[PATCH 056/124] staging: lustre: statahead: use dcache-like interface for sa entry

From: James Simmons
Date: Sun Sep 18 2016 - 16:59:16 EST


From: Lai Siyao <lai.siyao@xxxxxxxxx>

Rename ll_sa_entry to sa_entry, and manage sa_entry cache with
dcache-like interfaces.

sa_entry is not needed to be refcounted, because only scanner
can free it, so after it's put in stat list, statahead thread
shouldn't access it any longer.

ll_statahead_interpret() doesn't need to take sai refcount,
because statahead thread will wait for all inflight RPC to
finish.

Signed-off-by: Lai Siyao <lai.siyao@xxxxxxxxx>
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-3270
Reviewed-on: http://review.whamcloud.com/9664
Reviewed-by: James Simmons <uja.ornl@xxxxxxxxx>
Reviewed-by: Fan Yong <fan.yong@xxxxxxxxx>
Reviewed-by: Oleg Drokin <oleg.drokin@xxxxxxxxx>
Signed-off-by: James Simmons <jsimmons@xxxxxxxxxxxxx>
---
drivers/staging/lustre/lustre/include/obd.h | 2 +-
.../staging/lustre/lustre/llite/llite_internal.h | 10 +-
drivers/staging/lustre/lustre/llite/statahead.c | 461 +++++++++-----------
3 files changed, 207 insertions(+), 266 deletions(-)

diff --git a/drivers/staging/lustre/lustre/include/obd.h b/drivers/staging/lustre/lustre/include/obd.h
index 1c884c0..6758bf4 100644
--- a/drivers/staging/lustre/lustre/include/obd.h
+++ b/drivers/staging/lustre/lustre/include/obd.h
@@ -812,7 +812,7 @@ struct md_enqueue_info {
struct inode *mi_dir;
int (*mi_cb)(struct ptlrpc_request *req,
struct md_enqueue_info *minfo, int rc);
- __u64 mi_cbdata;
+ void *mi_cbdata;
};

struct obd_ops {
diff --git a/drivers/staging/lustre/lustre/llite/llite_internal.h b/drivers/staging/lustre/lustre/llite/llite_internal.h
index 9a9fefd..cd639f4 100644
--- a/drivers/staging/lustre/lustre/llite/llite_internal.h
+++ b/drivers/staging/lustre/lustre/llite/llite_internal.h
@@ -1131,10 +1131,12 @@ struct ll_statahead_info {
wait_queue_head_t sai_waitq; /* stat-ahead wait queue */
struct ptlrpc_thread sai_thread; /* stat-ahead thread */
struct ptlrpc_thread sai_agl_thread; /* AGL thread */
- struct list_head sai_entries; /* entry list */
- struct list_head sai_entries_received; /* entries returned */
- struct list_head sai_entries_stated; /* entries stated */
- struct list_head sai_entries_agl; /* AGL entries to be sent */
+ struct list_head sai_interim_entries; /* entries which got async
+ * stat reply, but not
+ * instantiated
+ */
+ struct list_head sai_entries; /* completed entries */
+ struct list_head sai_agls; /* AGLs to be sent */
struct list_head sai_cache[LL_SA_CACHE_SIZE];
spinlock_t sai_cache_lock[LL_SA_CACHE_SIZE];
atomic_t sai_cache_count; /* entry count in cache */
diff --git a/drivers/staging/lustre/lustre/llite/statahead.c b/drivers/staging/lustre/lustre/llite/statahead.c
index 5760974..d041720 100644
--- a/drivers/staging/lustre/lustre/llite/statahead.c
+++ b/drivers/staging/lustre/lustre/llite/statahead.c
@@ -49,24 +49,26 @@ enum se_stat {
SA_ENTRY_INIT = 0, /** init entry */
SA_ENTRY_SUCC = 1, /** stat succeed */
SA_ENTRY_INVA = 2, /** invalid entry */
- SA_ENTRY_DEST = 3, /** entry to be destroyed */
};

-struct ll_sa_entry {
- /* link into sai->sai_entries */
- struct list_head se_link;
- /* link into sai->sai_entries_{received,stated} */
+/*
+ * sa_entry is not refcounted: statahead thread allocates it and do async stat,
+ * and in async stat callback ll_statahead_interpret() will add it into
+ * sai_cb_entries, later statahead thread will call sa_handle_callback() to
+ * instantiate entry and move it into sai_entries, and then only scanner process
+ * can access and free it.
+ */
+struct sa_entry {
+ /* link into sai_cb_entries or sai_entries */
struct list_head se_list;
/* link into sai hash table locally */
struct list_head se_hash;
- /* entry reference count */
- atomic_t se_refcount;
/* entry index in the sai */
__u64 se_index;
/* low layer ldlm lock handle */
__u64 se_handle;
/* entry status */
- enum se_stat se_stat;
+ enum se_stat se_state;
/* entry size, contains name */
int se_size;
/* pointer to async getattr enqueue info */
@@ -85,13 +87,13 @@ static DEFINE_SPINLOCK(sai_generation_lock);
/*
* The entry only can be released by the caller, it is necessary to hold lock.
*/
-static inline int ll_sa_entry_stated(struct ll_sa_entry *entry)
+static inline int sa_ready(struct sa_entry *entry)
{
smp_rmb();
- return (entry->se_stat != SA_ENTRY_INIT);
+ return (entry->se_state != SA_ENTRY_INIT);
}

