From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) (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 6C21F341648; Fri, 14 Nov 2025 17:40:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=216.40.44.12 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763142022; cv=none; b=tQo58xc4U1jY+GotT9r+89Ue+JwimuBPNyFYBg0iH85FFEtKRO4W9fa09SPax8eZDTnc7tMDdvG5wp/Kold2mHDYwu6oEXqofjK0ctkkzCMWyK0lvT+2KhZkgIZMwufzrJrNXKKsUWaRUEyGgb2SAV+7yniVdzZfw9cGjaf4T7o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763142022; c=relaxed/simple; bh=99NdwDFZJn/cCp/dcNoJetsRLN6GI95BBSiRaN3xBWc=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=hhKA4is9hWYmIcSnRIYFab3FAJ+/5tds91b/Pky6huZXeFdcD/V73HwBaM2VdS0vIGOoeuDyGf2u0damfhiYOZe65gM3138KWd2uPs6Friz1oBYQs2I+MSIrJqLPSSBLOMOJc6s7km3YT8FIQ+vSZysZsdDlBJuM+LDBI38XHsA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=goodmis.org; spf=pass smtp.mailfrom=goodmis.org; arc=none smtp.client-ip=216.40.44.12 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=goodmis.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=goodmis.org Received: from omf12.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id 5D23612E280; Fri, 14 Nov 2025 17:40:17 +0000 (UTC) Received: from [HIDDEN] (Authenticated sender: rostedt@goodmis.org) by omf12.hostedemail.com (Postfix) with ESMTPA id 11B7019; Fri, 14 Nov 2025 17:40:14 +0000 (UTC) Date: Fri, 14 Nov 2025 12:40:33 -0500 From: Steven Rostedt To: "Paul E. McKenney" Cc: Sebastian Andrzej Siewior , Stephen Rothwell , Frederic Weisbecker , Neeraj Upadhyay , Boqun Feng , Uladzislau Rezki , Masami Hiramatsu , Linux Kernel Mailing List , Linux Next Mailing List , yonghong.song@linux.dev Subject: Re: linux-next: manual merge of the rcu tree with the ftrace tree Message-ID: <20251114124033.78500cf3@gandalf.local.home> In-Reply-To: <747d4324-55f9-495d-b1ec-ca23cc472f3f@paulmck-laptop> References: <20251114135226.64831207@canb.auug.org.au> <20251114074255.3e535084@gandalf.local.home> <20251114133532.mmdi2dca@linutronix.de> <20251114104633.0721bdbe@gandalf.local.home> <20251114160017.CrDJHi5w@linutronix.de> <20251114112202.08e1e3c1@gandalf.local.home> <20251114163330.pi9Nm3Vb@linutronix.de> <348528a9-7e1a-4aa7-8219-5cad81969137@paulmck-laptop> <20251114171052.gJRc-2A3@linutronix.de> <747d4324-55f9-495d-b1ec-ca23cc472f3f@paulmck-laptop> X-Mailer: Claws Mail 3.20.0git84 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-next@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspamout04 X-Rspamd-Queue-Id: 11B7019 X-Stat-Signature: 7x6eg9pujow64f7tmf9yg4fqwosrfop1 X-Session-Marker: 726F737465647440676F6F646D69732E6F7267 X-Session-ID: U2FsdGVkX1+mODEt8u8m3VhtgyRdzT5SOY26JZgkzfQ= X-HE-Tag: 1763142014-455411 X-HE-Meta: U2FsdGVkX1+Q2S3fcasH8LS7M8YdYVzm2CRlpojEqI+k9IJ9IXSYy+gjACEJ2f9bMNM5Yfu0gUPC/OUP5WzMYYWzwtAkxfkIlRI2A5ZU2GxzU/skFKXOniQK69M40rJ/hvCOp0flDJ2RTVpGm0sW99ulq8VtmfLXBYy9kHTJhz939gu2FHaHtnSYoLlouIRJyGmzpSn37N4cZn7HP3eBofzKgQ7pR6Lc9hrEeQspcRaZ1mhCs2Dg9SNxb4KfmTlHZ3uBbLeSh6Eop+OLr6UkU+Ijbcf9Iyj6Y2p5SHVHyu5y+qx7VsIV+QxAyv7eVj53gpDerZakozlK18K0q0quhYvMDU/YA2Bh On Fri, 14 Nov 2025 09:25:06 -0800 "Paul E. McKenney" wrote: > > This means srcu_read_lock_notrace() is much more overhead compared to > > rcu_read_lock_sched_notrace()? > > I am a bit afraid of different bugs here and there. > > No, the concern is instead overhead due to any actual preemption. So the > goal is to actually disable preemption across the BPF program *except* > in PREEMPT_RT kernels. If this is a BPF issue only, can we move this logic into the tracepoint callbacks that BPF uses? Because, as we can see in this patch. This logic has a ripple effect throughout the tracing code where it may not be needed. I see that the callbacks seem to call the bpf_func directly. Could there be some kind of wrapper around these? -- Steve