Re: [PATCH 1/3] vfs: factor out inode hash head calculation
On Tue, Apr 06, 2021 at 10:33:41PM +1000, Dave Chinner wrote:
> From: Dave Chinner
>
> In preparation for changing the inode hash table implementation.
>
> Signed-off-by: Dave Chinner
Reviewed-by: Kent Overstreet
> ---
> fs/inode.c | 44 +---
> 1 file changed, 25 insertions(+), 19 deletions(-)
>
> diff --git a/fs/inode.c b/fs/inode.c
> index a047ab306f9a..b8d9eb3454dc 100644
> --- a/fs/inode.c
> +++ b/fs/inode.c
> @@ -60,6 +60,22 @@ 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);
>
> +static unsigned long hash(struct super_block *sb, unsigned long hashval)
> +{
> + unsigned long tmp;
> +
> + tmp = (hashval * (unsigned long)sb) ^ (GOLDEN_RATIO_PRIME + hashval) /
> + L1_CACHE_BYTES;
> + tmp = tmp ^ ((tmp ^ GOLDEN_RATIO_PRIME) >> i_hash_shift);
> + return tmp & i_hash_mask;
> +}
> +
> +static inline struct hlist_head *i_hash_head(struct super_block *sb,
> + unsigned int hashval)
> +{
> + return inode_hashtable + hash(sb, hashval);
> +}
> +
> /*
> * Empty aops. Can be used for the cases where the user does not
> * define any of the address_space operations.
> @@ -475,16 +491,6 @@ static inline void inode_sb_list_del(struct inode *inode)
> }
> }
>
> -static unsigned long hash(struct super_block *sb, unsigned long hashval)
> -{
> - unsigned long tmp;
> -
> - tmp = (hashval * (unsigned long)sb) ^ (GOLDEN_RATIO_PRIME + hashval) /
> - L1_CACHE_BYTES;
> - tmp = tmp ^ ((tmp ^ GOLDEN_RATIO_PRIME) >> i_hash_shift);
> - return tmp & i_hash_mask;
> -}
> -
> /**
> * __insert_inode_hash - hash an inode
> * @inode: unhashed inode
> @@ -1073,7 +1079,7 @@ struct inode *inode_insert5(struct inode *inode,
> unsigned long hashval,
> int (*test)(struct inode *, void *),
> int (*set)(struct inode *, void *), void *data)
> {
> - struct hlist_head *head = inode_hashtable + hash(inode->i_sb, hashval);
> + struct hlist_head *head = i_hash_head(inode->i_sb, hashval);
> struct inode *old;
> bool creating = inode->i_state & I_CREATING;
>
> @@ -1173,7 +1179,7 @@ EXPORT_SYMBOL(iget5_locked);
> */
> struct inode *iget_locked(struct super_block *sb, unsigned long ino)
> {
> - struct hlist_head *head = inode_hashtable + hash(sb, ino);
> + struct hlist_head *head = i_hash_head(sb, ino);
> struct inode *inode;
> again:
> spin_lock(_hash_lock);
> @@ -1241,7 +1247,7 @@ EXPORT_SYMBOL(iget_locked);
> */
> static int test_inode_iunique(struct super_block *sb, unsigned long ino)
> {
> - struct hlist_head *b = inode_hashtable + hash(sb, ino);
> + struct hlist_head *b = i_hash_head(sb, ino);
> struct inode *inode;
>
> hlist_for_each_entry_rcu(inode, b, i_hash) {
> @@ -1328,7 +1334,7 @@ EXPORT_SYMBOL(igrab);
> struct inode *ilookup5_nowait(struct super_block *sb, unsigned long hashval,
> int (*test)(struct inode *, void *), void *data)
> {
> - struct hlist_head *head = inode_hashtable + hash(sb, hashval);
> + struct hlist_head *head = i_hash_head(sb, hashval);
> struct inode *inode;
>
> spin_lock(_hash_lock);
> @@ -1383,7 +1389,7 @@ EXPORT_SYMBOL(ilookup5);
> */
> struct inode *ilookup(struct super_block *sb, unsigned long ino)
> {
> - struct hlist_head *head = inode_hashtable + hash(sb, ino);
> + struct hlist_head *head = i_hash_head(sb, ino);
> struct inode *inode;
> again:
> spin_lock(_hash_lock);
> @@ -1432,7 +1438,7 @@ struct inode *find_inode_nowait(struct super_block *sb,
>void *),
> void *data)
> {
> - struct hlist_head *head = inode_hashtable + hash(sb, hashval);
> + struct hlist_head *head = i_hash_head(sb, hashval);
> struct inode *inode, *ret_inode = NULL;
> int mval;
>
> @@ -1477,7 +1483,7 @@ EXPORT_SYMBOL(find_inode_nowait);
> struct inode *find_inode_rcu(struct super_block *sb, unsigned long hashval,
>int (*test)(struct inode *, void *), void *data)
> {
> - struct hlist_head *head = inode_hashtable + hash(sb, hashval);
> + struct hlist_head *head = i_hash_head(sb, hashval);
> struct inode *inode;
>
> RCU_LOCKDEP_WARN(!rcu_read_lock_held(),
> @@ -1515,7 +1521,7 @@ EXPORT_SYMBOL(find_inode_rcu);
> struct inode *find_inode_by_ino_rcu(struct super_block *sb,
> unsigned long ino)
> {
> - struct hlist_head *head = inode_hashtable + hash(sb, ino);
> + struct hlist_head *head = i_hash_head(sb, ino);
> struct inode *inode;
>
> RCU_LOCKDEP_WARN(!rcu_read_lock_held(),
> @@ -1535,7 +1541,7 @@ int insert_inode_locked(struct inode *inode)
> {
> struct super_block *sb
[PATCH 1/3] vfs: factor out inode hash head calculation
From: Dave Chinner
In preparation for changing the inode hash table implementation.
