Introduce a dedicated cache pool for ovl_entry to optimize
memory allocation adn deallocation.
Signed-off-by: Chengguang Xu <cgxu519@xxxxxxx>
---
fs/overlayfs/export.c | 11 +++++++----
fs/overlayfs/namei.c | 7 +++++--
fs/overlayfs/overlayfs.h | 4 ++++
fs/overlayfs/ovl_entry.h | 9 +++++----
fs/overlayfs/super.c | 38 +++++++++++++++++++++++++++++---------
fs/overlayfs/util.c | 28 ++++++++++++++++++++++++----
6 files changed, 74 insertions(+), 23 deletions(-)
diff --git a/fs/overlayfs/export.c b/fs/overlayfs/export.c
index f2ba5fb..b1047ae 100644
--- a/fs/overlayfs/export.c
+++ b/fs/overlayfs/export.c
@@ -321,8 +321,8 @@ static struct dentry *ovl_obtain_alias(struct super_block *sb,
goto nomem;
if (lower) {
- oe->lowerstack->dentry = dget(lower);
- oe->lowerstack->layer = lowerpath->layer;
+ oe->lowerstack.dentry = dget(lower);
+ oe->lowerstack.layer = lowerpath->layer;
}
dentry->d_fsdata = oe;
if (upper_alias)
@@ -346,9 +346,12 @@ static struct dentry *ovl_dentry_real_at(struct dentry *dentry, int idx)
if (!idx)
return ovl_dentry_upper(dentry);
+ if (oe->numlower == 1 && oe->lowerstack.layer->idx == idx)
+ return oe->lowerstack.dentry;
+
for (i = 0; i < oe->numlower; i++) {
- if (oe->lowerstack[i].layer->idx == idx)
- return oe->lowerstack[i].dentry;
+ if (oe->lowerstacks[i].layer->idx == idx)
+ return oe->lowerstacks[i].dentry;
}
return NULL;
diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c
index eb3ec6c..51fd914 100644
--- a/fs/overlayfs/namei.c
+++ b/fs/overlayfs/namei.c
@@ -994,7 +994,10 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
if (!oe)
goto out_put;
- memcpy(oe->lowerstack, stack, sizeof(struct ovl_path) * ctr);
+ if (oe->numlower == 1)
+ memcpy(&oe->lowerstack, stack, sizeof(struct ovl_path));
+ else
+ memcpy(oe->lowerstacks, stack, sizeof(struct ovl_path) * ctr);
dentry->d_fsdata = oe;
if (upperopaque)
@@ -1028,7 +1031,7 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
out_free_oe:
dentry->d_fsdata = NULL;
- kfree(oe);
+ ovl_free_entry(oe);
out_put:
dput(index);
for (i = 0; i < ctr; i++)
diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index 8039602..a104e02 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -207,6 +207,7 @@ static inline struct dentry *ovl_do_tmpfile(struct dentry *dentry, umode_t mode)
bool ovl_index_all(struct super_block *sb);
bool ovl_verify_lower(struct super_block *sb);
struct ovl_entry *ovl_alloc_entry(unsigned int numlower);
+void ovl_free_entry(struct ovl_entry *oe);
bool ovl_dentry_remote(struct dentry *dentry);
bool ovl_dentry_weird(struct dentry *dentry);
enum ovl_path_type ovl_path_type(struct dentry *dentry);
@@ -378,3 +379,6 @@ int ovl_set_origin(struct dentry *dentry, struct dentry *lower,
/* export.c */
extern const struct export_operations ovl_export_operations;
+
+/* super.c */
+extern struct kmem_cache *ovl_entry_cachep;
diff --git a/fs/overlayfs/ovl_entry.h b/fs/overlayfs/ovl_entry.h
index 41655a7..3ed8ab4 100644
--- a/fs/overlayfs/ovl_entry.h
+++ b/fs/overlayfs/ovl_entry.h
@@ -71,13 +71,14 @@ struct ovl_fs {
/* private information held for every overlayfs dentry */
struct ovl_entry {
union {
- struct {
- unsigned long flags;
- };
+ unsigned long flags;
struct rcu_head rcu;
};
unsigned numlower;
- struct ovl_path lowerstack[];
+ union {
+ struct ovl_path lowerstack;
+ struct ovl_path *lowerstacks;
+ };
};
struct ovl_entry *ovl_alloc_entry(unsigned int numlower);
