linux-kernel - Re: [PATCH] replace kmem_cache_alloc with kmem_cache_zalloc to remove some following zero initializations.

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Date:	Fri, 13 Jul 2007 12:19:06 +0400
From:	Kirill Korotaev <dev@...ru>
To:	Denis Cheng <crquan@...il.com>
CC:	trivial@...nel.org, Denis <cr_quan@....com>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] replace kmem_cache_alloc with kmem_cache_zalloc to remove
 some following zero initializations.

This doesn't look worth zeroing half of the struct
when it is initialized to non-zeros then.

Denis Cheng wrote:
>>>From 4d87e14b67890f06885a76b5792ca034de2e9d06 Mon Sep 17 00:00:00 2001
> From: Denis Cheng <crquan@...il.com>
> Date: Thu, 12 Jul 2007 11:53:58 +0800
> Subject: [PATCH] replace kmem_cache_alloc with kmem_cache_zalloc to
> remove some following zero initializations.
> 
> Signed-off-by: Denis Cheng <crquan@...il.com>
> ---
>  fs/dcache.c |   12 ++----------
>  1 files changed, 2 insertions(+), 10 deletions(-)
> 
> diff --git a/fs/dcache.c b/fs/dcache.c
> index 0e73aa0..8c559b2 100644
> --- a/fs/dcache.c
> +++ b/fs/dcache.c
> @@ -898,7 +898,7 @@ struct dentry *d_alloc(struct dentry * parent, const
> struct qstr *name)
>  	struct dentry *dentry;
>  	char *dname;
>  
> -	dentry = kmem_cache_alloc(dentry_cache, GFP_KERNEL); 
> +	dentry = kmem_cache_zalloc(dentry_cache, GFP_KERNEL); 
>  	if (!dentry)
>  		return NULL;
>  
> @@ -921,15 +921,7 @@ struct dentry *d_alloc(struct dentry * parent,
> const struct qstr *name)
>  	atomic_set(&dentry->d_count, 1);
>  	dentry->d_flags = DCACHE_UNHASHED;
>  	spin_lock_init(&dentry->d_lock);
> -	dentry->d_inode = NULL;
> -	dentry->d_parent = NULL;
> -	dentry->d_sb = NULL;
> -	dentry->d_op = NULL;
> -	dentry->d_fsdata = NULL;
> -	dentry->d_mounted = 0;
> -#ifdef CONFIG_PROFILING
> -	dentry->d_cookie = NULL;
> -#endif
> +
>  	INIT_HLIST_NODE(&dentry->d_hash);
>  	INIT_LIST_HEAD(&dentry->d_lru);
>  	INIT_LIST_HEAD(&dentry->d_subdirs);

-
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