[lustre-devel] [PATCH 14/17] staging: lustre: change sai_thread to sai_task.
NeilBrown
neilb at suse.com
Thu Mar 1 15:31:25 PST 2018
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 at suse.com>
---
.../staging/lustre/lustre/llite/llite_internal.h | 2
drivers/staging/lustre/lustre/llite/statahead.c | 118 +++++++++-----------
2 files changed, 54 insertions(+), 66 deletions(-)
diff --git a/drivers/staging/lustre/lustre/llite/llite_internal.h b/drivers/staging/lustre/lustre/llite/llite_internal.h
index 0c2d717fd526..d46bcf71b273 100644
--- a/drivers/staging/lustre/lustre/llite/llite_internal.h
+++ b/drivers/staging/lustre/lustre/llite/llite_internal.h
@@ -1070,7 +1070,7 @@ struct ll_statahead_info {
sai_agl_valid:1,/* AGL is valid for the dir */
sai_in_readpage:1;/* statahead in readdir() */
wait_queue_head_t sai_waitq; /* stat-ahead wait queue */
- struct ptlrpc_thread sai_thread; /* stat-ahead thread */
+ struct task_struct *sai_task; /* stat-ahead thread */
struct task_struct *sai_agl_task; /* AGL thread */
struct list_head sai_interim_entries; /* entries which got async
* stat reply, but not
diff --git a/drivers/staging/lustre/lustre/llite/statahead.c b/drivers/staging/lustre/lustre/llite/statahead.c
index 39241b952bf4..155ce3cf6f60 100644
--- a/drivers/staging/lustre/lustre/llite/statahead.c
+++ b/drivers/staging/lustre/lustre/llite/statahead.c
@@ -267,7 +267,7 @@ sa_kill(struct ll_statahead_info *sai, struct sa_entry *entry)
/* called by scanner after use, sa_entry will be killed */
static void
-sa_put(struct ll_statahead_info *sai, struct sa_entry *entry)
+sa_put(struct ll_statahead_info *sai, struct sa_entry *entry, struct ll_inode_info *lli)
{
struct sa_entry *tmp, *next;
@@ -295,7 +295,11 @@ sa_put(struct ll_statahead_info *sai, struct sa_entry *entry)
sa_kill(sai, tmp);
}
- wake_up(&sai->sai_thread.t_ctl_waitq);
+ spin_lock(&lli->lli_sa_lock);
+ if (sai->sai_task)
+ wake_up_process(sai->sai_task);
+ spin_unlock(&lli->lli_sa_lock);
+
}
/*
@@ -403,7 +407,6 @@ static struct ll_statahead_info *ll_sai_alloc(struct dentry *dentry)
sai->sai_max = LL_SA_RPC_MIN;
sai->sai_index = 1;
init_waitqueue_head(&sai->sai_waitq);
- init_waitqueue_head(&sai->sai_thread.t_ctl_waitq);
INIT_LIST_HEAD(&sai->sai_interim_entries);
INIT_LIST_HEAD(&sai->sai_entries);
@@ -465,7 +468,7 @@ static void ll_sai_put(struct ll_statahead_info *sai)
lli->lli_sai = NULL;
spin_unlock(&lli->lli_sa_lock);
- LASSERT(thread_is_stopped(&sai->sai_thread));
+ LASSERT(sai->sai_task == NULL);
LASSERT(sai->sai_agl_task == NULL);
LASSERT(sai->sai_sent == sai->sai_replied);
LASSERT(!sa_has_callback(sai));
@@ -646,7 +649,6 @@ static int ll_statahead_interpret(struct ptlrpc_request *req,
struct ll_inode_info *lli = ll_i2info(dir);
struct ll_statahead_info *sai = lli->lli_sai;
struct sa_entry *entry = (struct sa_entry *)minfo->mi_cbdata;
- wait_queue_head_t *waitq = NULL;
__u64 handle = 0;
if (it_disposition(it, DISP_LOOKUP_NEG))
@@ -657,7 +659,6 @@ static int ll_statahead_interpret(struct ptlrpc_request *req,
* sai should be always valid, no need to refcount
*/
LASSERT(sai);
- LASSERT(!thread_is_stopped(&sai->sai_thread));
LASSERT(entry);
CDEBUG(D_READA, "sa_entry %.*s rc %d\n",
@@ -681,8 +682,9 @@ static int ll_statahead_interpret(struct ptlrpc_request *req,
spin_lock(&lli->lli_sa_lock);
if (rc) {
if (__sa_make_ready(sai, entry, rc))
- waitq = &sai->sai_waitq;
