From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <7f5a01030a00fc411c0dfb2f62182b6c@felloff.net> Date: Sun, 8 Jun 2014 19:49:00 +0200 From: cinap_lenrek@felloff.net To: 9fans@9fans.net In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Subject: Re: [9fans] duppage Topicbox-Message-UUID: f7f3471e-ead8-11e9-9d60-3106f5b1d025 duppage() causes the freelist to be shuffled differently. without stuffing cached pages at the freelist tail, the tail accumulates a uncached "stopper" page which breaks the invariant of imagereclaim which just scans from the tail backwards as long as the pages are cached. imagereclaim does not move the pages to the head after uncaching them! so by default imagereclaim prevents the cached pages before the ones it reclaimed from being reclaimed ever. before image reclaim: H UUUUUUUUCCCCCCCCCC T after image reclaim: H UUUUUUUUCCCCUUUUUU T ^- as far was imagereclaim went nwith duppage, theres always new cached pages added at the tail. i suspect once you run out of images, imagereclaim will run constantly and blow away the little usefull image cache you still have causing additional reads to page them back in. -- cinap