};
/*
+ * Jobid can be set for a session (see setsid(2)) by writing to
+ * a sysfs file from any process in that session.
+ * The jobids are stored in a hash table indexed by the relevant
+ * struct pid. We periodically look for entries where the pid has
+ * no PIDTYPE_SID tasks any more, and prune them. This happens within
+ * 5 seconds of a jobid being added, and every 5 minutes when jobids exist,
+ * but none are added.
+ */
+#define JOBID_EXPEDITED_CLEAN (5)
+#define JOBID_BACKGROUND_CLEAN (5 * 60)
+
+struct session_jobid {
+ struct pid *sj_session;
+ struct rhash_head sj_linkage;
+ struct rcu_head sj_rcu;
+ char sj_jobid[1];
+};
+
+static const struct rhashtable_params jobid_params = {
+ .key_len = sizeof(struct pid *),
+ .key_offset = offsetof(struct session_jobid, sj_session),
+ .head_offset = offsetof(struct session_jobid, sj_linkage),
+};
+
+static struct rhashtable session_jobids;
+
+/*
+ * jobid_current must be called with rcu_read_lock held.
+ * if it returns non-NULL, the string can only be used
+ * until rcu_read_unlock is called.
+ */
+char *jobid_current(void)
+{
+ struct pid *sid = task_session(current);
+ struct session_jobid *sj;
+
+ sj = rhashtable_lookup_fast(&session_jobids, &sid, jobid_params);
+ if (sj)
+ return sj->sj_jobid;
+ return NULL;
+}
+
+static void jobid_prune_expedite(void);
+/*
+ * jobid_set_current will try to add a new entry
+ * to the table. If one exists with the same key, the
+ * jobid will be replaced
+ */
+int jobid_set_current(char *jobid)
+{
+ struct pid *sid;
+ struct session_jobid *sj, *origsj;
+ int ret;
+ int len = strlen(jobid);
+
+ sj = kmalloc(sizeof(*sj) + len, GFP_KERNEL);
+ if (!sj)
+ return -ENOMEM;
+ rcu_read_lock();
+ sid = task_session(current);
+ sj->sj_session = get_pid(sid);
+ strncpy(sj->sj_jobid, jobid, len+1);
+ origsj = rhashtable_lookup_get_insert_fast(&session_jobids,
+ &sj->sj_linkage,
+ jobid_params);
+ if (origsj == NULL) {
+ /* successful insert */
+ rcu_read_unlock();
+ jobid_prune_expedite();
+ return 0;
+ }
+
+ if (IS_ERR(origsj)) {
+ put_pid(sj->sj_session);
+ kfree(sj);
+ rcu_read_unlock();
+ return PTR_ERR(origsj);
+ }
+ ret = rhashtable_replace_fast(&session_jobids,
+ &origsj->sj_linkage,
+ &sj->sj_linkage,
+ jobid_params);
+ if (ret) {
+ put_pid(sj->sj_session);
+ kfree(sj);
+ rcu_read_unlock();
+ return ret;
+ }
+ put_pid(origsj->sj_session);
+ rcu_read_unlock();
+ kfree_rcu(origsj, sj_rcu);
+ jobid_prune_expedite();
+
+ return 0;
+}
+
+static void jobid_free(void *vsj, void *arg)
+{
+ struct session_jobid *sj = vsj;
+
+ put_pid(sj->sj_session);
+ kfree(sj);
+}
+
+static void jobid_prune(struct work_struct *work);
+static DECLARE_DELAYED_WORK(jobid_prune_work, jobid_prune);
+static int jobid_prune_expedited;
+static void jobid_prune(struct work_struct *work)
+{
+ int remaining = 0;
+ struct rhashtable_iter iter;
+ struct session_jobid *sj;
+
+ jobid_prune_expedited = 0;
+ rhashtable_walk_enter(&session_jobids, &iter);
+ rhashtable_walk_start(&iter);
+ while ((sj = rhashtable_walk_next(&iter)) != NULL) {
+ if (!hlist_empty(&sj->sj_session->tasks[PIDTYPE_SID])) {
+ remaining++;
+ continue;
+ }
+ if (rhashtable_remove_fast(&session_jobids,
+ &sj->sj_linkage,
+ jobid_params) == 0) {
+ put_pid(sj->sj_session);
+ kfree_rcu(sj, sj_rcu);
+ }
+ }
+ rhashtable_walk_stop(&iter);
+ rhashtable_walk_exit(&iter);
+ if (remaining)
+ schedule_delayed_work(&jobid_prune_work,
+ cfs_time_seconds(JOBID_BACKGROUND_CLEAN));
+}
+
+static void jobid_prune_expedite(void)
+{
+ if (!jobid_prune_expedited) {
+ jobid_prune_expedited = 1;
+ mod_delayed_work(system_wq, &jobid_prune_work,
+ cfs_time_seconds(JOBID_EXPEDITED_CLEAN));
+ }
+}
+
+/*
* Get jobid of current process by reading the environment variable
* stored in between the "env_start" & "env_end" of task struct.
