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Date: Wed, 5 Jan 2011 10:45:43 +0200
From: Alexey Dobriyan <adobriyan@gmail.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH] proc: make proc entry's len "unsigned int"
Message-ID: <20110105084543.GA4598@p183.telecom.by>
References: <20101126211033.GA14339@core2.telecom.by>
 <20110104165159.49c257b7.akpm@linux-foundation.org>
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On Tue, Jan 04, 2011 at 04:51:59PM -0800, Andrew Morton wrote:
> On Fri, 26 Nov 2010 23:10:33 +0200
> Alexey Dobriyan <adobriyan@gmail.com> wrote:

> >  struct proc_dir_entry {
> >  	unsigned int low_ino;
> > -	unsigned short namelen;
> > +	unsigned int namelen;
> >  	const char *name;
> >  	mode_t mode;
> >  	nlink_t nlink;
> 
> Well, if we _can_ save some space here then the returns would be
> appreciable.
> 
> akpm:/home/akpm# find /proc | wc -l
> 95543
> 
> (wtf?)
> 
> akpm:/home/akpm# find /proc/[0-9]* | wc -l
> 94212
> 
> (oh.)

Different number of processes?

> Do all of those things have a proc_dir_entry?

No!

> IIRC we changed things so they're somewhat allocate-on-demand.

Only /proc/$PID and /proc/sys/* are on-demand allocated.
The rest has struct proc_dir_entry associated.