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-rw-r--r--fs/fscache/cookie.c218
-rw-r--r--fs/fscache/internal.h5
-rw-r--r--fs/fscache/stats.c12
3 files changed, 234 insertions, 1 deletions
diff --git a/fs/fscache/cookie.c b/fs/fscache/cookie.c
index 336046de08ee..2f5ee717f2bb 100644
--- a/fs/fscache/cookie.c
+++ b/fs/fscache/cookie.c
@@ -15,6 +15,8 @@
struct kmem_cache *fscache_cookie_jar;
+static void fscache_cookie_lru_timed_out(struct timer_list *timer);
+static void fscache_cookie_lru_worker(struct work_struct *work);
static void fscache_cookie_worker(struct work_struct *work);
static void fscache_unhash_cookie(struct fscache_cookie *cookie);
@@ -22,7 +24,12 @@ static void fscache_unhash_cookie(struct fscache_cookie *cookie);
static struct hlist_bl_head fscache_cookie_hash[1 << fscache_cookie_hash_shift];
static LIST_HEAD(fscache_cookies);
static DEFINE_RWLOCK(fscache_cookies_lock);
-static const char fscache_cookie_states[FSCACHE_COOKIE_STATE__NR] = "-LCAFWRD";
+static LIST_HEAD(fscache_cookie_lru);
+static DEFINE_SPINLOCK(fscache_cookie_lru_lock);
+DEFINE_TIMER(fscache_cookie_lru_timer, fscache_cookie_lru_timed_out);
+static DECLARE_WORK(fscache_cookie_lru_work, fscache_cookie_lru_worker);
+static const char fscache_cookie_states[FSCACHE_COOKIE_STATE__NR] = "-LCAFUWRD";
+unsigned int fscache_lru_cookie_timeout = 10 * HZ;
void fscache_print_cookie(struct fscache_cookie *cookie, char prefix)
{
@@ -47,6 +54,14 @@ void fscache_print_cookie(struct fscache_cookie *cookie, char prefix)
static void fscache_free_cookie(struct fscache_cookie *cookie)
{
+ if (WARN_ON_ONCE(!list_empty(&cookie->commit_link))) {
+ spin_lock(&fscache_cookie_lru_lock);
+ list_del_init(&cookie->commit_link);
+ spin_unlock(&fscache_cookie_lru_lock);
+ fscache_stat_d(&fscache_n_cookies_lru);
+ fscache_stat(&fscache_n_cookies_lru_removed);
+ }
+
if (WARN_ON_ONCE(test_bit(FSCACHE_COOKIE_IS_HASHED, &cookie->flags))) {
fscache_print_cookie(cookie, 'F');
return;
@@ -499,6 +514,126 @@ out:
}
/*
+ * Begin the process of looking up a cookie. We offload the actual process to
+ * a worker thread.
+ */
+static bool fscache_begin_lookup(struct fscache_cookie *cookie, bool will_modify)
+{
+ if (will_modify) {
+ set_bit(FSCACHE_COOKIE_LOCAL_WRITE, &cookie->flags);
+ set_bit(FSCACHE_COOKIE_DO_PREP_TO_WRITE, &cookie->flags);
+ }
+ if (!fscache_begin_volume_access(cookie->volume, cookie,
+ fscache_access_lookup_cookie))
+ return false;
+
+ __fscache_begin_cookie_access(cookie, fscache_access_lookup_cookie);
+ __fscache_set_cookie_state(cookie, FSCACHE_COOKIE_STATE_LOOKING_UP);
+ set_bit(FSCACHE_COOKIE_IS_CACHING, &cookie->flags);
+ set_bit(FSCACHE_COOKIE_HAS_BEEN_CACHED, &cookie->flags);
+ return true;
+}
+
+/*
+ * Start using the cookie for I/O. This prevents the backing object from being
+ * reaped by VM pressure.