-static inline int ll_sa_entry_hash(int val)
+static inline int sa_hash(int val)
{
return val & LL_SA_CACHE_MASK;
}
@@ -100,9 +102,9 @@ static inline int ll_sa_entry_hash(int val)
* Insert entry to hash SA table.
*/
static inline void
-ll_sa_entry_enhash(struct ll_statahead_info *sai, struct ll_sa_entry *entry)
+sa_rehash(struct ll_statahead_info *sai, struct sa_entry *entry)
{
- int i = ll_sa_entry_hash(entry->se_qstr.hash);
+ int i = sa_hash(entry->se_qstr.hash);

spin_lock(&sai->sai_cache_lock[i]);
list_add_tail(&entry->se_hash, &sai->sai_cache[i]);
@@ -113,9 +115,9 @@ ll_sa_entry_enhash(struct ll_statahead_info *sai, struct ll_sa_entry *entry)
* Remove entry from SA table.
*/
static inline void
-ll_sa_entry_unhash(struct ll_statahead_info *sai, struct ll_sa_entry *entry)
+sa_unhash(struct ll_statahead_info *sai, struct sa_entry *entry)
{
- int i = ll_sa_entry_hash(entry->se_qstr.hash);
+ int i = sa_hash(entry->se_qstr.hash);

spin_lock(&sai->sai_cache_lock[i]);
list_del_init(&entry->se_hash);
@@ -133,14 +135,14 @@ static inline int sa_sent_full(struct ll_statahead_info *sai)
return atomic_read(&sai->sai_cache_count) >= sai->sai_max;
}

-static inline int sa_received_empty(struct ll_statahead_info *sai)
+static inline int sa_has_callback(struct ll_statahead_info *sai)
{
- return list_empty(&sai->sai_entries_received);
+ return !list_empty(&sai->sai_interim_entries);
}

static inline int agl_list_empty(struct ll_statahead_info *sai)
{
- return list_empty(&sai->sai_entries_agl);
+ return list_empty(&sai->sai_agls);
}

/**
@@ -168,17 +170,16 @@ static inline int is_omitted_entry(struct ll_statahead_info *sai, __u64 index)
/*
* Insert it into sai_entries tail when init.
*/
-static struct ll_sa_entry *
-ll_sa_entry_alloc(struct dentry *parent,
- struct ll_statahead_info *sai, __u64 index,
- const char *name, int len)
+static struct sa_entry *
+sa_alloc(struct dentry *parent, struct ll_statahead_info *sai, __u64 index,
+ const char *name, int len)
{
struct ll_inode_info *lli;
- struct ll_sa_entry *entry;
+ struct sa_entry *entry;
int entry_size;
char *dname;

- entry_size = sizeof(struct ll_sa_entry) + (len & ~3) + 4;
+ entry_size = sizeof(struct sa_entry) + (len & ~3) + 4;
entry = kzalloc(entry_size, GFP_NOFS);
if (unlikely(!entry))
return ERR_PTR(-ENOMEM);
@@ -187,34 +188,9 @@ ll_sa_entry_alloc(struct dentry *parent,
len, name, entry, index);

entry->se_index = index;
-
- /*
- * Statahead entry reference rules:
- *
- * 1) When statahead entry is initialized, its reference is set as 2.
- * One reference is used by the directory scanner. When the scanner
- * searches the statahead cache for the given name, it can perform
- * lockless hash lookup (only the scanner can remove entry from hash
- * list), and once found, it needn't to call "atomic_inc()" for the
- * entry reference. So the performance is improved. After using the
- * statahead entry, the scanner will call "atomic_dec()" to drop the
- * reference held when initialization. If it is the last reference,
- * the statahead entry will be freed.
- *
- * 2) All other threads, including statahead thread and ptlrpcd thread,
- * when they process the statahead entry, the reference for target
- * should be held to guarantee the entry will not be released by the
- * directory scanner. After processing the entry, these threads will
- * drop the entry reference. If it is the last reference, the entry
- * will be freed.
- *
- * The second reference when initializes the statahead entry is used
- * by the statahead thread, following the rule 2).
- */
- atomic_set(&entry->se_refcount, 2);
- entry->se_stat = SA_ENTRY_INIT;
+ entry->se_state = SA_ENTRY_INIT;
entry->se_size = entry_size;
- dname = (char *)entry + sizeof(struct ll_sa_entry);
+ dname = (char *)entry + sizeof(struct sa_entry);
memcpy(dname, name, len);
dname[len] = 0;

@@ -224,9 +200,8 @@ ll_sa_entry_alloc(struct dentry *parent,

lli = ll_i2info(sai->sai_inode);
spin_lock(&lli->lli_sa_lock);
- list_add_tail(&entry->se_link, &sai->sai_entries);
INIT_LIST_HEAD(&entry->se_list);
- ll_sa_entry_enhash(sai, entry);
+ sa_rehash(sai, entry);
spin_unlock(&lli->lli_sa_lock);

atomic_inc(&sai->sai_cache_count);
@@ -234,151 +209,130 @@ ll_sa_entry_alloc(struct dentry *parent,
return entry;
}

