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 3B5D215D1; Fri, 4 Oct 2024 20:58:33 +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=1728075514; cv=none; b=c8K8eXncRFy2mObhUJekA+p+NPCYNiT/T4BVgNoEA2NKEvfdNmct8zp8o9MmaRm7/QhDQYbEq9llO9ds22+isXI38O1mhscFQNj8flTC+9xTEtEVdPHRsgHSn4Sj8oACKXLyRXRdLHuAnbvmh7cimbTrP0D5ziU3gi+GmRrVnG0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728075514; c=relaxed/simple; bh=+Ef3UyjsUB+Ar1A7IpIt4SHw+OpwXL1vVhNlffc6fuk=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=DaGw2uKtzzg2o+oJkf350z9CsKm4YB9g8W6IyNx1oDzUAN76L/ltGWdV65WvKuQXycPaCloysAIP/FoT0npRfIL0tJMkOI0Rw5rM/fo9f1HXTsvuwqCB4T/CRIOTywiXZCI5YMLkqxsw/wlv08oLCb0yX+RIVT34yUxJwrCsxaE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 Received: by smtp.kernel.org (Postfix) with ESMTPSA id D6C84C4CEC6; Fri, 4 Oct 2024 20:58:31 +0000 (UTC) Date: Fri, 4 Oct 2024 16:59:27 -0400 From: Steven Rostedt To: Andrii Nakryiko Cc: Mathieu Desnoyers , Masami Hiramatsu , linux-kernel@vger.kernel.org, Peter Zijlstra , Alexei Starovoitov , Yonghong Song , "Paul E . McKenney" , Ingo Molnar , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Namhyung Kim , bpf@vger.kernel.org, Joel Fernandes , linux-trace-kernel@vger.kernel.org, Michael Jeanson Subject: Re: [PATCH v1 2/8] tracing/ftrace: guard syscall probe with preempt_notrace Message-ID: <20241004165927.774e7d35@gandalf.local.home> In-Reply-To: References: <20241003151638.1608537-1-mathieu.desnoyers@efficios.com> <20241003151638.1608537-3-mathieu.desnoyers@efficios.com> <20241003182304.2b04b74a@gandalf.local.home> <6dc21f67-52e1-4ed5-af7f-f047c3c22c11@efficios.com> <20241003210403.71d4aa67@gandalf.local.home> <90ca2fee-cdfb-4d48-ab9e-57d8d2b8b8d8@efficios.com> <20241004092619.0be53f90@gandalf.local.home> <20241004105211.13ea45da@gandalf.local.home> <4f1046e7-7b62-4db3-93d4-815dc8c27185@efficios.com> X-Mailer: Claws Mail 3.20.0git84 (GTK+ 2.24.33; x86_64-pc-linux-gnu) 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-Transfer-Encoding: 7bit On Fri, 4 Oct 2024 13:04:21 -0700 Andrii Nakryiko wrote: > > AFAIU eBPF folks are very eager to start making use of this, so we won't > > have to wait long. > > I already gave my ack on BPF parts of this patch set, but I'll > elaborate a bit more here for the record. There seems to be two things > that's been discussed. > > First, preempt_disable() vs migrate_disable(). We only need the > latter, but the former just preserves current behavior and I think > it's fine, we can follow up with BPF-specific bits later to optimize > and clean this up further. No big deal. > > Second, whether BPF can utilize sleepable (faultable) tracepoints > right now with these changes. No, we need a bit more work (again, in > BPF specific parts) to allow faultable tracepoint attachment for BPF > programs. But it's a bit nuanced piece of code to get everything > right, and it's best done by someone more familiar with BPF internals. > So I wouldn't expect Mathieu to do this either. > > So, tl;dr, I think patches are fine as-is (from BPF perspective), and > we'd like to see them applied and get to bpf-next for further > development on top of that. Thanks Andrii for elaborating. -- Steve