Date: Wed, 16 Mar 2005 14:43:59 +0100 From: "Colin J. Raven" <colin@kenmore.kozy-kabin.nl> To: Giorgos Keramidas <keramida@ceid.upatras.gr> Cc: freebsd-questions@freebsd.org Subject: Re: Illogical usage of swap Message-ID: <20050316143538.Y2949@kenmore.kozy-kabin.nl> In-Reply-To: <20050316133401.GA8571@orion.daedalusnetworks.priv> References: <20050316123901.U2949@kenmore.kozy-kabin.nl> <444qfbpydd.fsf@be-well.ilk.org> <20050316125446.GA7986@orion.daedalusnetworks.priv> <20050316130754.GC7986@orion.daedalusnetworks.priv> <20050316133401.GA8571@orion.daedalusnetworks.priv>
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On Mar 16 at 15:34, Giorgos Keramidas suggested: >>>>>> Free memory (or the lack thereof) isn't the issue though. >>>>>> >>>>>> The issue is this: >>>>>> Swap: 8192M Total, 116K Used, 8192M Free >>>>>> and that's the piece of the puzzle that has us all utterly baffled. >>>>>> >>>>>> No way in creation this box should be swapping. >>>>> >>>>> Do you, by any chance, have vm.swap_idle_enabled set to 1? >>>> >>>> No, it isn't: >>>> gonzo# sysctl -a |grep vm.swap_idle_enabled >>>> vm.swap_idle_enabled: 0 >>> >>> Strange. AFAIK, processes are not swapped out to disk unless there is a >>> severe memory shortage. The usual case is to have them "paged" out, >>> which is a bit different. >> >> That was my understanding also, and that's what's baffling us > > Unless, of course, there _was_ a short period of memory shortage, some > processes were swapped out (a pair of idle getty instances, for example) > and they were never swapped back in because they are still idle. > > You can probably track this down to the specific process or processes > that have the PS_INMEM bit turned off in their proc->p_sflag. But 116K > seems too small to be a complete process. This is going way above my head now, but great as a learning process anyway! May I ask how we would go about tracking processes with the PS-INMEM bit turned off? That sounds as if - to me, still a journeyman on the road to knowledge - grepping multiple source trees might be necessary, which frankly is a daunting process (to say the very least). Is there one meta-search string that would show this? and if so, where should this search be applied? Regards, -Colin -- Colin J. Raven Wed Mar 16 14:43:00 CET 2005
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