-/*
- * Used by the directory scanner to search entry with name.
- *
- * Only the caller can remove the entry from hash, so it is unnecessary to hold
- * hash lock. It is caller's duty to release the init refcount on the entry, so
- * it is also unnecessary to increase refcount on the entry.
- */
-static struct ll_sa_entry *
-ll_sa_entry_get_byname(struct ll_statahead_info *sai, const struct qstr *qstr)
+/* free sa_entry, which should have been unhashed and not in any list */
+static void sa_free(struct ll_statahead_info *sai, struct sa_entry *entry)
{
- struct ll_sa_entry *entry;
- int i = ll_sa_entry_hash(qstr->hash);
+ CDEBUG(D_READA, "free sa entry %.*s(%p) index %llu\n",
+ entry->se_qstr.len, entry->se_qstr.name, entry,
+ entry->se_index);

- list_for_each_entry(entry, &sai->sai_cache[i], se_hash) {
- if (entry->se_qstr.hash == qstr->hash &&
- entry->se_qstr.len == qstr->len &&
- memcmp(entry->se_qstr.name, qstr->name, qstr->len) == 0)
- return entry;
- }
- return NULL;
+ LASSERT(list_empty(&entry->se_list));
+ LASSERT(list_empty(&entry->se_hash));
+
+ kfree(entry);
+ atomic_dec(&sai->sai_cache_count);
}

/*
- * Used by the async getattr request callback to find entry with index.
- *
- * Inside lli_sa_lock to prevent others to change the list during the search.
- * It needs to increase entry refcount before returning to guarantee that the
- * entry cannot be freed by others.
+ * find sa_entry by name, used by directory scanner, lock is not needed because
+ * only scanner can remove the entry from cache.
*/
-static struct ll_sa_entry *
-ll_sa_entry_get_byindex(struct ll_statahead_info *sai, __u64 index)
+static struct sa_entry *
+sa_get(struct ll_statahead_info *sai, const struct qstr *qstr)
{
- struct ll_sa_entry *entry;
+ struct sa_entry *entry;
+ int i = sa_hash(qstr->hash);

- list_for_each_entry(entry, &sai->sai_entries, se_link) {
- if (entry->se_index == index) {
- LASSERT(atomic_read(&entry->se_refcount) > 0);
- atomic_inc(&entry->se_refcount);
+ list_for_each_entry(entry, &sai->sai_cache[i], se_hash) {
+ if (entry->se_qstr.hash == qstr->hash &&
+ entry->se_qstr.len == qstr->len &&
+ memcmp(entry->se_qstr.name, qstr->name, qstr->len) == 0)
return entry;
- }
- if (entry->se_index > index)
- break;
}
return NULL;
}

-static void ll_sa_entry_put(struct ll_statahead_info *sai,
- struct ll_sa_entry *entry)
-{
- if (atomic_dec_and_test(&entry->se_refcount)) {
- CDEBUG(D_READA, "free sa entry %.*s(%p) index %llu\n",
- entry->se_qstr.len, entry->se_qstr.name, entry,
- entry->se_index);
-
- LASSERT(list_empty(&entry->se_link));
- LASSERT(list_empty(&entry->se_list));
- LASSERT(list_empty(&entry->se_hash));
-
- iput(entry->se_inode);
-
- kfree(entry);
- atomic_dec(&sai->sai_cache_count);
- }
-}
-
+/* unhash and unlink sa_entry, and then free it */
static inline void
-do_sa_entry_fini(struct ll_statahead_info *sai, struct ll_sa_entry *entry)
+sa_kill(struct ll_statahead_info *sai, struct sa_entry *entry)
{
struct ll_inode_info *lli = ll_i2info(sai->sai_inode);

LASSERT(!list_empty(&entry->se_hash));
- LASSERT(!list_empty(&entry->se_link));
+ LASSERT(!list_empty(&entry->se_list));
+ LASSERT(sa_ready(entry));

- ll_sa_entry_unhash(sai, entry);
+ sa_unhash(sai, entry);

spin_lock(&lli->lli_sa_lock);
- entry->se_stat = SA_ENTRY_DEST;
- list_del_init(&entry->se_link);
- if (likely(!list_empty(&entry->se_list)))
- list_del_init(&entry->se_list);
+ list_del_init(&entry->se_list);
spin_unlock(&lli->lli_sa_lock);

- ll_sa_entry_put(sai, entry);
+ if (entry->se_inode)
+ iput(entry->se_inode);
+
+ sa_free(sai, entry);
}