+ */
+void __fscache_use_cookie(struct fscache_cookie *cookie, bool will_modify)
+{
+ enum fscache_cookie_state state;
+ bool queue = false;
+
+ _enter("c=%08x", cookie->debug_id);
+
+ if (WARN(test_bit(FSCACHE_COOKIE_RELINQUISHED, &cookie->flags),
+ "Trying to use relinquished cookie\n"))
+ return;
+
+ spin_lock(&cookie->lock);
+
+ atomic_inc(&cookie->n_active);
+
+again:
+ state = fscache_cookie_state(cookie);
+ switch (state) {
+ case FSCACHE_COOKIE_STATE_QUIESCENT:
+ queue = fscache_begin_lookup(cookie, will_modify);
+ break;
+
+ case FSCACHE_COOKIE_STATE_LOOKING_UP:
+ case FSCACHE_COOKIE_STATE_CREATING:
+ if (will_modify)
+ set_bit(FSCACHE_COOKIE_LOCAL_WRITE, &cookie->flags);
+ break;
+ case FSCACHE_COOKIE_STATE_ACTIVE:
+ if (will_modify &&
+ !test_and_set_bit(FSCACHE_COOKIE_LOCAL_WRITE, &cookie->flags)) {
+ set_bit(FSCACHE_COOKIE_DO_PREP_TO_WRITE, &cookie->flags);
+ queue = true;
+ }
+ break;
+
+ case FSCACHE_COOKIE_STATE_FAILED:
+ case FSCACHE_COOKIE_STATE_WITHDRAWING:
+ break;
+
+ case FSCACHE_COOKIE_STATE_LRU_DISCARDING:
+ spin_unlock(&cookie->lock);
+ wait_var_event(&cookie->state,
+ fscache_cookie_state(cookie) !=
+ FSCACHE_COOKIE_STATE_LRU_DISCARDING);
+ spin_lock(&cookie->lock);
+ goto again;
+
+ case FSCACHE_COOKIE_STATE_DROPPED:
+ case FSCACHE_COOKIE_STATE_RELINQUISHING:
+ WARN(1, "Can't use cookie in state %u\n", state);
+ break;
+ }
+
+ spin_unlock(&cookie->lock);
+ if (queue)
+ fscache_queue_cookie(cookie, fscache_cookie_get_use_work);
+ _leave("");
+}
+EXPORT_SYMBOL(__fscache_use_cookie);
+
+static void fscache_unuse_cookie_locked(struct fscache_cookie *cookie)
+{
+ clear_bit(FSCACHE_COOKIE_DISABLED, &cookie->flags);
+ if (!test_bit(FSCACHE_COOKIE_IS_CACHING, &cookie->flags))
+ return;
+
+ cookie->unused_at = jiffies;
+ spin_lock(&fscache_cookie_lru_lock);
+ if (list_empty(&cookie->commit_link)) {
+ fscache_get_cookie(cookie, fscache_cookie_get_lru);
+ fscache_stat(&fscache_n_cookies_lru);
+ }
+ list_move_tail(&cookie->commit_link, &fscache_cookie_lru);
+
+ spin_unlock(&fscache_cookie_lru_lock);
+ timer_reduce(&fscache_cookie_lru_timer,
+ jiffies + fscache_lru_cookie_timeout);
+}
+
+/*
+ * Stop using the cookie for I/O.
