Date: Thu, 4 Sep 1997 00:27:38 -0500 (EST) From: "John S. Dyson" <toor@dyson.iquest.net> To: brianc@pobox.com (Brian Campbell) Cc: freebsd-hackers@FreeBSD.ORG Subject: Re: 2.2-stable swap usage? Message-ID: <199709040527.AAA03237@dyson.iquest.net> In-Reply-To: <19970904000812.60761@pobox.com> from Brian Campbell at "Sep 4, 97 00:08:12 am"
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Brian Campbell said: > > Mike Smith said: > > The simple answer is that once swap is allocated to a process, it is > > never freed. You have, in the case above, 24M worth of text which at > > some stage has been swapped out, and thus has had swap allocated to it. > > It doesn't mean you have 24M worth of swap currently "in use". > > John S. Dyson wrote: > > Once the pages in MFS or any other process are paged out, those pages will be > > persistant in swap until the process exits (or the memory is explicitly > > deallocated by the process.) > > Ok. So, contrary to what Mike Smith says, pages that belonged to > a process that has since exited will no longer be marked in-use by > swap? > I think that he meant to say it. > > If they are still marked "in-use", is there a program other than > pstat that gives a more accurate picture of how many [active] pages > are in swap? > No. > > So, if 90% of MFS is consumed by files which are later unlinked > (and not in use by any process), is swap thereafter limited to 10% > of its original size? > If you use MFS, it's swap allocation (whatever it is) will persist until you unmount. I have thought about cleaning MFS up, but there are many more important things to do, and am overloaded trying to do them... :-(. -- John dyson@freebsd.org jdyson@nc.com
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