--- /dev/null
+/*
+ * taskstats.c - Export per-task statistics to userland
+ *
+ * Copyright (C) Shailabh Nagar, IBM Corp. 2006
+ * (C) Balbir Singh, IBM Corp. 2006
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/taskstats_kern.h>
+#include <linux/delayacct.h>
+#include <linux/cpumask.h>
+#include <linux/percpu.h>
+#include <net/genetlink.h>
+#include <asm/atomic.h>
+
+/*
+ * Maximum length of a cpumask that can be specified in
+ * the TASKSTATS_CMD_ATTR_REGISTER/DEREGISTER_CPUMASK attribute
+ */
+#define TASKSTATS_CPUMASK_MAXLEN (100+6*NR_CPUS)
+
+static DEFINE_PER_CPU(__u32, taskstats_seqnum) = { 0 };
+static int family_registered;
+kmem_cache_t *taskstats_cache;
+
+static struct genl_family family = {
+ .id = GENL_ID_GENERATE,
+ .name = TASKSTATS_GENL_NAME,
+ .version = TASKSTATS_GENL_VERSION,
+ .maxattr = TASKSTATS_CMD_ATTR_MAX,
+};
+
+static struct nla_policy taskstats_cmd_get_policy[TASKSTATS_CMD_ATTR_MAX+1]
+__read_mostly = {
+ [TASKSTATS_CMD_ATTR_PID] = { .type = NLA_U32 },
+ [TASKSTATS_CMD_ATTR_TGID] = { .type = NLA_U32 },
+ [TASKSTATS_CMD_ATTR_REGISTER_CPUMASK] = { .type = NLA_STRING },
+ [TASKSTATS_CMD_ATTR_DEREGISTER_CPUMASK] = { .type = NLA_STRING },};
+
+struct listener {
+ struct list_head list;
+ pid_t pid;
+ char valid;
+};
+
+struct listener_list {
+ struct rw_semaphore sem;
+ struct list_head list;
+};
+static DEFINE_PER_CPU(struct listener_list, listener_array);
+
+enum actions {
+ REGISTER,
+ DEREGISTER,
+ CPU_DONT_CARE
+};
+
+static int prepare_reply(struct genl_info *info, u8 cmd, struct sk_buff **skbp,
+ void **replyp, size_t size)
+{
+ struct sk_buff *skb;
+ void *reply;
+
+ /*
+ * If new attributes are added, please revisit this allocation
+ */
+ skb = nlmsg_new(size);
+ if (!skb)
+ return -ENOMEM;
+
+ if (!info) {
+ int seq = get_cpu_var(taskstats_seqnum)++;
+ put_cpu_var(taskstats_seqnum);
+
+ reply = genlmsg_put(skb, 0, seq,
+ family.id, 0, 0,
+ cmd, family.version);
+ } else
+ reply = genlmsg_put(skb, info->snd_pid, info->snd_seq,
+ family.id, 0, 0,
+ cmd, family.version);
+ if (reply == NULL) {
+ nlmsg_free(skb);
+ return -EINVAL;
+ }
+
+ *skbp = skb;
+ *replyp = reply;
+ return 0;
+}
+
+/*
+ * Send taskstats data in @skb to listener with nl_pid @pid
+ */
+static int send_reply(struct sk_buff *skb, pid_t pid)
+{
+ struct genlmsghdr *genlhdr = nlmsg_data((struct nlmsghdr *)skb->data);
+ void *reply = genlmsg_data(genlhdr);
+ int rc;
+
+ rc = genlmsg_end(skb, reply);
+ if (rc < 0) {
+ nlmsg_free(skb);
+ return rc;
+ }
+
+ return genlmsg_unicast(skb, pid);
+}
+
+/*
+ * Send taskstats data in @skb to listeners registered for @cpu's exit data
+ */
+static void send_cpu_listeners(struct sk_buff *skb, unsigned int cpu)
+{
+ struct genlmsghdr *genlhdr = nlmsg_data((struct nlmsghdr *)skb->data);
+ struct listener_list *listeners;
+ struct listener *s, *tmp;
+ struct sk_buff *skb_next, *skb_cur = skb;