Signed-off-by: Dave Chinner
---
fs/inode.c | 44 +---
1 file changed, 25 insertions(+), 19 deletions(-)
diff --git a/fs/inode.c b/fs/inode.c
index a047ab306f9a..b8d9eb3454dc 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -60,6 +60,22 @@ 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);
+static unsigned long hash(struct super_block *sb, unsigned long hashval)
+{
+ unsigned long tmp;
+
+ tmp = (hashval * (unsigned long)sb) ^ (GOLDEN_RATIO_PRIME + hashval) /
+ L1_CACHE_BYTES;
+ tmp = tmp ^ ((tmp ^ GOLDEN_RATIO_PRIME) >> i_hash_shift);
+ return tmp & i_hash_mask;
+}
+
+static inline struct hlist_head *i_hash_head(struct super_block *sb,
+ unsigned int hashval)
+{
+ return inode_hashtable + hash(sb, hashval);
+}
+
/*
* Empty aops. Can be used for the cases where the user does not
* define any of the address_space operations.
@@ -475,16 +491,6 @@ static inline void inode_sb_list_del(struct inode *inode)
}
}
-static unsigned long hash(struct super_block *sb, unsigned long hashval)
-{
- unsigned long tmp;
-
- tmp = (hashval * (unsigned long)sb) ^ (GOLDEN_RATIO_PRIME + hashval) /
- L1_CACHE_BYTES;
- tmp = tmp ^ ((tmp ^ GOLDEN_RATIO_PRIME) >> i_hash_shift);
- return tmp & i_hash_mask;
-}
-
/**
* __insert_inode_hash - hash an inode
* @inode: unhashed inode
@@ -1073,7 +1079,7 @@ struct inode *inode_insert5(struct inode *inode, unsigned
long hashval,
int (*test)(struct inode *, void *),
int (*set)(struct inode *, void *), void *data)
{
- struct hlist_head *head = inode_hashtable + hash(inode->i_sb, hashval);
+ struct hlist_head *head = i_hash_head(inode->i_sb, hashval);
struct inode *old;
bool creating = inode->i_state & I_CREATING;
@@ -1173,7 +1179,7 @@ EXPORT_SYMBOL(iget5_locked);
*/
struct inode *iget_locked(struct super_block *sb, unsigned long ino)
{
- struct hlist_head *head = inode_hashtable + hash(sb, ino);
+ struct hlist_head *head = i_hash_head(sb, ino);
struct inode *inode;
again:
spin_lock(_hash_lock);
@@ -1241,7 +1247,7 @@ EXPORT_SYMBOL(iget_locked);
*/
static int test_inode_iunique(struct super_block *sb, unsigned long ino)
{
- struct hlist_head *b = inode_hashtable + hash(sb, ino);
+ struct hlist_head *b = i_hash_head(sb, ino);
struct inode *inode;
hlist_for_each_entry_rcu(inode, b, i_hash) {
@@ -1328,7 +1334,7 @@ EXPORT_SYMBOL(igrab);
struct inode *ilookup5_nowait(struct super_block *sb, unsigned long hashval,
int (*test)(struct inode *, void *), void *data)
{
- struct hlist_head *head = inode_hashtable + hash(sb, hashval);
+ struct hlist_head *head = i_hash_head(sb, hashval);
struct inode *inode;
spin_lock(_hash_lock);
@@ -1383,7 +1389,7 @@ EXPORT_SYMBOL(ilookup5);
*/
struct inode *ilookup(struct super_block *sb, unsigned long ino)
{
- struct hlist_head *head = inode_hashtable + hash(sb, ino);
+ struct hlist_head *head = i_hash_head(sb, ino);
struct inode *inode;
again:
spin_lock(_hash_lock);
@@ -1432,7 +1438,7 @@ struct inode *find_inode_nowait(struct super_block *sb,
void *),
void *data)
{
- struct hlist_head *head = inode_hashtable + hash(sb, hashval);
+ struct hlist_head *head = i_hash_head(sb, hashval);
struct inode *inode, *ret_inode = NULL;
int mval;
@@ -1477,7 +1483,7 @@ EXPORT_SYMBOL(find_inode_nowait);
struct inode *find_inode_rcu(struct super_block *sb, unsigned long hashval,
int (*test)(struct inode *, void *), void *data)
{
- struct hlist_head *head = inode_hashtable + hash(sb, hashval);
+ struct hlist_head *head = i_hash_head(sb, hashval);
struct inode *inode;
RCU_LOCKDEP_WARN(!rcu_read_lock_held(),
@@ -1515,7 +1521,7 @@ EXPORT_SYMBOL(find_inode_rcu);
struct inode *find_inode_by_ino_rcu(struct super_block *sb,
unsigned long ino)
{
- struct hlist_head *head = inode_hashtable + hash(sb, ino);
+ struct hlist_head *head = i_hash_head(sb, ino);
struct inode *inode;
RCU_LOCKDEP_WARN(!rcu_read_lock_held(),
@@ -1535,7 +1541,7 @@ int insert_inode_locked(struct inode *inode)
{
struct super_block *sb = inode->i_sb;
ino_t ino = inode->i_ino;
- struct hlist_head *head = inode_hashtable + hash(sb, ino);
+ struct hlist_head *head = i_hash_head(sb, ino);
while (1) {
struct inode *old = NULL;
--
