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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id BF704C0502C for ; Thu, 1 Sep 2022 14:23:56 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 31BA28D0005; Thu, 1 Sep 2022 10:23:56 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 2CB2E8D0001; Thu, 1 Sep 2022 10:23:56 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 16BA88D0005; Thu, 1 Sep 2022 10:23:56 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 05BB88D0001 for ; Thu, 1 Sep 2022 10:23:56 -0400 (EDT) Received: from smtpin30.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id D4D12C0F51 for ; Thu, 1 Sep 2022 14:23:55 +0000 (UTC) X-FDA: 79863735630.30.6E9A5F2 Received: from out0.migadu.com (out0.migadu.com [94.23.1.103]) by imf19.hostedemail.com (Postfix) with ESMTP id 201F91A003D for ; Thu, 1 Sep 2022 14:23:54 +0000 (UTC) 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 ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1662042235; a=rsa-sha256; cv=none; b=Vpz7rxKuYzhmB2lBZ89KwDijdI1DLPK8tpEeuFJBsJXhcutMN6p2FETjL6l9TKfbmJ+qQT Cizcf6JEtOS5NDygK6i7QeiOTAwONNpoKa2mj1x1foYl+8oU4psiFGxwAOR/qesZUyTAyv XNtfVUvGD109YEV2nigxzHLPgPH9vnU= ARC-Authentication-Results: i=1; imf19.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=P+qdlVJW; spf=pass (imf19.hostedemail.com: domain of kent.overstreet@linux.dev designates 94.23.1.103 as permitted sender) smtp.mailfrom=kent.overstreet@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1662042235; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=JsB2G8WqLnYprEF0GcA9GFFIGkQht/MFH67dN0NC9t0=; b=HwtGTrfWHCK3XDKDzKP7I2Vqsszk17POmXjOAg0qDPRqjAiSDhGEjcLrOTCkNlxFg7q916 Pr4OqRt0hVFOCOfopI/0qKIeQf8OPwUTwjphRWqPaJ9/kpsVzBeHqcWcxwRHj0o3+1vEXq vdiDmpLENajimHmdM7NwF7/QYYlZOj4= X-Rspamd-Queue-Id: 201F91A003D Authentication-Results: imf19.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=P+qdlVJW; spf=pass (imf19.hostedemail.com: domain of kent.overstreet@linux.dev designates 94.23.1.103 as permitted sender) smtp.mailfrom=kent.overstreet@linux.dev; dmarc=pass (policy=none) header.from=linux.dev X-Rspam-User: X-Rspamd-Server: rspam01 X-Stat-Signature: mi17p5nme37d69bfoqf4s983xoqsqmia X-HE-Tag: 1662042234-377955 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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...