staging: lustre: change sai_thread to sai_task.
Rather than allocating a ptlrpc_thread for the stat-ahead thread, just use the task_struct provided by kthreads directly. As nothing ever waits for the sai_task, it must call do_exit() directly rather than simply return from the function. Also it cannot use kthread_should_stop() to know when to stop. There is one caller which can ask it to stop so we need a simple signaling mechanism. I've chosen to set ->sai_task to NULL when the thread should finish up. The thread notices this and cleans up and exits. lli_sa_lock is used to avoid races between waking up the process and the process exiting. Signed-off-by: NeilBrown <neilb@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
NeilBrown
Greg Kroah-Hartman
Родитель
c044fb0f83
Коммит
165020462d
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@ -1070,7 +1070,7 @@ struct ll_statahead_info {
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sai_agl_valid:1,/* AGL is valid for the dir */
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sai_in_readpage:1;/* statahead in readdir() */
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wait_queue_head_t sai_waitq; /* stat-ahead wait queue */
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struct ptlrpc_thread sai_thread; /* stat-ahead thread */
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struct task_struct *sai_task; /* stat-ahead thread */
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struct task_struct *sai_agl_task; /* AGL thread */
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struct list_head sai_interim_entries; /* entries which got async
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* stat reply, but not
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@ -267,7 +267,7 @@ sa_kill(struct ll_statahead_info *sai, struct sa_entry *entry)
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/* called by scanner after use, sa_entry will be killed */
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static void
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sa_put(struct ll_statahead_info *sai, struct sa_entry *entry)
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sa_put(struct ll_statahead_info *sai, struct sa_entry *entry, struct ll_inode_info *lli)
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{
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struct sa_entry *tmp, *next;
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@ -295,7 +295,11 @@ sa_put(struct ll_statahead_info *sai, struct sa_entry *entry)
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sa_kill(sai, tmp);
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}
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wake_up(&sai->sai_thread.t_ctl_waitq);
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spin_lock(&lli->lli_sa_lock);
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if (sai->sai_task)
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wake_up_process(sai->sai_task);
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spin_unlock(&lli->lli_sa_lock);
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}
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/*
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@ -403,7 +407,6 @@ static struct ll_statahead_info *ll_sai_alloc(struct dentry *dentry)
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sai->sai_max = LL_SA_RPC_MIN;
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sai->sai_index = 1;
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init_waitqueue_head(&sai->sai_waitq);
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init_waitqueue_head(&sai->sai_thread.t_ctl_waitq);
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INIT_LIST_HEAD(&sai->sai_interim_entries);
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INIT_LIST_HEAD(&sai->sai_entries);
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@ -465,7 +468,7 @@ static void ll_sai_put(struct ll_statahead_info *sai)
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lli->lli_sai = NULL;
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spin_unlock(&lli->lli_sa_lock);
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LASSERT(thread_is_stopped(&sai->sai_thread));
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LASSERT(sai->sai_task == NULL);
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LASSERT(sai->sai_agl_task == NULL);
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LASSERT(sai->sai_sent == sai->sai_replied);
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LASSERT(!sa_has_callback(sai));
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@ -646,7 +649,6 @@ static int ll_statahead_interpret(struct ptlrpc_request *req,
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struct ll_inode_info *lli = ll_i2info(dir);
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struct ll_statahead_info *sai = lli->lli_sai;
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struct sa_entry *entry = (struct sa_entry *)minfo->mi_cbdata;
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wait_queue_head_t *waitq = NULL;
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__u64 handle = 0;
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if (it_disposition(it, DISP_LOOKUP_NEG))
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@ -657,7 +659,6 @@ static int ll_statahead_interpret(struct ptlrpc_request *req,
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* sai should be always valid, no need to refcount
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*/
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LASSERT(sai);
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LASSERT(!thread_is_stopped(&sai->sai_thread));
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LASSERT(entry);
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CDEBUG(D_READA, "sa_entry %.*s rc %d\n",
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@ -681,8 +682,9 @@ static int ll_statahead_interpret(struct ptlrpc_request *req,
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spin_lock(&lli->lli_sa_lock);
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if (rc) {
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if (__sa_make_ready(sai, entry, rc))
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waitq = &sai->sai_waitq;
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wake_up(&sai->sai_waitq);
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} else {
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int first = 0;
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entry->se_minfo = minfo;
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entry->se_req = ptlrpc_request_addref(req);
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/*
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@ -693,14 +695,15 @@ static int ll_statahead_interpret(struct ptlrpc_request *req,
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*/
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entry->se_handle = handle;
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if (!sa_has_callback(sai))
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waitq = &sai->sai_thread.t_ctl_waitq;
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first = 1;
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list_add_tail(&entry->se_list, &sai->sai_interim_entries);
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if (first && sai->sai_task)