-/*
- * Delete it from sai_entries_stated list when fini.
- */
+/* called by scanner after use, sa_entry will be killed */
static void
-ll_sa_entry_fini(struct ll_statahead_info *sai, struct ll_sa_entry *entry)
+sa_put(struct ll_statahead_info *sai, struct sa_entry *entry)
{
- struct ll_sa_entry *pos, *next;
+ struct sa_entry *tmp, *next;
+
+ if (entry && entry->se_state == SA_ENTRY_SUCC) {
+ struct ll_sb_info *sbi = ll_i2sbi(sai->sai_inode);
+
+ sai->sai_hit++;
+ sai->sai_consecutive_miss = 0;
+ sai->sai_max = min(2 * sai->sai_max, sbi->ll_sa_max);
+ } else {
+ sai->sai_miss++;
+ sai->sai_consecutive_miss++;
+ }

if (entry)
- do_sa_entry_fini(sai, entry);
+ sa_kill(sai, entry);

- /* drop old entry, only 'scanner' process does this, no need to lock */
- list_for_each_entry_safe(pos, next, &sai->sai_entries, se_link) {
- if (!is_omitted_entry(sai, pos->se_index))
+ /*
+ * kill old completed entries, only scanner process does this, no need
+ * to lock
+ */
+ list_for_each_entry_safe(tmp, next, &sai->sai_entries, se_list) {
+ if (!is_omitted_entry(sai, tmp->se_index))
break;
- /* keep those whose statahead RPC not finished */
- if (pos->se_stat == SA_ENTRY_SUCC ||
- pos->se_stat == SA_ENTRY_INVA)
- do_sa_entry_fini(sai, pos);
+ sa_kill(sai, tmp);
}
+ wake_up(&sai->sai_thread.t_ctl_waitq);
}

/*
- * Inside lli_sa_lock.
+ * update state and sort add entry to sai_entries by index, return true if
+ * scanner is waiting on this entry.
*/
-static void
-__sa_entry_post_stat(struct ll_statahead_info *sai, struct ll_sa_entry *entry,
- enum se_stat stat)
+static bool
+__sa_make_ready(struct ll_statahead_info *sai, struct sa_entry *entry, int ret)
{
- struct ll_sa_entry *se;
- struct list_head *pos = &sai->sai_entries_stated;
-
- LASSERT(entry->se_stat == SA_ENTRY_INIT);
+ struct list_head *pos = &sai->sai_entries;
+ __u64 index = entry->se_index;
+ struct sa_entry *se;

- if (!list_empty(&entry->se_list))
- list_del_init(&entry->se_list);
+ LASSERT(!sa_ready(entry));
+ LASSERT(list_empty(&entry->se_list));

- list_for_each_entry_reverse(se, &sai->sai_entries_stated, se_list) {
+ list_for_each_entry_reverse(se, &sai->sai_entries, se_list) {
if (se->se_index < entry->se_index) {
pos = &se->se_list;
break;
}
}
-
list_add(&entry->se_list, pos);
- entry->se_stat = stat;
+ entry->se_state = ret < 0 ? SA_ENTRY_INVA : SA_ENTRY_SUCC;
+
+ return (index == sai->sai_index_wait);
}

/*
- * Move entry to sai_entries_stated and sort with the index.
- * \retval 1 -- entry to be destroyed.
- * \retval 0 -- entry is inserted into stated list.
+ * release resources used in async stat RPC, update entry state and wakeup if
+ * scanner process it waiting on this entry.
*/
static void
-sa_entry_post_stat(struct ll_statahead_info *sai, struct ll_sa_entry *entry,
- enum se_stat stat)
+sa_make_ready(struct ll_statahead_info *sai, struct sa_entry *entry, int ret)
{
struct ll_inode_info *lli = ll_i2info(sai->sai_inode);
struct md_enqueue_info *minfo = entry->se_minfo;
struct ptlrpc_request *req = entry->se_req;
+ bool wakeup;

/* release resources used in RPC */
if (minfo) {
@@ -394,12 +348,15 @@ sa_entry_post_stat(struct ll_statahead_info *sai, struct ll_sa_entry *entry,
}

spin_lock(&lli->lli_sa_lock);
- __sa_entry_post_stat(sai, entry, stat);
+ wakeup = __sa_make_ready(sai, entry, ret);
spin_unlock(&lli->lli_sa_lock);
+
+ if (wakeup)
+ wake_up(&sai->sai_waitq);
}

/*
- * Insert inode into the list of sai_entries_agl.
+ * Insert inode into the list of sai_agls.
*/
static void ll_agl_add(struct ll_statahead_info *sai,
struct inode *inode, int index)
@@ -417,9 +374,9 @@ static void ll_agl_add(struct ll_statahead_info *sai,

igrab(inode);
spin_lock(&parent->lli_agl_lock);
- if (list_empty(&sai->sai_entries_agl))
+ if (list_empty(&sai->sai_agls))
added = 1;
- list_add_tail(&child->lli_agl_list, &sai->sai_entries_agl);
+ list_add_tail(&child->lli_agl_list, &sai->sai_agls);
spin_unlock(&parent->lli_agl_lock);
} else {
spin_unlock(&child->lli_agl_lock);
@@ -429,6 +386,7 @@ static void ll_agl_add(struct ll_statahead_info *sai,
wake_up(&sai->sai_agl_thread.t_ctl_waitq);
}

+/* allocate sai */
static struct ll_statahead_info *ll_sai_alloc(void)
{
struct ll_statahead_info *sai;
@@ -452,10 +410,9 @@ static struct ll_statahead_info *ll_sai_alloc(void)
init_waitqueue_head(&sai->sai_thread.t_ctl_waitq);
init_waitqueue_head(&sai->sai_agl_thread.t_ctl_waitq);

