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=-2.5 required=3.0 tests=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 7C261C432C0 for ; Tue, 26 Nov 2019 16:54:30 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 461FD2075C for ; Tue, 26 Nov 2019 16:54:30 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 461FD2075C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id B9A1E6B032B; Tue, 26 Nov 2019 11:54:29 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id AFCB96B032D; Tue, 26 Nov 2019 11:54:29 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9EC546B032E; Tue, 26 Nov 2019 11:54:29 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0123.hostedemail.com [216.40.44.123]) by kanga.kvack.org (Postfix) with ESMTP id 8D8D56B032B for ; Tue, 26 Nov 2019 11:54:29 -0500 (EST) Received: from smtpin28.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with SMTP id 57004824999B for ; Tue, 26 Nov 2019 16:54:29 +0000 (UTC) X-FDA: 76199027058.28.step19_2724c4f442050 X-HE-Tag: step19_2724c4f442050 X-Filterd-Recvd-Size: 3406 Received: from mail-wm1-f46.google.com (mail-wm1-f46.google.com [209.85.128.46]) by imf14.hostedemail.com (Postfix) with ESMTP for ; Tue, 26 Nov 2019 16:54:28 +0000 (UTC) Received: by mail-wm1-f46.google.com with SMTP id u18so3978928wmc.3 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=N9NRBtYqxicVxcWHntqUkKyVdjcTss8MQyjeTuXqbMgIYnNheiSlcYGeq349ax+7RF t6dyNmwvhxrE8vXEAkEY721VkDmtY+bJNxocShpVSA7/vG6W1im9uL3JkuQ4FPKhi1vJ I95iu62lfJdqhc/coSVZogqEDT45OSkxHLW4JEa7JcI0pdWxRvpK6tVbJ1GjWijaW91z LFRDqDwR6Y41sOfS1rPwfwS7x9VayDeo0C/qYn/PqCy9YgZlI+9Xwx2YfE+b11ukrN0q YIo5e974ROdaV6oef7eh3ZO/E+E+nwAWX+swKQDtIqdtE7PRRsVVJlfuRji38xsjZE7y Vbqw== X-Gm-Message-State: APjAAAUYa6fzOoGBa8wGXbvqwt0r8oMu6Am+6kPfNj1BA6FO363Ouvwk 00l9+GoAlyRgtn1O56l9xz0= 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) X-Bogosity: Ham, tests=bogofilter, spamicity=0.000002, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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