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

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) { list_for_each_entry_safe(dentry, tmp, &dir->d_subdirs, d_u.d_child) {
spin_lock(&dentry->d_lock); spin_lock(&dentry->d_lock);
if (!(d_unhashed(dentry)) && dentry->d_inode) { if (!(d_unhashed(dentry)) && dentry->d_inode) {
dget_locked_dlock(dentry); dget_dlock(dentry);
__d_drop(dentry); __d_drop(dentry);
spin_unlock(&dentry->d_lock); spin_unlock(&dentry->d_lock);
simple_unlink(dir->d_inode, dentry); simple_unlink(dir->d_inode, dentry);

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

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

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

View File

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

View File

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

View File

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

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

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

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@ -287,23 +287,17 @@ extern char *dentry_path(struct dentry *, char *, int);
/* Allocation counts.. */ /* 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 * @dentry: dentry to get a reference to
* *
* Given a dentry or %NULL pointer increment the reference count * Given a dentry or %NULL pointer increment the reference count
* if appropriate and return the dentry. A dentry will not be * if appropriate and return the dentry. A dentry will not be
* destroyed when it has references. dget() should never be * destroyed when it has references.
* 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().
*/ */
static inline struct dentry *dget_dlock(struct dentry *dentry) static inline struct dentry *dget_dlock(struct dentry *dentry)
{ {
if (dentry) { if (dentry)
BUG_ON(!dentry->d_count);
dentry->d_count++; dentry->d_count++;
}
return dentry; return dentry;
} }
@ -317,9 +311,6 @@ static inline struct dentry *dget(struct dentry *dentry)
return 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); extern struct dentry *dget_parent(struct dentry *dentry);
/** /**

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

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