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fs: dcache rationalise dget variants 

dget_locked was a shortcut to avoid the lazy lru manipulation when we already
held dcache_lock (lru manipulation was relatively cheap at that point).
However, how that the lru lock is an innermost one, we never hold it at any
caller, so the lock cost can now be avoided. We already have well working lazy
dcache LRU, so it should be fine to defer LRU manipulations to scan time.

Signed-off-by: Nick Piggin <npiggin@kernel.dk>
This commit is contained in:
Nick Piggin 2011-01-07 17:49:43 +11:00
parent 357f8e658b
commit dc0474be3e
12 changed files with 24 additions and 47 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
arch/powerpc/platforms/cell/spufs/inode.c
View File

@ -161,7 +161,7 @@ static void spufs_prune_dir(struct dentry *dir)
list_for_each_entry_safe(dentry, tmp, &dir->d_subdirs, d_u.d_child) {
spin_lock(&dentry->d_lock);
if (!(d_unhashed(dentry)) && dentry->d_inode) {
dget_locked_dlock(dentry);
dget_dlock(dentry);
__d_drop(dentry);
spin_unlock(&dentry->d_lock);
simple_unlink(dir->d_inode, dentry);

2
drivers/infiniband/hw/ipath/ipath_fs.c
View File

@ -279,7 +279,7 @@ static int remove_file(struct dentry *parent, char *name)
spin_lock(&tmp->d_lock);
if (!(d_unhashed(tmp) && tmp->d_inode)) {
dget_locked_dlock(tmp);
dget_dlock(tmp);
__d_drop(tmp);
spin_unlock(&tmp->d_lock);
simple_unlink(parent->d_inode, tmp);

2
drivers/infiniband/hw/qib/qib_fs.c
View File

@ -455,7 +455,7 @@ static int remove_file(struct dentry *parent, char *name)
spin_lock(&tmp->d_lock);
if (!(d_unhashed(tmp) && tmp->d_inode)) {
dget_locked_dlock(tmp);
dget_dlock(tmp);
__d_drop(tmp);
spin_unlock(&tmp->d_lock);
simple_unlink(parent->d_inode, tmp);

2
drivers/staging/smbfs/cache.c
View File

@ -102,7 +102,7 @@ smb_dget_fpos(struct dentry *dentry, struct dentry *parent, unsigned long fpos)
dent = list_entry(next, struct dentry, d_u.d_child);
if ((unsigned long)dent->d_fsdata == fpos) {
if (dent->d_inode)
dget_locked(dent);
dget(dent);
else
dent = NULL;
goto out_unlock;

2
fs/configfs/inode.c
View File

@ -252,7 +252,7 @@ void configfs_drop_dentry(struct configfs_dirent * sd, struct dentry * parent)
if (dentry) {
spin_lock(&dentry->d_lock);
if (!(d_unhashed(dentry) && dentry->d_inode)) {
dget_locked_dlock(dentry);
dget_dlock(dentry);
__d_drop(dentry);
spin_unlock(&dentry->d_lock);
simple_unlink(parent->d_inode, dentry);

36
fs/dcache.c
View File

@ -429,33 +429,18 @@ int d_invalidate(struct dentry * dentry)
EXPORT_SYMBOL(d_invalidate);
/* This must be called with d_lock held */
static inline struct dentry * __dget_locked_dlock(struct dentry *dentry)
static inline void __dget_dlock(struct dentry *dentry)
{
dentry->d_count++;
dentry_lru_del(dentry);
return dentry;
}
/* This must be called with d_lock held */
static inline struct dentry * __dget_locked(struct dentry *dentry)
static inline void __dget(struct dentry *dentry)
{
spin_lock(&dentry->d_lock);
__dget_locked_dlock(dentry);
__dget_dlock(dentry);
spin_unlock(&dentry->d_lock);
return dentry;
}
struct dentry * dget_locked_dlock(struct dentry *dentry)
{
return __dget_locked_dlock(dentry);
}
struct dentry * dget_locked(struct dentry *dentry)
{
return __dget_locked(dentry);
}
EXPORT_SYMBOL(dget_locked);
struct dentry *dget_parent(struct dentry *dentry)
{
struct dentry *ret;
@ -512,7 +497,7 @@ static struct dentry *__d_find_alias(struct inode *inode, int want_discon)
(alias->d_flags & DCACHE_DISCONNECTED)) {
discon_alias = alias;
} else if (!want_discon) {
__dget_locked_dlock(alias);
__dget_dlock(alias);
spin_unlock(&alias->d_lock);
return alias;
}
@ -525,7 +510,7 @@ static struct dentry *__d_find_alias(struct inode *inode, int want_discon)
if (S_ISDIR(inode->i_mode) || !d_unhashed(alias)) {
if (IS_ROOT(alias) &&
(alias->d_flags & DCACHE_DISCONNECTED)) {
__dget_locked_dlock(alias);
__dget_dlock(alias);
spin_unlock(&alias->d_lock);
return alias;
}
@ -561,7 +546,7 @@ void d_prune_aliases(struct inode *inode)
list_for_each_entry(dentry, &inode->i_dentry, d_alias) {
spin_lock(&dentry->d_lock);
if (!dentry->d_count) {
__dget_locked_dlock(dentry);
__dget_dlock(dentry);
__d_drop(dentry);
spin_unlock(&dentry->d_lock);
spin_unlock(&dcache_inode_lock);
@ -1257,7 +1242,8 @@ struct dentry *d_alloc(struct dentry * parent, const struct qstr *name)
* don't need child lock because it is not subject
* to concurrency here
*/
dentry->d_parent = dget_dlock(parent);
__dget_dlock(parent);
dentry->d_parent = parent;
dentry->d_sb = parent->d_sb;
list_add(&dentry->d_u.d_child, &parent->d_subdirs);
spin_unlock(&parent->d_lock);
@ -1360,7 +1346,7 @@ static struct dentry *__d_instantiate_unique(struct dentry *entry,
continue;
if (memcmp(qstr->name, name, len))
continue;
dget_locked(alias);
__dget(alias);
return alias;
}
@ -1613,7 +1599,7 @@ struct dentry *d_add_ci(struct dentry *dentry, struct inode *inode,
* reference to it, move it in place and use it.
*/
new = list_entry(inode->i_dentry.next, struct dentry, d_alias);
dget_locked(new);
__dget(new);
spin_unlock(&dcache_inode_lock);
security_d_instantiate(found, inode);
d_move(new, found);
@ -1789,7 +1775,7 @@ int d_validate(struct dentry *dentry, struct dentry *dparent)
list_for_each_entry(child, &dparent->d_subdirs, d_u.d_child) {
if (dentry == child) {
spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED);
__dget_locked_dlock(dentry);
__dget_dlock(dentry);
spin_unlock(&dentry->d_lock);
spin_unlock(&dparent->d_lock);
return 1;

