From owner-freebsd-arch Sun Jul 14 2:59:39 2002 Delivered-To: freebsd-arch@freebsd.org Received: from mx1.FreeBSD.org (mx1.FreeBSD.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id ABCAD37B400 for ; Sun, 14 Jul 2002 02:59:36 -0700 (PDT) Received: from critter.freebsd.dk (critter.freebsd.dk [212.242.86.163]) by mx1.FreeBSD.org (Postfix) with ESMTP id EBCEE43E4A for ; Sun, 14 Jul 2002 02:59:35 -0700 (PDT) (envelope-from phk@critter.freebsd.dk) Received: from critter.freebsd.dk (localhost [127.0.0.1]) by critter.freebsd.dk (8.12.3/8.12.2) with ESMTP id g6E9vTXB056793; Sun, 14 Jul 2002 11:57:29 +0200 (CEST) (envelope-from phk@critter.freebsd.dk) To: Don Lewis Cc: arch@FreeBSD.ORG Subject: Re: wiring the sysctl output buffer In-Reply-To: Your message of "Sun, 14 Jul 2002 02:54:11 PDT." <200207140954.g6E9sBwr020599@gw.catspoiler.org> Date: Sun, 14 Jul 2002 11:57:29 +0200 Message-ID: <56792.1026640649@critter.freebsd.dk> From: Poul-Henning Kamp Sender: owner-freebsd-arch@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG In message <200207140954.g6E9sBwr020599@gw.catspoiler.org>, Don Lewis writes: >On 14 Jul, Poul-Henning Kamp wrote: >> In message <200207140916.g6E9Ghwr020552@gw.catspoiler.org>, Don Lewis writes: >> >>>I think the best solution to this problem is to add a sysctl system API >>>to prewire the output buffer that can be called before grabbing the >>>locks. Doing so allows the existing code to operate properly with only >>>minimal changes. >> >> It used to be that sysctl unconditionally wired the output buffer, >> but that gave rise to a host of other problems. > >Anything specific that I should be aware of? No, just bad deadlocks and such. You may also want to restrict the amount of buffer you pin if I hand the kernel a 2G buffer for a 4 byte sysctl integer you wouldn't want to pin it all. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk@FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message