linux-kernel - Re: [PATCH 1/1] f2fs: allocate trace path buffer from names

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Message-ID: <e2ec7e19-634c-a065-fe7a-b052d02d4752@kernel.org>
Date:   Tue, 18 Apr 2023 23:51:02 +0800
From:   Chao Yu <chao@...nel.org>
To:     Wu Bo <bo.wu@...o.com>, Jaegeuk Kim <jaegeuk@...nel.org>
Cc:     linux-f2fs-devel@...ts.sourceforge.net,
        linux-kernel@...r.kernel.org, wubo.oduw@...il.com
Subject: Re: [PATCH 1/1] f2fs: allocate trace path buffer from names_cache

On 2023/4/14 18:43, Wu Bo wrote:
> It would be better to use the dedicated slab to store path.
> 
> Signed-off-by: Wu Bo <bo.wu@...o.com>
> ---
>   fs/f2fs/file.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> index 15dabeac4690..27137873958f 100644
> --- a/fs/f2fs/file.c
> +++ b/fs/f2fs/file.c
> @@ -4361,7 +4361,7 @@ static void f2fs_trace_rw_file_path(struct kiocb *iocb, size_t count, int rw)
>   	struct inode *inode = file_inode(iocb->ki_filp);
>   	char *buf, *path;
>   
> -	buf = f2fs_kmalloc(F2FS_I_SB(inode), PATH_MAX, GFP_KERNEL);
> +	buf = __getname();

How about:

buf = f2fs_kmem_cache_alloc(names_cachep, GFP_KERNEL, NULL, F2FS_I_SB(inode));

>   	if (!buf)
>   		return;
>   	path = dentry_path_raw(file_dentry(iocb->ki_filp), buf, PATH_MAX);
> @@ -4374,7 +4374,7 @@ static void f2fs_trace_rw_file_path(struct kiocb *iocb, size_t count, int rw)
>   		trace_f2fs_dataread_start(inode, iocb->ki_pos, count,
>   				current->pid, path, current->comm);
>   free_buf:
> -	kfree(buf);
> +	__putname(buf);

kmem_cache_free(names_cachep, buf);

Thanks,

>   }
>   
>   static ssize_t f2fs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)