+ wake_up(&sai->sai_waitq);
} else {
+ int first = 0;
entry->se_minfo = minfo;
entry->se_req = ptlrpc_request_addref(req);
/*
@@ -693,14 +695,15 @@ static int ll_statahead_interpret(struct ptlrpc_request *req,
*/
entry->se_handle = handle;
if (!sa_has_callback(sai))
- waitq = &sai->sai_thread.t_ctl_waitq;
+ first = 1;
list_add_tail(&entry->se_list, &sai->sai_interim_entries);
+
+ if (first && sai->sai_task)
+ wake_up_process(sai->sai_task);
}
sai->sai_replied++;
- if (waitq)
- wake_up(waitq);
spin_unlock(&lli->lli_sa_lock);
return rc;
@@ -942,17 +945,13 @@ static int ll_statahead_thread(void *arg)
struct inode *dir = d_inode(parent);
struct ll_inode_info *lli = ll_i2info(dir);
struct ll_sb_info *sbi = ll_i2sbi(dir);
- struct ll_statahead_info *sai;
- struct ptlrpc_thread *sa_thread;
+ struct ll_statahead_info *sai = lli->lli_sai;
struct page *page = NULL;
__u64 pos = 0;
int first = 0;
int rc = 0;
struct md_op_data *op_data;
- sai = ll_sai_get(dir);
- sa_thread = &sai->sai_thread;
- sa_thread->t_pid = current_pid();
CDEBUG(D_READA, "statahead thread starting: sai %p, parent %pd\n",
sai, parent);
@@ -965,21 +964,7 @@ static int ll_statahead_thread(void *arg)
op_data->op_max_pages = ll_i2sbi(dir)->ll_md_brw_pages;
- if (sbi->ll_flags & LL_SBI_AGL_ENABLED)
- ll_start_agl(parent, sai);
-
- atomic_inc(&sbi->ll_sa_total);
- spin_lock(&lli->lli_sa_lock);
- if (thread_is_init(sa_thread))
- /* If someone else has changed the thread state
- * (e.g. already changed to SVC_STOPPING), we can't just
- * blindly overwrite that setting.
- */
- thread_set_flags(sa_thread, SVC_RUNNING);
- spin_unlock(&lli->lli_sa_lock);
- wake_up(&sa_thread->t_ctl_waitq);
-
- while (pos != MDS_DIR_END_OFF && thread_is_running(sa_thread)) {
+ while (pos != MDS_DIR_END_OFF && sai->sai_task) {
struct lu_dirpage *dp;
struct lu_dirent *ent;
@@ -996,7 +981,7 @@ static int ll_statahead_thread(void *arg)
dp = page_address(page);
for (ent = lu_dirent_start(dp);
- ent && thread_is_running(sa_thread) && !sa_low_hit(sai);
+ ent && sai->sai_task && !sa_low_hit(sai);
ent = lu_dirent_next(ent)) {
struct lu_fid fid;
__u64 hash;
@@ -1046,13 +1031,7 @@ static int ll_statahead_thread(void *arg)
fid_le_to_cpu(&fid, &ent->lde_fid);
- /* wait for spare statahead window */
do {
- wait_event_idle(sa_thread->t_ctl_waitq,
- !sa_sent_full(sai) ||
- sa_has_callback(sai) ||
- !list_empty(&sai->sai_agls) ||
- !thread_is_running(sa_thread));
sa_handle_callback(sai);
spin_lock(&lli->lli_agl_lock);
@@ -1072,8 +1051,16 @@ static int ll_statahead_thread(void *arg)
spin_lock(&lli->lli_agl_lock);
}
spin_unlock(&lli->lli_agl_lock);
- } while (sa_sent_full(sai) &&
- thread_is_running(sa_thread));
+
+ set_current_state(TASK_IDLE);
+ if (sa_sent_full(sai) &&
+ !sa_has_callback(sai) &&
+ agl_list_empty(sai) &&
+ sai->sai_task)
+ /* wait for spare statahead window */
+ schedule();
+ __set_current_state(TASK_RUNNING);
+ } while (sa_sent_full(sai) && sai->sai_task);
sa_statahead(parent, name, namelen, &fid);
}
@@ -1096,7 +1083,7 @@ static int ll_statahead_thread(void *arg)
if (rc < 0) {
spin_lock(&lli->lli_sa_lock);
- thread_set_flags(sa_thread, SVC_STOPPING);
+ sai->sai_task = NULL;
lli->lli_sa_enabled = 0;
spin_unlock(&lli->lli_sa_lock);
}
@@ -1105,12 +1092,14 @@ static int ll_statahead_thread(void *arg)
* statahead is finished, but statahead entries need to be cached, wait
* for file release to stop me.