+ INIT_LIST_HEAD(&sai->sai_interim_entries);
INIT_LIST_HEAD(&sai->sai_entries);
- INIT_LIST_HEAD(&sai->sai_entries_received);
- INIT_LIST_HEAD(&sai->sai_entries_stated);
- INIT_LIST_HEAD(&sai->sai_entries_agl);
+ INIT_LIST_HEAD(&sai->sai_agls);

for (i = 0; i < LL_SA_CACHE_SIZE; i++) {
INIT_LIST_HEAD(&sai->sai_cache[i]);
@@ -486,7 +443,7 @@ static void ll_sai_put(struct ll_statahead_info *sai)

if (atomic_dec_and_lock(&sai->sai_refcount, &lli->lli_sa_lock)) {
struct ll_sb_info *sbi = ll_i2sbi(sai->sai_inode);
- struct ll_sa_entry *entry, *next;
+ struct sa_entry *entry, *next;

lli->lli_sai = NULL;
spin_unlock(&lli->lli_sa_lock);
@@ -494,14 +451,14 @@ static void ll_sai_put(struct ll_statahead_info *sai)
LASSERT(thread_is_stopped(&sai->sai_thread));
LASSERT(thread_is_stopped(&sai->sai_agl_thread));
LASSERT(sai->sai_sent == sai->sai_replied);
+ LASSERT(!sa_has_callback(sai));

list_for_each_entry_safe(entry, next, &sai->sai_entries,
- se_link)
- do_sa_entry_fini(sai, entry);
+ se_list)
+ sa_kill(sai, entry);

LASSERT(atomic_read(&sai->sai_cache_count) == 0);
- LASSERT(list_empty(&sai->sai_entries_agl));
- LASSERT(atomic_read(&sai->sai_refcount) == 0);
+ LASSERT(list_empty(&sai->sai_agls));

iput(sai->sai_inode);
kfree(sai);
@@ -509,7 +466,7 @@ static void ll_sai_put(struct ll_statahead_info *sai)
}
}

-/* Do NOT forget to drop inode refcount when into sai_entries_agl. */
+/* Do NOT forget to drop inode refcount when into sai_agls. */
static void ll_agl_trigger(struct inode *inode, struct ll_statahead_info *sai)
{
struct ll_inode_info *lli = ll_i2info(inode);
@@ -569,9 +526,12 @@ static void ll_agl_trigger(struct inode *inode, struct ll_statahead_info *sai)
iput(inode);
}

-/* prepare inode for received statahead entry, and add it into agl list */
-static void sa_post_one(struct ll_statahead_info *sai,
- struct ll_sa_entry *entry)
+/*
+ * prepare inode for sa entry, add it into agl list, now sa_entry is ready
+ * to be used by scanner process.
+ */
+static void sa_instantiate(struct ll_statahead_info *sai,
+ struct sa_entry *entry)
{
struct inode *dir = sai->sai_inode;
struct inode *child;
@@ -629,8 +589,9 @@ static void sa_post_one(struct ll_statahead_info *sai,
if (rc)
goto out;

- CDEBUG(D_DLMTRACE, "%s: setting l_data to inode "DFID"%p\n",
+ CDEBUG(D_READA, "%s: setting %.*s" DFID " l_data to inode %p\n",
ll_get_fsname(child->i_sb, NULL, 0),
+ entry->se_qstr.len, entry->se_qstr.name,
PFID(ll_inode2fid(child)), child);
ll_set_lock_data(ll_i2sbi(dir)->ll_md_exp, child, it, NULL);

@@ -640,45 +601,42 @@ static void sa_post_one(struct ll_statahead_info *sai,
ll_agl_add(sai, child, entry->se_index);

out:
- /* The "sa_entry_post_stat()" will drop related ldlm ibits lock
- * reference count by calling "ll_intent_drop_lock()" in spite of the
- * above operations failed or not. Do not worry about calling
- * "ll_intent_drop_lock()" more than once.
+ /*
+ * sa_make_ready() will drop ldlm ibits lock refcount by calling
+ * ll_intent_drop_lock() in spite of failures. Do not worry about
+ * calling ll_intent_drop_lock() more than once.
*/
- sa_entry_post_stat(sai, entry, rc < 0 ? SA_ENTRY_INVA : SA_ENTRY_SUCC);
- if (entry->se_index == sai->sai_index_wait)
- wake_up(&sai->sai_waitq);
- ll_sa_entry_put(sai, entry);
+ sa_make_ready(sai, entry, rc);
}

-static void ll_post_statahead(struct ll_statahead_info *sai)
+/* once there are async stat replies, instantiate sa_entry */
+static void sa_handle_callback(struct ll_statahead_info *sai)
{
struct ll_inode_info *lli;

lli = ll_i2info(sai->sai_inode);

