From: npiggin@suse.de
To: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [patch 12/14] fs: dcache per-bucket dcache hash locking
Date: Mon, 30 Mar 2009 02:55:51 +1100 [thread overview]
Message-ID: <20090329155750.062096365@nick.local0.net> (raw)
In-Reply-To: <20090329155539.275927173@nick.local0.net>
[-- Attachment #1: dcache-chain-hashlock.patch --]
[-- Type: text/plain, Size: 10010 bytes --]
We can turn the dcache hash locking from a global dcache_hash_lock into
per-bucket locking.
---
fs/dcache.c | 150 +++++++++++++++++++++++++++++--------------------
include/linux/dcache.h | 20 ------
2 files changed, 92 insertions(+), 78 deletions(-)
Index: linux-2.6/fs/dcache.c
===================================================================
--- linux-2.6.orig/fs/dcache.c
+++ linux-2.6/fs/dcache.c
@@ -38,7 +38,7 @@
* Usage:
* dcache_inode_lock protects:
* - the inode alias lists, d_inode
- * dcache_hash_lock protects:
+ * dcache_hash_bucket->lock protects:
* - the dcache hash table
* dcache_lru_lock protects:
* - the dcache lru lists and counters
@@ -53,18 +53,16 @@
* dcache_inode_lock
* dentry->d_lock
* dcache_lru_lock
- * dcache_hash_lock
+ * dcache_hash_bucket->lock
*/
int sysctl_vfs_cache_pressure __read_mostly = 100;
EXPORT_SYMBOL_GPL(sysctl_vfs_cache_pressure);
__cacheline_aligned_in_smp DEFINE_SPINLOCK(dcache_inode_lock);
-__cacheline_aligned_in_smp DEFINE_SPINLOCK(dcache_hash_lock);
__cacheline_aligned_in_smp DEFINE_SPINLOCK(dcache_lru_lock);
__cacheline_aligned_in_smp DEFINE_SEQLOCK(rename_lock);
EXPORT_SYMBOL(dcache_inode_lock);
-EXPORT_SYMBOL(dcache_hash_lock);
static struct kmem_cache *dentry_cache __read_mostly;
@@ -83,7 +81,12 @@ static struct kmem_cache *dentry_cache _
static unsigned int d_hash_mask __read_mostly;
static unsigned int d_hash_shift __read_mostly;
-static struct hlist_head *dentry_hashtable __read_mostly;
+
+struct dcache_hash_bucket {
+ spinlock_t lock;
+ struct hlist_head head;
+};
+static struct dcache_hash_bucket *dentry_hashtable __read_mostly;
/* Statistics gathering. */
struct dentry_stat_t dentry_stat = {
@@ -91,6 +94,14 @@ struct dentry_stat_t dentry_stat = {
.age_limit = 45,
};
+static inline struct dcache_hash_bucket *d_hash(struct dentry *parent,
+ unsigned long hash)
+{
+ hash += ((unsigned long) parent ^ GOLDEN_RATIO_PRIME) / L1_CACHE_BYTES;
+ hash = hash ^ ((hash ^ GOLDEN_RATIO_PRIME) >> D_HASHBITS);
+ return dentry_hashtable + (hash & D_HASHMASK);
+}
+
static void __d_free(struct dentry *dentry)
{
WARN_ON(!list_empty(&dentry->d_alias));
@@ -230,6 +241,51 @@ static struct dentry *d_kill(struct dent
return parent;
}
+void __d_drop(struct dentry *dentry)
+{
+ if (!(dentry->d_flags & DCACHE_UNHASHED)) {
+ struct dcache_hash_bucket *b;
+ b = d_hash(dentry->d_parent, dentry->d_name.hash);
+ dentry->d_flags |= DCACHE_UNHASHED;
+ spin_lock(&b->lock);
+ hlist_del_rcu(&dentry->d_hash);
+ spin_unlock(&b->lock);
+ }
+}
+
+void d_drop(struct dentry *dentry)
+{
+ spin_lock(&dentry->d_lock);
+ __d_drop(dentry);
+ spin_unlock(&dentry->d_lock);
+}
+
+/* This should be called _only_ with dcache_lock held */
+static inline struct dentry * __dget_locked_dlock(struct dentry *dentry)
