560 lines
12 KiB
C
560 lines
12 KiB
C
/*
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* taskstats.c - Export per-task statistics to userland
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*
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* Copyright (C) Shailabh Nagar, IBM Corp. 2006
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* (C) Balbir Singh, IBM Corp. 2006
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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*/
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#include <linux/kernel.h>
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#include <linux/taskstats_kern.h>
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#include <linux/tsacct_kern.h>
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#include <linux/delayacct.h>
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#include <linux/tsacct_kern.h>
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#include <linux/cpumask.h>
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#include <linux/percpu.h>
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#include <net/genetlink.h>
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#include <asm/atomic.h>
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/*
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* Maximum length of a cpumask that can be specified in
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* the TASKSTATS_CMD_ATTR_REGISTER/DEREGISTER_CPUMASK attribute
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*/
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#define TASKSTATS_CPUMASK_MAXLEN (100+6*NR_CPUS)
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static DEFINE_PER_CPU(__u32, taskstats_seqnum) = { 0 };
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static int family_registered;
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struct kmem_cache *taskstats_cache;
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static struct genl_family family = {
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.id = GENL_ID_GENERATE,
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.name = TASKSTATS_GENL_NAME,
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.version = TASKSTATS_GENL_VERSION,
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.maxattr = TASKSTATS_CMD_ATTR_MAX,
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};
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static struct nla_policy taskstats_cmd_get_policy[TASKSTATS_CMD_ATTR_MAX+1]
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__read_mostly = {
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[TASKSTATS_CMD_ATTR_PID] = { .type = NLA_U32 },
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[TASKSTATS_CMD_ATTR_TGID] = { .type = NLA_U32 },
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[TASKSTATS_CMD_ATTR_REGISTER_CPUMASK] = { .type = NLA_STRING },
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[TASKSTATS_CMD_ATTR_DEREGISTER_CPUMASK] = { .type = NLA_STRING },};
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struct listener {
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struct list_head list;
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pid_t pid;
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char valid;
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};
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struct listener_list {
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struct rw_semaphore sem;
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struct list_head list;
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};
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static DEFINE_PER_CPU(struct listener_list, listener_array);
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enum actions {
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REGISTER,
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DEREGISTER,
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CPU_DONT_CARE
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};
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static int prepare_reply(struct genl_info *info, u8 cmd, struct sk_buff **skbp,
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size_t size)
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{
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struct sk_buff *skb;
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void *reply;
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/*
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* If new attributes are added, please revisit this allocation
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*/
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skb = genlmsg_new(size, GFP_KERNEL);
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if (!skb)
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return -ENOMEM;
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if (!info) {
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int seq = get_cpu_var(taskstats_seqnum)++;
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put_cpu_var(taskstats_seqnum);
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reply = genlmsg_put(skb, 0, seq, &family, 0, cmd);
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} else
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reply = genlmsg_put_reply(skb, info, &family, 0, cmd);
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if (reply == NULL) {
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nlmsg_free(skb);
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return -EINVAL;
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}
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*skbp = skb;
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return 0;
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}
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/*
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* Send taskstats data in @skb to listener with nl_pid @pid
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*/
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static int send_reply(struct sk_buff *skb, pid_t pid)
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{
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struct genlmsghdr *genlhdr = nlmsg_data(nlmsg_hdr(skb));
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void *reply = genlmsg_data(genlhdr);
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int rc;
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rc = genlmsg_end(skb, reply);
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if (rc < 0) {
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nlmsg_free(skb);
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return rc;
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}
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return genlmsg_unicast(skb, pid);
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}
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/*
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* Send taskstats data in @skb to listeners registered for @cpu's exit data
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*/
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static void send_cpu_listeners(struct sk_buff *skb,
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struct listener_list *listeners)
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{
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struct genlmsghdr *genlhdr = nlmsg_data(nlmsg_hdr(skb));
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struct listener *s, *tmp;
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struct sk_buff *skb_next, *skb_cur = skb;
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void *reply = genlmsg_data(genlhdr);
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int rc, delcount = 0;