+ void *reply = genlmsg_data(genlhdr);
+ int rc, delcount = 0;
+
+ rc = genlmsg_end(skb, reply);
+ if (rc < 0) {
+ nlmsg_free(skb);
+ return;
+ }
+
+ rc = 0;
+ listeners = &per_cpu(listener_array, cpu);
+ down_read(&listeners->sem);
+ list_for_each_entry(s, &listeners->list, list) {
+ skb_next = NULL;
+ if (!list_is_last(&s->list, &listeners->list)) {
+ skb_next = skb_clone(skb_cur, GFP_KERNEL);
+ if (!skb_next)
+ break;
+ }
+ rc = genlmsg_unicast(skb_cur, s->pid);
+ if (rc == -ECONNREFUSED) {
+ s->valid = 0;
+ delcount++;
+ }
+ skb_cur = skb_next;
+ }
+ up_read(&listeners->sem);
+
+ if (skb_cur)
+ nlmsg_free(skb_cur);
+
+ if (!delcount)
+ return;
+
+ /* Delete invalidated entries */
+ down_write(&listeners->sem);
+ list_for_each_entry_safe(s, tmp, &listeners->list, list) {
+ if (!s->valid) {
+ list_del(&s->list);
+ kfree(s);
+ }
+ }
+ up_write(&listeners->sem);
+}
+
+static int fill_pid(pid_t pid, struct task_struct *pidtsk,
+ struct taskstats *stats)
+{
+ int rc = 0;
+ struct task_struct *tsk = pidtsk;
+
+ if (!pidtsk) {
+ read_lock(&tasklist_lock);
+ tsk = find_task_by_pid(pid);
+ if (!tsk) {
+ read_unlock(&tasklist_lock);
+ return -ESRCH;
+ }
+ get_task_struct(tsk);
+ read_unlock(&tasklist_lock);
+ } else
+ get_task_struct(tsk);
+
+ /*
+ * Each accounting subsystem adds calls to its functions to
+ * fill in relevant parts of struct taskstsats as follows
+ *
+ * per-task-foo(stats, tsk);
+ */
+
+ delayacct_add_tsk(stats, tsk);
+ stats->version = TASKSTATS_VERSION;
+
+ /* Define err: label here if needed */
+ put_task_struct(tsk);
+ return rc;
+
+}
+
+static int fill_tgid(pid_t tgid, struct task_struct *tgidtsk,
+ struct taskstats *stats)
+{
+ struct task_struct *tsk, *first;
+ unsigned long flags;
+
+ /*
+ * Add additional stats from live tasks except zombie thread group
+ * leaders who are already counted with the dead tasks
+ */
+ first = tgidtsk;
+ if (!first) {
+ read_lock(&tasklist_lock);
+ first = find_task_by_pid(tgid);
+ if (!first) {
+ read_unlock(&tasklist_lock);
+ return -ESRCH;
+ }
+ get_task_struct(first);
+ read_unlock(&tasklist_lock);
+ } else
+ get_task_struct(first);
+
+
+ tsk = first;
+ read_lock(&tasklist_lock);
+ /* Start with stats from dead tasks */
+ if (first->signal) {
+ spin_lock_irqsave(&first->signal->stats_lock, flags);
+ if (first->signal->stats)
+ memcpy(stats, first->signal->stats, sizeof(*stats));
+ spin_unlock_irqrestore(&first->signal->stats_lock, flags);
+ }
+
+ do {
+ if (tsk->exit_state == EXIT_ZOMBIE && thread_group_leader(tsk))
+ continue;
+ /*
+ * Accounting subsystem can call its functions here to
+ * fill in relevant parts of struct taskstsats as follows
+ *
+ * per-task-foo(stats, tsk);
+ */
+ delayacct_add_tsk(stats, tsk);
+
+ } while_each_thread(first, tsk);
+ read_unlock(&tasklist_lock);
+ stats->version = TASKSTATS_VERSION;
+
+ /*
+ * Accounting subsytems can also add calls here to modify
+ * fields of taskstats.
