From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) (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 F41321EA7C6; Thu, 1 May 2025 15:03:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.50.34 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746111791; cv=none; b=A1NB3QJuSlt0AQJcIAzD5Glj4GSf98aU4GhqvCEBi9zz/UQ/v3vlbQl75P/LWG3EFuuXHRy2XnBKrZ6KQF3tIKpxURGOumJ3nyWyqS8zTo/GUqEeWFwZEbsjq0wo17l0W7GFY8VJkuQhXmsw1/P6PMMZKcSwRKirm3FTa4ylEus= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746111791; c=relaxed/simple; bh=4ySaPdEMd4+Vb4yQ+0YUSkKNLjFLCkYhYBoAAExMs3U=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=mkA40cvOe/OtEv8hBUGlPDxu68SZALFpXB3HobIqYdNeHwgSfoTWLTJZ5JUaYhONFPxWvst8EFgVOjLN10UQWtklOi2tY02YJ5IR9q9NZJ1UFQwpGz/Bl1d7ChOcc8FtSc0eCQ0qGX8rybZc9CV1WKY1Ja0eSpow47+EvI3u3GE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=QE9K7S0F; arc=none smtp.client-ip=90.155.50.34 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="QE9K7S0F" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=SknNweDJMYv6Cc7JXUCuginAJHi4T0ZKllMpOn1Yf9A=; b=QE9K7S0FqJXdRMiI2MUQfyFVKN zJkaOZZAvX0UK9xBOJnD6xr1oo4dLko0vESRIIkP4sjHHPxZkleb2D8Zai321exEYA2JJr82ElX7s y72vsCa48dbNhj3sR2u6AvvpDc6GUftTpqrd7fLDiVr8l4ZJcPOvCc/B4Kso/X5VwtY001koeorb7 w0lpR1LpdbzQwtNNGzQXqNnli6Sbl3pH+QAdCVePhkf3FUFd/ngVNiv41q8dPOdm8t1mbTM/UmJ5P NuryBBTCcNBBOjT/+JRWnUfQQL+DhMwA+igl0308JTBNEPRBnnqN+OImNHFtw2Imib6YH9ERSKUcP cmUpe09A==; Received: from 77-249-17-252.cable.dynamic.v4.ziggo.nl ([77.249.17.252] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.98.2 #2 (Red Hat Linux)) id 1uAVQk-00000000oH8-33tB; Thu, 01 May 2025 15:02:30 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id 1B7DC30072F; Thu, 1 May 2025 17:02:30 +0200 (CEST) Date: Thu, 1 May 2025 17:02:29 +0200 From: Peter Zijlstra To: Brendan Jackman Cc: Christoph Hellwig , chenlinxuan@uniontech.com, Keith Busch , Jens Axboe , Sagi Grimberg , Andrew Morton , Yishai Hadas , Jason Gunthorpe , Shameer Kolothum , Kevin Tian , Alex Williamson , Peter Huewe , Jarkko Sakkinen , Masahiro Yamada , Nathan Chancellor , Nicolas Schier , Nick Desaulniers , Bill Wendling , Justin Stitt , Vlastimil Babka , Suren Baghdasaryan , Michal Hocko , Johannes Weiner , Zi Yan , Mathieu Desnoyers , "Paul E. McKenney" , Boqun Feng , Dmitry Vyukov , Andrey Konovalov , Juergen Gross , Boris Ostrovsky , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, kvm@vger.kernel.org, virtualization@lists.linux.dev, linux-integrity@vger.kernel.org, linux-kbuild@vger.kernel.org, llvm@lists.linux.dev, Winston Wen , kasan-dev@googlegroups.com, xen-devel@lists.xenproject.org, Changbin Du , Linus Torvalds Subject: Re: [PATCH RFC v3 0/8] kernel-hacking: introduce CONFIG_NO_AUTO_INLINE Message-ID: <20250501150229.GU4439@noisy.programming.kicks-ass.net> References: <20250429-noautoinline-v3-0-4c49f28ea5b5@uniontech.com> <20250429123504.GA13093@lst.de> Precedence: bulk X-Mailing-List: kvm@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: On Thu, May 01, 2025 at 02:19:47PM +0000, Brendan Jackman wrote: > On Tue Apr 29, 2025 at 12:35 PM UTC, Christoph Hellwig wrote: > > On Tue, Apr 29, 2025 at 12:06:04PM +0800, Chen Linxuan via B4 Relay wrote: > >> This series introduces a new kernel configuration option NO_AUTO_INLINE, > >> which can be used to disable the automatic inlining of functions. > >> > >> This will allow the function tracer to trace more functions > >> because it only traces functions that the compiler has not inlined. > > > > This still feels like a bad idea because it is extremely fragile. > > Can you elaborate on that - does it introduce new fragility? given it needs to sprinkle __always_inline around where it wasn't needed before, yeah. Also, why would you want this? function tracer is already too much output. Why would you want even more?