[PATCH 3/3] fs: move i_hash out from under inode_lock
From: Dave Chinner
Date: Thu Oct 28 2010 - 07:43:50 EST
From: Dave Chinner <dchinner@xxxxxxxxxx>
Protect the inode hash lists with a new global lock
inode_hash_lock and use it to protect the list manipulations and
traversals. This lock replaces the inode_lock as the inodes on the
list can be validity checked while holding the inode->i_lock and
hence the inode_lock is no longer needed to protect the lists.
Signed-off-by: Dave Chinner <dchinner@xxxxxxxxxx>
---
fs/inode.c | 69 ++++++++++++++++++++++++++++++++++-------------------------
1 files changed, 40 insertions(+), 29 deletions(-)
diff --git a/fs/inode.c b/fs/inode.c
index 130aa74..738ba4e 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -37,6 +37,8 @@
* sb->s_inodes, inode->i_sb_list
* inode_sb_list_lock protects:
* bdi->wb.b_{dirty,io,more_io}, inode->i_wb_list
+ * inode_hash_lock protects:
+ * inode_hashtable, inode->i_hash
*
* Lock ordering:
* inode_lock
@@ -48,6 +50,12 @@
*
* inode_wb_list_lock
* inode->i_lock
+ *
+ * inode_hash_lock
+ * inode->i_lock
+ *
+ * iunique_lock
+ * inode_hash_lock
*/
/*
@@ -83,6 +91,8 @@
static unsigned int i_hash_mask __read_mostly;
static unsigned int i_hash_shift __read_mostly;
+static struct hlist_head *inode_hashtable __read_mostly;
+static __cacheline_aligned_in_smp DEFINE_SPINLOCK(inode_hash_lock);
/*
* Each inode can be on two separate lists. One is
@@ -98,7 +108,6 @@ static unsigned int i_hash_shift __read_mostly;
static LIST_HEAD(inode_lru);
static DEFINE_SPINLOCK(inode_lru_lock);
-static struct hlist_head *inode_hashtable __read_mostly;
/*
* A simple spinlock to protect the list manipulations.
@@ -420,9 +429,9 @@ void __insert_inode_hash(struct inode *inode, unsigned long hashval)
{
struct hlist_head *b = inode_hashtable + hash(inode->i_sb, hashval);
- spin_lock(&inode_lock);
+ spin_lock(&inode_hash_lock);
hlist_add_head(&inode->i_hash, b);
- spin_unlock(&inode_lock);
+ spin_unlock(&inode_hash_lock);
}
EXPORT_SYMBOL(__insert_inode_hash);
@@ -434,9 +443,9 @@ EXPORT_SYMBOL(__insert_inode_hash);
*/
void remove_inode_hash(struct inode *inode)
{
- spin_lock(&inode_lock);
+ spin_lock(&inode_hash_lock);
hlist_del_init(&inode->i_hash);
- spin_unlock(&inode_lock);
+ spin_unlock(&inode_hash_lock);
}
EXPORT_SYMBOL(remove_inode_hash);
@@ -914,7 +923,7 @@ static struct inode *get_new_inode(struct super_block *sb,
if (inode) {
struct inode *old;
- spin_lock(&inode_lock);
+ spin_lock(&inode_hash_lock);
/* We released the lock, so.. */
old = find_inode(sb, head, test, data);
if (!old) {
@@ -925,8 +934,8 @@ static struct inode *get_new_inode(struct super_block *sb,
inode->i_state = I_NEW;
spin_unlock(&inode->i_lock);
hlist_add_head(&inode->i_hash, head);
+ spin_unlock(&inode_hash_lock);
inode_sb_list_add(inode);
- spin_unlock(&inode_lock);
/* Return the locked inode with I_NEW set, the
* caller is responsible for filling in the contents
@@ -939,7 +948,7 @@ static struct inode *get_new_inode(struct super_block *sb,
* us. Use the old inode instead of the one we just
* allocated.
*/
- spin_unlock(&inode_lock);
+ spin_unlock(&inode_hash_lock);
destroy_inode(inode);
inode = old;
wait_on_inode(inode);
@@ -947,7 +956,7 @@ static struct inode *get_new_inode(struct super_block *sb,
return inode;
set_failed:
- spin_unlock(&inode_lock);
+ spin_unlock(&inode_hash_lock);
destroy_inode(inode);
return NULL;
}
@@ -965,7 +974,7 @@ static struct inode *get_new_inode_fast(struct super_block *sb,
if (inode) {
struct inode *old;
- spin_lock(&inode_lock);
+ spin_lock(&inode_hash_lock);
/* We released the lock, so.. */
old = find_inode_fast(sb, head, ino);
if (!old) {
@@ -974,8 +983,8 @@ static struct inode *get_new_inode_fast(struct super_block *sb,
inode->i_state = I_NEW;
spin_unlock(&inode->i_lock);
hlist_add_head(&inode->i_hash, head);
+ spin_unlock(&inode_hash_lock);
inode_sb_list_add(inode);
- spin_unlock(&inode_lock);
/* Return the locked inode with I_NEW set, the
* caller is responsible for filling in the contents
@@ -988,7 +997,7 @@ static struct inode *get_new_inode_fast(struct super_block *sb,
* us. Use the old inode instead of the one we just
* allocated.
