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Date: Fri, 30 Nov 2001 13:44:42 -0200 (BRST)
From: Marcelo Tosatti <marcelo@conectiva.com.br>
To: Andrew Morton <akpm@zip.com.au>
Cc: Linus Torvalds <torvalds@transmeta.com>,
        lkml <linux-kernel@vger.kernel.org>
Subject: Re: [patch] smarter atime updates
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Now are you sure this can't break anything ? 

On Thu, 29 Nov 2001, Andrew Morton wrote:

> mark_inode_dirty() is quite expensive for journalling filesystems,
> and we're calling it a lot more than we need to.
> 
> --- linux-2.4.17-pre1/fs/inode.c	Mon Nov 26 11:52:07 2001
> +++ linux-akpm/fs/inode.c	Thu Nov 29 21:53:02 2001
> @@ -1187,6 +1187,8 @@ void __init inode_init(unsigned long mem
>   
>  void update_atime (struct inode *inode)
>  {
> +	if (inode->i_atime == CURRENT_TIME)
> +		return;
>  	if ( IS_NOATIME (inode) ) return;
>  	if ( IS_NODIRATIME (inode) && S_ISDIR (inode->i_mode) ) return;
>  	if ( IS_RDONLY (inode) ) return;
> 
> 
> with this patch, the time to read a 10 meg file with 10 million
> read()s falls from 38 seconds (ext3), 39 seconds (reiserfs) and
> 11.6 seconds (ext2) down to 10.5 seconds.
> 
> -
>