+{
+ dentry->d_count++;
+ dentry_lru_del_init(dentry);
+ return dentry;
+}
+
+static inline struct dentry * __dget_locked(struct dentry *dentry)
+{
+ spin_lock(&dentry->d_lock);
+ __dget_locked_dlock(dentry);
+ spin_lock(&dentry->d_lock);
+ return dentry;
+}
+
+struct dentry * dget_locked(struct dentry *dentry)
+{
+ return __dget_locked(dentry);
+}
+
+struct dentry * dget_locked_dlock(struct dentry *dentry)
+{
+ return __dget_locked_dlock(dentry);
+}
+
/*
* This is dput
*
@@ -378,31 +434,6 @@ int d_invalidate(struct dentry * dentry)
return 0;
}
-static inline struct dentry * __dget_locked_dlock(struct dentry *dentry)
-{
- dentry->d_count++;
- dentry_lru_del_init(dentry);
- return dentry;
-}
-
-static inline struct dentry * __dget_locked(struct dentry *dentry)
-{
- spin_lock(&dentry->d_lock);
- __dget_locked_dlock(dentry);
- spin_lock(&dentry->d_lock);
- return dentry;
-}
-
-struct dentry * dget_locked(struct dentry *dentry)
-{
- return __dget_locked(dentry);
-}
-
-struct dentry * dget_locked_dlock(struct dentry *dentry)
-{
- return __dget_locked_dlock(dentry);
-}
-
/**
* d_find_alias - grab a hashed alias of inode
* @inode: inode in question
@@ -1282,14 +1313,6 @@ struct dentry * d_alloc_root(struct inod
return res;
}
-static inline struct hlist_head *d_hash(struct dentry *parent,
- unsigned long hash)
-{
- hash += ((unsigned long) parent ^ GOLDEN_RATIO_PRIME) / L1_CACHE_BYTES;
- hash = hash ^ ((hash ^ GOLDEN_RATIO_PRIME) >> D_HASHBITS);
- return dentry_hashtable + (hash & D_HASHMASK);
-}
-
/**
* d_obtain_alias - find or allocate a dentry for a given inode
* @inode: inode to allocate the dentry for
@@ -1548,7 +1571,8 @@ struct dentry * __d_lookup(struct dentry
unsigned int len = name->len;
unsigned int hash = name->hash;
const unsigned char *str = name->name;
- struct hlist_head *head = d_hash(parent,hash);
+ struct dcache_hash_bucket *b = d_hash(parent, hash);
+ struct hlist_head *head = &b->head;
struct dentry *found = NULL;
struct hlist_node *node;
struct dentry *dentry;
@@ -1642,6 +1666,7 @@ out:
int d_validate(struct dentry *dentry, struct dentry *dparent)
{
+ struct dcache_hash_bucket *b;
struct hlist_head *base;
struct hlist_node *lhp;
@@ -1652,19 +1677,20 @@ int d_validate(struct dentry *dentry, st
if (dentry->d_parent != dparent)
goto out;
- spin_lock(&dcache_hash_lock);
- base = d_hash(dparent, dentry->d_name.hash);
+ b = d_hash(dparent, dentry->d_name.hash);
+ base = &b->head;
+ spin_lock(&b->lock);
hlist_for_each(lhp,base) {
/* hlist_for_each_entry_rcu() not required for d_hash list
- * as it is parsed under dcache_hash_lock
+ * as it is parsed under dcache_hash_bucket->lock
*/
if (dentry == hlist_entry(lhp, struct dentry, d_hash)) {
- spin_unlock(&dcache_hash_lock);
+ spin_unlock(&b->lock);
__dget_locked(dentry);
return 1;
}
}
- spin_unlock(&dcache_hash_lock);
+ spin_unlock(&b->lock);
out:
return 0;
}
@@ -1714,11 +1740,12 @@ void d_delete(struct dentry * dentry)
fsnotify_nameremove(dentry, isdir);
}
-static void __d_rehash(struct dentry * entry, struct hlist_head *list)
+static void __d_rehash(struct dentry * entry, struct dcache_hash_bucket *b)
{
-
entry->d_flags &= ~DCACHE_UNHASHED;
