From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 60FC7A3B for ; Thu, 1 Sep 2022 07:06:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=PMcMlRof4aBmW9ZRc+eOO/2dgQwguo+jd6/zOIwkXz4=; b=CRTVAsmAK2cWYW898rb6ABFc5M uLACuGzlIMyaVe8YmnHdnMTCzaRgU/yORC/GoxdMYsKfSqUkdBcV9CHFquRDxtBp1mrHH1Ek8iUcr mn1JgrUbBdWhUq0dshggnSScCFSCXwzSSm1KuWPF7x5mOnsP+VDfpzlLoRknLlMRFYgTP9KQNHlgH CH7qbZF+ZmtxkOzs27I6vkqhMH23AuEUp5/xcLcIfVX3lpAkPrSHOObJikPLlUvDymQfq9PPQJW2d ahsXPS2phTb5F2Rtarg5EDnzM/T3m8B4GVcztEaB4FRglzTR7JDiDhZuuZYYAbZtb5/Iw4ZAPbP6X Wmout+LA==; Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1oTeGh-005oq6-Bs; 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> Precedence: bulk X-Mailing-List: iommu@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220831155941.q5umplytbx6offku@moria.home.lan> 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.