From owner-freebsd-hackers@FreeBSD.ORG Mon Apr 2 21:19:23 2012 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 408A71065676 for ; Mon, 2 Apr 2012 21:19:23 +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 AEC488FC1B for ; Mon, 2 Apr 2012 21:19:22 +0000 (UTC) Received: by lagv3 with SMTP id v3so5273776lag.13 for ; Mon, 02 Apr 2012 14:19:21 -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=i977cmIYi0VjPziBONqp26cVdExJxIpmWTsh9EhIEhA=; b=gIIAvWOAd9QZ56FGJhD6IrlrIwSs4TdnQ8H3O9lcOYzA8bu9aZRePA7msag1ZwEjqg /0EbwRsAMLKLjZ4+BOiqJ96JN7IpHBxWVyVTjZvwuf9D9Xa9mjvI5Omi+z8SF6VyxFak XR3/MW6K7vvrN5W+kGU4tyLPEwvHl2YqUahx5QYx+0tlzVp92igY0+qKyvjnGgywBnfV Nq259AR1uMVKI7em/NmcXPge22PDN9K9+0K/n/8+ASFY72of7BwGV5HNVjGqqPs9E/z5 uXN3fIFGDkEuquFIj19/VB29CLuAvjspox11xXjrQGTrzxjHHW5gV5kxIdBGwApC87Xk WPxg== MIME-Version: 1.0 Received: by 10.152.132.132 with SMTP id ou4mr11331139lab.26.1333401561115; Mon, 02 Apr 2012 14:19:21 -0700 (PDT) Received: by 10.112.145.138 with HTTP; Mon, 2 Apr 2012 14:19:21 -0700 (PDT) X-Originating-IP: [216.223.13.111] In-Reply-To: <201204021123.53055.jhb@freebsd.org> References: <201203220803.57000.jhb@freebsd.org> <201204021123.53055.jhb@freebsd.org> Date: Mon, 2 Apr 2012 17:19:21 -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: ALoCoQlYO0sy507ApGZplVKh9PscEHCAaof9hJWLvfsp3ukj4oCey7e3wfLGDHDCXOHWPB18Iyjs 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: Mon, 02 Apr 2012 21:19:23 -0000 On Mon, Apr 2, 2012 at 11:23 AM, John Baldwin wrote: > On Thursday, March 22, 2012 1:48:29 pm Mark Saad wrote: >> 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 wrote: >> >> > 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 wro= te: >> >> >>> > Hello All >> >> >>> >> >> >>> [found this mail in my drafts, not sure if my answer is still use= ful] >> >> >>> >> >> >>> > =C2=A0I want to get to the bottom of a warning in dmesg. On 7.2= -RELEASE and >> >> >>> > 7.3-RELEASE I have seen the following warning in dmesg. >> >> >>> > >> >> >>> > Approaching the limit on PV entries, consider increasing either= the >> >> >>> > 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= tune >> >> >>> > the sysctls to address the warning however I am not 100% sure w= hat >> >> >>> > 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 fro= m HEAD >> >> >> 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 amd= 64?) >> >> > 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 ? > > I just merged it to stable/7. > > -- > John Baldwin Thanks again john . --=20 mark saad | nonesuch@longcount.org