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Date:      Thu, 07 Dec 2000 17:50:31 +0900
From:      "Daniel C. Sobral" <dcs@newsguy.com>
To:        Matt Dillon <dillon@earth.backplane.com>
Cc:        News History File User <newsuser@free-pr0n.netscum.dk>, hackers@FreeBSD.ORG, usenet@tdk.net
Subject:   Re: vm_pageout_scan badness
Message-ID:  <3A2F4F57.A7EDEAEC@newsguy.com>
References:  <200012011918.eB1JIol53670@earth.backplane.com> <200012020525.eB25PPQ92768@newsmangler.inet.tele.dk> <200012021904.eB2J4An63970@earth.backplane.com> <200012030700.eB370XJ22476@newsmangler.inet.tele.dk> <200012040053.eB40rnm69425@earth.backplane.com> <200012050545.eB55jL453889@crotchety.newsbastards.org> <200012060519.eB65JS910042@crotchety.newsbastards.org> <200012060713.eB67D8I91529@earth.backplane.com>

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Matt Dillon wrote:
> 
>     You may be able to achieve an effect very similar to mlock(), but
>     runnable by the 'news' user without hacking the kernel, by
>     writing a quick little C program to mmap() the two smaller history
>     files and then madvise() the map using MADV_WILLNEED in a loop
>     with a sleep(15).  Keeping in mind that expire may recreate those
>     files, the program should unmap, close(), and re-open()/mmap/madvise the
>     descriptors every so often (like once a minute).  You shouldn't have
>     to access the underlying pages but that would also have a similar
>     effect.  If you do, use a volatile pointer so GCC doesn't optimize
>     the access out of the loop.  e.g.

Err... wouldn't it be better to write a quick little C program that
mlocked the files? It would need suid, sure, but as a small program
without user input it wouldn't have security problems.

-- 
Daniel C. Sobral			(8-DCS)
dcs@newsguy.com
dcs@freebsd.org
capo@the.great.underground.bsdconpiracy.org

		"The bronze landed last, which canceled that method of impartial
choice."




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