From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (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 94ED217C96; Wed, 27 Nov 2024 16:53:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732726442; cv=none; b=LaQewCJKiCLysDXbu0QCwXaTLZvjLWSDmX5714+ttkyt1qcqTRU4jnf1coXx+4T5U8iXbRKetumV+5sRRb5q2eKWo71gtfhkswSF6h5HtReJNnr1izDnIGTn/C0AlszzZ4+i8TsBZugOmAVwkjMIFs9zEcuELymH2fdaISID/d8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732726442; c=relaxed/simple; bh=kmTGzgyDpZn1Fn4Eb1y+CbLVGkXnVF3S86LX6rvnkz4=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=oVU6/F4ctveyyCppFDGwK2GR0r5CI9i/4ccbgWiX5Ikucx9ChkOwlK2kP0Y8yogtSWXCV/W5+YtZdw07yvQ/9AwYkY1IC6g/4aDO2OFJR3jtkqvyIe5y7IrF35cN3n9zaKQaCmjZ90amvBLsU56gZfJsxsDmDWNk5jOWroFdC1Y= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=QJVvUvJG; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=Md3FlJmX; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="QJVvUvJG"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="Md3FlJmX" Date: Wed, 27 Nov 2024 17:53:56 +0100 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1732726437; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=V6TLBvyInykSDFc+FqVHujzt1ulKNH1trpfBPs+rUlI=; b=QJVvUvJGyXssfjIQAzeKVpAA4U5DupcTHtuwGVBYXulNp+475oBpy67vuJQWIYm7gLNEIm 7aGd/ZaSjdJstXk0LA0Ckqcwjc5NmoP3eZz8nFVYl97ap2L9LMRMydXlpT81Xm0B1TNJsx 7+7asV4TOsSYeCdaQYP9qKllMZh5kMTALUYQaGgvFLdDExwMunv9W8G1VhgPaRWODFhvSv FKqq+5My9vac1BHuEcsHgW3QhylUQ72erfwZjF92YT/n4DkvQrqXUn1g+BAWTLFmMOxHoW S2P3UsxbeIGgLiw70YvDjpVNOXoPsonxZIFGtA4ri1UOjKE7PaPSflYNgznTkA== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1732726437; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=V6TLBvyInykSDFc+FqVHujzt1ulKNH1trpfBPs+rUlI=; b=Md3FlJmXY3YKf3NtQnqrRCfazRFvbuPR//i3H5C0gpb5wyZJLUndUCvS1HNv8Ebl91rsyt KN0RAUrLZb2pAwAQ== From: Sebastian Andrzej Siewior To: Guenter Roeck Cc: Andreas Larsson , Waiman Long , sparclinux@vger.kernel.org, linux-kernel@vger.kernel.org, Boqun Feng , Ingo Molnar , Peter Zijlstra , Thomas Gleixner , Will Deacon , "David S. Miller" Subject: Re: [PATCH] sparc/pci: Make pci_poke_lock a raw_spinlock_t. Message-ID: <20241127165356.hnkqmgcc@linutronix.de> References: <20241125181231.XpOsxxHx@linutronix.de> <72991b83-173e-492e-a4aa-5049304c1bd0@roeck-us.net> <5d269249-afd1-44f5-8faf-9ac11d9a3beb@redhat.com> <2a940822-b4d4-43ea-b4f7-4294043b76ea@roeck-us.net> <88f47cea-baba-4673-9bd7-7b7c3f421008@redhat.com> <20241126112000.UkTwR0Iv@linutronix.de> <48b9d642-9739-4333-b4b9-319df8a85e2d@redhat.com> <4eb7bb8e-c2aa-4ce5-9f15-3086fccf4e46@roeck-us.net> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <4eb7bb8e-c2aa-4ce5-9f15-3086fccf4e46@roeck-us.net> On 2024-11-27 08:02:50 [-0800], Guenter Roeck wrote: > On 11/27/24 07:39, Andreas Larsson wrote: > > Even though this is for sparc64, there is work being done looking into > > enabling RT for sparc32. If the amount of fixes needed to keep > > PROVE_RAW_LOCK_NESTING enabled is quite small at the moment I'd rather > > see it enabled for sparc rather than risking it becoming worse in the > > future. Okay. So you seem to be in favour of fixing the sparc64 splats Guenter reported? > > I don't know what the situation is for other architectures that does not > > support RT. > > > > For my part I still don't understand why PROVE_RAW_LOCK_NESTING is no longer > a configurable option, or in other words why it is mandated even for architectures > not supporting RT. To me this means that I'll either have to disable PROVE_LOCKING > for sparc or live with endless warning backtraces. The latter obscures real > problems, so it is a no-go. It is documented in Documentation/locking/locktypes.rst how the locks should nest. It is just nobody enabled it on sparc64 and tested. The option was meant temporary until the big read blocks are cleared. > So, if people want to keep mandating PROVE_RAW_LOCK_NESTING together with > PROVE_LOCKING for all architectures, I'll disable PROVE_LOCKING for sparc > in my testing. NP, just let me know. I'll then do the same for other > architectures not supporting RT if I hit the same problem there. Waiman posted a patch to disable it on architectures that don't support PREEMPT_RT. You could also post the patches you discussed. Andreas does not seem to be against it (but then I don't know if he is a 32 or 64bit guy). I did not year from other architectures so far. > Guenter Sebastian