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From: Marcelo Tosatti <marcelo.tosatti@cyclades.com>
To: akpm@osdl.org
Cc: linux-mm@kvack.org
Subject: use for page_state accounting fields
Date: Mon, 16 Aug 2004 16:29:42 -0300	[thread overview]
Message-ID: <20040816192941.GB21238@logos.cnet> (raw)

Hi Andrew,

I suppose you wrote the page_state per-CPU statistics structure.

There are some fields, for instance pgactivate/pgdeactivate, that
do not seem to be used anywhere. Sure, they are useful for statistics, 
but no place in the kernel exports them to userspace AFAICS.

        unsigned long pgactivate;       /* pages moved inactive->active */
        unsigned long pgdeactivate;     /* pages moved active->inactive */

Counting them is somewhat expensive I believe (need to disable IRQ), based
on the assumption that these days any cycle is a loss.

So, from my POV we should 

a) export them to userspace
b) surround them by CONFIG_DEBUG_MMSTATS or something similar

Tell me I'm wrong.


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             reply	other threads:[~2004-08-16 19:29 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-08-16 19:29 Marcelo Tosatti [this message]
2004-08-16 21:31 ` use for page_state accounting fields Andrew Morton
2004-08-16 20:33   ` Marcelo Tosatti
2004-08-16 22:34     ` Andrew Morton

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