+ */
+ put_task_struct(first);
+ return 0;
+}
+
+
+static void fill_tgid_exit(struct task_struct *tsk)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&tsk->signal->stats_lock, flags);
+ if (!tsk->signal->stats)
+ goto ret;
+
+ /*
+ * Each accounting subsystem calls its functions here to
+ * accumalate its per-task stats for tsk, into the per-tgid structure
+ *
+ * per-task-foo(tsk->signal->stats, tsk);
+ */
+ delayacct_add_tsk(tsk->signal->stats, tsk);
+ret:
+ spin_unlock_irqrestore(&tsk->signal->stats_lock, flags);
+ return;
+}
+
+static int add_del_listener(pid_t pid, cpumask_t *maskp, int isadd)
+{
+ struct listener_list *listeners;
+ struct listener *s, *tmp;
+ unsigned int cpu;
+ cpumask_t mask = *maskp;
+
+ if (!cpus_subset(mask, cpu_possible_map))
+ return -EINVAL;
+
+ if (isadd == REGISTER) {
+ for_each_cpu_mask(cpu, mask) {
+ s = kmalloc_node(sizeof(struct listener), GFP_KERNEL,
+ cpu_to_node(cpu));
+ if (!s)
+ goto cleanup;
+ s->pid = pid;
+ INIT_LIST_HEAD(&s->list);
+ s->valid = 1;
+
+ listeners = &per_cpu(listener_array, cpu);
+ down_write(&listeners->sem);
+ list_add(&s->list, &listeners->list);
+ up_write(&listeners->sem);
+ }
+ return 0;
+ }
+
+ /* Deregister or cleanup */
+cleanup:
+ for_each_cpu_mask(cpu, mask) {
+ listeners = &per_cpu(listener_array, cpu);
+ down_write(&listeners->sem);
+ list_for_each_entry_safe(s, tmp, &listeners->list, list) {
+ if (s->pid == pid) {
+ list_del(&s->list);
+ kfree(s);
+ break;
+ }
+ }
+ up_write(&listeners->sem);
+ }
+ return 0;
+}
+
+static int parse(struct nlattr *na, cpumask_t *mask)
+{
+ char *data;
+ int len;
+ int ret;
+
+ if (na == NULL)
+ return 1;
+ len = nla_len(na);
+ if (len > TASKSTATS_CPUMASK_MAXLEN)
+ return -E2BIG;
+ if (len < 1)
+ return -EINVAL;
+ data = kmalloc(len, GFP_KERNEL);
+ if (!data)
+ return -ENOMEM;
+ nla_strlcpy(data, na, len);
+ ret = cpulist_parse(data, *mask);
+ kfree(data);
+ return ret;
+}
+
+static int taskstats_user_cmd(struct sk_buff *skb, struct genl_info *info)
+{
+ int rc = 0;
+ struct sk_buff *rep_skb;
+ struct taskstats stats;
+ void *reply;
+ size_t size;
+ struct nlattr *na;
+ cpumask_t mask;
+
+ rc = parse(info->attrs[TASKSTATS_CMD_ATTR_REGISTER_CPUMASK], &mask);
+ if (rc < 0)
+ return rc;
+ if (rc == 0)
+ return add_del_listener(info->snd_pid, &mask, REGISTER);
+
+ rc = parse(info->attrs[TASKSTATS_CMD_ATTR_DEREGISTER_CPUMASK], &mask);
+ if (rc < 0)
+ return rc;
+ if (rc == 0)
+ return add_del_listener(info->snd_pid, &mask, DEREGISTER);
+
+ /*
+ * Size includes space for nested attributes
+ */
+ size = nla_total_size(sizeof(u32)) +
+ nla_total_size(sizeof(struct taskstats)) + nla_total_size(0);
+
+ memset(&stats, 0, sizeof(stats));
+ rc = prepare_reply(info, TASKSTATS_CMD_NEW, &rep_skb, &reply, size);
+ if (rc < 0)
+ return rc;
+
+ if (info->attrs[TASKSTATS_CMD_ATTR_PID]) {
+ u32 pid = nla_get_u32(info->attrs[TASKSTATS_CMD_ATTR_PID]);
+ rc = fill_pid(pid, NULL, &stats);
+ if (rc < 0)
+ goto err;
+
+ na = nla_nest_start(rep_skb, TASKSTATS_TYPE_AGGR_PID);
+ NLA_PUT_U32(rep_skb, TASKSTATS_TYPE_PID, pid);
+ NLA_PUT_TYPE(rep_skb, struct taskstats, TASKSTATS_TYPE_STATS,
+ stats);
+ } else if (info->attrs[TASKSTATS_CMD_ATTR_TGID]) {
+ u32 tgid = nla_get_u32(info->attrs[TASKSTATS_CMD_ATTR_TGID]);
+ rc = fill_tgid(tgid, NULL, &stats);
+ if (rc < 0)
+ goto err;
+
+ na = nla_nest_start(rep_skb, TASKSTATS_TYPE_AGGR_TGID);
+ NLA_PUT_U32(rep_skb, TASKSTATS_TYPE_TGID, tgid);
+ NLA_PUT_TYPE(rep_skb, struct taskstats, TASKSTATS_TYPE_STATS,
+ stats);
+ } else {
+ rc = -EINVAL;
+ goto err;
+ }
+
+ nla_nest_end(rep_skb, na);
+
+ return send_reply(rep_skb, info->snd_pid);
+
+nla_put_failure:
+ return genlmsg_cancel(rep_skb, reply);
+err:
+ nlmsg_free(rep_skb);
+ return rc;
+}
+
+void taskstats_exit_alloc(struct taskstats **ptidstats, unsigned int *mycpu)
+{
+ struct listener_list *listeners;
+ struct taskstats *tmp;
+ /*
+ * This is the cpu on which the task is exiting currently and will
+ * be the one for which the exit event is sent, even if the cpu
+ * on which this function is running changes later.
