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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id F0721ECAAD3 for ; Mon, 5 Sep 2022 22:16:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230074AbiIEWQX (ORCPT ); Mon, 5 Sep 2022 18:16:23 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38422 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229577AbiIEWQW (ORCPT ); Mon, 5 Sep 2022 18:16:22 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6B59559253; Mon, 5 Sep 2022 15:16:21 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 1675FB81598; Mon, 5 Sep 2022 22:16:20 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7D5E2C433C1; Mon, 5 Sep 2022 22:16:13 +0000 (UTC) Date: Mon, 5 Sep 2022 18:16:50 -0400 From: Steven Rostedt To: Kent Overstreet Cc: Suren Baghdasaryan , Michal Hocko , Mel Gorman , Peter Zijlstra , Andrew Morton , Vlastimil Babka , Johannes Weiner , Roman Gushchin , Davidlohr Bueso , Matthew Wilcox , "Liam R. Howlett" , David Vernet , Juri Lelli , Laurent Dufour , Peter Xu , David Hildenbrand , Jens Axboe , mcgrof@kernel.org, masahiroy@kernel.org, nathan@kernel.org, changbin.du@intel.com, ytcoode@gmail.com, Vincent Guittot , Dietmar Eggemann , Benjamin Segall , Daniel Bristot de Oliveira , Valentin Schneider , Christopher Lameter , Pekka Enberg , Joonsoo Kim , 42.hyeyoo@gmail.com, Alexander Potapenko , Marco Elver , Dmitry Vyukov , Shakeel Butt , Muchun Song , arnd@arndb.de, jbaron@akamai.com, David Rientjes , Minchan Kim , Kalesh Singh , kernel-team , linux-mm , iommu@lists.linux.dev, kasan-dev@googlegroups.com, io-uring@vger.kernel.org, linux-arch@vger.kernel.org, xen-devel@lists.xenproject.org, linux-bcache@vger.kernel.org, linux-modules@vger.kernel.org, LKML Subject: Re: [RFC PATCH 00/30] Code tagging framework and applications Message-ID: <20220905181650.71e9d02c@gandalf.local.home> In-Reply-To: <20220905204229.xqrqxmaax37n3ody@moria.home.lan> References: <20220831084230.3ti3vitrzhzsu3fs@moria.home.lan> <20220831101948.f3etturccmp5ovkl@suse.de> <20220831190154.qdlsxfamans3ya5j@moria.home.lan> <20220905110713.27304149@gandalf.local.home> <20220905204229.xqrqxmaax37n3ody@moria.home.lan> X-Mailer: Claws Mail 3.17.8 (GTK+ 2.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-bcache@vger.kernel.org On Mon, 5 Sep 2022 16:42:29 -0400 Kent Overstreet wrote: > > Haven't tried that yet but will do. Thanks for the reference code! > > Is it really worth the effort of benchmarking tracing API overhead here? > > The main cost of a tracing based approach is going to to be the data structure > for remembering outstanding allocations so that free events can be matched to > the appropriate callsite. Regardless of whether it's done with BFP or by > attaching to the tracepoints directly, that's going to be the main overhead. The point I was making here is that you do not need your own hooking mechanism. You can get the information directly by attaching to the tracepoint. > > static void my_callback(void *data, unsigned long call_site, > > const void *ptr, struct kmem_cache *s, > > size_t bytes_req, size_t bytes_alloc, > > gfp_t gfp_flags) > > { > > struct my_data_struct *my_data = data; > > > > { do whatever } > > } The "do whatever" is anything you want to do. Or is the data structure you create with this approach going to be too much overhead? How hard is it for a hash or binary search lookup? -- Steve