Re: [PATCH] Remove some pointless conditionals before kfree() in kernel/cgroup.c

From: Paul Menage
Date: Mon Feb 23 2009 - 03:13:13 EST


On Sun, Feb 22, 2009 at 2:05 PM, Jesper Juhl <jj@xxxxxxxxxxxxx> wrote:
> Hi,
>
> Here's a small patch for kernel/cgroup.c
>
> Removes a few pointless tests of pointer == 0 before kfree() in
> kernel/cgroup.c.
> If the pointer we hand to kfree() is 0, then kfree() is a noop, so there
> is no need to test.
>
> Reduces object file size a bit :
>
> Before:
> $ size kernel/cgroup.o
> text data bss dec hex filename
> 21593 7804 4924 34321 8611 kernel/cgroup.o
> After:
> $ size kernel/cgroup.o
> text data bss dec hex filename
> 21537 7744 4924 34205 859d kernel/cgroup.o

Thanks. I'm a bit surprised that it also shrunk the data segment size
(and in fact, by more than the text segment size). Any idea how that
came about?

>
> Signed-off-by: Jesper Juhl <jj@xxxxxxxxxxxxx>

Acked-by: Paul Menage <menage@xxxxxxxxxx>

Paul

> ---
>
> diff --git a/kernel/cgroup.c b/kernel/cgroup.c
> index 9edb5c4..1c0a9b5 100644
> --- a/kernel/cgroup.c
> +++ b/kernel/cgroup.c
> @@ -865,8 +865,7 @@ static int cgroup_remount(struct super_block *sb, int *flags, char *data)
> if (opts.release_agent)
> strcpy(root->release_agent_path, opts.release_agent);
> out_unlock:
> - if (opts.release_agent)
> - kfree(opts.release_agent);
> + kfree(opts.release_agent);
> mutex_unlock(&cgroup_mutex);
> mutex_unlock(&cgrp->dentry->d_inode->i_mutex);
> return ret;
> @@ -969,15 +968,13 @@ static int cgroup_get_sb(struct file_system_type *fs_type,
> /* First find the desired set of subsystems */
> ret = parse_cgroupfs_options(data, &opts);
> if (ret) {
> - if (opts.release_agent)
> - kfree(opts.release_agent);
> + kfree(opts.release_agent);
> return ret;
> }
>
> root = kzalloc(sizeof(*root), GFP_KERNEL);
> if (!root) {
> - if (opts.release_agent)
> - kfree(opts.release_agent);
> + kfree(opts.release_agent);
> return -ENOMEM;
> }
>
>
>
> --
> Jesper Juhl <jj@xxxxxxxxxxxxx> http://www.chaosbits.net/
> Plain text mails only, please http://www.expita.com/nomime.html
> Don't top-post http://www.catb.org/~esr/jargon/html/T/top-post.html
>
>
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