+ */
+ *mycpu = raw_smp_processor_id();
+
+ *ptidstats = NULL;
+ tmp = kmem_cache_zalloc(taskstats_cache, SLAB_KERNEL);
+ if (!tmp)
+ return;
+
+ listeners = &per_cpu(listener_array, *mycpu);
+ down_read(&listeners->sem);
+ if (!list_empty(&listeners->list)) {
+ *ptidstats = tmp;
+ tmp = NULL;
+ }
+ up_read(&listeners->sem);
+ kfree(tmp);
+}
+
+/* Send pid data out on exit */
+void taskstats_exit_send(struct task_struct *tsk, struct taskstats *tidstats,
+ int group_dead, unsigned int mycpu)
+{
+ int rc;
+ struct sk_buff *rep_skb;
+ void *reply;
+ size_t size;
+ int is_thread_group;
+ struct nlattr *na;
+ unsigned long flags;
+
+ if (!family_registered || !tidstats)
+ return;
+
+ spin_lock_irqsave(&tsk->signal->stats_lock, flags);
+ is_thread_group = tsk->signal->stats ? 1 : 0;
+ spin_unlock_irqrestore(&tsk->signal->stats_lock, flags);
+
+ rc = 0;
+ /*
+ * Size includes space for nested attributes
+ */
+ size = nla_total_size(sizeof(u32)) +
+ nla_total_size(sizeof(struct taskstats)) + nla_total_size(0);
+
+ if (is_thread_group)
+ size = 2 * size; /* PID + STATS + TGID + STATS */
+
+ rc = prepare_reply(NULL, TASKSTATS_CMD_NEW, &rep_skb, &reply, size);
+ if (rc < 0)
+ goto ret;
+
+ rc = fill_pid(tsk->pid, tsk, tidstats);
+ if (rc < 0)
+ goto err_skb;
+
+ na = nla_nest_start(rep_skb, TASKSTATS_TYPE_AGGR_PID);
+ NLA_PUT_U32(rep_skb, TASKSTATS_TYPE_PID, (u32)tsk->pid);
+ NLA_PUT_TYPE(rep_skb, struct taskstats, TASKSTATS_TYPE_STATS,
+ *tidstats);
+ nla_nest_end(rep_skb, na);
+
+ if (!is_thread_group)
+ goto send;
+
+ /*
+ * tsk has/had a thread group so fill the tsk->signal->stats structure
+ * Doesn't matter if tsk is the leader or the last group member leaving
+ */
+
+ fill_tgid_exit(tsk);
+ if (!group_dead)
+ goto send;
+
+ na = nla_nest_start(rep_skb, TASKSTATS_TYPE_AGGR_TGID);
+ NLA_PUT_U32(rep_skb, TASKSTATS_TYPE_TGID, (u32)tsk->tgid);
+ /* No locking needed for tsk->signal->stats since group is dead */
+ NLA_PUT_TYPE(rep_skb, struct taskstats, TASKSTATS_TYPE_STATS,
+ *tsk->signal->stats);
+ nla_nest_end(rep_skb, na);
+
+send:
+ send_cpu_listeners(rep_skb, mycpu);
+ return;
+
+nla_put_failure:
+ genlmsg_cancel(rep_skb, reply);
+ goto ret;
+err_skb:
+ nlmsg_free(rep_skb);
+ret:
+ return;
+}
+
+static struct genl_ops taskstats_ops = {
+ .cmd = TASKSTATS_CMD_GET,
+ .doit = taskstats_user_cmd,
+ .policy = taskstats_cmd_get_policy,
+};
+
+/* Needed early in initialization */
+void __init taskstats_init_early(void)
+{
+ unsigned int i;
+
+ taskstats_cache = kmem_cache_create("taskstats_cache",
+ sizeof(struct taskstats),
+ 0, SLAB_PANIC, NULL, NULL);
+ for_each_possible_cpu(i) {
+ INIT_LIST_HEAD(&(per_cpu(listener_array, i).list));
+ init_rwsem(&(per_cpu(listener_array, i).sem));
+ }
+}
+
+static int __init taskstats_init(void)
+{
+ int rc;
+
+ rc = genl_register_family(&family);
+ if (rc)
+ return rc;
+
+ rc = genl_register_ops(&family, &taskstats_ops);
+ if (rc < 0)
+ goto err;
+
+ family_registered = 1;
+ return 0;
+err:
+ genl_unregister_family(&family);
+ return rc;
+}
+
+/*
+ * late initcall ensures initialization of statistics collection
+ * mechanisms precedes initialization of the taskstats interface
+ */
+late_initcall(taskstats_init);
git://git.onelab.eu / linux-2.6.git / blobdiff