2
fs/exportfs/expfs.c
View File

@ -49,7 +49,7 @@ find_acceptable_alias(struct dentry *result,
spin_lock(&dcache_inode_lock);
list_for_each_entry(dentry, &result->d_inode->i_dentry, d_alias) {
dget_locked(dentry);
dget(dentry);
spin_unlock(&dcache_inode_lock);
if (toput)
dput(toput);

2
fs/ncpfs/dir.c
View File

@ -397,7 +397,7 @@ ncp_dget_fpos(struct dentry *dentry, struct dentry *parent, unsigned long fpos)
dent = list_entry(next, struct dentry, d_u.d_child);
if ((unsigned long)dent->d_fsdata == fpos) {
if (dent->d_inode)
dget_locked(dent);
dget(dent);
else
dent = NULL;
spin_unlock(&parent->d_lock);

2
fs/ocfs2/dcache.c
View File

@ -178,7 +178,7 @@ struct dentry *ocfs2_find_local_alias(struct inode *inode,
mlog(0, "dentry found: %.*s\n",
dentry->d_name.len, dentry->d_name.name);
dget_locked_dlock(dentry);
dget_dlock(dentry);
spin_unlock(&dentry->d_lock);
break;
}

15
include/linux/dcache.h
View File

@ -287,23 +287,17 @@ extern char *dentry_path(struct dentry *, char *, int);
/* Allocation counts.. */
/**
* dget, dget_locked - get a reference to a dentry
* dget, dget_dlock - get a reference to a dentry
* @dentry: dentry to get a reference to
*
* Given a dentry or %NULL pointer increment the reference count
* if appropriate and return the dentry. A dentry will not be
* destroyed when it has references. dget() should never be
* called for dentries with zero reference counter. For these cases
* (preferably none, functions in dcache.c are sufficient for normal
* needs and they take necessary precautions) you should hold d_lock
* and call dget_dlock() instead of dget().
* destroyed when it has references.
*/
static inline struct dentry *dget_dlock(struct dentry *dentry)
{
if (dentry) {
BUG_ON(!dentry->d_count);
if (dentry)
dentry->d_count++;
}
return dentry;
}
@ -317,9 +311,6 @@ static inline struct dentry *dget(struct dentry *dentry)
return dentry;
}
extern struct dentry * dget_locked(struct dentry *);
extern struct dentry * dget_locked_dlock(struct dentry *);
extern struct dentry *dget_parent(struct dentry *dentry);
/**

2
kernel/cgroup.c
View File

@ -887,7 +887,7 @@ static void cgroup_clear_directory(struct dentry *dentry)
/* This should never be called on a cgroup
* directory with child cgroups */
BUG_ON(d->d_inode->i_mode & S_IFDIR);
dget_locked_dlock(d);
dget_dlock(d);
spin_unlock(&d->d_lock);
spin_unlock(&dentry->d_lock);
d_delete(d);

2
security/selinux/selinuxfs.c
View File

@ -1154,7 +1154,7 @@ static void sel_remove_entries(struct dentry *de)
list_del_init(node);
if (d->d_inode) {
dget_locked_dlock(d);
dget_dlock(d);
spin_unlock(&de->d_lock);
spin_unlock(&d->d_lock);
d_delete(d);