running = false;
/* We might be stuck waiting, so wake it up again */
pthread_mutex_lock(&self->reaper.mutex);
pthread_cond_signal(&self->reaper.condition);
pthread_mutex_unlock(&self->reaper.mutex);
/* Join the thread as soon as possible */
pthread_join(self->reaper.thread, NULL);
pthread_cond_destroy(&self->reaper.condition);
pthread_mutex_destroy(&self->reaper.mutex);
}
void game_mode_context_destroy(GameModeContext *self)
@ -143,18 +165,8 @@ void game_mode_context_destroy(GameModeContext *self)
had_context_init = false;
game_mode_client_free(self->client);
self->reaper.running = false;
/* We might be stuck waiting, so wake it up again */
pthread_mutex_lock(&self->reaper.mutex);
pthread_cond_signal(&self->reaper.condition);
pthread_mutex_unlock(&self->reaper.mutex);
/* Join the thread as soon as possible */
pthread_join(self->reaper.thread, NULL);
pthread_cond_destroy(&self->reaper.condition);
pthread_mutex_destroy(&self->reaper.mutex);
end_reaper_thread(self);
/* Destroy the gpu object */
game_mode_free_gpu(&self->stored_gpu);
@ -324,6 +336,20 @@ int game_mode_context_num_clients(GameModeContext *self)
return atomic_load(&self->refcount);
}
static int game_mode_apply_client_optimisations(GameModeContext *self, pid_t client)
{
/* Store current renice and apply */
game_mode_apply_renice(self, client, 0 /* expect zero value to start with */);
/* Store current ioprio value and apply */
game_mode_apply_ioprio(self, client, IOPRIO_DEFAULT);
/* Apply scheduler policies */
game_mode_apply_scheduling(self, client);
return 0;
}
int game_mode_context_register(GameModeContext *self, pid_t client, pid_t requester)
{
errno = 0;
@ -410,21 +436,16 @@ int game_mode_context_register(GameModeContext *self, pid_t client, pid_t reques
/* Update the list */
cl->next = self->client;
self->client = cl;
pthread_rwlock_unlock(&self->rwlock);
/* First add, init */
if (atomic_fetch_add_explicit(&self->refcount, 1, memory_order_seq_cst) == 0) {
game_mode_context_enter(self);
}
/* Store current renice and apply */
game_mode_apply_renice(self, client, 0 /* expect zero value to start with */);
game_mode_apply_client_optimisations(self, client);
/* Store current ioprio value and apply */
game_mode_apply_ioprio(self, client, IOPRIO_DEFAULT);
/* Apply scheduler policies */
game_mode_apply_scheduling(self, client);
/* Unlock now we're done applying optimisations */
pthread_rwlock_unlock(&self->rwlock);
game_mode_client_count_changed();
@ -438,6 +459,17 @@ error_cleanup:
return err;
}
static int game_mode_remove_client_optimisations(GameModeContext *self, pid_t client)
{
/* Restore the ioprio value for the process, expecting it to be the config value */
game_mode_apply_ioprio(self, client, (int)config_get_ioprio_value(self->config));
/* Restore the renice value for the process, expecting it to be our config value */
game_mode_apply_renice(self, client, (int)config_get_renice_value(self->config));
return 0;
}
int game_mode_context_unregister(GameModeContext *self, pid_t client, pid_t requester)
{
GameModeClient *cl = NULL;
@ -491,9 +523,6 @@ int game_mode_context_unregister(GameModeContext *self, pid_t client, pid_t requ
break;
}
/* Unlock here, potentially yielding */
pthread_rwlock_unlock(&self->rwlock);
if (!found) {
LOG_HINTED(
ERROR,
@ -503,6 +532,7 @@ int game_mode_context_unregister(GameModeContext *self, pid_t client, pid_t requ
" -- with a nearby 'Removing expired game' which means we cleaned up properly\n"
" -- (we will log this event). This hint will be displayed only once.\n",
client);
pthread_rwlock_unlock(&self->rwlock);
return -1;
}
@ -511,14 +541,13 @@ int game_mode_context_unregister(GameModeContext *self, pid_t client, pid_t requ
game_mode_context_leave(self);
}
game_mode_remove_client_optimisations(self, client);
/* Unlock now we're done applying optimisations */
pthread_rwlock_unlock(&self->rwlock);
game_mode_client_count_changed();
/* Restore the ioprio value for the process, expecting it to be the config value */
game_mode_apply_ioprio(self, client, (int)config_get_ioprio_value(self->config));
/* Restore the renice value for the process, expecting it to be our config value */
game_mode_apply_renice(self, client, (int)config_get_renice_value(self->config));
return 0;
}
@ -613,6 +642,39 @@ static void game_mode_client_free(GameModeClient *client)
free(client);
}
/* Internal refresh config function (assumes no contention with reaper thread) */
static void game_mode_reload_config_internal(GameModeContext *self)
{
LOG_MSG("Reloading config...\n");
/* Make sure we have a readwrite lock on ourselves */
pthread_rwlock_wrlock(&self->rwlock);
/* Remove current optimisations when we're already active */
if (game_mode_context_num_clients(self)) {
for (GameModeClient *cl = self->client; cl; cl = cl->next)
game_mode_remove_client_optimisations(self, cl->pid);
game_mode_context_leave(self);
}
/* Reload the config */
config_reload(self->config);
/* Re-apply all current optimisations */
if (game_mode_context_num_clients(self)) {
/* Start the global context back up */
game_mode_context_enter(self);
for (GameModeClient *cl = self->client; cl; cl = cl->next)
game_mode_apply_client_optimisations(self, cl->pid);
}
pthread_rwlock_unlock(&self->rwlock);
LOG_MSG("Config reload complete\n");
}
/**
* We continuously run until told otherwise.
*/
@ -640,6 +702,12 @@ static void *game_mode_context_reaper(void *userdata)
/* Expire remaining entries */
game_mode_context_auto_expire(self);
/* Check if we should be reloading the config, and do so if needed */
if (config_needs_reload(self->config)) {
LOG_MSG("Detected config file changes\n");
game_mode_reload_config_internal(self);
}
ts.tv_sec = time(NULL) + reaper_interval;
}
@ -736,3 +804,23 @@ static void game_mode_execute_scripts(char scripts[CONFIG_LIST_MAX][CONFIG_VALUE
i++;
}
}
/*
* Reload the current configuration
*
* Reloading the configuration completely live would be problematic for various optimisation values,
* to ensure we have a fully clean state, we tear down the whole gamemode state and regrow it with a
* new config, remembering the registered games
*/
int game_mode_reload_config(GameModeContext *self)
{
/* Stop the reaper thread first */
end_reaper_thread(self);
game_mode_reload_config_internal(self);
/* Restart the reaper thread back up again */
start_reaper_thread(self);
return 0;
}

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@ -111,6 +111,11 @@ int game_mode_context_query_status(GameModeContext *self, pid_t pid, pid_t reque
*/
GameModeConfig *game_mode_config_from_context(const GameModeContext *context);
/*
* Reload the current configuration
*/
int game_mode_reload_config(GameModeContext *context);
/** gamemode-env.c
* Provides internal API functions specific to working environment
* variables.

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@ -1,5 +1,5 @@
[general]
; The reaper thread will check every 5 seconds for exited clients
; The reaper thread will check every 5 seconds for exited clients and for config file changes
reaper_freq=5
; The desired governor is used when entering GameMode instead of "performance"