- while (!sa_received_empty(sai)) {
- struct ll_sa_entry *entry;
+ while (sa_has_callback(sai)) {
+ struct sa_entry *entry;

spin_lock(&lli->lli_sa_lock);
- if (unlikely(sa_received_empty(sai))) {
+ if (unlikely(!sa_has_callback(sai))) {
spin_unlock(&lli->lli_sa_lock);
break;
}
- entry = list_entry(sai->sai_entries_received.next,
- struct ll_sa_entry, se_list);
- atomic_inc(&entry->se_refcount);
+ entry = list_entry(sai->sai_interim_entries.next,
+ struct sa_entry, se_list);
list_del_init(&entry->se_list);
spin_unlock(&lli->lli_sa_lock);

- sa_post_one(sai, entry);
+ sa_instantiate(sai, entry);
}

spin_lock(&lli->lli_agl_lock);
while (!agl_list_empty(sai)) {
struct ll_inode_info *clli;

- clli = list_entry(sai->sai_entries_agl.next,
+ clli = list_entry(sai->sai_agls.next,
struct ll_inode_info, lli_agl_list);
list_del_init(&clli->lli_agl_list);
spin_unlock(&lli->lli_agl_lock);
@@ -690,29 +648,38 @@ static void ll_post_statahead(struct ll_statahead_info *sai)
spin_unlock(&lli->lli_agl_lock);
}

+/*
+ * callback for async stat, because this is called in ptlrpcd context, we only
+ * put sa_entry in sai_cb_entries list, and let sa_handle_callback() to really
+ * prepare inode and instantiate sa_entry later.
+ */
static int ll_statahead_interpret(struct ptlrpc_request *req,
struct md_enqueue_info *minfo, int rc)
{
struct lookup_intent *it = &minfo->mi_it;
struct inode *dir = minfo->mi_dir;
struct ll_inode_info *lli = ll_i2info(dir);
- struct ll_statahead_info *sai = NULL;
- struct ll_sa_entry *entry;
- int wakeup;
+ struct ll_statahead_info *sai = lli->lli_sai;
+ struct sa_entry *entry = (struct sa_entry *)minfo->mi_cbdata;
+ bool wakeup;

if (it_disposition(it, DISP_LOOKUP_NEG))
rc = -ENOENT;

- sai = ll_sai_get(dir);
+ /*
+ * because statahead thread will wait for all inflight RPC to finish,
+ * 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",
+ entry->se_qstr.len, entry->se_qstr.name, rc);

spin_lock(&lli->lli_sa_lock);
- entry = ll_sa_entry_get_byindex(sai, minfo->mi_cbdata);
- LASSERT(entry);
if (rc) {
- __sa_entry_post_stat(sai, entry, SA_ENTRY_INVA);
- wakeup = (entry->se_index == sai->sai_index_wait);
+ wakeup = __sa_make_ready(sai, entry, rc);
} else {
entry->se_minfo = minfo;
entry->se_req = ptlrpc_request_addref(req);
@@ -724,27 +691,24 @@ static int ll_statahead_interpret(struct ptlrpc_request *req,
*/
entry->se_handle = it->it_lock_handle;
ll_intent_drop_lock(it);
- wakeup = sa_received_empty(sai);
- list_add_tail(&entry->se_list, &sai->sai_entries_received);
+ wakeup = !sa_has_callback(sai);
+ list_add_tail(&entry->se_list, &sai->sai_interim_entries);
}
sai->sai_replied++;
- spin_unlock(&lli->lli_sa_lock);

- ll_sa_entry_put(sai, entry);
if (wakeup)
wake_up(&sai->sai_thread.t_ctl_waitq);
+ spin_unlock(&lli->lli_sa_lock);

if (rc) {
ll_intent_release(it);
iput(dir);
kfree(minfo);
}
- if (sai)
- ll_sai_put(sai);
return rc;
}

-static void sa_args_fini(struct md_enqueue_info *minfo,
+static void sa_fini_data(struct md_enqueue_info *minfo,
struct ldlm_enqueue_info *einfo)
{
LASSERT(minfo && einfo);
@@ -756,8 +720,8 @@ static void sa_args_fini(struct md_enqueue_info *minfo,
/**
* prepare arguments for async stat RPC.
*/
-static int sa_args_init(struct inode *dir, struct inode *child,
- struct ll_sa_entry *entry, struct md_enqueue_info **pmi,
+static int sa_prep_data(struct inode *dir, struct inode *child,
+ struct sa_entry *entry, struct md_enqueue_info **pmi,
struct ldlm_enqueue_info **pei)
{
const struct qstr *qstr = &entry->se_qstr;
@@ -786,7 +750,7 @@ static int sa_args_init(struct inode *dir, struct inode *child,
minfo->mi_it.it_op = IT_GETATTR;
minfo->mi_dir = igrab(dir);
minfo->mi_cb = ll_statahead_interpret;
- minfo->mi_cbdata = entry->se_index;
+ minfo->mi_cbdata = entry;

einfo->ei_type = LDLM_IBITS;
einfo->ei_mode = it_to_lock_mode(&minfo->mi_it);
@@ -801,19 +765,19 @@ static int sa_args_init(struct inode *dir, struct inode *child,
return 0;
}

-static int do_sa_lookup(struct inode *dir, struct ll_sa_entry *entry)
+static int sa_lookup(struct inode *dir, struct sa_entry *entry)
{
struct md_enqueue_info *minfo;
struct ldlm_enqueue_info *einfo;
int rc;