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rc = genlmsg_end(skb, reply);
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if (rc < 0) {
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nlmsg_free(skb);
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return;
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}
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rc = 0;
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down_read(&listeners->sem);
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list_for_each_entry(s, &listeners->list, list) {
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skb_next = NULL;
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if (!list_is_last(&s->list, &listeners->list)) {
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skb_next = skb_clone(skb_cur, GFP_KERNEL);
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if (!skb_next)
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break;
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}
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rc = genlmsg_unicast(skb_cur, s->pid);
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if (rc == -ECONNREFUSED) {
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s->valid = 0;
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delcount++;
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}
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skb_cur = skb_next;
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}
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up_read(&listeners->sem);
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if (skb_cur)
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nlmsg_free(skb_cur);
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if (!delcount)
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return;
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/* Delete invalidated entries */
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down_write(&listeners->sem);
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list_for_each_entry_safe(s, tmp, &listeners->list, list) {
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if (!s->valid) {
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list_del(&s->list);
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kfree(s);
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}
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}
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up_write(&listeners->sem);
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}
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static int fill_pid(pid_t pid, struct task_struct *tsk,
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struct taskstats *stats)
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{
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int rc = 0;
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if (!tsk) {
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rcu_read_lock();
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tsk = find_task_by_pid(pid);
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if (tsk)
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get_task_struct(tsk);
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rcu_read_unlock();
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if (!tsk)
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return -ESRCH;
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} else
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get_task_struct(tsk);
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memset(stats, 0, sizeof(*stats));
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/*
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* Each accounting subsystem adds calls to its functions to
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* fill in relevant parts of struct taskstsats as follows
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*
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* per-task-foo(stats, tsk);
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*/
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delayacct_add_tsk(stats, tsk);
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/* fill in basic acct fields */
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stats->version = TASKSTATS_VERSION;
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bacct_add_tsk(stats, tsk);
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/* fill in extended acct fields */
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xacct_add_tsk(stats, tsk);
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/* Define err: label here if needed */
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put_task_struct(tsk);
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return rc;
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}
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static int fill_tgid(pid_t tgid, struct task_struct *first,
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struct taskstats *stats)
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{
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struct task_struct *tsk;
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unsigned long flags;
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int rc = -ESRCH;
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/*
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* Add additional stats from live tasks except zombie thread group
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* leaders who are already counted with the dead tasks
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*/
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rcu_read_lock();
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if (!first)
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first = find_task_by_pid(tgid);
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if (!first || !lock_task_sighand(first, &flags))
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goto out;
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if (first->signal->stats)
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memcpy(stats, first->signal->stats, sizeof(*stats));
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else
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memset(stats, 0, sizeof(*stats));
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tsk = first;
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do {
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if (tsk->exit_state)
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continue;
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/*
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* Accounting subsystem can call its functions here to
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* fill in relevant parts of struct taskstsats as follows
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*
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* per-task-foo(stats, tsk);
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*/
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delayacct_add_tsk(stats, tsk);
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} while_each_thread(first, tsk);
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unlock_task_sighand(first, &flags);
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rc = 0;
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out:
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rcu_read_unlock();
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stats->version = TASKSTATS_VERSION;
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/*
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* Accounting subsytems can also add calls here to modify
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* fields of taskstats.
