ref: 4bf9cb19de3716b50eb5e570fc5683eafbe83b71
parent: 194157e32579d8677af0077be0f72462aa124d37
author: Timo Teräs <timo.teras@iki.fi>
date: Fri Nov 18 14:34:59 CST 2016
nlplug-findfs: convert to kernel style linked lists and track spawned pids
--- a/nlplug-findfs.c
+++ b/nlplug-findfs.c
@@ -80,7 +80,75 @@
#define envcmp(env, key) (strncmp(env, key "=", strlen(key "=")) == 0)
+#ifndef container_of
+#define container_of(ptr, type, member) ({ \+ const typeof( ((type *)0)->member ) *__mptr = (ptr); \
+ (type *)( (char *)__mptr - offsetof(type,member) );})
+#endif
+struct list_head {+ struct list_head *next, *prev;
+};
+
+static inline void list_init(struct list_head *list)
+{+ list->next = list;
+ list->prev = list;
+}
+
+static inline void __list_add(struct list_head *new, struct list_head *prev,
+ struct list_head *next)
+{+ next->prev = new;
+ new->next = next;
+ new->prev = prev;
+ prev->next = new;
+}
+
+static inline void list_add(struct list_head *new, struct list_head *head)
+{+ __list_add(new, head, head->next);
+}
+
+static inline void list_add_tail(struct list_head *new, struct list_head *head)
+{+ __list_add(new, head->prev, head);
+}
+
+static inline void __list_del(struct list_head * prev, struct list_head * next)
+{+ next->prev = prev;
+ prev->next = next;
+}
+
+static inline void list_del(struct list_head *entry)
+{+ __list_del(entry->prev, entry->next);
+ entry->next = NULL;
+ entry->prev = NULL;
+}
+
+static inline int list_hashed(const struct list_head *n)
+{+ return n->next != n && n->next != NULL;
+}
+
+static inline int list_empty(const struct list_head *n)
+{+ return !list_hashed(n);
+}
+
+#define list_next(ptr, type, member) \
+ (list_hashed(ptr) ? container_of((ptr)->next,type,member) : NULL)
+
+#define list_entry(ptr, type, member) container_of(ptr,type,member)
+
+#define list_for_each_entry(pos, head, member) \
+ for (pos = list_entry((head)->next, typeof(*pos), member); \
+ &pos->member != (head); \
+ pos = list_entry(pos->member.next, typeof(*pos), member))
+
+
static char **clone_array(char *const *const a)
{size_t i, s;
@@ -102,34 +170,50 @@
}
struct spawn_task {- struct spawn_task *next;
+ struct list_head node;
+ pid_t pid;
char **argv, **envp;
};
+
+#define SPAWNMGR_PID_HASH_SIZE 32
struct spawn_manager {int num_running;
int max_running;
- struct spawn_task *first, *last;
+ struct list_head queue;
+ struct list_head running[SPAWNMGR_PID_HASH_SIZE];
};
static struct spawn_manager spawnmgr;
-static void spawn_execute(struct spawn_manager *mgr, char **argv, char **envp)
+static void spawn_init(struct spawn_manager *mgr)
{+ int i;
+
+ mgr->max_running = sysconf(_SC_NPROCESSORS_ONLN);
+ list_init(&mgr->queue);
+ for (i = 0; i < SPAWNMGR_PID_HASH_SIZE; i++)
+ list_init(&mgr->running[i]);
+}
+
+static void spawn_execute(struct spawn_manager *mgr, struct spawn_task *task)
+{pid_t pid;
- dbg("[%d/%d] running %s", mgr->num_running+1, mgr->max_running, argv[0]);+ dbg("[%d/%d] running %s", mgr->num_running+1, mgr->max_running, task->argv[0]); if (!(pid = fork())) {- if (execve(argv[0], argv, envp ? envp : default_envp) < 0)
- err(1, argv[0]);
+ if (execve(task->argv[0], task->argv, task->envp ? task->envp : default_envp) < 0)
+ err(1, task->argv[0]);
exit(0);
}
if (pid < 0)
err(1,"fork");
+ task->pid = pid;
+ list_add_tail(&task->node, &mgr->running[pid % SPAWNMGR_PID_HASH_SIZE]);
mgr->num_running++;
}
-static void spawn_queue(struct spawn_manager *mgr, char **argv, char **envp)
+static void spawn_command(struct spawn_manager *mgr, char **argv, char **envp)
{struct spawn_task *task;
@@ -136,47 +220,45 @@
task = malloc(sizeof *task);
if (!task) return;
*task = (struct spawn_task) {- .next = NULL,
.argv = clone_array(argv),
.envp = clone_array(envp),
};
- if (mgr->last) {- mgr->last->next = task;
- mgr->last = task;
- } else {- mgr->first = mgr->last = task;
- }
-}
+ list_init(&task->node);
-static void spawn_command(struct spawn_manager *mgr, char **argv, char **envp)
-{- if (!mgr->max_running)
- mgr->max_running = sysconf(_SC_NPROCESSORS_ONLN);
if (mgr->num_running < mgr->max_running)
- spawn_execute(mgr, argv, envp);
+ spawn_execute(mgr, task);
else
- spawn_queue(mgr, argv, envp);
+ list_add_tail(&task->node, &mgr->queue);
}
static void spawn_reap(struct spawn_manager *mgr, pid_t pid)
{+ struct spawn_task *task;
+
+ list_for_each_entry(task, &mgr->running[pid % SPAWNMGR_PID_HASH_SIZE], node) {+ if (task->pid == pid)
+ goto found;
+ }
+ dbg("pid %d not found", pid);+ return;
+
+found:
mgr->num_running--;
- if (mgr->first && mgr->num_running < mgr->max_running) {- struct spawn_task *task = mgr->first;
- if (task->next)
- mgr->first = task->next;
- else
- mgr->first = mgr->last = NULL;
- spawn_execute(mgr, task->argv, task->envp);
- free(task->argv);
- free(task->envp);
- free(task);
+ list_del(&task->node);
+ free(task->argv);
+ free(task->envp);
+ free(task);
+
+ if (!list_empty(&mgr->queue) && mgr->num_running < mgr->max_running) {+ struct spawn_task *task = list_next(&mgr->queue, struct spawn_task, node);
+ list_del(&task->node);
+ spawn_execute(mgr, task);
}
}
static int spawn_active(struct spawn_manager *mgr)
{- return mgr->num_running || mgr->first;
+ return mgr->num_running || !list_empty(&mgr->queue);
}
struct uevent {@@ -876,6 +958,8 @@
if (envcmp(environ[r], "PATH"))
default_envp[0] = environ[r];
}
+
+ spawn_init(&spawnmgr);
memset(&conf, 0, sizeof(conf));
conf.program_argv = program_argv;