Date: Tue, 31 Jul 2018 09:02:59 -0700 (PDT) From: "Rodney W. Grimes" <freebsd-rwg@pdx.rh.CN85.dnsmgr.net> To: bob prohaska <fbsd@www.zefox.net> Cc: Trev <freebsd-arm@sentry.org>, freebsd-arm@freebsd.org Subject: Re: RPI3 swap experiments Message-ID: <201807311602.w6VG2xcN072497@pdx.rh.CN85.dnsmgr.net> In-Reply-To: <20180731153531.GA94742@www.zefox.net>
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> On Tue, Jul 31, 2018 at 10:31:33PM +1000, Trev wrote: > > bob prohaska wrote on 31/07/2018 15:47: > > > > > It would be most interesting to see what happens if OOMA > > > could be turned off. Is that possible? > > > > Possibly, but you might find you're treating the symptom(s) rather than > > the cause(s) ... something must be triggering the condition whether > > correctly or not. > > That's my point. To determine if OOMA is triggered correctly or not. I'm starting > to think not. > > The reason is the dependency on swap layout (mixed USB/microSD vs all one or the > other) and the fact that OOMA kills don't seem to coincide with periods of > maximum storage read/write delay, which is the conventional explanation for > why OOMA kills happen in the first place. If turning off OOMA allows buildworld > to complete successfully it suggests OOMA isn't correctly implemented. > An easy way of triggering OOM that I ran accross the other day is simply: truncate -s 4G foo grep Anything foo grep(1) well gladly grow up to 4G trying to create a "line" of text to search for the string "Anything". On a system with less than 4G of free memory this triggers an OOM and starts killing processes. Probably has to be run as root or limits get hit. -- Rod Grimes rgrimes@freebsd.org
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