Re: [PATCH v4 08/10] eventfs: Implement tracefs_inode_cache

Steven Rostedt
2023-07-14T20:27:21Z

I wonder if this should be patch 2?

On Thu, 13 Jul 2023 17:03:22 +0530
Ajay Kaher <akaher@vmware.com> wrote:

> Creating tracefs_inode_cache which is a cache of tracefs_inode.

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.

> Adding helping functions:

Add helper functions:

> tracefs_alloc_inode()
> tracefs_free_inode()
>

-- Steve

> 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 +++++++++++++++++++++++++++++++++++++++
> 1 file changed, 39 insertions(+)
>
> diff --git a/fs/tracefs/inode.c b/fs/tracefs/inode.c
> index 7dc692a5fee1..76820d3e97eb 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,
> @@ -675,10 +698,26 @@ 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;