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Message-ID: <3f250c7105030100085ab86bd2@mail.gmail.com>
Date: Tue, 1 Mar 2005 04:08:15 -0400
From: Mauricio Lin <mauriciolin@gmail.com>
Reply-To: Mauricio Lin <mauriciolin@gmail.com>
To: Hugh Dickins <hugh@veritas.com>
Subject: Re: [PATCH] A new entry for /proc
Cc: Andrew Morton <akpm@osdl.org>, wli@holomorphy.com,
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       marcelo.tosatti@cyclades.com, nickpiggin@yahoo.com.au
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On Mon, 28 Feb 2005 20:41:31 +0000 (GMT), Hugh Dickins <hugh@veritas.com> wrote:
> On Mon, 28 Feb 2005, Mauricio Lin wrote:
> >
> > Now I am testing with /proc/pid/smaps and the values are showing that
> > the old one is faster than the new one. So I will keep using the old
> > smaps version.
> 
> Sorry, I don't have time for more than the briefest look.
> 
> It appears that your old resident_mem_size method is just checking
> pte_present, whereas your new smaps_pte_range method is also doing
> pte_page (yet no prior check for pfn_valid: wrong) and checking
> !PageReserved i.e. accessing the struct page corresponding to each
> pte.  So it's not a fair comparison, your new method is accessing
> many more cachelines than your old method.
> 
> Though it's correct to check pfn_valid and !PageReserved to get the
> same total rss as would be reported elsewhere, I'd suggest that it's
> really not worth the overhead of those struct page accesses: just
> stick with the pte_present test.
So, I can remove the PageReserved macro without no problems, right?


> 
> Your smaps_pte_range is missing pte_unmap?
Yes, but I already fixed this problem.  Paul Mundt has checked the
unmap missing.

Thanks,

Let me perform new experiments now.

BR,

Mauricio Lin.
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