Introduce a dedicated cache pool for ovl_entry which only has
one lowerpath to optimize memory allocation and deallocation.
For multi-lowerpath ovl_entry, using kzalloc/kfree as usual.
Signed-off-by: Chengguang Xu <cgxu519@xxxxxxx>
---
Changes since v1:
- Using lowerstack[1] array statement to replace union statement in ovl_entry,
so that we can avoid unnecessary modification in many calling places.
fs/overlayfs/namei.c | 2 +-
fs/overlayfs/overlayfs.h | 4 ++++
fs/overlayfs/ovl_entry.h | 6 ++----
fs/overlayfs/super.c | 23 ++++++++++++++++++-----
fs/overlayfs/util.c | 19 +++++++++++++++++--
5 files changed, 42 insertions(+), 12 deletions(-)
diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c
index 2dba29e..bee559a6 100644
--- a/fs/overlayfs/namei.c
+++ b/fs/overlayfs/namei.c
@@ -1026,7 +1026,7 @@ 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 e0b7de7..4057e5b 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);
@@ -376,3 +377,6 @@ 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..b274181 100644
--- a/fs/overlayfs/ovl_entry.h
+++ b/fs/overlayfs/ovl_entry.h
@@ -71,13 +71,11 @@ 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[];
+ struct ovl_path lowerstack[1];
};
struct ovl_entry *ovl_alloc_entry(unsigned int numlower);
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index e8551c9..b28fe3d 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -191,6 +191,7 @@ 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)
{
@@ -1484,7 +1485,7 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
out_free_oe:
ovl_entry_stack_free(oe);
- kfree(oe);
+ ovl_free_entry(oe);
out_err:
path_put(&upperpath);
ovl_free_fs(ofs);
@@ -1515,19 +1516,31 @@ 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)
+ if (!ovl_inode_cachep)
return -ENOMEM;
+ 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 out_err;
+
+ return 0;
+
+out_err:
+ kmem_cache_destroy(ovl_entry_cachep);
+bad_entry_cachep:
+ kmem_cache_destroy(ovl_inode_cachep);
return err;
}
@@ -1541,8 +1554,8 @@ static void __exit ovl_exit(void)
* destroy cache.
*/
rcu_barrier();
+ kmem_cache_destroy(ovl_entry_cachep);
kmem_cache_destroy(ovl_inode_cachep);
-
}
module_init(ovl_init);
diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c
index 6f10780..8c4968f 100644
--- a/fs/overlayfs/util.c
+++ b/fs/overlayfs/util.c
@@ -95,10 +95,25 @@ 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);
+ else
+ 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;
+ struct ovl_entry *oe;
+
+ if (numlower > 1) {
+ size = offsetof(struct ovl_entry, lowerstack[numlower]);
+ oe = kzalloc(size, GFP_KERNEL);
+ } else {
+ oe = kmem_cache_zalloc(ovl_entry_cachep, GFP_KERNEL);
+ }
if (oe)
oe->numlower = numlower;
--
1.8.3.1
--
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