Date: Wed, 14 Apr 1999 22:04:26 +0900 From: "Daniel C. Sobral" <dcs@newsguy.com> To: Ladavac Marino <mladavac@metropolitan.at> Cc: "'mi@aldan.algebra.com'" <mi@aldan.algebra.com>, current@FreeBSD.ORG Subject: Re: swap-related problems Message-ID: <3714925A.D348A0DB@newsguy.com> References: <55586E7391ACD211B9730000C11002761795E9@r-lmh-wi-100.corpnet.at>
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Ladavac Marino wrote: > > Another strategy is to reserve the swap space as soon as it is > allocated by the program. This strategy is much more conservative and > inherently safer, but it needs much more space: for instance, if you > have a program with WSS of a gigabyte and you want to system( "date" ), > you will need at least 2 gigs of swap because system() does fork() first > which means that you get 2 copies of your big program and the system > cannot know that in one of the copies an exec() will be shortly > forthcoming--thus, it has to reserve the full WSS for the copy because > it will potentially write to all pages of its WSS. > > It would be nice if memory overcommit were configurable (on-off, > or per process). On AIX, you can have it set as a global option and on/off per process. In my experience, though, setting it to off never solved anything: if you need memory, you have to add memory. -- Daniel C. Sobral (8-DCS) dcs@newsguy.com dcs@freebsd.org "nothing better than the ability to perform cunning linguistics" To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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