From owner-freebsd-hackers@FreeBSD.ORG Sun May 20 07:26:04 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 0854C1065670; Sun, 20 May 2012 07:26:02 +0000 (UTC) (envelope-from alan.l.cox@gmail.com) Received: from mail-pb0-f54.google.com (mail-pb0-f54.google.com [209.85.160.54]) by mx1.freebsd.org (Postfix) with ESMTP id C8E2B8FC08; Sun, 20 May 2012 07:26:01 +0000 (UTC) Received: by pbbro2 with SMTP id ro2so6079916pbb.13 for ; Sun, 20 May 2012 00:25:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:reply-to:in-reply-to:references:date:message-id :subject:from:to:cc:content-type; bh=xKYg64oQ2049hcmN3hiXpwIa8A+EScJareT06D+AZ0M=; b=jdCr+4C3tm/uPvx2qwfBmPqJMAj8h62frZRFdaQH/LmTxqCgtwyCAc2Exn3ZrLw0cL xDw1xAn+XaYecUCptpToIlVrF2Ss9b6c0ON2F+BSxe2yEyKDvh1F7QD7YYLYIi7sLq8f /eWBLycOA6YpMmrNqnWWSuBsh4cxflG2N5uxZB7R9jD0dirz685VN7S9XSUJH+fcJDWh WhADeWOmI1TicKrerQ33Ot3+ao6lqclPphm8r4hGeRdBvlPgFMR23hyEjA6S7IjZjpjr ka84DLGAxvOlJ8WsFkzHfKJedXeq/+IXO9J/ZwW6t0eE3uaD4HLhzFcLL/tF70wm2Pxr /AMw== MIME-Version: 1.0 Received: by 10.68.238.73 with SMTP id vi9mr23354111pbc.14.1337498759601; Sun, 20 May 2012 00:25:59 -0700 (PDT) Received: by 10.68.226.7 with HTTP; Sun, 20 May 2012 00:25:59 -0700 (PDT) In-Reply-To: <201205200901.32613.zec@fer.hr> References: <201205200901.32613.zec@fer.hr> Date: Sun, 20 May 2012 02:25:59 -0500 Message-ID: From: Alan Cox To: Marko Zec Content-Type: text/plain; charset=ISO-8859-1 X-Content-Filtered-By: Mailman/MimeDel 2.1.5 Cc: freebsd-hackers@freebsd.org, freebsd-amd64@freebsd.org Subject: Re: superpages and kmem on amd64 X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: alc@freebsd.org List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 20 May 2012 07:26:04 -0000 On Sun, May 20, 2012 at 2:01 AM, Marko Zec wrote: > Hi all, > > I'm playing with an algorithm which makes use of large contiguous blocks of > kernel memory (ranging from 1M to 1G in size), so it would be nice if those > could be somehow forcibly mapped to superpages. I was hoping that the VM > system would automagically map (merge) contiguous 4k pages to superpages, > but > apparently it doesn't: > > vm.pmap.pdpe.demotions: 2 > vm.pmap.pde.promotions: 543 > vm.pmap.pde.p_failures: 266253 > vm.pmap.pde.mappings: 0 > vm.pmap.pde.demotions: 31 > > No, your conclusion is incorrect. These counts show that 543 superpage mappings were created by promotion. Alan