Date: Mon, 14 Jan 2008 13:30:43 +0100 From: Miroslav Lachman <000.fbsd@quip.cz> To: Andrew Snow <andrew@modulus.org> Cc: freebsd-jail@freebsd.org Subject: Re: Jails as a VPS Message-ID: <478B55F3.5080505@quip.cz> In-Reply-To: <47841D07.20902@modulus.org> References: <47841D07.20902@modulus.org>
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Andrew Snow wrote: > > Hi Guys, > > I am running a hoster providing "VPS" using FreeBSD Jails on 6.2 > > FYI, I have patched my kernel in several places to make it work for me: > * jails have their own SYSV shared memory and semaphores > * per-jail number of processes limit > * jail ability to be bound to a given CPU core > * jails have a limited range of nice values (10 to -10) compared to the > host environment > > and last but not least: > * memory usage measurement and limiting. > > It is this last one that is causing me the most problems. I modified > obreak() to deny requests for more memory when memory limit is exceeded, > and that works OK. > > But measuring the jail memory usage in the first place is proving to be > a pain, and I wonder if you guys have any ideas. > > I am doing something similar to the Google SoC, by measuring the > resident page count of every VM map held by every process in the jail. > > This does not measure memory fairly - it counts shared memory too many > times. To see this in action, I can allocate a jail with 500mb memory > limit then try to start 10 or 20 large apache HTTPD processes. While > using only a small amount of actual system ram (under 100mb probably), > it measures it to be much larger. > > I am now looking at adding fields to VM memory maps and tagging them so > I can ensure I don't count them twice, but this is starting to get > non-trivial. > > Anyone else been able to solve this problem or have any better knowledge? It would be nice to have those features in base FreeBSD 6/7. Can I (we) hope you publish your work? Miroslav Lachman
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