From owner-freebsd-arch@freebsd.org Wed Oct 19 21:31:56 2016 Return-Path: Delivered-To: freebsd-arch@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 719AEC1969A for ; Wed, 19 Oct 2016 21:31:56 +0000 (UTC) (envelope-from bright@mu.org) Received: from elvis.mu.org (elvis.mu.org [192.203.228.196]) by mx1.freebsd.org (Postfix) with ESMTP id 64926D7; Wed, 19 Oct 2016 21:31:56 +0000 (UTC) (envelope-from bright@mu.org) Received: from AlfredMacbookAir.local (104-244-24-105.PUBLIC.monkeybrains.net [104.244.24.105]) by elvis.mu.org (Postfix) with ESMTPSA id 46FA9346DEA8; Wed, 19 Oct 2016 14:31:49 -0700 (PDT) Subject: Re: watchdog end-user interface To: Poul-Henning Kamp , Andriy Gapon References: <21377.1476875898@critter.freebsd.dk> Cc: freebsd-arch@FreeBSD.org From: Alfred Perlstein Message-ID: <126689b6-c44b-688f-faff-4a27d3bd29b8@mu.org> Date: Wed, 19 Oct 2016 14:31:48 -0700 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.12; rv:45.0) Gecko/20100101 Thunderbird/45.3.0 MIME-Version: 1.0 In-Reply-To: <21377.1476875898@critter.freebsd.dk> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit X-BeenThere: freebsd-arch@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Discussion related to FreeBSD architecture List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 19 Oct 2016 21:31:56 -0000 On 10/19/16 4:18 AM, Poul-Henning Kamp wrote: > -------- > In message , Andriy Gapon wri > tes: > >> I want to question if those options really belong to watchdogd. >> When a watchdog timer expires that results in a system-wide action (like a >> system reset). To me, that implies that there should be a single system-wide >> configuration point. And I am not sure that the daemon is the best choice for it. > The reason I originally put it in a daemon, was to have the watchdog > implicitly test the kernels ability to schedule trivial processes. > > It used to be, and may still be so that, there are deadlocks where > the kernel was twiddling its thumbs but userland did not progress. > Typical triggers for this are disk-I/O errors, corrupt filesystems, > memory overcommit etc. > > A kernel-only watchdog patter would not trigger in that case. Exactly. -Alfred