From owner-freebsd-hackers@FreeBSD.ORG Thu Mar 22 17:48:31 2012 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id C7773106566C for ; Thu, 22 Mar 2012 17:48:31 +0000 (UTC) (envelope-from nonesuch@longcount.org) Received: from mail-lpp01m010-f54.google.com (mail-lpp01m010-f54.google.com [209.85.215.54]) by mx1.freebsd.org (Postfix) with ESMTP id 3D6C78FC14 for ; Thu, 22 Mar 2012 17:48:30 +0000 (UTC) Received: by lagv3 with SMTP id v3so2462714lag.13 for ; Thu, 22 Mar 2012 10:48:29 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20120113; h=mime-version:x-originating-ip:in-reply-to:references:date :message-id:subject:from:to:content-type:content-transfer-encoding :x-gm-message-state; bh=JLfV0o5exSLjN67kpUAPlzd2l7thCKBXK4bHuxGTUjI=; b=iXPq8DGvR/6guuXQHwRrWuVea50zfgDOCbCCsUSUHbewt2Hg8sGM3ubn2puL/phBjI wdilTuxdQHKGAqh0aTf6UX5rAmZz54a13zVjw2RQBWL62ahlzbYod4JHACVFXvI0FeuJ awEneE3KJdIGkenOtDdgbVYeSWmds4pDQV9ke0Pp4Pgf8Vty0DkjflXHmQejjD155nAO +g4OJWhOYoX/TWG5rEFlXNHuRz1JJvZgh/39+givhQKtp9jTqZOmlzLdulTSZybztXgt GtuwQ3fmyobiO/AkctAr7bycXz99J5QWCR4Fef9qtg3d3pvhE5BoOqRlDL+BE5yTZF/u zwzw== MIME-Version: 1.0 Received: by 10.112.23.38 with SMTP id j6mr3372506lbf.15.1332438509616; Thu, 22 Mar 2012 10:48:29 -0700 (PDT) Received: by 10.112.36.135 with HTTP; Thu, 22 Mar 2012 10:48:29 -0700 (PDT) X-Originating-IP: [209.66.78.50] In-Reply-To: <201203220803.57000.jhb@freebsd.org> References: <201203220803.57000.jhb@freebsd.org> Date: Thu, 22 Mar 2012 13:48:29 -0400 Message-ID: From: Mark Saad To: freebsd-hackers@freebsd.org Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Gm-Message-State: ALoCoQlEMEHA8INcUj714+q66bBU19Y+en8m42PCTUlAwdSBpDa8ie9bYsD7CCp6KL8GzUO+VSFr Subject: Re: Approaching the limit on PV entries X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 22 Mar 2012 17:48:32 -0000 On Thu, Mar 22, 2012 at 8:03 AM, John Baldwin wrote: > On Wednesday, March 21, 2012 4:20:17 pm Mark Saad wrote: >> On Wed, Mar 21, 2012 at 12:39 PM, Sergey Kandaurov w= rote: >> > On 21 March 2012 19:19, John Baldwin wrote: >> >> On Tuesday, March 20, 2012 11:37:57 am Sergey Kandaurov wrote: >> >>> On 22 November 2011 19:29, Mark Saad wrote: >> >>> > Hello All >> >>> >> >>> [found this mail in my drafts, not sure if my answer is still useful= ] >> >>> >> >>> > =C2=A0I want to get to the bottom of a warning in dmesg. On 7.2-RE= LEASE and >> >>> > 7.3-RELEASE I have seen the following warning in dmesg. >> >>> > >> >>> > Approaching the limit on PV entries, consider increasing either th= e >> >>> > vm.pmap.shpgperproc or the vm.pmap.pv_entry_max sysctl. >> >>> > >> >>> > So looking around I see a few posts here and there about how to tu= ne >> >>> > the sysctls to address the warning however I am not 100% sure what >> >>> > each value does. >> >>> > It appears changing vm.pmap.shpgperproc affects the value of >> >>> > vm.pmap.pv_entry_max . Can someone explain the relationship of the= two >> >>> > sysctls. Also >> >>> >> >>> This is how they are calculated. >> >>> >> >>> pv_entry_max =3D shpgperproc * maxproc + cnt.v_page_count; >> >>> >> >>> and, respectively, >> >>> >> >>> shpgperproc =3D (pv_entry_max - cnt.v_page_count) / maxproc; >> >>> >> >>> So, changing one sysctl will change another and vice versa. >> >>> >> >>> > what pitfalls of changing them are. >> >>> >> >>> Not known to me (on amd64 platform). >> >>> I have had vm.pmap.shpgperproc=3D15000 on 8.1 amd64 with 4G RAM >> >>> to make some badly written commercial software to work until it >> >>> was decommissioned to the scrap. >> >> >> >> FYI, Alan just removed this warning and the associated sysctls from H= EAD >> >> yesterday because they were made obsolete several years ago. =C2=A0I = think they are >> >> obsolete even on 7. =C2=A0Certainly on 8. >> > >> > Yep, and since switching to direct map (somewhere around 7.x on amd64?= ) >> > made PV entry limit factually obsolete, this is really cool. >> > >> > -- >> > wbr, >> > pluknet >> >> Interesting so this warning is relevant in 7.x ? > > No, looks like it was obsolete starting with 7.0. > > -- > John Baldwin Any chance it could be mfc'ed to 7-STABLE ? --=20 mark saad | nonesuch@longcount.org