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=-1.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 72718C433E0 for ; Fri, 19 Jun 2020 22:24:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4E7C922314 for ; Fri, 19 Jun 2020 22:24:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592605443; bh=lpWOFSAg1+TkOuoqTZhM/vkmwNWUocGtdWu/J2wCakI=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=t1bllwyJB+gqtWBictRQWfL4H4P97MFmLdXuJDpWMfRbl55LOGuT8v1+28bqzAV3l Migzz9PytzOAfjcTevAhiI7CkWWBCiG3HQn5dymVbN2ZjVVDyJ/kn/A/mN3ABYpiIh BzcrFt6BAFCONZc0uPAULGe1o5J+r9gw367cbudo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729298AbgFSWX7 (ORCPT ); Fri, 19 Jun 2020 18:23:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39516 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729229AbgFSWX7 (ORCPT ); Fri, 19 Jun 2020 18:23:59 -0400 Received: from mail-qk1-x741.google.com (mail-qk1-x741.google.com [IPv6:2607:f8b0:4864:20::741]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 48D93C06174E; Fri, 19 Jun 2020 15:23:59 -0700 (PDT) Received: by mail-qk1-x741.google.com with SMTP id b4so10456929qkn.11; Fri, 19 Jun 2020 15:23:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=145gDxPs4UjYBcZ4oStF0WngBWodlGruxxsqd7FuCUg=; b=Kk6pcx/vpw5c9Vm519/nmC7IlCQ5PEgq77a4uNMJGFxHMnh81Y5hPAZ3kOKOXBblvC 4kxQp4oHPCFH7vgM8ziZkSyRmBMOV1DHRoES6At3qq3L1qqTcuAjwLmQj/maA1U1GOLJ 0vIkEluNxZw05LAYudI9dv9VTQFnKfMoa/cfUokbxNz6QAJWpdyr8BcUYHiL6qXZmoD2 rk5Cjvq7JyAGTPwJALA6zpwtU8zyxYAJJ8U+7cbONSRLMQy1X+Q6cLUlrUAv+8cKDYbO NP0xyF4452zygPMvuiqsfwgb21qKLDs/7QT8mqXscjNpQ3OSNP/WSwmzRCOhcVHpY74U AUgA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to; bh=145gDxPs4UjYBcZ4oStF0WngBWodlGruxxsqd7FuCUg=; b=VLyw5VqV0IDOzCw+1vVb55W/NdbVZaUYUjUJvk9lOOz0gNOhiFZZCshSycu0YaA/Yh GolO10m+IOHH8vKSzbKQInx5zyjr6HYTHfxHafu2ySu2jK2n/Ylz54aTkdk3aunSj33q D4sIn/9UlyBiONu7RNOLtMkBwrkS4T816Vd0qCTS+hxun/WexToyoTskDBPNsR2NvZiu aMUqI1OMYQ41L5uSaa83kSwlt+OZ0R5Th+OUzjlFKaopvmCnfyarTJkjegtwa0/46kIS /zml2Iz2eQldOx2XsbYTWJroJbVlAZqBVya42e//wH5XJxhGl/FshifC69Ft934zFgrH CwKQ== X-Gm-Message-State: AOAM532Xn0SUksusMemS0p8DBTl6oCoflw6iz8ZbPyKI7Nun4ax2PSRK EArzCVrCUSqtXe3U3WT4RFI= X-Google-Smtp-Source: ABdhPJxMlduq8nlFoUJ1WNTxjYcATahyZco+/QgnyHvmhYWPBmhSWSNmkIKbLWhVUjx4HWOpGO34ng== X-Received: by 2002:a37:5805:: with SMTP id m5mr5773473qkb.176.1592605438317; Fri, 19 Jun 2020 15:23:58 -0700 (PDT) Received: from localhost ([199.96.181.106]) by smtp.gmail.com with ESMTPSA id g51sm7850276qtb.69.2020.06.19.15.23.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 19 Jun 2020 15:23:57 -0700 (PDT) Date: Fri, 19 Jun 2020 18:23:56 -0400 From: Tejun Heo To: Rick Lindsley Cc: Ian Kent , Greg Kroah-Hartman , Stephen Rothwell , Andrew Morton , Al Viro , David Howells , Miklos Szeredi , linux-fsdevel , Kernel Mailing List Subject: Re: [PATCH v2 0/6] kernfs: proposed locking and concurrency improvement Message-ID: <20200619222356.GA13061@mtj.duckdns.org> References: <159237905950.89469.6559073274338175600.stgit@mickey.themaw.net> <20200619153833.GA5749@mtj.thefacebook.com> <16d9d5aa-a996-d41d-cbff-9a5937863893@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <16d9d5aa-a996-d41d-cbff-9a5937863893@linux.vnet.ibm.com> Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Fri, Jun 19, 2020 at 01:41:39PM -0700, Rick Lindsley wrote: > On 6/19/20 8:38 AM, Tejun Heo wrote: > > > I don't have strong objections to the series but the rationales don't seem > > particularly strong. It's solving a suspected problem but only half way. It > > isn't clear whether this can be the long term solution for the problem > > machine and whether it will benefit anyone else in a meaningful way either. > > I don't understand your statement about solving the problem halfway. Could > you elaborate? Spending 5 minutes during boot creating sysfs objects doesn't seem like a particularly good solution and I don't know whether anyone else would experience similar issues. Again, not necessarily against improving the scalability of kernfs code but the use case seems a bit out there. > > I think Greg already asked this but how are the 100,000+ memory objects > > used? Is that justified in the first place? > > They are used for hotplugging and partitioning memory. The size of the > segments (and thus the number of them) is dictated by the underlying > hardware. This sounds so bad. There gotta be a better interface for that, right? Thanks. -- tejun