*/
- while (thread_is_running(sa_thread)) {
- wait_event_idle(sa_thread->t_ctl_waitq,
- sa_has_callback(sai) ||
- !thread_is_running(sa_thread));
-
+ while (sai->sai_task) {
sa_handle_callback(sai);
+
+ set_current_state(TASK_IDLE);
+ if (!sa_has_callback(sai) &&
+ sai->sai_task)
+ schedule();
+ __set_current_state(TASK_RUNNING);
}
out:
if (sai->sai_agl_task) {
@@ -1126,26 +1115,23 @@ static int ll_statahead_thread(void *arg)
*/
while (sai->sai_sent != sai->sai_replied) {
/* in case we're not woken up, timeout wait */
- wait_event_idle_timeout(sa_thread->t_ctl_waitq,
- sai->sai_sent == sai->sai_replied,
- HZ>>3);
+ schedule_timeout_idle(HZ>>3);
}
/* release resources held by statahead RPCs */
sa_handle_callback(sai);
- spin_lock(&lli->lli_sa_lock);
- thread_set_flags(sa_thread, SVC_STOPPED);
- spin_unlock(&lli->lli_sa_lock);
-
CDEBUG(D_READA, "statahead thread stopped: sai %p, parent %pd\n",
sai, parent);
+ spin_lock(&lli->lli_sa_lock);
+ sai->sai_task = NULL;
+ spin_unlock(&lli->lli_sa_lock);
+
wake_up(&sai->sai_waitq);
- wake_up(&sa_thread->t_ctl_waitq);
ll_sai_put(sai);
- return rc;
+ do_exit(rc);
}
/* authorize opened dir handle @key to statahead */
@@ -1187,13 +1173,13 @@ void ll_deauthorize_statahead(struct inode *dir, void *key)
lli->lli_opendir_pid = 0;
lli->lli_sa_enabled = 0;
sai = lli->lli_sai;
- if (sai && thread_is_running(&sai->sai_thread)) {
+ if (sai && sai->sai_task) {
/*
* statahead thread may not quit yet because it needs to cache
* entries, now it's time to tell it to quit.
*/
- thread_set_flags(&sai->sai_thread, SVC_STOPPING);
- wake_up(&sai->sai_thread.t_ctl_waitq);
+ wake_up_process(sai->sai_task);
+ sai->sai_task = NULL;
}
spin_unlock(&lli->lli_sa_lock);
}
@@ -1463,7 +1449,7 @@ static int revalidate_statahead_dentry(struct inode *dir,
*/
ldd = ll_d2d(*dentryp);
ldd->lld_sa_generation = lli->lli_sa_generation;
- sa_put(sai, entry);
+ sa_put(sai, entry, lli);
return rc;
}
@@ -1483,7 +1469,6 @@ static int start_statahead_thread(struct inode *dir, struct dentry *dentry)
{
struct ll_inode_info *lli = ll_i2info(dir);
struct ll_statahead_info *sai = NULL;
- struct ptlrpc_thread *thread;
struct task_struct *task;
struct dentry *parent = dentry->d_parent;
int rc;
@@ -1523,18 +1508,21 @@ static int start_statahead_thread(struct inode *dir, struct dentry *dentry)
CDEBUG(D_READA, "start statahead thread: [pid %d] [parent %pd]\n",
current_pid(), parent);
- task = kthread_run(ll_statahead_thread, parent, "ll_sa_%u",
- lli->lli_opendir_pid);
- thread = &sai->sai_thread;
+ task = kthread_create(ll_statahead_thread, parent, "ll_sa_%u",
+ lli->lli_opendir_pid);
if (IS_ERR(task)) {
rc = PTR_ERR(task);
CERROR("can't start ll_sa thread, rc : %d\n", rc);
goto out;
}
- wait_event_idle(thread->t_ctl_waitq,
- thread_is_running(thread) || thread_is_stopped(thread));
- ll_sai_put(sai);
+ if (ll_i2sbi(parent->d_inode)->ll_flags & LL_SBI_AGL_ENABLED)
+ ll_start_agl(parent, sai);
+
+ atomic_inc(&ll_i2sbi(parent->d_inode)->ll_sa_total);
+ sai->sai_task = task;
+
+ wake_up_process(task);
/*
* We don't stat-ahead for the first dirent since we are already in
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