+ */
+void __fscache_unuse_cookie(struct fscache_cookie *cookie,
+ const void *aux_data, const loff_t *object_size)
+{
+ if (aux_data || object_size)
+ __fscache_update_cookie(cookie, aux_data, object_size);
+
+ if (atomic_dec_and_lock(&cookie->n_active, &cookie->lock)) {
+ fscache_unuse_cookie_locked(cookie);
+ spin_unlock(&cookie->lock);
+ }
+}
+EXPORT_SYMBOL(__fscache_unuse_cookie);
+
+/*
* Perform work upon the cookie, such as committing its cache state,
* relinquishing it or withdrawing the backing cache. We're protected from the
* cache going away under us as object withdrawal must come through this
@@ -542,6 +677,12 @@ again_locked:
fscache_prepare_to_write(cookie);
spin_lock(&cookie->lock);
}
+ if (test_bit(FSCACHE_COOKIE_DO_LRU_DISCARD, &cookie->flags)) {
+ __fscache_set_cookie_state(cookie,
+ FSCACHE_COOKIE_STATE_LRU_DISCARDING);
+ wake = true;
+ goto again_locked;
+ }
fallthrough;
case FSCACHE_COOKIE_STATE_FAILED:
@@ -561,6 +702,7 @@ again_locked:
}
break;
+ case FSCACHE_COOKIE_STATE_LRU_DISCARDING:
case FSCACHE_COOKIE_STATE_RELINQUISHING:
case FSCACHE_COOKIE_STATE_WITHDRAWING:
if (cookie->cache_priv) {
@@ -577,6 +719,9 @@ again_locked:
FSCACHE_COOKIE_STATE_DROPPED);
wake = true;
goto out;
+ case FSCACHE_COOKIE_STATE_LRU_DISCARDING:
+ fscache_see_cookie(cookie, fscache_cookie_see_lru_discard);
+ break;
case FSCACHE_COOKIE_STATE_WITHDRAWING:
fscache_see_cookie(cookie, fscache_cookie_see_withdraw);
break;
@@ -639,6 +784,76 @@ static void __fscache_withdraw_cookie(struct fscache_cookie *cookie)
fscache_queue_cookie(cookie, fscache_cookie_get_end_access);
}
+static void fscache_cookie_lru_do_one(struct fscache_cookie *cookie)
+{
+ fscache_see_cookie(cookie, fscache_cookie_see_lru_do_one);
+
+ spin_lock(&cookie->lock);
+ if (cookie->state != FSCACHE_COOKIE_STATE_ACTIVE ||
+ time_before(jiffies, cookie->unused_at + fscache_lru_cookie_timeout) ||
+ atomic_read(&cookie->n_active) > 0) {
+ spin_unlock(&cookie->lock);
+ fscache_stat(&fscache_n_cookies_lru_removed);
+ } else {
+ set_bit(FSCACHE_COOKIE_DO_LRU_DISCARD, &cookie->flags);
+ spin_unlock(&cookie->lock);
+ fscache_stat(&fscache_n_cookies_lru_expired);
+ _debug("lru c=%x", cookie->debug_id);
+ __fscache_withdraw_cookie(cookie);
+ }
+
+ fscache_put_cookie(cookie, fscache_cookie_put_lru);
+}
+
+static void fscache_cookie_lru_worker(struct work_struct *work)
+{
+ struct fscache_cookie *cookie;
+ unsigned long unused_at;
+
+ spin_lock(&fscache_cookie_lru_lock);
+
+ while (!list_empty(&fscache_cookie_lru)) {
+ cookie = list_first_entry(&fscache_cookie_lru,
+ struct fscache_cookie, commit_link);
+ unused_at = cookie->unused_at + fscache_lru_cookie_timeout;
+ if (time_before(jiffies, unused_at)) {
+ timer_reduce(&fscache_cookie_lru_timer, unused_at);
+ break;
+ }
+
+ list_del_init(&cookie->commit_link);
+ fscache_stat_d(&fscache_n_cookies_lru);
+ spin_unlock(&fscache_cookie_lru_lock);
+ fscache_cookie_lru_do_one(cookie);
+ spin_lock(&fscache_cookie_lru_lock);
+ }
+
+ spin_unlock(&fscache_cookie_lru_lock);
+}
+
+static void fscache_cookie_lru_timed_out(struct timer_list *timer)
+{
+ queue_work(fscache_wq, &fscache_cookie_lru_work);
+}
+
+static void fscache_cookie_drop_from_lru(struct fscache_cookie *cookie)
+{
+ bool need_put = false;
+
+ if (!list_empty(&cookie->commit_link)) {
+ spin_lock(&fscache_cookie_lru_lock);
+ if (!list_empty(&cookie->commit_link)) {
+ list_del_init(&cookie->commit_link);
+ fscache_stat_d(&fscache_n_cookies_lru);
+ fscache_stat(&fscache_n_cookies_lru_dropped);
+ need_put = true;
+ }
+ spin_unlock(&fscache_cookie_lru_lock);
+ if (need_put)
+ fscache_put_cookie(cookie, fscache_cookie_put_lru);
+ }
+}
+
/*
* Remove a cookie from the hash table.
