From: Marco Stornelli <marco.stornelli@xxxxxxxxx>
This patch adds the possibility for an application to receive statistics information only
for processes belonging to a cgroup. The mechanism is the same of the cpu's exit data statistics.
With this patch, instead of waiting on a specific cpumask, an application can wait for
exit data on a specific container. Through this patch it's possible to have a simple death
notifier mechanism. We can select the processes to watch and wait for their death.
A death notify mechanism is especially useful for embedded systems.
Signed-off-by: Marco Stornelli <marco.stornelli@xxxxxxxxx>
---
diff -uprN linux-2.6.29-orig/Documentation/accounting/getdelays.c linux-2.6.29/Documentation/accounting/getdelays.c
--- linux-2.6.29-orig/Documentation/accounting/getdelays.c 2009-03-24 00:12:14.000000000 +0100
+++ linux-2.6.29/Documentation/accounting/getdelays.c 2009-06-02 15:47:01.000000000 +0200
@@ -77,9 +77,11 @@ static void usage(void)
"[-m cpumask] [-t tgid] [-p pid]\n");
fprintf(stderr, " -d: print delayacct stats\n");
fprintf(stderr, " -i: print IO accounting (works only with -p)\n");
+ fprintf(stderr, " -q: print context switch accounting\n");
fprintf(stderr, " -l: listen forever\n");
fprintf(stderr, " -v: debug on\n");
- fprintf(stderr, " -C: container path\n");
+ fprintf(stderr, " -C: container path (container statistics)\n");
+ fprintf(stderr, " -N: container path (death notify)\n");
}
/*
@@ -263,13 +265,14 @@ int main(int argc, char *argv[])
char *logfile = NULL;
int loop = 0;
int containerset = 0;
+ int containernotify = 0;
char containerpath[1024];
int cfd = 0;
struct msgtemplate msg;
while (1) {
- c = getopt(argc, argv, "qdiw:r:m:t:p:vlC:");
+ c = getopt(argc, argv, "qdiw:r:m:t:p:vlC:N:");
if (c < 0)
break;
@@ -290,6 +293,10 @@ int main(int argc, char *argv[])
containerset = 1;
strncpy(containerpath, optarg, strlen(optarg) + 1);
break;
+ case 'N':
+ containernotify = 1;
+ strncpy(containerpath, optarg, strlen(optarg) + 1);
+ break;
case 'w':
logfile = strdup(optarg);
printf("write to file %s\n", logfile);
@@ -364,8 +371,13 @@ int main(int argc, char *argv[])
}
}
- if (tid && containerset) {
- fprintf(stderr, "Select either -t or -C, not both\n");
+ if (tid && (containerset || containernotify)) {
+ fprintf(stderr, "Select either -t or -C or -N\n");
+ goto err;
+ }
+
+ if (containerset && containernotify) {
+ fprintf(stderr, "Select either -C or -N, not both\n");
goto err;
}
@@ -392,7 +404,23 @@ int main(int argc, char *argv[])
goto err;
}
}
- if (!maskset && !tid && !containerset) {
+
+ if (containernotify) {
+ cfd = open(containerpath, O_RDONLY);
+ if (cfd < 0) {
+ perror("error opening container file");
+ goto err;
+ }
+ rc = send_cmd(nl_sd, id, mypid, CGROUPSTATS_CMD_GET,
+ CGROUPSTATS_CMD_ATTR_REGISTER_FD,
+ &cfd, sizeof(__u32));
+ if (rc < 0) {
+ perror("error sending cgroupstats command");
+ goto err;
+ }
+ }
+
+ if (!maskset && !tid && !containerset && !containernotify) {
usage();
goto err;
}
@@ -400,6 +428,7 @@ int main(int argc, char *argv[])
do {
int i;
+ PRINTF("Recv...\n");
rep_len = recv(nl_sd, &msg, sizeof(msg), 0);
PRINTF("received %d bytes\n", rep_len);
@@ -495,6 +524,14 @@ done:
if (rc < 0)
err(rc, "error sending deregister cpumask\n");
}
+ if (containernotify) {
+ rc = send_cmd(nl_sd, id, mypid, CGROUPSTATS_CMD_GET,
+ CGROUPSTATS_CMD_ATTR_DEREGISTER_FD,
+ &cfd, sizeof(__u32));
+ printf("Sent deregister container, retval %d\n", rc);
+ if (rc < 0)
+ err(rc, "error sending deregister container\n");
+ }
err:
close(nl_sd);
if (fd)
--- linux-2.6.29-orig/kernel/taskstats.c 2009-03-24 00:12:14.000000000 +0100
+++ linux-2.6.29/kernel/taskstats.c 2009-06-02 15:54:37.000000000 +0200
@@ -56,6 +56,8 @@ __read_mostly = {
static struct nla_policy
cgroupstats_cmd_get_policy[CGROUPSTATS_CMD_ATTR_MAX+1] __read_mostly = {
