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, URIBL_BLOCKED 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 AB7B6CA9EB9 for ; Sat, 26 Oct 2019 11:32:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7AF0A20863 for ; Sat, 26 Oct 2019 11:32:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1572089577; bh=rvu33MKZ1ENxUGvB8aqXdYk2dUn12u4LBeAhcGjvlIc=; h=References:In-Reply-To:From:Date:Subject:To:Cc:List-ID:From; b=RD772jG4hIIycCXLJYfkgDpoA9XZoMwsyalTmBhT0BpvrzKS0fuoeED2/hPvjKkbj 9eXwsjSJQlIit/A93JZQCNpwFC6gDhRhj3Mo+OblsakyZeyQz8QRUCRGMUlc8dhwvG ZsF7DTrBPQmfobHQooq4esid99AScJQFLDjHb1zQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726258AbfJZLc4 (ORCPT ); Sat, 26 Oct 2019 07:32:56 -0400 Received: from mail-wr1-f65.google.com ([209.85.221.65]:46013 "EHLO mail-wr1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726198AbfJZLcz (ORCPT ); Sat, 26 Oct 2019 07:32:55 -0400 Received: by mail-wr1-f65.google.com with SMTP id q13so5084926wrs.12 for ; Sat, 26 Oct 2019 04:32:54 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=2mzFdXY7nlu6Oj/Y7GlnSaFqo3rbBofg+FlIWTx9SRE=; b=t+0nrrj1/PMClURc5GdCFsIeHrJb+AJyZ5QsyeiRLRUfEB89t/n11GDEYdYYFdQpQf aPuKC76MXt2sLii1hgQpkSsYekt4EjP1ySwzWSahZRcqtazKiDqaJbbvgLlZXSGVjdpw MeESh1TlqLhyESks9bOFNPkSkq1MwK9NZgcp+XbYevgiRfQ6rFCjOnYiHL8tCH+SuqGc lpN0tmZY25+IMmrzXewCVN8kmewOdGJEY0eBVzjZe9ez0EphLGKT+42tZxYzIs5iATVV if/PZHSbFzGM9wCoro1o2+z0KEcYEMin2QYkDppwcG9avS9PDan6PN8AsqsgWZ0qjuWX /M3Q== X-Gm-Message-State: APjAAAXWrAQe4JpyzMhhfuLNu4/c3IA3XQ603hSCPKu0APRNf7bod/cw du1UibvDlN/Q7MYRXsrkAaFU8rYEjMWN2M3vm3g= X-Google-Smtp-Source: APXvYqzfTVCiUHj4eoz6ahNeDOU7NKGVNv1q+EXWae7BCJdTa21Ewxr4e3UkMcKvvkgAUb2XFMBju4fmOxFCvYZjLCg= X-Received: by 2002:adf:e2c5:: with SMTP id d5mr4806756wrj.283.1572089573596; Sat, 26 Oct 2019 04:32:53 -0700 (PDT) MIME-Version: 1.0 References: <20191016125019.157144-1-namhyung@kernel.org> <20191016125019.157144-2-namhyung@kernel.org> <20191024174433.GA3622521@devbig004.ftw2.facebook.com> <20191025105654.GG3622521@devbig004.ftw2.facebook.com> In-Reply-To: <20191025105654.GG3622521@devbig004.ftw2.facebook.com> From: Namhyung Kim Date: Sat, 26 Oct 2019 20:32:42 +0900 Message-ID: Subject: Re: [PATCH 1/2] cgroup: Add generation number with cgroup id To: Tejun Heo Cc: Johannes Weiner , Li Zefan , LKML , Greg Kroah-Hartman , "Rafael J. Wysocki" , Song Liu Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Tejun, On Fri, Oct 25, 2019 at 7:57 PM Tejun Heo wrote: > > Hello, > > On Fri, Oct 25, 2019 at 06:38:00PM +0900, Namhyung Kim wrote: > > On Fri, Oct 25, 2019 at 5:30 PM Namhyung Kim wrote: > > > > > /* > > > > > * A cgroup_root represents the root of a cgroup hierarchy, and may be > > > > > * associated with a kernfs_root to form an active hierarchy. This is > > > > > @@ -521,7 +529,7 @@ struct cgroup_root { > > > > > unsigned int flags; > > > > > > > > > > /* IDs for cgroups in this hierarchy */ > > > > > - struct idr cgroup_idr; > > > > > + struct cgroup_idr cgroup_idr; > > > > > > > > Given that there's cgroup->self css, can we get rid of the above? > > > > > > I don't follow. Do you want to remove cgroup_idr and share the > > > css_idr for cgroup id? > > Yeah, so, each cgroup has its own css at cgroup->self which has css id > and everything, so I was wondering whether it'd make sense to get rid > of the cgroup id and use cgroup->self.id in its place. I think it's possible to use self.id as cgroup id. But css->id is managed for each subsys, so it still needs to have an idr in cgroup_root for cgroup->self.id, right? Or do you want to get rid of subsys->idr and use a single idr for both cgroup and css? Thanks Namhyung