--- /dev/null
+/*
+ * 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 <linux/pid_namespace.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);
+
+ genlmsg_end(skb, reply);
+
+ 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;
+
+ genlmsg_end(skb, reply);
+
+ 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 user_namespace *user_ns,
+ struct pid_namespace *pid_ns,
+ 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(user_ns, pid_ns, 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(current_user_ns(), task_active_pid_ns(current), 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;
+ int ret = 0;
+
+ if (!cpumask_subset(mask, cpu_possible_mask))
+ return -EINVAL;
+
+ if (current_user_ns() != &init_user_ns)
+ return -EINVAL;
+
+ if (task_active_pid_ns(current) != &init_pid_ns)
+ return -EINVAL;
+
+ if (isadd == REGISTER) {
+ for_each_cpu(cpu, mask) {
+ s = kmalloc_node(sizeof(struct listener),
+ GFP_KERNEL, cpu_to_node(cpu));
+ if (!s) {
+ ret = -ENOMEM;
+ 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 ret;
+}
+
+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) {
+ nla_nest_cancel(skb, na);
+ goto err;
+ }
+ ret = nla_reserve(skb, TASKSTATS_TYPE_STATS, sizeof(struct taskstats));
+ if (!ret) {
+ nla_nest_cancel(skb, na);
+ 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 fd f;
+
+ na = info->attrs[CGROUPSTATS_CMD_ATTR_FD];
+ if (!na)
+ return -EINVAL;
+
+ fd = nla_get_u32(info->attrs[CGROUPSTATS_CMD_ATTR_FD]);
+ f = fdget(fd);
+ if (!f.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));
+ if (na == NULL) {
+ nlmsg_free(rep_skb);
+ rc = -EMSGSIZE;
+ goto err;
+ }
+
+ stats = nla_data(na);
+ memset(stats, 0, sizeof(*stats));
+
+ rc = cgroupstats_build(stats, f.file->f_path.dentry);
+ if (rc < 0) {
+ nlmsg_free(rep_skb);
+ goto err;
+ }
+
+ rc = send_reply(rep_skb, info);
+
+err:
+ fdput(f);
+ 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_portid, 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_portid, 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 = raw_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,
+ task_pid_nr_ns(tsk, &init_pid_ns));
+ if (!stats)
+ goto err;
+
+ fill_stats(&init_user_ns, &init_pid_ns, 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,
+ task_tgid_nr_ns(tsk, &init_pid_ns));
+ 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 const struct genl_ops taskstats_ops[] = {
+ {
+ .cmd = TASKSTATS_CMD_GET,
+ .doit = taskstats_user_cmd,
+ .policy = taskstats_cmd_get_policy,
+ .flags = GENL_ADMIN_PERM,
+ },
+ {
+ .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_with_ops(&family, taskstats_ops);
+ if (rc)
+ return rc;
+
+ family_registered = 1;
+ pr_info("registered taskstats version %d\n", TASKSTATS_GENL_VERSION);
+ return 0;
+}
+
+/*
+ * late initcall ensures initialization of statistics collection
+ * mechanisms precedes initialization of the taskstats interface
+ */
+late_initcall(taskstats_init);
Code Review / kvmfornfv.git / blobdiff