Merge branch 'master'

1 files changed, 568 insertions, 0 deletions

diff --git a/kernel/taskstats.c b/kernel/taskstats.c
new file mode 100644
index 000000000000..f45179ce028e
--- /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);