/* * 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; struct kmem_cache *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, size_t size) { struct sk_buff *skb; void *reply; /* * If new attributes are added, please revisit this allocation */ skb = genlmsg_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, 0, cmd); } else reply = genlmsg_put_reply(skb, info, &family, 0, cmd); if (reply == NULL) { nlmsg_free(skb); return -EINVAL; } *skbp = skb; 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(nlmsg_hdr(skb)); 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, struct listener_list *listeners) { struct genlmsghdr *genlhdr = nlmsg_data(nlmsg_hdr(skb)); 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; 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 *tsk, struct taskstats *stats) { int rc = 0; if (!tsk) { rcu_read_lock(); tsk = find_task_by_pid(pid); if (tsk) get_task_struct(tsk); rcu_read_unlock(); if (!tsk) return -ESRCH; } else get_task_struct(tsk); memset(stats, 0, sizeof(*stats)); /* * 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; stats->nvcsw = tsk->nvcsw; stats->nivcsw = tsk->nivcsw; 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 *first, struct taskstats *stats) { struct task_struct *tsk; unsigned long flags; int rc = -ESRCH; /* * Add additional stats from live tasks except zombie thread group * leaders who are already counted with the dead tasks */ rcu_read_lock(); if (!first) first = find_task_by_pid(tgid); if (!first || !lock_task_sighand(first, &flags)) goto out; if (first->signal->stats) memcpy(stats, first->signal->stats, sizeof(*stats)); else memset(stats, 0, sizeof(*stats)); tsk = first; do { if (tsk->exit_state) 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); stats->nvcsw += tsk->nvcsw; stats->nivcsw += tsk->nivcsw; } while_each_thread(first, tsk); unlock_task_sighand(first, &flags); rc = 0; out: rcu_read_unlock(); stats->version = TASKSTATS_VERSION; /* * Accounting subsytems can also add calls here to modify * fields of taskstats. */ return rc; } static void fill_tgid_exit(struct task_struct *tsk) { unsigned long flags; spin_lock_irqsave(&tsk->sighand->siglock, 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->sighand->siglock, 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 struct taskstats *mk_reply(struct sk_buff *skb, int type, u32 pid) { struct nlattr *na, *ret; int aggr; aggr = (type == TASKSTATS_TYPE_PID) ? TASKSTATS_TYPE_AGGR_PID : TASKSTATS_TYPE_AGGR_TGID; na = nla_nest_start(skb, aggr); if (!na) goto err; if (nla_put(skb, type, sizeof(pid), &pid) < 0) goto err; ret = nla_reserve(skb, TASKSTATS_TYPE_STATS, sizeof(struct taskstats)); if (!ret) goto err; nla_nest_end(skb, na); return nla_data(ret); err: return NULL; } static int taskstats_user_cmd(struct sk_buff *skb, struct genl_info *info) { int rc = 0; struct sk_buff *rep_skb; struct taskstats *stats; size_t size; 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); rc = prepare_reply(info, TASKSTATS_CMD_NEW, &rep_skb, size); if (rc < 0) return rc; rc = -EINVAL; if (info->attrs[TASKSTATS_CMD_ATTR_PID]) { u32 pid = nla_get_u32(info->attrs[TASKSTATS_CMD_ATTR_PID]); stats = mk_reply(rep_skb, TASKSTATS_TYPE_PID, pid); if (!stats) goto err; rc = fill_pid(pid, NULL, stats); if (rc < 0) goto err; } else if (info->attrs[TASKSTATS_CMD_ATTR_TGID]) { u32 tgid = nla_get_u32(info->attrs[TASKSTATS_CMD_ATTR_TGID]); stats = mk_reply(rep_skb, TASKSTATS_TYPE_TGID, tgid); if (!stats) goto err; rc = fill_tgid(tgid, NULL, stats); if (rc < 0) goto err; } else goto err; return send_reply(rep_skb, info->snd_pid); err: nlmsg_free(rep_skb); return rc; } static struct taskstats *taskstats_tgid_alloc(struct task_struct *tsk) { struct signal_struct *sig = tsk->signal; struct taskstats *stats; if (sig->stats || thread_group_empty(tsk)) goto ret; /* No problem if kmem_cache_zalloc() fails */ stats = kmem_cache_zalloc(taskstats_cache, GFP_KERNEL); spin_lock_irq(&tsk->sighand->siglock); if (!sig->stats) { sig->stats = stats; stats = NULL; } spin_unlock_irq(&tsk->sighand->siglock); if (stats) kmem_cache_free(taskstats_cache, stats); ret: return sig->stats; } /* Send pid data out on exit */ void taskstats_exit(struct task_struct *tsk, int group_dead) { int rc; struct listener_list *listeners; struct taskstats *stats; struct sk_buff *rep_skb; size_t size; int is_thread_group; if (!family_registered) return; /* * Size includes space for nested attributes */ size = nla_total_size(sizeof(u32)) + nla_total_size(sizeof(struct taskstats)) + nla_total_size(0); is_thread_group = !!taskstats_tgid_alloc(tsk); if (is_thread_group) { /* PID + STATS + TGID + STATS */ size = 2 * size; /* fill the tsk->signal->stats structure */ fill_tgid_exit(tsk); } listeners = &__raw_get_cpu_var(listener_array); if (list_empty(&listeners->list)) return; rc = prepare_reply(NULL, TASKSTATS_CMD_NEW, &rep_skb, size); if (rc < 0) return; stats = mk_reply(rep_skb, TASKSTATS_TYPE_PID, tsk->pid); if (!stats) goto err; rc = fill_pid(tsk->pid, tsk, stats); if (rc < 0) goto err; /* * Doesn't matter if tsk is the leader or the last group member leaving */ if (!is_thread_group || !group_dead) goto send; stats = mk_reply(rep_skb, TASKSTATS_TYPE_TGID, tsk->tgid); if (!stats) goto err; memcpy(stats, tsk->signal->stats, sizeof(*stats)); send: send_cpu_listeners(rep_skb, listeners); return; err: nlmsg_free(rep_skb); } 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(taskstats, SLAB_PANIC); 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);