[patch 04/23] dentries: Extract common code to remove dentry from lru

Christoph Lameter
2007-11-07T01:13:51Z

[-- Attachment #1: 0023-slab_defrag_dentry_remove_lru.patch --]
[-- Type: text/plain, Size: 3281 bytes --]

Extract the common code to remove a dentry from the lru into a new function
dentry_lru_remove().

Two call sites used list_del() instead of list_del_init(). AFAIK the
performance of both is the same. dentry_lru_remove() does a list_del_init().

As a result dentry->d_lru is now always empty when a dentry is freed.
A consistent state is useful to establish dentry state from slab defrag.

[This patch is already in mm]

Reviewed-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Christoph Lameter <clameter@sgi.com>
---
fs/dcache.c | 42 ++++++++++++++----------------------------
1 file changed, 14 insertions(+), 28 deletions(-)

Index: linux-2.6/fs/dcache.c
===================================================================
--- linux-2.6.orig/fs/dcache.c 2007-10-25 18:28:40.000000000 -0700
+++ linux-2.6/fs/dcache.c 2007-11-06 12:56:31.000000000 -0800
@@ -95,6 +95,14 @@ static void d_free(struct dentry *dentry
call_rcu(&dentry->d_u.d_rcu, d_callback);
}

+static void dentry_lru_remove(struct dentry *dentry)
+{
+ if (!list_empty(&dentry->d_lru)) {
+ list_del_init(&dentry->d_lru);
+ dentry_stat.nr_unused--;
+ }
+}
+
/*
* Release the dentry's inode, using the filesystem
* d_iput() operation if defined.
@@ -211,13 +219,7 @@ repeat:
unhash_it:
__d_drop(dentry);
kill_it:
- /* If dentry was on d_lru list
- * delete it from there
- */
- if (!list_empty(&dentry->d_lru)) {
- list_del(&dentry->d_lru);
- dentry_stat.nr_unused--;
- }
+ dentry_lru_remove(dentry);
dentry = d_kill(dentry);
if (dentry)
goto repeat;
@@ -285,10 +287,7 @@ int d_invalidate(struct dentry * dentry)
static inline struct dentry * __dget_locked(struct dentry *dentry)
{
atomic_inc(&dentry->d_count);
- if (!list_empty(&dentry->d_lru)) {
- dentry_stat.nr_unused--;
- list_del_init(&dentry->d_lru);
- }
+ dentry_lru_remove(dentry);
return dentry;
}

@@ -404,10 +403,7 @@ static void prune_one_dentry(struct dent

if (dentry->d_op && dentry->d_op->d_delete)
dentry->d_op->d_delete(dentry);
- if (!list_empty(&dentry->d_lru)) {
- list_del(&dentry->d_lru);
- dentry_stat.nr_unused--;
- }
+ dentry_lru_remove(dentry);
__d_drop(dentry);
dentry = d_kill(dentry);
spin_lock(&dcache_lock);
@@ -596,10 +592,7 @@ static void shrink_dcache_for_umount_sub

/* detach this root from the system */
spin_lock(&dcache_lock);
- if (!list_empty(&dentry->d_lru)) {
- dentry_stat.nr_unused--;
- list_del_init(&dentry->d_lru);
- }
+ dentry_lru_remove(dentry);
__d_drop(dentry);
spin_unlock(&dcache_lock);

@@ -613,11 +606,7 @@ static void shrink_dcache_for_umount_sub
spin_lock(&dcache_lock);
list_for_each_entry(loop, &dentry->d_subdirs,
d_u.d_child) {
- if (!list_empty(&loop->d_lru)) {
- dentry_stat.nr_unused--;
- list_del_init(&loop->d_lru);
- }
-
+ dentry_lru_remove(dentry);
__d_drop(loop);
cond_resched_lock(&dcache_lock);
}
@@ -799,10 +788,7 @@ resume:
struct dentry *dentry = list_entry(tmp, struct dentry, d_u.d_child);
next = tmp->next;

- if (!list_empty(&dentry->d_lru)) {
- dentry_stat.nr_unused--;
- list_del_init(&dentry->d_lru);
- }
+ dentry_lru_remove(dentry);
/*
* move only zero ref count dentries to the end
* of the unused list for prune_dcache

--