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wake_up_process(sai->sai_task);
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}
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sai->sai_replied++;
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if (waitq)
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wake_up(waitq);
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spin_unlock(&lli->lli_sa_lock);
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return rc;
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@ -942,17 +945,13 @@ static int ll_statahead_thread(void *arg)
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struct inode *dir = d_inode(parent);
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struct ll_inode_info *lli = ll_i2info(dir);
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struct ll_sb_info *sbi = ll_i2sbi(dir);
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struct ll_statahead_info *sai;
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struct ptlrpc_thread *sa_thread;
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struct ll_statahead_info *sai = lli->lli_sai;
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struct page *page = NULL;
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__u64 pos = 0;
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int first = 0;
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int rc = 0;
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struct md_op_data *op_data;
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sai = ll_sai_get(dir);
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sa_thread = &sai->sai_thread;
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sa_thread->t_pid = current_pid();
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CDEBUG(D_READA, "statahead thread starting: sai %p, parent %pd\n",
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sai, parent);
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@ -965,21 +964,7 @@ static int ll_statahead_thread(void *arg)
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op_data->op_max_pages = ll_i2sbi(dir)->ll_md_brw_pages;
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if (sbi->ll_flags & LL_SBI_AGL_ENABLED)
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ll_start_agl(parent, sai);
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atomic_inc(&sbi->ll_sa_total);
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spin_lock(&lli->lli_sa_lock);
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if (thread_is_init(sa_thread))
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/* If someone else has changed the thread state
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* (e.g. already changed to SVC_STOPPING), we can't just
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* blindly overwrite that setting.
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*/
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thread_set_flags(sa_thread, SVC_RUNNING);
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spin_unlock(&lli->lli_sa_lock);
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wake_up(&sa_thread->t_ctl_waitq);
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while (pos != MDS_DIR_END_OFF && thread_is_running(sa_thread)) {
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while (pos != MDS_DIR_END_OFF && sai->sai_task) {
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struct lu_dirpage *dp;
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struct lu_dirent *ent;
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@ -996,7 +981,7 @@ static int ll_statahead_thread(void *arg)
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dp = page_address(page);
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for (ent = lu_dirent_start(dp);
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ent && thread_is_running(sa_thread) && !sa_low_hit(sai);
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ent && sai->sai_task && !sa_low_hit(sai);
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ent = lu_dirent_next(ent)) {
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struct lu_fid fid;
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__u64 hash;
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@ -1046,13 +1031,7 @@ static int ll_statahead_thread(void *arg)
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fid_le_to_cpu(&fid, &ent->lde_fid);
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/* wait for spare statahead window */
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do {
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wait_event_idle(sa_thread->t_ctl_waitq,
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!sa_sent_full(sai) ||
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sa_has_callback(sai) ||
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!list_empty(&sai->sai_agls) ||
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!thread_is_running(sa_thread));
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sa_handle_callback(sai);
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spin_lock(&lli->lli_agl_lock);
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@ -1072,8 +1051,16 @@ static int ll_statahead_thread(void *arg)
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spin_lock(&lli->lli_agl_lock);
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}
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spin_unlock(&lli->lli_agl_lock);
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} while (sa_sent_full(sai) &&
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thread_is_running(sa_thread));
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set_current_state(TASK_IDLE);
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if (sa_sent_full(sai) &&
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!sa_has_callback(sai) &&
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agl_list_empty(sai) &&
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sai->sai_task)
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/* wait for spare statahead window */
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schedule();
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__set_current_state(TASK_RUNNING);
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} while (sa_sent_full(sai) && sai->sai_task);
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sa_statahead(parent, name, namelen, &fid);
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}
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@ -1096,7 +1083,7 @@ static int ll_statahead_thread(void *arg)
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if (rc < 0) {
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spin_lock(&lli->lli_sa_lock);
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thread_set_flags(sa_thread, SVC_STOPPING);
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sai->sai_task = NULL;
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lli->lli_sa_enabled = 0;
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spin_unlock(&lli->lli_sa_lock);
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}
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@ -1105,12 +1092,14 @@ static int ll_statahead_thread(void *arg)
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* statahead is finished, but statahead entries need to be cached, wait
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* for file release to stop me.