*/
- spin_unlock(&inode_lock);
+ spin_unlock(&inode_hash_lock);
destroy_inode(inode);
inode = old;
wait_on_inode(inode);
@@ -1009,10 +1018,14 @@ static int test_inode_iunique(struct super_block *sb, unsigned long ino)
struct hlist_node *node;
struct inode *inode;
+ spin_lock(&inode_hash_lock);
hlist_for_each_entry(inode, node, b, i_hash) {
- if (inode->i_ino == ino && inode->i_sb == sb)
+ if (inode->i_ino == ino && inode->i_sb == sb) {
+ spin_unlock(&inode_hash_lock);
return 0;
+ }
}
+ spin_unlock(&inode_hash_lock);
return 1;
}
@@ -1042,7 +1055,6 @@ ino_t iunique(struct super_block *sb, ino_t max_reserved)
static unsigned int counter;
ino_t res;
- spin_lock(&inode_lock);
spin_lock(&iunique_lock);
do {
if (counter <= max_reserved)
@@ -1050,7 +1062,6 @@ ino_t iunique(struct super_block *sb, ino_t max_reserved)
res = counter++;
} while (!test_inode_iunique(sb, res));
spin_unlock(&iunique_lock);
- spin_unlock(&inode_lock);
return res;
}
@@ -1102,15 +1113,15 @@ static struct inode *ifind(struct super_block *sb,
{
struct inode *inode;
- spin_lock(&inode_lock);
+ spin_lock(&inode_hash_lock);
inode = find_inode(sb, head, test, data);
if (inode) {
- spin_unlock(&inode_lock);
+ spin_unlock(&inode_hash_lock);
if (likely(wait))
wait_on_inode(inode);
return inode;
}
- spin_unlock(&inode_lock);
+ spin_unlock(&inode_hash_lock);
return NULL;
}
@@ -1134,14 +1145,14 @@ static struct inode *ifind_fast(struct super_block *sb,
{
struct inode *inode;
- spin_lock(&inode_lock);
+ spin_lock(&inode_hash_lock);
inode = find_inode_fast(sb, head, ino);
if (inode) {
- spin_unlock(&inode_lock);
+ spin_unlock(&inode_hash_lock);
wait_on_inode(inode);
return inode;
}
- spin_unlock(&inode_lock);
+ spin_unlock(&inode_hash_lock);
return NULL;
}
@@ -1306,7 +1317,7 @@ int insert_inode_locked(struct inode *inode)
while (1) {
struct hlist_node *node;
struct inode *old = NULL;
- spin_lock(&inode_lock);
+ spin_lock(&inode_hash_lock);
hlist_for_each_entry(old, node, head, i_hash) {
if (old->i_ino != ino)
continue;
@@ -1321,12 +1332,12 @@ int insert_inode_locked(struct inode *inode)
}
if (likely(!node)) {
hlist_add_head(&inode->i_hash, head);
- spin_unlock(&inode_lock);
+ spin_unlock(&inode_hash_lock);
return 0;
}
__iget(old);
spin_unlock(&old->i_lock);
- spin_unlock(&inode_lock);
+ spin_unlock(&inode_hash_lock);
wait_on_inode(old);
if (unlikely(!inode_unhashed(old))) {
iput(old);
@@ -1351,7 +1362,7 @@ int insert_inode_locked4(struct inode *inode, unsigned long hashval,
struct hlist_node *node;
struct inode *old = NULL;
- spin_lock(&inode_lock);
+ spin_lock(&inode_hash_lock);
hlist_for_each_entry(old, node, head, i_hash) {
if (old->i_sb != sb)
continue;
@@ -1366,12 +1377,12 @@ int insert_inode_locked4(struct inode *inode, unsigned long hashval,
}
if (likely(!node)) {
hlist_add_head(&inode->i_hash, head);
- spin_unlock(&inode_lock);
+ spin_unlock(&inode_hash_lock);
return 0;
}
__iget(old);
spin_unlock(&old->i_lock);
- spin_unlock(&inode_lock);
+ spin_unlock(&inode_hash_lock);
wait_on_inode(old);
if (unlikely(!inode_unhashed(old))) {
iput(old);
@@ -1651,10 +1662,10 @@ static void __wait_on_freeing_inode(struct inode *inode)
wq = bit_waitqueue(&inode->i_state, __I_NEW);
prepare_to_wait(wq, &wait.wait, TASK_UNINTERRUPTIBLE);
spin_unlock(&inode->i_lock);
- spin_unlock(&inode_lock);
+ spin_unlock(&inode_hash_lock);
schedule();
finish_wait(wq, &wait.wait);
- spin_lock(&inode_lock);
+ spin_lock(&inode_hash_lock);
}
static __initdata unsigned long ihash_entries;
--
1.7.1
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/