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=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 4E44BC432C3 for ; Tue, 26 Nov 2019 16:54:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1869A2075C for ; Tue, 26 Nov 2019 16:54:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1574787271; bh=LrdXgBpIGmBm6VAtSBexvelo9GbjQWOHUdqZz8tzBQk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=MHnAa57EwSsVpFqQ/oWkXnSbb8HixOougEaRlcl1xHUSQ4IIn1cmOVkeZZeEt0Sj/ o7bD0JyNXm9HH/RI9+kNq4PsvhzuY98xFrsJj5lsAnsexNa0vJEoPr/UJGpzuMG7J8 Vnn7MoqKAJYqv2PIXWhX52u1C79X9hkwLle3KDxM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728466AbfKZQya (ORCPT ); Tue, 26 Nov 2019 11:54:30 -0500 Received: from mail-wm1-f41.google.com ([209.85.128.41]:39270 "EHLO mail-wm1-f41.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727756AbfKZQya (ORCPT ); Tue, 26 Nov 2019 11:54:30 -0500 Received: by mail-wm1-f41.google.com with SMTP id t26so4158000wmi.4 for ; Tue, 26 Nov 2019 08:54:28 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=jTx9XvAoitX5ElOHyXfUJ5O+w+mtZmpTIHTRwny9Xek=; b=hpyqvE9VeMaWI/eZXjmt+RGFOApuV/H9pWeb7ytb3XEgK/upMTknPdqtDJZ+QrruaF oj4dl5xb8mUb0PGQ3pn4NehC2HtcZjtAvX+ZGXe7qiNpN5Y+gtlPjFdrTXn0A3Nl0GLv nXwHN7hd+fje3Jw2Tiia2BkL+u6ddqshMPNpyJ+1h7JfwFlPXEEAT1TUu7l/x+zYB8Wz zYxw9m5dgtKDGXk8QFqcW4SuZT3dyD8F5rlbFJXqqnoc/TUiwksCnQJuST0she6qq7Jg QoPZVpw/xzIeWDx5bJZp1DcMfMtO75WeS9I3fHWVUwupzxXDbfU32QhYqNiE+kNztg4S h3XQ== X-Gm-Message-State: APjAAAWJNIigUJfLuSCdYSFiW3fJ0h5YdU0cpdBbR/LxbmlTjK0KEp+/ XbatrEq2s0kx4gik2AC1NFwBmAZB X-Google-Smtp-Source: APXvYqyNQMXlfZcrpPbACcE9XEaIY+zXE74QnRlwETHHnA9AoeY9wlB4/0H5Mi4sPRDNtH7ng3/Gtw== X-Received: by 2002:a1c:a906:: with SMTP id s6mr5400635wme.125.1574787267780; Tue, 26 Nov 2019 08:54:27 -0800 (PST) Received: from localhost (ip-37-188-250-171.eurotel.cz. [37.188.250.171]) by smtp.gmail.com with ESMTPSA id b14sm3679664wmj.18.2019.11.26.08.54.24 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 26 Nov 2019 08:54:26 -0800 (PST) Date: Tue, 26 Nov 2019 17:54:20 +0100 From: Michal Hocko To: Christopher Lameter Cc: LKML , linux-mm@kvack.org Subject: Re: SLUB: purpose of sysfs events on cache creation/removal Message-ID: <20191126165420.GL20912@dhcp22.suse.cz> References: <20191126121901.GE20912@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue 26-11-19 16:32:56, Cristopher Lameter wrote: > On Tue, 26 Nov 2019, Michal Hocko wrote: > > > Hi, > > I have just learnt about KOBJ_{ADD,REMOVE} sysfs events triggered on > > kmem cache creation/removal when SLUB is configured. This functionality > > goes all the way down to initial SLUB merge. I do not see any references > > in the Documentation explaining what those events are used for and > > whether there are any real users. > > > > Could you shed some more light into this? > > I have no idea about what this is. It seems to be there since the initial merge. I suspect this is just following a generic sysfs rule that each file has to provide those events? > There have been many people who > reworked the sysfs support and this has been the cause for a lot of > breakage over the years. Remember any specifics? I am mostly interested in potential users. In other words I am thinking to suppress those events. There is already ke knob to control existence of memcg caches but I do not see anything like this for root caches. -- Michal Hocko SUSE Labs