[CGROUPSTATS_CMD_ATTR_FD] = { .type = NLA_U32 },
+ [CGROUPSTATS_CMD_ATTR_REGISTER_FD] = { .type = NLA_U32 },
+ [CGROUPSTATS_CMD_ATTR_DEREGISTER_FD] = { .type = NLA_U32 },
};
struct listener {
@@ -70,6 +72,16 @@ struct listener_list {
};
static DEFINE_PER_CPU(struct listener_list, listener_array);
+struct cgroup_listener {
+ struct list_head list;
+ pid_t pid;
+ char valid;
+ struct dentry *d_cgroup;
+ int ready_to_send;
+};
+
+static struct listener_list cgroup_listener_array;
+
enum actions {
REGISTER,
DEREGISTER,
@@ -124,6 +136,63 @@ static int send_reply(struct sk_buff *sk
}
/*
+ * Send taskstats data in @skb to listeners registered for cgroup members exit
+ * data
+ */
+static void send_cgroup_listeners(struct sk_buff *skb,
+ struct listener_list *listeners)
+{
+ struct genlmsghdr *genlhdr = nlmsg_data(nlmsg_hdr(skb));
+ struct cgroup_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) {
+ if (!s->ready_to_send)
+ continue;
+ 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++;
+ }
+ s->ready_to_send = 0;
+ 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);
+}
+
+/*
* Send taskstats data in @skb to listeners registered for @cpu's exit data
*/
static void send_cpu_listeners(struct sk_buff *skb,
@@ -290,6 +359,43 @@ ret:
return;
}
+
+static int add_cgroup_del_listener(pid_t pid, struct dentry *d_cgroup,
+ int isadd)
+{
+ struct listener_list *listeners = &cgroup_listener_array;
+ struct cgroup_listener *s, *tmp;
+
+ if (isadd == REGISTER) {
+ s = kmalloc(sizeof(struct cgroup_listener), GFP_KERNEL);
+ if (!s)
+ goto cleanup;
+ s->pid = pid;
+ INIT_LIST_HEAD(&s->list);
+ s->valid = 1;
+ s->d_cgroup = d_cgroup;
+ s->ready_to_send = 0;
+
+ down_write(&listeners->sem);
+ list_add(&s->list, &listeners->list);
+ up_write(&listeners->sem);
+ return 0;
+ }
+
+ /* Deregister or cleanup */
+cleanup:
+ 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 add_del_listener(pid_t pid, const struct cpumask *mask, int isadd)
{
struct listener_list *listeners;
@@ -391,6 +497,32 @@ static int cgroupstats_user_cmd(struct s
struct file *file;
int fput_needed;
+ na = info->attrs[CGROUPSTATS_CMD_ATTR_REGISTER_FD];
+ if (na) {
+ fd = nla_get_u32(info->attrs[CGROUPSTATS_CMD_ATTR_REGISTER_FD]);
+ file = fget_light(fd, &fput_needed);
+ if (!file)
+ return 0;
+
+ rc = add_cgroup_del_listener(info->snd_pid, file->f_dentry,
+ REGISTER);
+ fput_light(file, fput_needed);
+ return rc;
+ }
+
+ na = info->attrs[CGROUPSTATS_CMD_ATTR_DEREGISTER_FD];
+ if (na) {
+ fd = nla_get_u32(info->attrs[CGROUPSTATS_CMD_ATTR_DEREGISTER_FD]);
+ file = fget_light(fd, &fput_needed);
+ if (!file)
+ return 0;
+
+ rc = add_cgroup_del_listener(info->snd_pid, file->f_dentry,
+ DEREGISTER);
+ fput_light(file, fput_needed);
+ return rc;
+ }
+
na = info->attrs[CGROUPSTATS_CMD_ATTR_FD];
if (!na)
return -EINVAL;
@@ -517,15 +649,32 @@ ret:
return sig->stats;
}
+int check_ready_to_send(pid_t pid, struct listener_list *cgroup_list)
+{
+ struct listener_list *listeners = cgroup_list;
+ struct cgroup_listener *s, *tmp;
+ int ready = 0;
+
+ list_for_each_entry_safe(s, tmp, &listeners->list, list) {
+ if (cgroup_verify_pid(pid, s->d_cgroup) > 0) {
+ s->ready_to_send = 1;
+ ready = 1;
+ }
+ }
+
+ return ready;
+}
+
/* Send pid data out on exit */
void taskstats_exit(struct task_struct *tsk, int group_dead)
{
int rc;
struct listener_list *listeners;
+ struct listener_list *cgroup_listeners = &cgroup_listener_array;
struct taskstats *stats;
struct sk_buff *rep_skb;
size_t size;
- int is_thread_group;
+ int is_thread_group, target = 0;
if (!family_registered)
return;
@@ -545,7 +694,16 @@ void taskstats_exit(struct task_struct *
}
listeners = &__raw_get_cpu_var(listener_array);
- if (list_empty(&listeners->list))
+ if (!list_empty(&listeners->list))
+ target |= CPU_TARGET;
+
+ down_write(&cgroup_listeners->sem);