*
if (obj == NULL)
return 0;
+ if (jobid == NULL) {
+ WARN_ON_ONCE(atomic_read(&pidmap->jp_refcount) != 1);
+ return 1;
+ }
+
spin_lock(&pidmap->jp_lock);
- if (jobid == NULL)
- rc = 1;
- else if (jobid[0] == '\0')
+ /* prevent newly inserted items from deleting */
+ if (jobid[0] == '\0' && atomic_read(&pidmap->jp_refcount) == 1)
rc = 1;
else if (ktime_get_real_seconds() - pidmap->jp_time > DELETE_INTERVAL)
rc = 1;
/*
* jobid_get_from_cache()
*
- * Returns contents of jobid_var from process environment for current PID.
- * This will be cached for some time to avoid overhead scanning environment.
+ * Returns contents of jobid_var from process environment for current PID,
+ * or from the per-session jobid table.
+ * Values fetch from process environment will be cached for some time to avoid
+ * the overhead of scanning the environment.
*
* Return: -ENOMEM if allocating a new pidmap fails
* -ENOENT if no entry could be found
int rc = 0;
ENTRY;
+ if (strcmp(obd_jobid_var, JOBSTATS_SESSION) == 0) {
+ char *jid;
+
+ rcu_read_lock();
+ jid = jobid_current();
+ if (jid) {
+ strlcpy(jobid, jid, joblen);
+ joblen = strlen(jobid);
+ } else {
+ rc = -ENOENT;
+ }
+ rcu_read_unlock();
+ GOTO(out, rc);
+ }
+
LASSERT(jobid_hash != NULL);
/* scan hash periodically to remove old PID entries from cache */
pidmap->jp_jobid[0] = '\0';
spin_lock_init(&pidmap->jp_lock);
INIT_HLIST_NODE(&pidmap->jp_hash);
+ /*
+ * @pidmap might be reclaimed just after it is added into
+ * hash list, init @jp_refcount as 1 to make sure memory
+ * could be not freed during access.
+ */
+ atomic_set(&pidmap->jp_refcount, 1);
/*
* Add the newly created map to the hash, on key collision we
pid);
OBD_FREE_PTR(pidmap);
pidmap = pidmap2;
- } else {
- cfs_hash_get(jobid_hash, &pidmap->jp_hash);
}
}
HASH_JOBID_MAX_BITS, HASH_JOBID_BKT_BITS,
0, CFS_HASH_MIN_THETA, CFS_HASH_MAX_THETA,
&jobid_hash_ops, CFS_HASH_DEFAULT);
- if (!jobid_hash)
+ if (!jobid_hash) {
rc = -ENOMEM;
+ } else {
+ rc = rhashtable_init(&session_jobids, &jobid_params);
+ if (rc) {
+ cfs_hash_putref(jobid_hash);
+ jobid_hash = NULL;
+ }
+ }
RETURN(rc);
}
jobid_hash = NULL;
spin_unlock(&jobid_hash_lock);
+ cancel_delayed_work_sync(&jobid_prune_work);
+
if (tmp_hash != NULL) {
cfs_hash_cond_del(tmp_hash, jobid_should_free_item, NULL);
cfs_hash_putref(tmp_hash);
+
+ rhashtable_free_and_destroy(&session_jobids, jobid_free, NULL);
}
+
EXIT;
}
EXPORT_SYMBOL(jobid_cache_fini);
*
* Fill in @jobid string based on the value of obd_jobid_var:
* JOBSTATS_DISABLE: none
- * JOBSTATS_NODELOCAL: content of obd_jobid_node (jobid_interpret_string())
+ * JOBSTATS_NODELOCAL: content of obd_jobid_name (jobid_interpret_string())
* JOBSTATS_PROCNAME_UID: process name/UID
+ * JOBSTATS_SESSION per-session value set by
+ * /sys/fs/lustre/jobid_this_session
* anything else: look up obd_jobid_var in the processes environment
*
* Return -ve error number, 0 on success.
rc = jobid_interpret_string(obd_jobid_name, jobid, joblen);
} else if (strcmp(obd_jobid_var, JOBSTATS_PROCNAME_UID) == 0) {
rc = jobid_interpret_string("%e.%u", jobid, joblen);
+ } else if (strcmp(obd_jobid_var, JOBSTATS_SESSION) == 0) {
+ char *jid;
+
+ rcu_read_lock();
+ jid = jobid_current();
+ if (jid)
+ strlcpy(jobid, jid, sizeof(jobid));
+ rcu_read_unlock();
} else if (jobid_name_is_valid(current_comm())) {
/*
* obd_jobid_var holds the jobid environment variable name.
git://git.whamcloud.com / fs / lustre-release.git / blobdiff