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index 38c1dd1..6327497 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -60,8 +60,11 @@ static void ovl_entry_stack_free(struct ovl_entry *oe)
{
unsigned int i;
- for (i = 0; i < oe->numlower; i++)
- dput(oe->lowerstack[i].dentry);
+ if (oe->numlower == 1)
+ dput(oe->lowerstack.dentry);
+ else
+ for (i = 0; i < oe->numlower; i++)
+ dput(oe->lowerstacks[i].dentry);
}
static void ovl_dentry_release(struct dentry *dentry)
@@ -191,6 +194,7 @@ static int ovl_dentry_weak_revalidate(struct dentry *dentry, unsigned int flags)
};
static struct kmem_cache *ovl_inode_cachep;
+struct kmem_cache *ovl_entry_cachep;
static struct inode *ovl_alloc_inode(struct super_block *sb)
{
@@ -1332,9 +1336,14 @@ static struct ovl_entry *ovl_get_lowerstack(struct super_block *sb,
if (!oe)
goto out_err;
- for (i = 0; i < numlower; i++) {
- oe->lowerstack[i].dentry = dget(stack[i].dentry);
- oe->lowerstack[i].layer = &ofs->lower_layers[i];
+ if (numlower == 1) {
+ oe->lowerstack.dentry = stack[0].dentry;
+ oe->lowerstack.layer = &ofs->lower_layers[0];
+ } else {
+ for (i = 0; i < numlower; i++) {
+ oe->lowerstacks[i].dentry = dget(stack[i].dentry);
+ oe->lowerstacks[i].layer = &ofs->lower_layers[i];
+ }
}
if (remote)
@@ -1515,20 +1524,31 @@ static void ovl_inode_init_once(void *foo)
static int __init ovl_init(void)
{
- int err;
+ int err = -ENOMEM;
ovl_inode_cachep = kmem_cache_create("ovl_inode",
sizeof(struct ovl_inode), 0,
(SLAB_RECLAIM_ACCOUNT|
SLAB_MEM_SPREAD|SLAB_ACCOUNT),
ovl_inode_init_once);
- if (ovl_inode_cachep == NULL)
- return -ENOMEM;
+ if (!ovl_inode_cachep)
+ return err;
+
+ ovl_entry_cachep = KMEM_CACHE(ovl_entry,
+ SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD);
+ if (!ovl_entry_cachep)
+ goto bad_entry_cachep;
err = register_filesystem(&ovl_fs_type);
if (err)
- kmem_cache_destroy(ovl_inode_cachep);
+ goto err_out;
+ return 0;
+
+err_out:
+ kmem_cache_destroy(ovl_entry_cachep);
+bad_entry_cachep:
+ kmem_cache_destroy(ovl_inode_cachep);
return err;
}
diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c
index a3459e6..7d4ff3e 100644
--- a/fs/overlayfs/util.c
+++ b/fs/overlayfs/util.c
@@ -95,13 +95,30 @@ bool ovl_verify_lower(struct super_block *sb)
return ofs->config.nfs_export && ofs->config.index;
}
+void ovl_free_entry(struct ovl_entry *oe)
+{
+ if (oe->numlower > 1)
+ kfree(oe->lowerstacks);
+
+ kmem_cache_free(ovl_entry_cachep, oe);
+}
+
struct ovl_entry *ovl_alloc_entry(unsigned int numlower)
{
- size_t size = offsetof(struct ovl_entry, lowerstack[numlower]);
- struct ovl_entry *oe = kzalloc(size, GFP_KERNEL);
+ size_t size = sizeof(struct ovl_path) * numlower;
+ struct ovl_entry *oe;
- if (oe)
+ oe = kmem_cache_zalloc(ovl_entry_cachep, GFP_KERNEL);
+ if (oe) {
oe->numlower = numlower;
+ if (numlower > 1) {
+ oe->lowerstacks = kzalloc(size, GFP_KERNEL);
+ if (!oe->lowerstacks) {
+ kmem_cache_free(ovl_entry_cachep, oe);
+ oe = NULL;
+ }
+ }
+ }
return oe;
}
@@ -186,7 +203,10 @@ struct ovl_path *__ovl_path_lower(struct ovl_entry *oe, int layer)
if (layer > oe->numlower)
return NULL;
- return &oe->lowerstack[layer - 1];
+ if (layer == 1 && oe->numlower == 1)
+ return &oe->lowerstack;
+ else
+ return &oe->lowerstacks[layer - 1];
}
struct vfsmount *ovl_mnt_lower(struct dentry *dentry)
--
1.8.3.1
--
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