+ if (!list_empty(&cgroup_listeners->list))
+ if (check_ready_to_send(tsk->pid, cgroup_listeners))
+ target |= CGROUP_TARGET;
+ up_write(&cgroup_listeners->sem);
+
+ if (!target)
return;
rc = prepare_reply(NULL, TASKSTATS_CMD_NEW, &rep_skb, size);
@@ -573,7 +731,10 @@ void taskstats_exit(struct task_struct *
memcpy(stats, tsk->signal->stats, sizeof(*stats));
send:
- send_cpu_listeners(rep_skb, listeners);
+ if (target & CPU_TARGET)
+ send_cpu_listeners(rep_skb, listeners);
+ if (target & CGROUP_TARGET)
+ send_cgroup_listeners(rep_skb, cgroup_listeners);
return;
err:
nlmsg_free(rep_skb);
@@ -595,12 +756,15 @@ static struct genl_ops cgroupstats_ops =
void __init taskstats_init_early(void)
{
unsigned int i;
+ struct listener_list *listeners = &cgroup_listener_array;
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));
}
+ INIT_LIST_HEAD(&listeners->list);
+ init_rwsem(&listeners->sem);
}
static int __init taskstats_init(void)
--- linux-2.6.29-orig/kernel/cgroup.c 2009-03-24 00:12:14.000000000 +0100
+++ linux-2.6.29/kernel/cgroup.c 2009-06-02 15:50:57.000000000 +0200
@@ -2040,6 +2040,44 @@ static int pid_array_load(pid_t *pidarra
}
/**
+ * cgroup_verify_pid - it verifies if a pid is in a cgroup
+ * @dentry: A dentry entry belonging to the cgroup for which stats have
+ * been requested.
+ *
+ * Return value can be < 0 for error, 0 not pid not found, > 0 pid found
+ */
+int cgroup_verify_pid(pid_t pid, struct dentry *dentry)
+{
+ int ret = -EINVAL;
+ struct cgroup *cgrp;
+ struct cgroup_iter it;
+ struct task_struct *tsk;
+
+ /*
+ * Validate dentry by checking the superblock operations,
+ * and make sure it's a directory.
+ */
+ if (dentry->d_sb->s_op != &cgroup_ops ||
+ !S_ISDIR(dentry->d_inode->i_mode))
+ goto err;
+
+ ret = 0;
+ cgrp = dentry->d_fsdata;
+
+ cgroup_iter_start(cgrp, &it);
+ while ((tsk = cgroup_iter_next(cgrp, &it))) {
+ if (tsk->pid == pid) {
+ cgroup_iter_end(cgrp, &it);
+ return 1;
+ }
+ }
+ cgroup_iter_end(cgrp, &it);
+
+err:
+ return ret;
+}
+
+/**
* cgroupstats_build - build and fill cgroupstats
* @stats: cgroupstats to fill information into
* @dentry: A dentry entry belonging to the cgroup for which stats have
--- linux-2.6.29-orig/include/linux/cgroup.h 2009-03-24 00:12:14.000000000 +0100
+++ linux-2.6.29/include/linux/cgroup.h 2009-06-02 15:55:11.000000000 +0200
@@ -32,6 +32,7 @@ extern void cgroup_fork(struct task_stru
extern void cgroup_fork_callbacks(struct task_struct *p);
extern void cgroup_post_fork(struct task_struct *p);
extern void cgroup_exit(struct task_struct *p, int run_callbacks);
+extern int cgroup_verify_pid(pid_t pid, struct dentry *dentry);
extern int cgroupstats_build(struct cgroupstats *stats,
struct dentry *dentry);
@@ -450,6 +451,10 @@ static inline void cgroup_exit(struct ta
static inline void cgroup_lock(void) {}
static inline void cgroup_unlock(void) {}
+static inline int cgroup_verify_pid(pid_t pid, struct dentry *dentry)
+{
+ return -EINVAL;
+}
static inline int cgroupstats_build(struct cgroupstats *stats,
struct dentry *dentry)
{
--- linux-2.6.29-orig/include/linux/cgroupstats.h 2009-03-24 00:12:14.000000000 +0100
+++ linux-2.6.29/include/linux/cgroupstats.h 2009-06-01 11:37:46.000000000 +0200
@@ -63,6 +63,8 @@ enum {
enum {
CGROUPSTATS_CMD_ATTR_UNSPEC = 0,
CGROUPSTATS_CMD_ATTR_FD,
+ CGROUPSTATS_CMD_ATTR_REGISTER_FD,
+ CGROUPSTATS_CMD_ATTR_DEREGISTER_FD,
__CGROUPSTATS_CMD_ATTR_MAX,
};
--- linux-2.6.29-orig/include/linux/taskstats.h 2009-03-24 00:12:14.000000000 +0100
+++ linux-2.6.29/include/linux/taskstats.h 2009-06-02 15:35:24.000000000 +0200
@@ -37,6 +37,9 @@
#define TS_COMM_LEN 32 /* should be >= TASK_COMM_LEN
* in linux/sched.h */
+#define CPU_TARGET 0x1
+#define CGROUP_TARGET 0x2
+
struct taskstats {
/* The version number of this struct. This field is always set to
--
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