From owner-freebsd-current@FreeBSD.ORG Fri Jun 29 10:17:10 2007 Return-Path: X-Original-To: current@freebsd.org Delivered-To: freebsd-current@FreeBSD.ORG Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 0ED7416A421 for ; Fri, 29 Jun 2007 10:17:10 +0000 (UTC) (envelope-from howard0su@gmail.com) Received: from py-out-1112.google.com (py-out-1112.google.com [64.233.166.177]) by mx1.freebsd.org (Postfix) with ESMTP id C2BE913C48A for ; Fri, 29 Jun 2007 10:17:09 +0000 (UTC) (envelope-from howard0su@gmail.com) Received: by py-out-1112.google.com with SMTP id u77so1225306pyb for ; Fri, 29 Jun 2007 03:17:09 -0700 (PDT) DKIM-Signature: a=rsa-sha1; c=relaxed/relaxed; d=gmail.com; s=beta; h=domainkey-signature:received:received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:references; b=FSwoDfHQLqPXQPbbkhoZld/vF2EL6PI8UuQSC036J71ntJmsoAVv0yUaIDA6c/gPhA6W+BGv6biTuJFkFqIJmPK2s2io7pEsQv8oRKs2x0jhqjcXDAV4Ui/Og0GcZxpIFc1W3YCmn0RpOBhbT883eDJODGBqWWBO26Ufk9FNFdQ= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:references; b=bBEUOr+K3+SBI5IwiCNBPnzjr9L+Ar2uTFGAjxx9X9Me0agUn1uOHQo0U9ErmBEF4AMYRU47noA/2+/9h4VZpEC0FQ5kjvDJt5IKIk78PZWsoKslqo3retudem21d20cnuHtLchcA7DqeUhccyBYVJoEUn4ua3Wqzqn9cMqpjIs= Received: by 10.35.10.13 with SMTP id n13mr362754pyi.1183112229052; Fri, 29 Jun 2007 03:17:09 -0700 (PDT) Received: by 10.35.78.11 with HTTP; Fri, 29 Jun 2007 03:17:09 -0700 (PDT) Message-ID: Date: Fri, 29 Jun 2007 18:17:09 +0800 From: "Howard Su" To: "Robert Watson" In-Reply-To: <20070628094219.W9286@fledge.watson.org> MIME-Version: 1.0 References: <20070628094219.W9286@fledge.watson.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Content-Disposition: inline X-Content-Filtered-By: Mailman/MimeDel 2.1.5 Cc: current@freebsd.org Subject: Re: concept prove patch for ktrace output to all file types X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 29 Jun 2007 10:17:10 -0000 On 6/28/07, Robert Watson wrote: > > What happens to processes associated with the same or other ktrace > sessions if > one ktrace session stalls due to a fifo or pipe buffer filling? I don't think my patch will bring the new problem here. Original, we write to disk still be blocked due to some things like disk busy, etc. If my reading is right, ktrace use two way to submit request. ktr_enqueue will put the request into a queue if it is not safe to enter VFS. ktr_submitrequest will be used to commit record to disk immediately. in my case, blocking will be safe there. The issue about losting some recording to fifo blocking. I don't think we can solve that in the kernel. It is userland code's responsiblity to read it to avoid losting data. -- -Howard