- hlist_add_head_rcu(&entry->d_hash, list);
+ spin_lock(&b->lock);
+ hlist_add_head_rcu(&entry->d_hash, &b->head);
+ spin_unlock(&b->lock);
}
static void _d_rehash(struct dentry * entry)
@@ -1736,9 +1763,7 @@ static void _d_rehash(struct dentry * en
void d_rehash(struct dentry * entry)
{
spin_lock(&entry->d_lock);
- spin_lock(&dcache_hash_lock);
_d_rehash(entry);
- spin_unlock(&dcache_hash_lock);
spin_unlock(&entry->d_lock);
}
@@ -1816,6 +1841,7 @@ static void switch_names(struct dentry *
*/
static void d_move_locked(struct dentry * dentry, struct dentry * target)
{
+ struct dcache_hash_bucket *b;
if (!dentry->d_inode)
printk(KERN_WARNING "VFS: moving negative dcache entry\n");
@@ -1844,11 +1870,13 @@ static void d_move_locked(struct dentry
}
/* Move the dentry to the target hash queue, if on different bucket */
- spin_lock(&dcache_hash_lock);
- if (!d_unhashed(dentry))
+ if (!d_unhashed(dentry)) {
+ b = d_hash(dentry->d_parent, dentry->d_name.hash);
+ spin_lock(&b->lock);
hlist_del_rcu(&dentry->d_hash);
+ spin_unlock(&b->lock);
+ }
__d_rehash(dentry, d_hash(target->d_parent, target->d_name.hash));
- spin_unlock(&dcache_hash_lock);
/* Unhash the target: dput() will then get rid of it */
__d_drop(target);
@@ -2055,9 +2083,7 @@ struct dentry *d_materialise_unique(stru
found_lock:
spin_lock(&actual->d_lock);
found:
- spin_lock(&dcache_hash_lock);
_d_rehash(actual);
- spin_unlock(&dcache_hash_lock);
spin_unlock(&actual->d_lock);
spin_unlock(&dcache_inode_lock);
out_nolock:
@@ -2504,7 +2530,7 @@ static void __init dcache_init_early(voi
dentry_hashtable =
alloc_large_system_hash("Dentry cache",
- sizeof(struct hlist_head),
+ sizeof(struct dcache_hash_bucket),
dhash_entries,
13,
HASH_EARLY,
@@ -2512,8 +2538,10 @@ static void __init dcache_init_early(voi
&d_hash_mask,
0);
- for (loop = 0; loop < (1 << d_hash_shift); loop++)
- INIT_HLIST_HEAD(&dentry_hashtable[loop]);
+ for (loop = 0; loop < (1 << d_hash_shift); loop++) {
+ spin_lock_init(&dentry_hashtable[loop].lock);
+ INIT_HLIST_HEAD(&dentry_hashtable[loop].head);
+ }
}
static void __init dcache_init(void)
@@ -2536,7 +2564,7 @@ static void __init dcache_init(void)
dentry_hashtable =
alloc_large_system_hash("Dentry cache",
- sizeof(struct hlist_head),
+ sizeof(struct dcache_hash_bucket),
dhash_entries,
13,
0,
@@ -2544,8 +2572,10 @@ static void __init dcache_init(void)
&d_hash_mask,
0);
- for (loop = 0; loop < (1 << d_hash_shift); loop++)
- INIT_HLIST_HEAD(&dentry_hashtable[loop]);
+ for (loop = 0; loop < (1 << d_hash_shift); loop++) {
+ spin_lock_init(&dentry_hashtable[loop].lock);
+ INIT_HLIST_HEAD(&dentry_hashtable[loop].head);
+ }
}
/* SLAB cache for __getname() consumers */
Index: linux-2.6/include/linux/dcache.h
===================================================================
--- linux-2.6.orig/include/linux/dcache.h
+++ linux-2.6/include/linux/dcache.h
@@ -185,7 +185,6 @@ d_iput: no no yes
#define DCACHE_COOKIE 0x0040 /* For use by dcookie subsystem */
extern spinlock_t dcache_inode_lock;
-extern spinlock_t dcache_hash_lock;
extern seqlock_t rename_lock;
/**
@@ -203,23 +202,8 @@ extern seqlock_t rename_lock;
*
* __d_drop requires dentry->d_lock.
