From owner-freebsd-questions@FreeBSD.ORG Thu Apr 26 18:03:13 2012 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 6E6741065670 for ; Thu, 26 Apr 2012 18:03:13 +0000 (UTC) (envelope-from rwmaillists@googlemail.com) Received: from mail-ee0-f54.google.com (mail-ee0-f54.google.com [74.125.83.54]) by mx1.freebsd.org (Postfix) with ESMTP id E81EA8FC0A for ; Thu, 26 Apr 2012 18:03:12 +0000 (UTC) Received: by eekd17 with SMTP id d17so780076eek.13 for ; Thu, 26 Apr 2012 11:03:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=googlemail.com; s=20120113; h=date:from:to:subject:message-id:in-reply-to:references:x-mailer :mime-version:content-type:content-transfer-encoding; bh=j1S8RDLsEuIe5/q1yJl4rZB1rOod4T/s1MnzQYD0eT4=; b=FFrxIGs4N9EIfr8BOX8PZm4ZUtWp5EkUSTMA+lPa15na84YLoztmjtwF9V35d+fB+D nfQ7U+wUpKo1UH09V0AOqOxz0wOMMOtk1RhvRDt18z5ob5L84x/RY7rW927YpGrc8dZR sRGOErRkWUmCDc7lLDxBzHcVkJaZbOsY0N91gaCrH+chmcuHBSrGml3W7sZyWpw9zXqV vT91ZV/cfvmQFYgYuqg0z5xAWna9EMtLNKh4+3/Vk+n2b6JVukpO+2z3wHut77IYsAOK V9J2Q1mWLWp/aDOEfH4Fi3RY0P72b1g+pq8AM1VDA0MuvgTddEVD2nw/TOyTJ7l/NDWr 8n9Q== Received: by 10.14.101.12 with SMTP id a12mr1980324eeg.55.1335463391791; Thu, 26 Apr 2012 11:03:11 -0700 (PDT) Received: from gumby.homeunix.com (87-194-105-247.bethere.co.uk. [87.194.105.247]) by mx.google.com with ESMTPS id p57sm17947801eei.8.2012.04.26.11.03.08 (version=SSLv3 cipher=OTHER); Thu, 26 Apr 2012 11:03:10 -0700 (PDT) Date: Thu, 26 Apr 2012 19:03:04 +0100 From: RW To: freebsd-questions@freebsd.org Message-ID: <20120426190304.0ec3330f@gumby.homeunix.com> In-Reply-To: References: <2FCC4ECF-DAC2-4701-B392-B0415528A4C7@mac.com> X-Mailer: Claws Mail 3.8.0 (GTK+ 2.24.6; amd64-portbld-freebsd8.2) Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Subject: Re: FreeBSD vice OS X memory management X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 26 Apr 2012 18:03:13 -0000 On Thu, 26 Apr 2012 08:32:39 +0000 (UTC) jb wrote: > Adam Vande More gmail.com> writes: >=20 > > ...=20 > > http://workstuff.tumblr.com/post/19036310553/two-things-that-really-hel= ped- > > speed-up-my-mac-and > > http://dywypi.org/2012/02/back-on-linux.html > >=20 >=20 > "2) Inactive memory (which is memory that has been recently used but > is no longer) is supposed to be seamlessly reclaimed automatically by > the OS when needed for new programs. In practice, I=E2=80=99ve found that > this isn=E2=80=99t the case, and my system slows to a crawl and starts pa= ging > out to disk when free memory drops to zero, even as half of the > available RAM (which is a lot) is marked as inactive. ..." That's not a good description of inactive memory, most of which contains useful data. The situation described is undesirable, but not abnormal. It can happen when your physical memory is spread thinly, but most of it isn't being frequently accessed. In that case the inactive queue can be dominated by dirty swap-backed pages.=20 > The above and the past FreeBSD thread here, both I referred to, have > something in common - the system seems to progressively come under > stress due to what one user experienced as "missing memory", The FreeBSD link involved ZFS which manages its own disk caching and is relatively new. My guess is that if there is a problem it's ZFS specific. If it were a more general problem I think we'd see a lot more complaints, whereas ZFS already has a reputation for needing lots of memory.