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*/
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return rc;
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}
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static void fill_tgid_exit(struct task_struct *tsk)
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{
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unsigned long flags;
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spin_lock_irqsave(&tsk->sighand->siglock, flags);
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if (!tsk->signal->stats)
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goto ret;
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/*
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* Each accounting subsystem calls its functions here to
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* accumalate its per-task stats for tsk, into the per-tgid structure
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*
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* per-task-foo(tsk->signal->stats, tsk);
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*/
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delayacct_add_tsk(tsk->signal->stats, tsk);
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ret:
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spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
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return;
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}
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static int add_del_listener(pid_t pid, cpumask_t *maskp, int isadd)
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{
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struct listener_list *listeners;
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struct listener *s, *tmp;
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unsigned int cpu;
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cpumask_t mask = *maskp;
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if (!cpus_subset(mask, cpu_possible_map))
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return -EINVAL;
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if (isadd == REGISTER) {
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for_each_cpu_mask(cpu, mask) {
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s = kmalloc_node(sizeof(struct listener), GFP_KERNEL,
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cpu_to_node(cpu));
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if (!s)
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goto cleanup;
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s->pid = pid;
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INIT_LIST_HEAD(&s->list);
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s->valid = 1;
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listeners = &per_cpu(listener_array, cpu);
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down_write(&listeners->sem);
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list_add(&s->list, &listeners->list);
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up_write(&listeners->sem);
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}
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return 0;
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}
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/* Deregister or cleanup */
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cleanup:
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for_each_cpu_mask(cpu, mask) {
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listeners = &per_cpu(listener_array, cpu);
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down_write(&listeners->sem);
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list_for_each_entry_safe(s, tmp, &listeners->list, list) {
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if (s->pid == pid) {
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list_del(&s->list);
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kfree(s);
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break;
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}
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}
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up_write(&listeners->sem);
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}
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return 0;
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}
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static int parse(struct nlattr *na, cpumask_t *mask)
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{
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char *data;
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int len;
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int ret;
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if (na == NULL)
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return 1;
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len = nla_len(na);
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if (len > TASKSTATS_CPUMASK_MAXLEN)
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return -E2BIG;
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if (len < 1)
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return -EINVAL;
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data = kmalloc(len, GFP_KERNEL);
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if (!data)
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return -ENOMEM;
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nla_strlcpy(data, na, len);
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ret = cpulist_parse(data, *mask);
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kfree(data);
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return ret;
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}
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static struct taskstats *mk_reply(struct sk_buff *skb, int type, u32 pid)
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{
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struct nlattr *na, *ret;
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int aggr;
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aggr = (type == TASKSTATS_TYPE_PID)
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? TASKSTATS_TYPE_AGGR_PID
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: TASKSTATS_TYPE_AGGR_TGID;
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na = nla_nest_start(skb, aggr);
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if (!na)
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goto err;
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if (nla_put(skb, type, sizeof(pid), &pid) < 0)
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goto err;
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ret = nla_reserve(skb, TASKSTATS_TYPE_STATS, sizeof(struct taskstats));
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if (!ret)
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goto err;
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nla_nest_end(skb, na);
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return nla_data(ret);
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err:
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return NULL;
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}
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static int taskstats_user_cmd(struct sk_buff *skb, struct genl_info *info)
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{
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int rc = 0;
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struct sk_buff *rep_skb;
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struct taskstats *stats;
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size_t size;
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cpumask_t mask;
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rc = parse(info->attrs[TASKSTATS_CMD_ATTR_REGISTER_CPUMASK], &mask);
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if (rc < 0)
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return rc;
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if (rc == 0)
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return add_del_listener(info->snd_pid, &mask, REGISTER);
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rc = parse(info->attrs[TASKSTATS_CMD_ATTR_DEREGISTER_CPUMASK], &mask);
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if (rc < 0)
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return rc;
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if (rc == 0)
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return add_del_listener(info->snd_pid, &mask, DEREGISTER);
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/*
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* Size includes space for nested attributes
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*/
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size = nla_total_size(sizeof(u32)) +
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nla_total_size(sizeof(struct taskstats)) + nla_total_size(0);
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rc = prepare_reply(info, TASKSTATS_CMD_NEW, &rep_skb, size);
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if (rc < 0)
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return rc;
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rc = -EINVAL;
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if (info->attrs[TASKSTATS_CMD_ATTR_PID]) {
