Date: Wed, 16 Feb 2005 15:13:46 -0800 From: Julian Elischer <julian@elischer.org> To: Brooks Davis <brooks@one-eyed-alien.net> Cc: current@freebsd.org Subject: Re: where did all my memory go? (file system cache) Message-ID: <4213D3AA.70809@elischer.org> In-Reply-To: <20050216214031.GA2787@odin.ac.hmc.edu> References: <1108584730.95661.12.camel@server.mcneil.com> <20050216201716.GA28436@odin.ac.hmc.edu> <4213B3C8.3090508@centtech.com> <1108588393.12275.9.camel@server.mcneil.com> <20050216214031.GA2787@odin.ac.hmc.edu>
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slightly off topic but..
Brooks Davis wrote:
>On Wed, Feb 16, 2005 at 01:13:13PM -0800, Sean McNeil wrote:
>
>
>The concept that most of your memory should be entierly free when the
>system is not under load is simply wrong. The simplistic world view of
>memory being allocated to a specific task or entierly free simply isn't
>correct for all that it makes for nice graphs anyone can pretend they
>understand. You can produce some sort of aproximation of the output you
>see on other systems by modifying the program to include inactive memory
>in free memory. That's what I did with Ganglia.
>
what I really want is a way to FORce certain pages out of cache.
In particular I need to verify teh correctness of the version on 2ndary
storage..
what I want is:
int fd = open("myfile",...);
write1GBfiletodisk(fd, data);
ioctl(fd, PURGEFROMCACHE);
perform_md5(fd);
and be sure that teh MD5 is that of what is on the disk.
not what is in RAM.
>
>-- Brooks
>
>
>
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