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 64A49ECAAD3 for ; Thu, 1 Sep 2022 14:24:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234735AbiIAOYn (ORCPT ); Thu, 1 Sep 2022 10:24:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51206 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234722AbiIAOYP (ORCPT ); Thu, 1 Sep 2022 10:24:15 -0400 Received: from out0.migadu.com (out0.migadu.com [94.23.1.103]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 514294DB07; Thu, 1 Sep 2022 07:23:55 -0700 (PDT) Date: Thu, 1 Sep 2022 10:23:45 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1662042233; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=JsB2G8WqLnYprEF0GcA9GFFIGkQht/MFH67dN0NC9t0=; b=P+qdlVJWY093c1JvjMpoBsAhuM3mvnI3jUKrYjXhcXjA7JDkTxBBu4A2hC17CCO8ZZ5R3D rLH5U4BLaxZ5HSxD5hP6U1jUXGFLfAJiihxtZ+Hfa0QaSzmc2WzHuvOvPKzjVyoQ9DuTBc CcLrAriFlVtUQ4Ne/7Ga0hI19yi31Mw= X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Kent Overstreet To: David Hildenbrand Cc: Michal Hocko , Mel Gorman , Peter Zijlstra , Suren Baghdasaryan , akpm@linux-foundation.org, vbabka@suse.cz, hannes@cmpxchg.org, roman.gushchin@linux.dev, dave@stgolabs.net, willy@infradead.org, liam.howlett@oracle.com, void@manifault.com, juri.lelli@redhat.com, ldufour@linux.ibm.com, peterx@redhat.com, axboe@kernel.dk, mcgrof@kernel.org, masahiroy@kernel.org, nathan@kernel.org, changbin.du@intel.com, ytcoode@gmail.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, bristot@redhat.com, vschneid@redhat.com, cl@linux.com, penberg@kernel.org, iamjoonsoo.kim@lge.com, 42.hyeyoo@gmail.com, glider@google.com, elver@google.com, dvyukov@google.com, shakeelb@google.com, songmuchun@bytedance.com, arnd@arndb.de, jbaron@akamai.com, rientjes@google.com, minchan@google.com, kaleshsingh@google.com, kernel-team@android.com, linux-mm@kvack.org, 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, linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH 00/30] Code tagging framework and applications Message-ID: <20220901142345.agkfp2d5lijdp6pt@moria.home.lan> References: <20220830214919.53220-1-surenb@google.com> <20220831084230.3ti3vitrzhzsu3fs@moria.home.lan> <20220831101948.f3etturccmp5ovkl@suse.de> <20220831190154.qdlsxfamans3ya5j@moria.home.lan> <404e947a-e1b2-0fae-8b4f-6f2e3ba6328d@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <404e947a-e1b2-0fae-8b4f-6f2e3ba6328d@redhat.com> X-Migadu-Flow: FLOW_OUT X-Migadu-Auth-User: linux.dev Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Sep 01, 2022 at 10:05:03AM +0200, David Hildenbrand wrote: > On 31.08.22 21:01, Kent Overstreet wrote: > > On Wed, Aug 31, 2022 at 12:47:32PM +0200, Michal Hocko wrote: > >> On Wed 31-08-22 11:19:48, Mel Gorman wrote: > >>> Whatever asking for an explanation as to why equivalent functionality > >>> cannot not be created from ftrace/kprobe/eBPF/whatever is reasonable. > >> > >> Fully agreed and this is especially true for a change this size > >> 77 files changed, 3406 insertions(+), 703 deletions(-) > > > > In the case of memory allocation accounting, you flat cannot do this with ftrace > > - you could maybe do a janky version that isn't fully accurate, much slower, > > more complicated for the developer to understand and debug and more complicated > > for the end user. > > > > But please, I invite anyone who's actually been doing this with ftrace to > > demonstrate otherwise. > > > > Ftrace just isn't the right tool for the job here - we're talking about adding > > per callsite accounting to some of the fastest fast paths in the kernel. > > > > And the size of the changes for memory allocation accounting are much more > > reasonable: > > 33 files changed, 623 insertions(+), 99 deletions(-) > > > > The code tagging library should exist anyways, it's been open coded half a dozen > > times in the kernel already. > > Hi Kent, > > independent of the other discussions, if it's open coded already, does > it make sense to factor that already-open-coded part out independently > of the remainder of the full series here? It's discussed in the cover letter, that is exactly how the patch series is structured. > [I didn't immediately spot if this series also attempts already to > replace that open-coded part] Uh huh. Honestly, some days it feels like lkml is just as bad as slashdot, with people wanting to get in their two cents without actually reading...