diff options
Diffstat (limited to 'kernel/taskstats.c')
| -rw-r--r-- | kernel/taskstats.c | 568 |
1 files changed, 568 insertions, 0 deletions
diff --git a/kernel/taskstats.c b/kernel/taskstats.c new file mode 100644 index 00000000000..f45179ce028 --- /dev/null +++ b/kernel/taskstats.c @@ -0,0 +1,568 @@ +/* + * 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 int 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, ret, delcount = 0; + + rc = genlmsg_end(skb, reply); + if (rc < 0) { + nlmsg_free(skb); + return rc; + } + + rc = 0; + listeners = &per_cpu(listener_array, cpu); + down_read(&listeners->sem); + list_for_each_entry_safe(s, tmp, &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) { + nlmsg_free(skb_cur); + rc = -ENOMEM; + break; + } + } + ret = genlmsg_unicast(skb_cur, s->pid); + if (ret == -ECONNREFUSED) { + s->valid = 0; + delcount++; + rc = ret; + } + skb_cur = skb_next; + } + up_read(&listeners->sem); + + if (!delcount) + return rc; + + /* 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); + return rc; +} + +static int fill_pid(pid_t pid, struct task_struct *pidtsk, + struct taskstats *stats) +{ + int rc; + 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 + * + * rc = per-task-foo(stats, tsk); + * if (rc) + * goto err; + */ + + rc = 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); + + /* 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 (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. + */ + + 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); |