Date: Thu, 4 Sep 1997 00:08:12 -0400 From: Brian Campbell <brianc@pobox.com> To: freebsd-hackers@FreeBSD.ORG Subject: Re: 2.2-stable swap usage? Message-ID: <19970904000812.60761@pobox.com> In-Reply-To: <199709040340.WAA01942@dyson.iquest.net>; from John S. Dyson on Wed, Sep 03, 1997 at 10:40:51PM -0500 References: <19970903223343.28431@pobox.com> <199709040340.WAA01942@dyson.iquest.net>
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Brian Campbell said: > On Wed, Sep 03, 1997 at 09:19:05PM -0500, John S. Dyson wrote: > > Brian Campbell said: > > > Is it normal for 24M of swap to be marked in-use when nothing appears to be using it? > > > System has 64M RAM, and has been up and running AccelX for about a week. > > > Killing syslogd and cron didn't help. There wasn't much left ... > > > > All of the address ranges marked by swap in the /proc/*/map can be in > > swap space. Looks like there is enough of 'em. Unmount the mfs, and > > I would suspect alot of your space will be freed up... > > I suppose I should've included a 'df' of /tmp. There was less than 50k in use at that point. > Next time it happens, I'll try to umount the mfs and see if it changes anything ... 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? 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? > MFS doesn't deallocate any of it's memory usage. 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?
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