/* * 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, 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); 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);