diff options
| -rw-r--r-- | fs/dcache.c | 100 | ||||
| -rw-r--r-- | fs/internal.h | 2 |
2 files changed, 85 insertions, 17 deletions
diff --git a/fs/dcache.c b/fs/dcache.c index c435398f2c81..01b8cae41a71 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -861,6 +861,32 @@ void dput(struct dentry *dentry) } EXPORT_SYMBOL(dput); +static void __dput_to_list(struct dentry *dentry, struct list_head *list) +__must_hold(&dentry->d_lock) +{ + if (dentry->d_flags & DCACHE_SHRINK_LIST) { + /* let the owner of the list it's on deal with it */ + --dentry->d_lockref.count; + } else { + if (dentry->d_flags & DCACHE_LRU_LIST) + d_lru_del(dentry); + if (!--dentry->d_lockref.count) + d_shrink_add(dentry, list); + } +} + +void dput_to_list(struct dentry *dentry, struct list_head *list) +{ + rcu_read_lock(); + if (likely(fast_dput(dentry))) { + rcu_read_unlock(); + return; + } + rcu_read_unlock(); + if (!retain_dentry(dentry)) + __dput_to_list(dentry, list); + spin_unlock(&dentry->d_lock); +} /* This must be called with d_lock held */ static inline void __dget_dlock(struct dentry *dentry) @@ -1067,7 +1093,7 @@ out: return false; } -static void shrink_dentry_list(struct list_head *list) +void shrink_dentry_list(struct list_head *list) { while (!list_empty(list)) { struct dentry *dentry, *parent; @@ -1089,18 +1115,9 @@ static void shrink_dentry_list(struct list_head *list) rcu_read_unlock(); d_shrink_del(dentry); parent = dentry->d_parent; + if (parent != dentry) + __dput_to_list(parent, list); __dentry_kill(dentry); - if (parent == dentry) - continue; - /* - * We need to prune ancestors too. This is necessary to prevent - * quadratic behavior of shrink_dcache_parent(), but is also - * expected to be beneficial in reducing dentry cache - * fragmentation. - */ - dentry = parent; - while (dentry && !lockref_put_or_lock(&dentry->d_lockref)) - dentry = dentry_kill(dentry); } } @@ -1445,8 +1462,11 @@ out: struct select_data { struct dentry *start; + union { + long found; + struct dentry *victim; + }; struct list_head dispose; - int found; }; static enum d_walk_ret select_collect(void *_data, struct dentry *dentry) @@ -1478,6 +1498,37 @@ out: return ret; } +static enum d_walk_ret select_collect2(void *_data, struct dentry *dentry) +{ + struct select_data *data = _data; + enum d_walk_ret ret = D_WALK_CONTINUE; + + if (data->start == dentry) + goto out; + + if (dentry->d_flags & DCACHE_SHRINK_LIST) { + if (!dentry->d_lockref.count) { + rcu_read_lock(); + data->victim = dentry; + return D_WALK_QUIT; + } + } else { + if (dentry->d_flags & DCACHE_LRU_LIST) + d_lru_del(dentry); + if (!dentry->d_lockref.count) + d_shrink_add(dentry, &data->dispose); + } + /* + * We can return to the caller if we have found some (this + * ensures forward progress). We'll be coming back to find + * the rest. + */ + if (!list_empty(&data->dispose)) + ret = need_resched() ? D_WALK_QUIT : D_WALK_NORETRY; +out: + return ret; +} + /** * shrink_dcache_parent - prune dcache * @parent: parent of entries to prune @@ -1487,12 +1538,9 @@ out: void shrink_dcache_parent(struct dentry *parent) { for (;;) { - struct select_data data; + struct select_data data = {.start = parent}; INIT_LIST_HEAD(&data.dispose); - data.start = parent; - data.found = 0; - d_walk(parent, &data, select_collect); if (!list_empty(&data.dispose)) { @@ -1503,6 +1551,24 @@ void shrink_dcache_parent(struct dentry *parent) cond_resched(); if (!data.found) break; + data.victim = NULL; + d_walk(parent, &data, select_collect2); + if (data.victim) { + struct dentry *parent; + spin_lock(&data.victim->d_lock); + if (!shrink_lock_dentry(data.victim)) { + spin_unlock(&data.victim->d_lock); + rcu_read_unlock(); + } else { + rcu_read_unlock(); + parent = data.victim->d_parent; + if (parent != data.victim) + __dput_to_list(parent, &data.dispose); + __dentry_kill(data.victim); + } + } + if (!list_empty(&data.dispose)) + shrink_dentry_list(&data.dispose); } } EXPORT_SYMBOL(shrink_dcache_parent); diff --git a/fs/internal.h b/fs/internal.h index a48ef81be37d..dc317abe31b5 100644 --- a/fs/internal.h +++ b/fs/internal.h @@ -156,6 +156,8 @@ extern int d_set_mounted(struct dentry *dentry); extern long prune_dcache_sb(struct super_block *sb, struct shrink_control *sc); extern struct dentry *d_alloc_cursor(struct dentry *); extern struct dentry * d_alloc_pseudo(struct super_block *, const struct qstr *); +extern void dput_to_list(struct dentry *, struct list_head *); +extern void shrink_dentry_list(struct list_head *); /* * read_write.c |