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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 2FFA1C2D0CD for ; Mon, 19 May 2025 16:49:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:MIME-Version:References:In-Reply-To:Message-ID:Subject:Cc:To: From:Date:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=IF+8Y5XDtCDzaYIkXfRn+LH/SIQenJqpfbsdfUWufDI=; b=v7uD5tOjU22fIYcGYK6SnhG+hg /pFjSA/GKri/8Pd+d/c2cIJsBMP0h4lBWQNNWUnMwwAjoifBZzUItVS9+SprjD5WvhqwGDPKGZQwR m3ekt6Zvq5Ns7lNElNJC9sj4Er0hmgUR5elSwsmtjaWgPMhCJOru7MoNj0s1bcGwMG1ph8w3XnLo4 DWbUEgL0KuCK1qq9WYPD4Yc26eQYFp54chJlt1PYK7NNd5WnInHQBui1wDVIzbG0cncmjwKNQR5kQ e5rsE/KyLXJfP92aj2rImTLbANjLsEsiAFqw4G3arI290nXdVQz/+JIV9x9SsvssMCLViP3dMB2yu 9kaJxZSA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1uH3fp-00000009rwv-27wj; Mon, 19 May 2025 16:49:09 +0000 Received: from dfw.source.kernel.org ([2604:1380:4641:c500::1]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1uH32e-00000009k8E-2WI2 for linux-arm-kernel@lists.infradead.org; Mon, 19 May 2025 16:08:41 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by dfw.source.kernel.org (Postfix) with ESMTP id 54AB75C4B2B; Mon, 19 May 2025 16:06:22 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 93023C4CEE9; Mon, 19 May 2025 16:08:38 +0000 (UTC) Date: Mon, 19 May 2025 12:08:37 -0400 From: Steven Rostedt To: Will Deacon Cc: Nam Cao , Gabriele Monaco , linux-trace-kernel@vger.kernel.org, linux-kernel@vger.kernel.org, john.ogness@linutronix.de, Catalin Marinas , linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH v6 17/22] arm64: mm: Add page fault trace points Message-ID: <20250519120837.794f6738@batman.local.home> In-Reply-To: <20250519151238.GB17177@willie-the-truck> References: <554038c996662282df8a9d0482ef06f8d44fccc5.1745999587.git.namcao@linutronix.de> <20250516140449.GB13612@willie-the-truck> <3E29A42D-8A6A-4342-8C60-2BEF1EDCD640@goodmis.org> <20250519151238.GB17177@willie-the-truck> X-Mailer: Claws Mail 3.17.8 (GTK+ 2.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250519_090840_693602_DDA67038 X-CRM114-Status: GOOD ( 17.16 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Mon, 19 May 2025 16:12:39 +0100 Will Deacon wrote: > > Perf events work for perf only. My question is why isn't this a tracepoint > > that perf could hook into? > > Well, the perf event came first in this case, so we're stuck with it :/ I wonder what effort it will take to convert perf events to tracepoints ;-) Note, I'm talking about tracepoints and not trace events, where the latter is exposed to tracefs and the former is not. > > I was hoping we could settle for a generic helper that could emit both > the trace event and the perf event (so that the ordering of the two is > portable across architectures) but, judging by Nam's reply, the trace > event is needed before kprobes gets a look in. Perhaps we could add a helper function that does both (perf and tracepoint) and hide the implementation from the code that calls it? But I'm currently still on PTO so I haven't looked at the details yet. -- Steve