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u32 pid = nla_get_u32(info->attrs[TASKSTATS_CMD_ATTR_PID]);
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stats = mk_reply(rep_skb, TASKSTATS_TYPE_PID, pid);
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if (!stats)
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goto err;
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rc = fill_pid(pid, NULL, stats);
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if (rc < 0)
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goto err;
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} else if (info->attrs[TASKSTATS_CMD_ATTR_TGID]) {
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u32 tgid = nla_get_u32(info->attrs[TASKSTATS_CMD_ATTR_TGID]);
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stats = mk_reply(rep_skb, TASKSTATS_TYPE_TGID, tgid);
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if (!stats)
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goto err;
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rc = fill_tgid(tgid, NULL, stats);
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if (rc < 0)
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goto err;
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} else
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goto err;
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return send_reply(rep_skb, info->snd_pid);
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err:
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nlmsg_free(rep_skb);
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return rc;
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}
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static struct taskstats *taskstats_tgid_alloc(struct task_struct *tsk)
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{
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struct signal_struct *sig = tsk->signal;
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struct taskstats *stats;
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if (sig->stats || thread_group_empty(tsk))
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goto ret;
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/* No problem if kmem_cache_zalloc() fails */
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stats = kmem_cache_zalloc(taskstats_cache, GFP_KERNEL);
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spin_lock_irq(&tsk->sighand->siglock);
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if (!sig->stats) {
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sig->stats = stats;
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stats = NULL;
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}
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spin_unlock_irq(&tsk->sighand->siglock);
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if (stats)
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kmem_cache_free(taskstats_cache, stats);
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ret:
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return sig->stats;
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}
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/* Send pid data out on exit */
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void taskstats_exit(struct task_struct *tsk, int group_dead)
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{
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int rc;
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struct listener_list *listeners;
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struct taskstats *stats;
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struct sk_buff *rep_skb;
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size_t size;
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int is_thread_group;
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if (!family_registered)
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return;
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/*
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* Size includes space for nested attributes
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*/
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size = nla_total_size(sizeof(u32)) +
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nla_total_size(sizeof(struct taskstats)) + nla_total_size(0);
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is_thread_group = !!taskstats_tgid_alloc(tsk);
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if (is_thread_group) {
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/* PID + STATS + TGID + STATS */
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size = 2 * size;
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/* fill the tsk->signal->stats structure */
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fill_tgid_exit(tsk);
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}
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listeners = &__raw_get_cpu_var(listener_array);
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if (list_empty(&listeners->list))
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return;
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rc = prepare_reply(NULL, TASKSTATS_CMD_NEW, &rep_skb, size);
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if (rc < 0)
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return;
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stats = mk_reply(rep_skb, TASKSTATS_TYPE_PID, tsk->pid);
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if (!stats)
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goto err;
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rc = fill_pid(tsk->pid, tsk, stats);
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if (rc < 0)
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goto err;
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/*
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* Doesn't matter if tsk is the leader or the last group member leaving
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*/
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if (!is_thread_group || !group_dead)
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goto send;
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stats = mk_reply(rep_skb, TASKSTATS_TYPE_TGID, tsk->tgid);
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if (!stats)
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goto err;
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memcpy(stats, tsk->signal->stats, sizeof(*stats));
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send:
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send_cpu_listeners(rep_skb, listeners);
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return;
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err:
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nlmsg_free(rep_skb);
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}
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static struct genl_ops taskstats_ops = {
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.cmd = TASKSTATS_CMD_GET,
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.doit = taskstats_user_cmd,
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.policy = taskstats_cmd_get_policy,
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};
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/* Needed early in initialization */
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void __init taskstats_init_early(void)
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{
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unsigned int i;
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taskstats_cache = kmem_cache_create("taskstats_cache",
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sizeof(struct taskstats),
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0, SLAB_PANIC, NULL, NULL);
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for_each_possible_cpu(i) {
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INIT_LIST_HEAD(&(per_cpu(listener_array, i).list));
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init_rwsem(&(per_cpu(listener_array, i).sem));
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}
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}
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static int __init taskstats_init(void)
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{
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int rc;
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rc = genl_register_family(&family);
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if (rc)
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return rc;
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rc = genl_register_ops(&family, &taskstats_ops);
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if (rc < 0)
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goto err;
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family_registered = 1;
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return 0;
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err:
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|
genl_unregister_family(&family);
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
* late initcall ensures initialization of statistics collection
|
|
* mechanisms precedes initialization of the taskstats interface
|
|
*/
|
|
late_initcall(taskstats_init);
|