- rc = sa_args_init(dir, NULL, entry, &minfo, &einfo);
+ rc = sa_prep_data(dir, NULL, entry, &minfo, &einfo);
if (rc)
return rc;

rc = md_intent_getattr_async(ll_i2mdexp(dir), minfo, einfo);
if (rc < 0)
- sa_args_fini(minfo, einfo);
+ sa_fini_data(minfo, einfo);

return rc;
}
@@ -824,8 +788,8 @@ static int do_sa_lookup(struct inode *dir, struct ll_sa_entry *entry)
* \retval 0 -- will send stat-ahead request
* \retval others -- prepare stat-ahead request failed
*/
-static int do_sa_revalidate(struct inode *dir, struct ll_sa_entry *entry,
- struct dentry *dentry)
+static int sa_revalidate(struct inode *dir, struct sa_entry *entry,
+ struct dentry *dentry)
{
struct inode *inode = d_inode(dentry);
struct lookup_intent it = { .it_op = IT_GETATTR,
@@ -849,7 +813,7 @@ static int do_sa_revalidate(struct inode *dir, struct ll_sa_entry *entry,
return 1;
}

- rc = sa_args_init(dir, inode, entry, &minfo, &einfo);
+ rc = sa_prep_data(dir, inode, entry, &minfo, &einfo);
if (rc) {
entry->se_inode = NULL;
iput(inode);
@@ -860,32 +824,30 @@ static int do_sa_revalidate(struct inode *dir, struct ll_sa_entry *entry,
if (rc < 0) {
entry->se_inode = NULL;
iput(inode);
- sa_args_fini(minfo, einfo);
+ sa_fini_data(minfo, einfo);
}

return rc;
}

-static void ll_statahead_one(struct dentry *parent, const char *name,
- const int name_len)
+static void sa_statahead(struct dentry *parent, const char *name, int len)
{
struct inode *dir = d_inode(parent);
struct ll_inode_info *lli = ll_i2info(dir);
struct ll_statahead_info *sai = lli->lli_sai;
struct dentry *dentry = NULL;
- struct ll_sa_entry *entry;
+ struct sa_entry *entry;
int rc;

- entry = ll_sa_entry_alloc(parent, sai, sai->sai_index, name,
- name_len);
+ entry = sa_alloc(parent, sai, sai->sai_index, name, len);
if (IS_ERR(entry))
return;

dentry = d_lookup(parent, &entry->se_qstr);
if (!dentry) {
- rc = do_sa_lookup(dir, entry);
+ rc = sa_lookup(dir, entry);
} else {
- rc = do_sa_revalidate(dir, entry, dentry);
+ rc = sa_revalidate(dir, entry, dentry);
if (rc == 1 && agl_should_run(sai, d_inode(dentry)))
ll_agl_add(sai, d_inode(dentry), entry->se_index);
}
@@ -893,18 +855,12 @@ static void ll_statahead_one(struct dentry *parent, const char *name,
if (dentry)
dput(dentry);

- if (rc) {
- sa_entry_post_stat(sai, entry,
- rc < 0 ? SA_ENTRY_INVA : SA_ENTRY_SUCC);
- if (entry->se_index == sai->sai_index_wait)
- wake_up(&sai->sai_waitq);
- } else {
+ if (rc)
+ sa_make_ready(sai, entry, rc);
+ else
sai->sai_sent++;
- }

sai->sai_index++;
- /* drop one refcount on entry by ll_sa_entry_alloc */
- ll_sa_entry_put(sai, entry);
}

static int ll_agl_thread(void *arg)
@@ -938,7 +894,7 @@ static int ll_agl_thread(void *arg)

while (1) {
l_wait_event(thread->t_ctl_waitq,
- !list_empty(&sai->sai_entries_agl) ||
+ !list_empty(&sai->sai_agls) ||
!thread_is_running(thread),
&lwi);

@@ -949,8 +905,8 @@ static int ll_agl_thread(void *arg)
/* The statahead thread maybe help to process AGL entries,
* so check whether list empty again.
*/
- if (!list_empty(&sai->sai_entries_agl)) {
- clli = list_entry(sai->sai_entries_agl.next,
+ if (!list_empty(&sai->sai_agls)) {
+ clli = list_entry(sai->sai_agls.next,
struct ll_inode_info, lli_agl_list);
list_del_init(&clli->lli_agl_list);
spin_unlock(&plli->lli_agl_lock);
@@ -962,8 +918,8 @@ static int ll_agl_thread(void *arg)

spin_lock(&plli->lli_agl_lock);
sai->sai_agl_valid = 0;
- while (!list_empty(&sai->sai_entries_agl)) {
- clli = list_entry(sai->sai_entries_agl.next,
+ while (!list_empty(&sai->sai_agls)) {
+ clli = list_entry(sai->sai_agls.next,
struct ll_inode_info, lli_agl_list);
list_del_init(&clli->lli_agl_list);
spin_unlock(&plli->lli_agl_lock);
@@ -1118,15 +1074,15 @@ static int ll_statahead_thread(void *arg)
do {
l_wait_event(thread->t_ctl_waitq,
!sa_sent_full(sai) ||
- !list_empty(&sai->sai_entries_received) ||
- !list_empty(&sai->sai_entries_agl) ||
+ sa_has_callback(sai) ||
+ !list_empty(&sai->sai_agls) ||
!thread_is_running(thread),
&lwi);
- ll_post_statahead(sai);
+ sa_handle_callback(sai);
} while (sa_sent_full(sai) &&
thread_is_running(thread));

