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Message-ID: <2cd57c90050817183942b217fa@mail.gmail.com>
Date: Thu, 18 Aug 2005 09:39:16 +0800
From: Coywolf Qi Hunt <coywolf@gmail.com>
To: Eric Dumazet <dada1@cosmosbay.com>
Subject: Re: [PATCH] struct file cleanup : the very large file_ra_state is now allocated only on demand.
Cc: Andi Kleen <ak@suse.de>, Benjamin LaHaise <bcrl@linux.intel.com>,
       "David S. Miller" <davem@davemloft.net>, netdev@vger.kernel.org,
       linux-kernel@vger.kernel.org
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On 8/18/05, Eric Dumazet <dada1@cosmosbay.com> wrote:
> Andi Kleen a écrit :
> 
> >
> >>(because of the insane struct file_ra_state f_ra. I wish this structure
> >>were dynamically allocated only for files that really use it)
> >
> >
> > How about you submit a patch for that instead?
> >
> > -Andi
> 
> OK, could you please comment this patch ?
> 
> The problem of dynamically allocating the readahead state data is that the allocation can fail and should not be fatal.
> I made some choices that might be not good.
> 
> I also chose not to align "file_ra" slab on SLAB_HWCACHE_ALIGN because the object size is 10*sizeof(long), so alignment would loose
> 6*sizeof(long) bytes for each object.
> 
> 
> [PATCH]
> 
> * struct file cleanup : the very large file_ra_state is now allocated only on demand, using a dedicated "file_ra" slab.
>         64bits machines handling lot of sockets can save about 72 bytes per file.
> * private_data : The field is moved close to f_count and f_op fields to speedup sockfd_lookups

Why not keep the comment or fix it?

-- 
Coywolf Qi Hunt
http://ahbl.org/~coywolf/