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*/
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while (thread_is_running(sa_thread)) {
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wait_event_idle(sa_thread->t_ctl_waitq,
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sa_has_callback(sai) ||
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!thread_is_running(sa_thread));
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while (sai->sai_task) {
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sa_handle_callback(sai);
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set_current_state(TASK_IDLE);
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if (!sa_has_callback(sai) &&
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sai->sai_task)
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schedule();
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__set_current_state(TASK_RUNNING);
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}
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out:
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if (sai->sai_agl_task) {
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@ -1126,26 +1115,23 @@ out:
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*/
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while (sai->sai_sent != sai->sai_replied) {
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/* in case we're not woken up, timeout wait */
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wait_event_idle_timeout(sa_thread->t_ctl_waitq,
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sai->sai_sent == sai->sai_replied,
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HZ>>3);
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schedule_timeout_idle(HZ>>3);
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}
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/* release resources held by statahead RPCs */
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sa_handle_callback(sai);
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spin_lock(&lli->lli_sa_lock);
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thread_set_flags(sa_thread, SVC_STOPPED);
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spin_unlock(&lli->lli_sa_lock);
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CDEBUG(D_READA, "statahead thread stopped: sai %p, parent %pd\n",
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sai, parent);
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spin_lock(&lli->lli_sa_lock);
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sai->sai_task = NULL;
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spin_unlock(&lli->lli_sa_lock);
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wake_up(&sai->sai_waitq);
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wake_up(&sa_thread->t_ctl_waitq);
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ll_sai_put(sai);
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return rc;
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do_exit(rc);
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}
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/* authorize opened dir handle @key to statahead */
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@ -1187,13 +1173,13 @@ void ll_deauthorize_statahead(struct inode *dir, void *key)
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lli->lli_opendir_pid = 0;
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lli->lli_sa_enabled = 0;
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sai = lli->lli_sai;
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if (sai && thread_is_running(&sai->sai_thread)) {
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if (sai && sai->sai_task) {
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/*
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* statahead thread may not quit yet because it needs to cache
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* entries, now it's time to tell it to quit.
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*/
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thread_set_flags(&sai->sai_thread, SVC_STOPPING);
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wake_up(&sai->sai_thread.t_ctl_waitq);
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wake_up_process(sai->sai_task);
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sai->sai_task = NULL;
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}
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spin_unlock(&lli->lli_sa_lock);
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}
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@ -1463,7 +1449,7 @@ out_unplug:
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*/
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ldd = ll_d2d(*dentryp);
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ldd->lld_sa_generation = lli->lli_sa_generation;
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sa_put(sai, entry);
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sa_put(sai, entry, lli);
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return rc;
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}
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@ -1483,7 +1469,6 @@ static int start_statahead_thread(struct inode *dir, struct dentry *dentry)
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{
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struct ll_inode_info *lli = ll_i2info(dir);
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struct ll_statahead_info *sai = NULL;
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struct ptlrpc_thread *thread;
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struct task_struct *task;
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struct dentry *parent = dentry->d_parent;
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int rc;
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@ -1523,18 +1508,21 @@ static int start_statahead_thread(struct inode *dir, struct dentry *dentry)
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CDEBUG(D_READA, "start statahead thread: [pid %d] [parent %pd]\n",
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current_pid(), parent);
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task = kthread_run(ll_statahead_thread, parent, "ll_sa_%u",
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lli->lli_opendir_pid);
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thread = &sai->sai_thread;
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task = kthread_create(ll_statahead_thread, parent, "ll_sa_%u",
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lli->lli_opendir_pid);
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if (IS_ERR(task)) {
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rc = PTR_ERR(task);
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CERROR("can't start ll_sa thread, rc : %d\n", rc);
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goto out;
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}
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wait_event_idle(thread->t_ctl_waitq,
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thread_is_running(thread) || thread_is_stopped(thread));
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ll_sai_put(sai);
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if (ll_i2sbi(parent->d_inode)->ll_flags & LL_SBI_AGL_ENABLED)
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ll_start_agl(parent, sai);
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atomic_inc(&ll_i2sbi(parent->d_inode)->ll_sa_total);
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sai->sai_task = task;
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wake_up_process(task);
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/*
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* We don't stat-ahead for the first dirent since we are already in
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