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Thu, 01 Sep 2022 07:05:39 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 417C030041D; Thu, 1 Sep 2022 09:05:36 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 110AE20981381; Thu, 1 Sep 2022 09:05:36 +0200 (CEST) Date: Thu, 1 Sep 2022 09:05:35 +0200 From: Peter Zijlstra To: Kent Overstreet 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: References: <20220830214919.53220-1-surenb@google.com> <20220831084230.3ti3vitrzhzsu3fs@moria.home.lan> <20220831101948.f3etturccmp5ovkl@suse.de> <20220831155941.q5umplytbx6offku@moria.home.lan> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220831155941.q5umplytbx6offku@moria.home.lan> ARC-Authentication-Results: i=1; imf11.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=CRTVAsmA; spf=none (imf11.hostedemail.com: domain of peterz@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=peterz@infradead.org; dmarc=none ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1662015955; a=rsa-sha256; cv=none; b=UeY4LTsHes5G/aiw0GNLtnvo94+uuHuiXyZwtY0Rtx72SCUpmtIRitwFvSCpfRu0zau5z2 I3jmJByJoyNMdBkYySnFrts8+LzYB92xYfUWjcjgqFlHjq7Rel6TkG7c5ji1XedRWVKPPn 51t8pecbc+U8LWkUuWT8zbjP9H2jVjU= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1662015955; 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=PMcMlRof4aBmW9ZRc+eOO/2dgQwguo+jd6/zOIwkXz4=; b=iNw9rW5DUEdXTKSK8s0JpcsgmgH8dVUuFx77hH2i1deUuQyZ2Bdtgvt1F//YeGGh4ndIPy 8IzyIX71lsNEhjB5XhvtYlL3yX3IYIbv3LSFrDZsLTYNN6IKcltDDYqKum9VZQzEJV0hzO lAEIPiZkvwtme9iB/vQLlKg2gQJOFO8= Authentication-Results: imf11.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=CRTVAsmA; spf=none (imf11.hostedemail.com: domain of peterz@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=peterz@infradead.org; dmarc=none X-Rspam-User: X-Stat-Signature: xroo1u817fu13aodyf7ri9bbz5cbg5s5 X-Rspamd-Queue-Id: 9DDAE4003C X-Rspamd-Server: rspam09 X-HE-Tag: 1662015955-595071 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 Wed, Aug 31, 2022 at 11:59:41AM -0400, Kent Overstreet wrote: > Also, ftrace can drop events. Not really ideal if under system load your memory > accounting numbers start to drift. You could attach custom handlers to tracepoints. If you were to replace these unconditional code hooks of yours with tracepoints then you could conditionally (say at boot) register custom handlers that do the accounting you want. Nobody is mandating you use the ftrace ringbuffer to consume tracepoints. Many people these days attach eBPF scripts to them and do whatever they want.