*/
@@ -659,6 +874,7 @@ static void fscache_unhash_cookie(struct fscache_cookie *cookie)
static void fscache_drop_withdraw_cookie(struct fscache_cookie *cookie)
{
+ fscache_cookie_drop_from_lru(cookie);
__fscache_withdraw_cookie(cookie);
}
diff --git a/fs/fscache/internal.h b/fs/fscache/internal.h
index e0d8ef212e82..ca938e00eaa0 100644
--- a/fs/fscache/internal.h
+++ b/fs/fscache/internal.h
@@ -57,6 +57,7 @@ static inline bool fscache_set_cache_state_maybe(struct fscache_cache *cache,
*/
extern struct kmem_cache *fscache_cookie_jar;
extern const struct seq_operations fscache_cookies_seq_ops;
+extern struct timer_list fscache_cookie_lru_timer;
extern void fscache_print_cookie(struct fscache_cookie *cookie, char prefix);
extern bool fscache_begin_cookie_access(struct fscache_cookie *cookie,
@@ -95,6 +96,10 @@ extern atomic_t fscache_n_volumes;
extern atomic_t fscache_n_volumes_collision;
extern atomic_t fscache_n_volumes_nomem;
extern atomic_t fscache_n_cookies;
+extern atomic_t fscache_n_cookies_lru;
+extern atomic_t fscache_n_cookies_lru_expired;
+extern atomic_t fscache_n_cookies_lru_removed;
+extern atomic_t fscache_n_cookies_lru_dropped;
extern atomic_t fscache_n_acquires;
extern atomic_t fscache_n_acquires_ok;
diff --git a/fs/fscache/stats.c b/fs/fscache/stats.c
index 252e883ae148..5aa4bd9fe207 100644
--- a/fs/fscache/stats.c
+++ b/fs/fscache/stats.c
@@ -17,6 +17,10 @@ atomic_t fscache_n_volumes;
atomic_t fscache_n_volumes_collision;
atomic_t fscache_n_volumes_nomem;
atomic_t fscache_n_cookies;
+atomic_t fscache_n_cookies_lru;
+atomic_t fscache_n_cookies_lru_expired;
+atomic_t fscache_n_cookies_lru_removed;
+atomic_t fscache_n_cookies_lru_dropped;
atomic_t fscache_n_acquires;
atomic_t fscache_n_acquires_ok;
@@ -47,6 +51,14 @@ int fscache_stats_show(struct seq_file *m, void *v)
atomic_read(&fscache_n_acquires_ok),
atomic_read(&fscache_n_acquires_oom));
+ seq_printf(m, "LRU : n=%u exp=%u rmv=%u drp=%u at=%ld\n",
+ atomic_read(&fscache_n_cookies_lru),
+ atomic_read(&fscache_n_cookies_lru_expired),
+ atomic_read(&fscache_n_cookies_lru_removed),
+ atomic_read(&fscache_n_cookies_lru_dropped),
+ timer_pending(&fscache_cookie_lru_timer) ?
+ fscache_cookie_lru_timer.expires - jiffies : 0);
+
seq_printf(m, "Updates: n=%u\n",
atomic_read(&fscache_n_updates));
generated by cgit v1.2.3 (git 2.39.0) at 2024-07-31 01:04:21 +0300