Re: [PATCH v5 02/10] eventfs: Implement tracefs_inode_cache

Some more nits.

On Sun, 23 Jul 2023 01:06:57 +0530 Ajay Kaher akaher@vmware.com wrote:

Create a kmem cache of tracefs_inodes. To be more efficient, as there are lots of tracefs inodes, create its own cache. This also allows to see how many tracefs inodes have been created.

Add helper functions: tracefs_alloc_inode() tracefs_free_inode() get_tracefs()

Signed-off-by: Ajay Kaher akaher@vmware.com Co-developed-by: Steven Rostedt (VMware) rostedt@goodmis.org Signed-off-by: Steven Rostedt (VMware) rostedt@goodmis.org Tested-by: Ching-lin Yu chinglinyu@google.com

---

fs/tracefs/inode.c | 39 +++++++++++++++++++++++++++++++++++++++ fs/tracefs/internal.h | 19 +++++++++++++++++++ 2 files changed, 58 insertions(+) create mode 100644 fs/tracefs/internal.h

diff --git a/fs/tracefs/inode.c b/fs/tracefs/inode.c index 57ac8aa4a724..2508944cc4d8 100644 --- a/fs/tracefs/inode.c +++ b/fs/tracefs/inode.c @@ -21,13 +21,33 @@ #include <linux/parser.h> #include <linux/magic.h> #include <linux/slab.h> +#include "internal.h" #define TRACEFS_DEFAULT_MODE 0700 +static struct kmem_cache *tracefs_inode_cachep __ro_after_init; static struct vfsmount *tracefs_mount; static int tracefs_mount_count; static bool tracefs_registered; +static struct inode *tracefs_alloc_inode(struct super_block *sb) +{

• struct tracefs_inode *ti;
• ti = kmem_cache_alloc(tracefs_inode_cachep, GFP_KERNEL);
• if (!ti)

• return NULL;
  

• ti->flags = 0;
• return &ti->vfs_inode;

+}

+static void tracefs_free_inode(struct inode *inode) +{

• kmem_cache_free(tracefs_inode_cachep, get_tracefs(inode));

+}

static ssize_t default_read_file(struct file *file, char __user *buf, size_t count, loff_t *ppos) { @@ -346,6 +366,9 @@ static int tracefs_show_options(struct seq_file *m, struct dentry *root) } static const struct super_operations tracefs_super_operations = {

• .alloc_inode = tracefs_alloc_inode,
• .free_inode = tracefs_free_inode,
• .drop_inode = generic_delete_inode, .statfs = simple_statfs, .remount_fs = tracefs_remount, .show_options = tracefs_show_options,

@@ -628,10 +651,26 @@ bool tracefs_initialized(void) return tracefs_registered; } +static void init_once(void *foo) +{

• struct tracefs_inode *ti = (struct tracefs_inode *) foo;
• inode_init_once(&ti->vfs_inode);

+}

static int __init tracefs_init(void) { int retval;

• tracefs_inode_cachep = kmem_cache_create("tracefs_inode_cache",

• 				 sizeof(struct tracefs_inode),
  

• 				 0, (SLAB_RECLAIM_ACCOUNT|
  

• 				     SLAB_MEM_SPREAD|
  

• 				     SLAB_ACCOUNT),
  

• 				 init_once);
  

• if (!tracefs_inode_cachep)

• return -ENOMEM;
  

• retval = sysfs_create_mount_point(kernel_kobj, "tracing"); if (retval) return -EINVAL;

diff --git a/fs/tracefs/internal.h b/fs/tracefs/internal.h new file mode 100644 index 000000000000..49b5e8949e1c --- /dev/null +++ b/fs/tracefs/internal.h @@ -0,0 +1,19 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _TRACEFS_INTERNAL_H +#define _TRACEFS_INTERNAL_H

+enum {

• TRACEFS_EVENT_INODE = BIT(1),

+};

Let's not introduce the enum until it is used.

-- Steve

+struct tracefs_inode {

• unsigned long flags;
• void *private;
• struct inode vfs_inode;

+};

+static inline struct tracefs_inode *get_tracefs(const struct inode *inode) +{

• return container_of(inode, struct tracefs_inode, vfs_inode);

+} +#endif /* _TRACEFS_INTERNAL_H */