From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.3 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED, USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 17C2AC32789 for ; Tue, 6 Nov 2018 13:03:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D6B532083D for ; Tue, 6 Nov 2018 13:03:00 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="WLJPHzVF" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D6B532083D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388251AbeKFW2F (ORCPT ); Tue, 6 Nov 2018 17:28:05 -0500 Received: from bombadil.infradead.org ([198.137.202.133]:53654 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387905AbeKFW2F (ORCPT ); Tue, 6 Nov 2018 17:28:05 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=aRKW4wlwG4QS07tI8fk4RLPuTZ5oNk/YVfNKZ1kRldA=; b=WLJPHzVFJkUJWwjet7VF0xwSi WqEGnZksiCUfBJ/CMHsiRZnUxOvfdiy4W3zc+LOHPC/KS8o0va1GSMHnKqYqprfiuX6RK5t2wnSsS YkdYsXEAacatLLLLdLtpxfAztM36fmcO/gCjj323JuTekeD3VKHUt+zO7fVHZUwrYbZZ7AYl0gNWY lVGV1iHL3SQsFlnKalwYpu6wwjKwif4WKFO6+KRc0y3w7NsPXeWGMaHlOrkwSHSsZuT0oci6Z3tPN EECEXgSO6AgszzjgxbNglI0WfVDxtOwsZur4wk5hJPUFlQ71wMC/mU/vB3L69PniGlOCQJ/La2eSg sxF/yVu2w==; Received: from willy by bombadil.infradead.org with local (Exim 4.90_1 #2 (Red Hat Linux)) id 1gK10O-0000CR-Tf; Tue, 06 Nov 2018 13:02:52 +0000 Date: Tue, 6 Nov 2018 05:02:52 -0800 From: Matthew Wilcox To: Waiman Long Cc: "Luis R. Rodriguez" , Kees Cook , Andrew Morton , Jonathan Corbet , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-doc@vger.kernel.org, Al Viro , "Eric W. Biederman" , Takashi Iwai , Davidlohr Bueso , Manfred Spraul Subject: Re: [PATCH v10 4/4] ipc: Add a cyclic mode for id generation Message-ID: <20181106130252.GC3074@bombadil.infradead.org> References: <1541432626-27780-1-git-send-email-longman@redhat.com> <1541432626-27780-5-git-send-email-longman@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1541432626-27780-5-git-send-email-longman@redhat.com> User-Agent: Mutt/1.9.2 (2017-12-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Nov 05, 2018 at 10:43:46AM -0500, Waiman Long wrote: > The idea of using the cyclic mode to reduce id reuse came from Manfred > Spraul . There may be a little bit of > additional memory/performance overhead in doing cyclic id allocation, > but it is a slow path anyway and a bit of overhead shouldn't be an issue. > > This patch differs from his as the cyclic mode is not the default and > has to be explicitly opted in for users who want that. I really don't like the "make the sysadmin choose" approach. It's shifting blame to someone who has no idea what the tradeoffs are. We should try to get it right rather than force more people to learn why we're incapable of making the right decision for them.