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/*
* 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/tsacct_kern.h>
#include <linux/delayacct.h>
#include <linux/tsacct_kern.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(genlmsg_total_size(size), GFP_KERNEL);
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);
/* fill in basic acct fields */
stats->version = TASKSTATS_VERSION;
bacct_add_tsk(stats, tsk);
/* fill in extended acct fields */
xacct_add_tsk(stats, tsk);
/* 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);
/* Start with stats from dead tasks */
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);
tsk = first;
read_lock(&tasklist_lock);
do {
if (
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