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=-2.9 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_NEOMUTT 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 E0137C04EB8 for ; Wed, 12 Dec 2018 08:00:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3AC0220811 for ; Wed, 12 Dec 2018 08:00:50 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3AC0220811 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=gondor.apana.org.au 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 S1726686AbeLLIAt (ORCPT ); Wed, 12 Dec 2018 03:00:49 -0500 Received: from orcrist.hmeau.com ([104.223.48.154]:47050 "EHLO deadmen.hmeau.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726007AbeLLIAs (ORCPT ); Wed, 12 Dec 2018 03:00:48 -0500 Received: from gondobar.mordor.me.apana.org.au ([192.168.128.4] helo=gondobar) by deadmen.hmeau.com with esmtps (Exim 4.89 #2 (Debian)) id 1gWzRi-0004mi-1i; Wed, 12 Dec 2018 16:00:42 +0800 Received: from herbert by gondobar with local (Exim 4.89) (envelope-from ) id 1gWzRd-0002Nx-HH; Wed, 12 Dec 2018 16:00:37 +0800 Date: Wed, 12 Dec 2018 16:00:37 +0800 From: Herbert Xu To: NeilBrown Cc: Thomas Graf , Tom Herbert , David Miller , netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH net-next] rhashtable: further improve stability of rhashtable_walk Message-ID: <20181212080037.j2zs22t57uxdu2jr@gondor.apana.org.au> References: <153086101070.2825.6850140624411927465.stgit@noble> <153086109256.2825.15329014177598382684.stgit@noble> <87zhtkeimx.fsf@notabene.neil.brown.name> <20181207053943.7zacyn5uvqkfnfoi@gondor.apana.org.au> <87k1kico1o.fsf@notabene.neil.brown.name> <20181211051755.modgomqzszkbiihe@gondor.apana.org.au> <87mupbvch0.fsf@notabene.neil.brown.name> <20181212054601.wbzpxjunnsfi62mz@gondor.apana.org.au> <87efanuu06.fsf@notabene.neil.brown.name> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87efanuu06.fsf@notabene.neil.brown.name> User-Agent: NeoMutt/20170113 (1.7.2) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Dec 12, 2018 at 05:41:29PM +1100, NeilBrown wrote: > > So you would substantially slow down the rhashtable_walk_start() step. This whole thing is meant for uses such as /proc and netlink enumeration. Speed is definitely not a prerogative of these iterators. For that matter, if speed was an issue then surely you would not drop out of the RCU read lock at all while iterating. It sounds to me like you're trying to use this interface for something that it's simply not designed to do. Cheers, -- Email: Herbert Xu Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt