Date: Tue, 25 Jun 1996 19:55:34 -0700 From: David Greenman <davidg@root.com> To: Juergen Lock <nox@jelal.hb.north.de> Cc: jhay@mikom.csir.co.za, stable@FreeBSD.org Subject: Re: lockups. Message-ID: <199606260255.TAA12927@root.com> In-Reply-To: Your message of "Wed, 26 Jun 1996 04:08:09 %2B0200." <199606260208.EAA00706@saturn.hb.north.de>
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>David Greenman writes: > >> Other than consistency checks, the only change that has been made to the >> pageout daemon was last Wednesday when the RSS limiting code was #if 0'd. >> The code shouldn't have come into play on most systems (since the default >> limit is 1/2 of all memory). The problem is that it might not be safe due to >> the recursive calling nature of the functions that do the trimming and because >> it walks through the 'allproc' list in a potentially dangerous manner. >> You could try to enable it and see if this is the "night and day" >> difference that you're describing. Change the #if 0 to a #if 1 at the end of >> /sys/vm/vm_pageout.c. > >Thats just what i did, and i put back the remove-cached-objects-that- >have-no-RSS code below the #if 0'd part. (havent tried the #if 1 alone) The other code that was removed has always been outside the while(1) loop, so it is NEVER executed. > i guess its not the rss-above-limit check that makes the big difference >but the one for process-swapped-out? if its disabled then entries >for swapped out processed remain in the list its traversing, causing >more page faults... up to the point where its doing little else. >am i talking nonsense yet? :) Yes, that appears to be the problem. We're going to turn this code back on after putting some controls on it to make sure it doesn't cause stability problems. John will have a fix soon (if not already), so please install the fix and get back to us ASAP. -DG David Greenman Core-team/Principal Architect, The FreeBSD Project
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