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 1DA2AECAAD3 for ; Thu, 1 Sep 2022 14:29:46 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 6EE9C8D0001; Thu, 1 Sep 2022 10:29:46 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 677216B0078; Thu, 1 Sep 2022 10:29:46 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 4F0188D0001; Thu, 1 Sep 2022 10:29:46 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id 389836B0075 for ; Thu, 1 Sep 2022 10:29:46 -0400 (EDT) Received: from smtpin23.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id 09F80AB140 for ; Thu, 1 Sep 2022 14:29:46 +0000 (UTC) X-FDA: 79863750372.23.0B3D77E Received: from out0.migadu.com (out0.migadu.com [94.23.1.103]) by imf20.hostedemail.com (Postfix) with ESMTP id 9825E1C005B for ; Thu, 1 Sep 2022 14:29:45 +0000 (UTC) Date: Thu, 1 Sep 2022 10:29:37 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1662042584; 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=M1aDaZlKYEwz8CxoGUE2hJszPL7mnQtqrJRQw3RcAgQ=; b=IK9QhIOZDhvhIHgjJAvozZeyNVUxpRDuv2a80UYwf9PmUNDsSXvx244cHMitGbjR3T3iGp 7sTtqClKi3PdI+46+oiLp/x5eTOLPULJGYd7PsGYsaj8KjDdrdJudl3cyWqngQc55MFiX/ TzPtdYtHcCsYBcEyFw2g+cdlpMBvH8I= X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Kent Overstreet To: Peter Zijlstra Cc: Mel Gorman , Suren Baghdasaryan , akpm@linux-foundation.org, mhocko@suse.com, 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, david@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: <20220901142937.vsnq62e6gqytyth2@moria.home.lan> References: <20220830214919.53220-1-surenb@google.com> <20220831084230.3ti3vitrzhzsu3fs@moria.home.lan> <20220831101948.f3etturccmp5ovkl@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Migadu-Flow: FLOW_OUT X-Migadu-Auth-User: linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1662042585; 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=M1aDaZlKYEwz8CxoGUE2hJszPL7mnQtqrJRQw3RcAgQ=; b=lpvaK9Sjf6quStsq3SXUIwl/TyKcd28w/yarmrBZszywJ/ELdXnbj5rxBPt/1644SGauTd vsFlQwdsfjWvVLIJFJ5f/4s+qbFxtIyhWc1XtkXfEHJwuVB7ksjml1ne7IG37fG3u07iUv lxQG8mF2GRfmVd+eh8nKGB5lO7ufQSk= ARC-Authentication-Results: i=1; imf20.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=IK9QhIOZ; spf=pass (imf20.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-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1662042585; a=rsa-sha256; cv=none; b=MtwTrx61gZU1+qRm/ecnt8An+NfeiJz84thZ3fnuuqh28b6hdmh/oXGUGDz7BOBuq7bE0/ Rkn7A7Hdmrj9R0FeEeXpb7P3q8kDVfS5vul5ya1QrnIDbWxjVHYxUCGh0AGcTuqXopcLZR ghxymGExHEwQYyOFI7hnvHZGUAKlQg0= X-Stat-Signature: s6shtaep8mqfbxign3h7hsesq38wh3ng X-Rspamd-Queue-Id: 9825E1C005B Authentication-Results: imf20.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=IK9QhIOZ; spf=pass (imf20.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-Rspamd-Server: rspam12 X-Rspam-User: X-HE-Tag: 1662042585-775452 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 09:00:17AM +0200, Peter Zijlstra wrote: > On Wed, Aug 31, 2022 at 11:19:48AM +0100, Mel Gorman wrote: > > > It's also unclear *who* would enable this. It looks like it would mostly > > have value during the development stage of an embedded platform to track > > kernel memory usage on a per-application basis in an environment where it > > may be difficult to setup tracing and tracking. Would it ever be enabled > > in production? > > Afaict this is developer only; it is all unconditional code. > > > Would a distribution ever enable this? > > I would sincerely hope not. Because: > > > If it's enabled, any overhead cannot be disabled/enabled at run or > > boot time so anyone enabling this would carry the cost without never > > necessarily consuming the data. > > this. We could make it a boot parameter, with the alternatives infrastructure - with a bit of refactoring there'd be a single function call to nop out, and then we could also drop the elf sections as well, so that when built in but disabled the overhead would be practically nil.