From owner-svn-src-head@FreeBSD.ORG Sun Dec 16 18:49:52 2012 Return-Path: Delivered-To: svn-src-head@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 30B29507; Sun, 16 Dec 2012 18:49:52 +0000 (UTC) (envelope-from asmrookie@gmail.com) Received: from mail-lb0-f182.google.com (mail-lb0-f182.google.com [209.85.217.182]) by mx1.freebsd.org (Postfix) with ESMTP id 138BD8FC0A; Sun, 16 Dec 2012 18:49:50 +0000 (UTC) Received: by mail-lb0-f182.google.com with SMTP id go10so4055447lbb.13 for ; Sun, 16 Dec 2012 10:49:49 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:reply-to:sender:in-reply-to:references:date :x-google-sender-auth:message-id:subject:from:to:cc:content-type; bh=MvIJTjkJ7xXBTJRzhnES3xiH7PHqY4d4wyhLrpTm3gc=; b=pWdg4jwZw0DCP511L6AeLD3OVhDFwv1kn0nyZYpEmBcE5DFnrsJl+KX9j0vtwePkj8 rJEZFknJ3OWRq3xDjKES/K3JgyjTsswWfHP0eqGmbpiNrX2+FiVZuirqcN/OlvuNIlF7 tF256deGQ+IogkbUuWCjzCt3TGLxdJYfsiA7pWh+0jfvVkCaYFCp2GLB2xNtKTO04q8g EbBGmFp7EeG9DrYzf8NZnxoVFHtF70eYE9O8FQGwgi+cEg2e5NtsooP5BYRpSibjtmg/ l+Fj38lb6urXo/O6+LL02/eIym2zxt5pKMSaUEaZebsPd0NCcMPpxvGocc4Avi7AI0jw ybxQ== MIME-Version: 1.0 Received: by 10.152.122.133 with SMTP id ls5mr8739597lab.9.1355683789876; Sun, 16 Dec 2012 10:49:49 -0800 (PST) Sender: asmrookie@gmail.com Received: by 10.112.84.193 with HTTP; Sun, 16 Dec 2012 10:49:49 -0800 (PST) In-Reply-To: <50CD9B85.1040404@FreeBSD.org> References: <201211251422.qAPEM8BV074656@svn.freebsd.org> <50C9B525.2060503@FreeBSD.org> <50CD9B85.1040404@FreeBSD.org> Date: Sun, 16 Dec 2012 10:49:49 -0800 X-Google-Sender-Auth: VdbwLrzuMaIXKnS18lj-BlxQkSE Message-ID: Subject: Re: svn commit: r243515 - head/sys/kern From: Attilio Rao To: Andriy Gapon Content-Type: text/plain; charset=UTF-8 Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list Reply-To: attilio@FreeBSD.org List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 16 Dec 2012 18:49:52 -0000 On Sun, Dec 16, 2012 at 1:59 AM, Andriy Gapon wrote: > on 13/12/2012 22:17 Attilio Rao said the following: >> Right, but as I said, for the time being we can at least have a >> correct panic() semantic and take the right time to fix the >> generic_stop_cpus() and then absorb also the panic() fix into it. >> Right now the mechanism is still broken in panic and it can be fixed >> with a very easy fix, so we should just do it. >> This will also help vendors like Sandvine which may have hit just this bug too. > > > Perhaps I got confused... > Could you please re-explain to me your suggestion to fix panic(9)? > Because I thought that it would require exactly the same steps as fixing > generic_stop_cpus(). Sorry about this. - about generic_stop_cpus() we need to implement all the things we discussed which are quite a few and for some things, like avoiding races between stop map, wakeup and set of cupid I admit I'm still not sure how easilly can be done without locking - about panic(), the check is much more easy, just see my first response to Ryan, because we don't have the wakeup/restart race as generic_stop_cpu() does. I propose to at least fix panic for the time being. Once generic_stop_cpus() is fully functional we can get rid of panic() chunk altogether. Attilio -- Peace can only be achieved by understanding - A. Einstein