Initial import

1 files changed, 710 insertions, 0 deletions

diff --git a/kernel/taskstats.c b/kernel/taskstats.c
new file mode 100644
index 000000000..21f82c29c
--- /dev/null
+++ b/kernel/taskstats.c
@@ -0,0 +1,710 @@
+/*
+ * 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);