Date: Wed, 17 Feb 1999 14:31:28 -0500 (EST) From: "John S. Dyson" <dyson@iquest.net> To: eivind@FreeBSD.ORG (Eivind Eklund) Cc: brandon@roguetrader.com, freebsd-hackers@FreeBSD.ORG Subject: Re: savecore before swapon? Message-ID: <199902171931.OAA69956@y.dyson.net> In-Reply-To: <19990217142628.F69668@bitbox.follo.net> from Eivind Eklund at "Feb 17, 99 02:26:28 pm"
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Eivind Eklund said: > On Tue, Feb 16, 1999 at 08:26:00AM -0700, Brandon Gillespie wrote: > > I havn't checked the source, but from my understanding shouldn't > > savecore be run before swapon is run, incase the swap device is the > > dump device? Or to look at it another way, when swapon is run on a > > swap device, does it look first to see if there is a dump in it, and > > if so what does it do? Right now we run swapon, then considerably > > later we run savecore. Assuming swapon just trashes whatever was in > > that device, running savecore is pretty much irrelevant, as most > > people I know (not necessarily in FreeBSD) use their swap device as a > > dump point. > > This is done intentionally, as fsck may in some cases require swap > to be able to fsck large filesystems. > > It would make sense to have a sysctl > 'only_swap_as_absolutely_last_resort_not_for_performance' AKA > 'do_linux_swapping_scheme' which was set before the swapon, and unset > after the crashdump. I don't know how to implement this. (It might > be that one of the present sysctls does something like this - I've not > checked). > sysctl -w vm.defer_swapspace_pageouts=1 It will still page nicely, but performance will be less when under memory load, because of less memory being available. -- John | Never try to teach a pig to sing, dyson@iquest.net | it makes one look stupid jdyson@nc.com | and it irritates the pig. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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