- ll_statahead_one(parent, name, namelen);
+ sa_statahead(parent, name, namelen);
}

pos = le64_to_cpu(dp->ldp_hash_end);
@@ -1158,12 +1114,12 @@ static int ll_statahead_thread(void *arg)
*/
while (thread_is_running(thread)) {
l_wait_event(thread->t_ctl_waitq,
- !sa_received_empty(sai) ||
+ sa_has_callback(sai) ||
!agl_list_empty(sai) ||
!thread_is_running(thread),
&lwi);

- ll_post_statahead(sai);
+ sa_handle_callback(sai);
}
out:
if (sai->sai_agl_valid) {
@@ -1193,8 +1149,8 @@ out:
sai->sai_sent == sai->sai_replied, &lwi);
}

- /* release resources held by received entries. */
- ll_post_statahead(sai);
+ /* release resources held by statahead RPCs */
+ sa_handle_callback(sai);

spin_lock(&lli->lli_sa_lock);
thread_set_flags(thread, SVC_STOPPED);
@@ -1251,7 +1207,7 @@ void ll_deauthorize_statahead(struct inode *dir, void *key)
if (sai && thread_is_running(&sai->sai_thread)) {
/*
* statahead thread may not quit yet because it needs to cache
- * stated entries, now it's time to tell it to quit.
+ * 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);
@@ -1389,29 +1345,12 @@ out:
return rc;
}

-static void
-ll_sai_unplug(struct ll_statahead_info *sai, struct ll_sa_entry *entry)
-{
- if (entry && entry->se_stat == SA_ENTRY_SUCC) {
- struct ll_sb_info *sbi = ll_i2sbi(sai->sai_inode);
-
- sai->sai_hit++;
- sai->sai_consecutive_miss = 0;
- sai->sai_max = min(2 * sai->sai_max, sbi->ll_sa_max);
- } else {
- sai->sai_miss++;
- sai->sai_consecutive_miss++;
- }
- ll_sa_entry_fini(sai, entry);
- wake_up(&sai->sai_thread.t_ctl_waitq);
-}
-
static int revalidate_statahead_dentry(struct inode *dir,
struct ll_statahead_info *sai,
struct dentry **dentryp,
int only_unplug)
{
- struct ll_sa_entry *entry = NULL;
+ struct sa_entry *entry = NULL;
struct l_wait_info lwi = { 0 };
int rc = 0;

@@ -1442,31 +1381,31 @@ static int revalidate_statahead_dentry(struct inode *dir,
}
}

- entry = ll_sa_entry_get_byname(sai, &(*dentryp)->d_name);
+ entry = sa_get(sai, &(*dentryp)->d_name);
if (!entry || only_unplug) {
- ll_sai_unplug(sai, entry);
+ sa_put(sai, entry);
return entry ? 1 : -EAGAIN;
}

/* if statahead is busy in readdir, help it do post-work */
- if (!ll_sa_entry_stated(entry) && sai->sai_in_readpage)
- ll_post_statahead(sai);
+ if (!sa_ready(entry) && sai->sai_in_readpage)
+ sa_handle_callback(sai);

- if (!ll_sa_entry_stated(entry)) {
+ if (!sa_ready(entry)) {
sai->sai_index_wait = entry->se_index;
lwi = LWI_TIMEOUT_INTR(cfs_time_seconds(30), NULL,
LWI_ON_SIGNAL_NOOP, NULL);
rc = l_wait_event(sai->sai_waitq,
- ll_sa_entry_stated(entry) ||
+ sa_ready(entry) ||
thread_is_stopped(&sai->sai_thread),
&lwi);
if (rc < 0) {
- ll_sai_unplug(sai, entry);
+ sa_put(sai, entry);
return -EAGAIN;
}
}

- if (entry->se_stat == SA_ENTRY_SUCC && entry->se_inode) {
+ if (entry->se_state == SA_ENTRY_SUCC && entry->se_inode) {
struct inode *inode = entry->se_inode;
struct lookup_intent it = { .it_op = IT_GETATTR,
.it_lock_handle = entry->se_handle };
@@ -1480,7 +1419,7 @@ static int revalidate_statahead_dentry(struct inode *dir,

alias = ll_splice_alias(inode, *dentryp);
if (IS_ERR(alias)) {
- ll_sai_unplug(sai, entry);
+ sa_put(sai, entry);
return PTR_ERR(alias);
}
*dentryp = alias;
@@ -1507,7 +1446,7 @@ static int revalidate_statahead_dentry(struct inode *dir,
}
}
out_unplug:
- ll_sai_unplug(sai, entry);
+ sa_put(sai, entry);
return rc;
}

--
1.7.1