*/
-
-static inline void __d_drop(struct dentry *dentry)
-{
- if (!(dentry->d_flags & DCACHE_UNHASHED)) {
- dentry->d_flags |= DCACHE_UNHASHED;
- spin_lock(&dcache_hash_lock);
- hlist_del_rcu(&dentry->d_hash);
- spin_unlock(&dcache_hash_lock);
- }
-}
-
-static inline void d_drop(struct dentry *dentry)
-{
- spin_lock(&dentry->d_lock);
- __d_drop(dentry);
- spin_unlock(&dentry->d_lock);
-}
+void d_drop(struct dentry *dentry);
+void __d_drop(struct dentry *dentry);
static inline int dname_external(struct dentry *dentry)
{
next prev parent reply other threads:[~2009-03-29 16:41 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-03-29 15:55 [rfc] scale dcache locking npiggin
2009-03-29 15:55 ` [patch 01/14] fs: dcache fix LRU ordering npiggin
2009-03-29 15:55 ` [patch 02/14] fs: dcache scale hash npiggin
2009-03-29 15:55 ` [patch 03/14] fs: dcache scale lru npiggin
2009-03-29 15:55 ` [patch 04/14] fs: dcache scale nr_dentry npiggin
2009-03-29 15:55 ` [patch 05/14] fs: dcache scale dentry refcount npiggin
2009-03-29 15:55 ` [patch 06/14] fs: dcache scale d_unhashed npiggin
2009-03-29 15:55 ` [patch 07/14] fs: dcache scale subdirs npiggin
2009-03-29 15:55 ` [patch 08/14] fs: scale inode alias list npiggin
2009-03-30 12:18 ` Andi Kleen
2009-03-30 12:31 ` Nick Piggin
2009-03-29 15:55 ` [patch 09/14] fs: use RCU / seqlock logic for reverse and multi-step operaitons npiggin
2009-03-30 12:16 ` Andi Kleen
2009-03-30 12:29 ` Nick Piggin
2009-03-30 12:43 ` Andi Kleen
2009-03-29 15:55 ` [patch 10/14] fs: dcache remove dcache_lock npiggin
2009-03-29 15:55 ` [patch 11/14] fs: dcache reduce dput locking npiggin
2009-03-29 15:55 ` npiggin [this message]
2009-03-30 12:14 ` [patch 12/14] fs: dcache per-bucket dcache hash locking Andi Kleen
2009-03-30 12:27 ` Nick Piggin
2009-03-30 12:47 ` Andi Kleen
2009-03-30 12:59 ` Nick Piggin
2009-03-30 18:00 ` Christoph Hellwig
2009-03-31 1:57 ` Nick Piggin
2009-03-29 15:55 ` [patch 13/14] fs: dcache reduce dcache_inode_lock npiggin
2009-03-29 15:55 ` [patch 14/14] fs: dcache per-inode inode alias locking npiggin
2009-04-01 14:23 ` [rfc] scale dcache locking Al Viro
2009-04-02 9:43 ` Nick Piggin
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