diff options
Diffstat (limited to 'kernel/taskstats.c')
| -rw-r--r-- | kernel/taskstats.c | 709 |
1 files changed, 709 insertions, 0 deletions
diff --git a/kernel/taskstats.c b/kernel/taskstats.c new file mode 100644 index 00000000..e6604645 --- /dev/null +++ b/kernel/taskstats.c @@ -0,0 +1,709 @@ +/* + * 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/cpumask.h> +#include <linux/percpu.h> +#include <linux/slab.h> +#include <linux/cgroupstats.h> +#include <linux/cgroup.h> +#include <linux/fs.h> +#include <linux/file.h> +#include <net/genetlink.h> +#include <linux/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); +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 const struct nla_policy taskstats_cmd_get_policy[TASKSTATS_CMD_ATTR_MAX+1] = { + [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 },}; + +static const struct nla_policy cgroupstats_cmd_get_policy[CGROUPSTATS_CMD_ATTR_MAX+1] = { + [CGROUPSTATS_CMD_ATTR_FD] = { .type = NLA_U32 }, +}; + +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 = this_cpu_inc_return(taskstats_seqnum) - 1; + + 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, struct genl_info *info) +{ + 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_reply(skb, info); +} + +/* + * 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(&init_net, 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 void fill_stats(struct task_struct *tsk, struct taskstats *stats) +{ + 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); +} + +static int fill_stats_for_pid(pid_t pid, struct taskstats *stats) +{ + struct task_struct *tsk; + + rcu_read_lock(); + tsk = find_task_by_vpid(pid); + if (tsk) + get_task_struct(tsk); + rcu_read_unlock(); + if (!tsk) + return -ESRCH; + fill_stats(tsk, stats); + put_task_struct(tsk); + return 0; +} + +static int fill_stats_for_tgid(pid_t tgid, struct taskstats *stats) +{ + struct task_struct *tsk, *first; + 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(); + first = find_task_by_vpid(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 subsystems 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, const struct cpumask *mask, int isadd) +{ + struct listener_list *listeners; + struct listener *s, *tmp, *s2; + unsigned int cpu; + + if (!cpumask_subset(mask, cpu_possible_mask)) + return -EINVAL; + + if (isadd == REGISTER) { + for_each_cpu(cpu, mask) { + s = kmalloc_node(sizeof(struct listener), + GFP_KERNEL, cpu_to_node(cpu)); + if (!s) + goto cleanup; + + s->pid = pid; + s->valid = 1; + + listeners = &per_cpu(listener_array, cpu); + down_write(&listeners->sem); + list_for_each_entry(s2, &listeners->list, list) { + if (s2->pid == pid && s2->valid) + goto exists; + } + list_add(&s->list, &listeners->list); + s = NULL; +exists: + up_write(&listeners->sem); + kfree(s); /* nop if NULL */ + } + return 0; + } + + /* Deregister or cleanup */ +cleanup: + for_each_cpu(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, struct cpumask *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; +} + +#if defined(CONFIG_64BIT) && !defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) +#define TASKSTATS_NEEDS_PADDING 1 +#endif + +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; + + /* + * The taskstats structure is internally aligned on 8 byte + * boundaries but the layout of the aggregrate reply, with + * two NLA headers and the pid (each 4 bytes), actually + * force the entire structure to be unaligned. This causes + * the kernel to issue unaligned access warnings on some + * architectures like ia64. Unfortunately, some software out there + * doesn't properly unroll the NLA packet and assumes that the start + * of the taskstats structure will always be 20 bytes from the start + * of the netlink payload. Aligning the start of the taskstats + * structure breaks this software, which we don't want. So, for now + * the alignment only happens on architectures that require it + * and those users will have to update to fixed versions of those + * packages. Space is reserved in the packet only when needed. + * This ifdef should be removed in several years e.g. 2012 once + * we can be confident that fixed versions are installed on most + * systems. We add the padding before the aggregate since the + * aggregate is already a defined type. + */ +#ifdef TASKSTATS_NEEDS_PADDING + if (nla_put(skb, TASKSTATS_TYPE_NULL, 0, NULL) < 0) + goto err; +#endif + 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 cgroupstats_user_cmd(struct sk_buff *skb, struct genl_info *info) +{ + int rc = 0; + struct sk_buff *rep_skb; + struct cgroupstats *stats; + struct nlattr *na; + size_t size; + u32 fd; + struct file *file; + int fput_needed; + + na = info->attrs[CGROUPSTATS_CMD_ATTR_FD]; + if (!na) + return -EINVAL; + + fd = nla_get_u32(info->attrs[CGROUPSTATS_CMD_ATTR_FD]); + file = fget_light(fd, &fput_needed); + if (!file) + return 0; + + size = nla_total_size(sizeof(struct cgroupstats)); + + rc = prepare_reply(info, CGROUPSTATS_CMD_NEW, &rep_skb, + size); + if (rc < 0) + goto err; + + na = nla_reserve(rep_skb, CGROUPSTATS_TYPE_CGROUP_STATS, + sizeof(struct cgroupstats)); + stats = nla_data(na); + memset(stats, 0, sizeof(*stats)); + + rc = cgroupstats_build(stats, file->f_dentry); + if (rc < 0) { + nlmsg_free(rep_skb); + goto err; + } + + rc = send_reply(rep_skb, info); + +err: + fput_light(file, fput_needed); + return rc; +} + +static int cmd_attr_register_cpumask(struct genl_info *info) +{ + cpumask_var_t mask; + int rc; + + if (!alloc_cpumask_var(&mask, GFP_KERNEL)) + return -ENOMEM; + rc = parse(info->attrs[TASKSTATS_CMD_ATTR_REGISTER_CPUMASK], mask); + if (rc < 0) + goto out; + rc = add_del_listener(info->snd_pid, mask, REGISTER); +out: + free_cpumask_var(mask); + return rc; +} + +static int cmd_attr_deregister_cpumask(struct genl_info *info) +{ + cpumask_var_t mask; + int rc; + + if (!alloc_cpumask_var(&mask, GFP_KERNEL)) + return -ENOMEM; + rc = parse(info->attrs[TASKSTATS_CMD_ATTR_DEREGISTER_CPUMASK], mask); + if (rc < 0) + goto out; + rc = add_del_listener(info->snd_pid, mask, DEREGISTER); +out: + free_cpumask_var(mask); + return rc; +} + +static size_t taskstats_packet_size(void) +{ + size_t size; + + size = nla_total_size(sizeof(u32)) + + nla_total_size(sizeof(struct taskstats)) + nla_total_size(0); +#ifdef TASKSTATS_NEEDS_PADDING + size += nla_total_size(0); /* Padding for alignment */ +#endif + return size; +} + +static int cmd_attr_pid(struct genl_info *info) +{ + struct taskstats *stats; + struct sk_buff *rep_skb; + size_t size; + u32 pid; + int rc; + + size = taskstats_packet_size(); + + rc = prepare_reply(info, TASKSTATS_CMD_NEW, &rep_skb, size); + if (rc < 0) + return rc; + + rc = -EINVAL; + 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_stats_for_pid(pid, stats); + if (rc < 0) + goto err; + return send_reply(rep_skb, info); +err: + nlmsg_free(rep_skb); + return rc; +} + +static int cmd_attr_tgid(struct genl_info *info) +{ + struct taskstats *stats; + struct sk_buff *rep_skb; + size_t size; + u32 tgid; + int rc; + + size = taskstats_packet_size(); + + rc = prepare_reply(info, TASKSTATS_CMD_NEW, &rep_skb, size); + if (rc < 0) + return rc; + + rc = -EINVAL; + 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_stats_for_tgid(tgid, stats); + if (rc < 0) + goto err; + return send_reply(rep_skb, info); +err: + nlmsg_free(rep_skb); + return rc; +} + +static int taskstats_user_cmd(struct sk_buff *skb, struct genl_info *info) +{ + if (info->attrs[TASKSTATS_CMD_ATTR_REGISTER_CPUMASK]) + return cmd_attr_register_cpumask(info); + else if (info->attrs[TASKSTATS_CMD_ATTR_DEREGISTER_CPUMASK]) + return cmd_attr_deregister_cpumask(info); + else if (info->attrs[TASKSTATS_CMD_ATTR_PID]) + return cmd_attr_pid(info); + else if (info->attrs[TASKSTATS_CMD_ATTR_TGID]) + return cmd_attr_tgid(info); + else + return -EINVAL; +} + +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 = taskstats_packet_size(); + + 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 = __this_cpu_ptr(&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; + + fill_stats(tsk, stats); + + /* + * 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, + .flags = GENL_ADMIN_PERM, +}; + +static struct genl_ops cgroupstats_ops = { + .cmd = CGROUPSTATS_CMD_GET, + .doit = cgroupstats_user_cmd, + .policy = cgroupstats_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; + + rc = genl_register_ops(&family, &cgroupstats_ops); + if (rc < 0) + goto err_cgroup_ops; + + family_registered = 1; + pr_info("registered taskstats version %d\n", TASKSTATS_GENL_VERSION); + return 0; +err_cgroup_ops: + genl_unregister_ops(&family, &taskstats_ops); +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); |