From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 6B003242D70; Tue, 20 May 2025 14:04:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747749899; cv=none; b=gStbrU55GBH+f0hYeaZhSGAeSX//R5sWhaRUEAHwRnyZjQEcAeK1g+qFmUztlozkDirSDwxvfsl/95gpV+vMNqztMU/fav6ubS7y6/D3aIre8W+cufM9oJu1xifasjpfU54hfI8PND0VCceb9rY9h9cvaBwfqNETohRDMhxa4HQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747749899; c=relaxed/simple; bh=FwTN2M9DsTfsj/6tueLnbl1Llxw38v4QaqUMi15NmgA=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=eBcdjTNEFMLjDBzhDeVQjZCxkb2PzJYQ9J1peyzFp/DtfGKztMiEyX5iDNrLe2F0IRXAfc/SRPKh3sHewtlha9KhmUlDAizz+RmWY1u3YCeafPlPM8khcYg35l900UPXPZkfi3Nz1AiKrZbo0ubPhJ7HFa8/+CIkbfDht4mg0A8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ES8SmexG; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="ES8SmexG" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C3917C4CEE9; Tue, 20 May 2025 14:04:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1747749899; bh=FwTN2M9DsTfsj/6tueLnbl1Llxw38v4QaqUMi15NmgA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=ES8SmexGvRqYBgMtzkBjOvrX8znCoPDidI0UZGzvGoeB4LDg48e4Pbi61iBWLDs+l vRwHMbBZr1dj9zKsF5t4lC+VmR7XYkv8nUYzycpmwY/LPtxMxPFPU5kmSKLGKE+ytf j/JYY/cXGPY2bd1DHz64piyGl6OT5jutJn9/54pWOyvUPGsY7rZ69SbkR+ICbTq9X6 YjQ3Ouo8oynmSUZlaTNCgBUIKWPJLzcf74ZCRQYXrlif7xBV0Sw1+17+s+XCdltnw7 1j2u3nI01jk9hQr0RxXck0JNmHTvm2RH3fy5aZBp6UwDQ2a6hsFmHL107VvNuyiP6p whQD/WTNnDIcQ== Date: Tue, 20 May 2025 15:04:54 +0100 From: Will Deacon To: Steven Rostedt 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: <20250520140453.GA18711@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> <20250519120837.794f6738@batman.local.home> Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250519120837.794f6738@batman.local.home> User-Agent: Mutt/1.10.1 (2018-07-13) On Mon, May 19, 2025 at 12:08:37PM -0400, Steven Rostedt wrote: > 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? Something like that sounds like a good idea, yes. > But I'm currently still on PTO so I haven't looked at the details yet. Enjoy! Will