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Date: Mon, 20 May 2002 11:32:27 -0700
From: Mike Fedyk <mfedyk@matchmail.com>
To: Manik Raina <manik@cisco.com>
Cc: Matti Aarnio <matti.aarnio@zmailer.org>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH]: adding counters to count bytes read/written
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On Mon, May 20, 2002 at 04:33:40PM +0530, Manik Raina wrote:
> 
> 	Thanks for the comments Matti, Please see inline ...
> 
> Matti Aarnio wrote:
> > 
> > On Mon, May 20, 2002 at 03:09:36PM +0530, Manik Raina wrote:
> > > Hi Linus,
> > >
> > >       This patch adds 2 counters to the task_struct for
> > >       counting how many bytes were read/written using
> > >       the read()/write() system calls.
> > >
> > >       These counters may be useful in determining how
> > >       many IO requests are made by each process.
> > 
> >   These are defined as UINTegers, are you sure that is appropriate type ?
> >   What to do when they will overflow ?  For short term activity tracking
> >   they may be ok (4GB/200 MB/sec = 20 sec to wrap around), but for accounting
> >   the overflow might not be liked thing..
> 
> 
> 	How about 64 bit counters ? i feel those should go on without
> 	wraparound for a _very_ long time.

I really doubt that 64bit counters in a fast path will be accepted.  You'll
really need to justify something like that.

Have you looked at the process accounting code?