From owner-freebsd-current@FreeBSD.ORG Tue May 19 01:26:53 2009 Return-Path: Delivered-To: current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 8A2681065674 for ; Tue, 19 May 2009 01:26:53 +0000 (UTC) (envelope-from mat.macy@gmail.com) Received: from an-out-0708.google.com (an-out-0708.google.com [209.85.132.249]) by mx1.freebsd.org (Postfix) with ESMTP id 3A8188FC13 for ; Tue, 19 May 2009 01:26:53 +0000 (UTC) (envelope-from mat.macy@gmail.com) Received: by an-out-0708.google.com with SMTP id c3so1982637ana.13 for ; Mon, 18 May 2009 18:26:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:sender:received:in-reply-to :references:date:x-google-sender-auth:message-id:subject:from:to:cc :content-type:content-transfer-encoding; bh=S7wC0CZ8C/chzWfmNWKP1zjx1FDzZirO8Lq1gwLH92U=; b=hBd3ZmN7cB1VXF+fpCIb9U9ffrelreb9S60IziTSaOAZc6USZg9MZ9mm4YrKKODVB6 JIChbw9OSTXpuOrKoH2XDJ5z05DJ26K9slO+CW8aLHmkb1zk9sE1+l8SybOweW034Wai j1aOOm8rSWE80aKCBMW2Ud2JikSzIxRZ/m6mk= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:sender:in-reply-to:references:date :x-google-sender-auth:message-id:subject:from:to:cc:content-type :content-transfer-encoding; b=kIBUO2EI292pWcpBZt8JCn6p1iIVtmvoRtjg9NZL+Dy896Yr8msW5v3H6+5jtpEJhA 4EqFH93XcAN/1FjHhj8nH0p4NC1Lsz66kCwemQ8KbDJa4iPjgGqR+g20IlB0daAFxrWQ 4dxfEPCInwW3IUmHwSCH2IWDTTVzvTH3vo4uQ= MIME-Version: 1.0 Sender: mat.macy@gmail.com Received: by 10.100.46.15 with SMTP id t15mr10063040ant.102.1242696411173; Mon, 18 May 2009 18:26:51 -0700 (PDT) In-Reply-To: <20090519012202.GR82547@egr.msu.edu> References: <20090518145614.GF82547@egr.msu.edu> <3c1674c90905181659g1d20f0f1w3f623966ae4440ec@mail.gmail.com> <20090519012202.GR82547@egr.msu.edu> Date: Mon, 18 May 2009 18:26:51 -0700 X-Google-Sender-Auth: 057463b1dd1da167 Message-ID: <3c1674c90905181826p787a346cie90429324444a9c4@mail.gmail.com> From: Kip Macy To: Adam McDougall Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Cc: current@freebsd.org, Larry Rosenman Subject: Re: Fatal trap 12: page fault panic with recent kernel with ZFS X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 19 May 2009 01:26:53 -0000 On Mon, May 18, 2009 at 6:22 PM, Adam McDougall wrot= e: > On Mon, May 18, 2009 at 07:06:57PM -0500, Larry Rosenman wrote: > > =A0On Mon, 18 May 2009, Kip Macy wrote: > > =A0> The ARC cache allocates wired memory. The ARC will grow until there = is > =A0> vm pressure. > =A0My crash this AM was with 4G real, and the ARC seemed to grow and grow= , then > =A0we started paging, and then crashed. > > =A0Even with the VM pressure it seemed to grow out of control. > > =A0Ideas? > > > Before that but since 191902 I was having the opposite problem, > my ARC and thus Wired would grow up to approx arc_max until my > Inactive memory put pressure on ARC making it shrink back down > to ~450M where some aspects of performance degraded. =A0A partial > workaround was to add a arc_min which isn't entirely successful > and I found I could restore ZFS performance by temporarily squeezing > down Inactive memory by allocating a bunch of it myself; after > freeing that, ARC had no pressure and could grow towards arc_max > again until Inactive eventually rose. =A0Reported to Kip last night > and some cvs commit lists. =A0I never did run into Swap. > That is a separate issue. I'm going to try adding a vm_lowmem event handler to drive reclamation instead of the current paging target. That shouldn't cause inactive pages to shrink the ARC. Most people consider out of the box stability more import than getting the maximum ARC. However, for people like you who want the safety catches removed I should make it possible to disable back-pressure. -Kip