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 4E4481F2380; Tue, 21 Jan 2025 13:56:50 +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=1737467811; cv=none; b=L+0URZx6AWuvPyo8sjRimcXuNIKo6eG1Src4FZa+9Sxn3YmiprshgVACUUjwVi78bcNmSOu5txNN6dlfWk3WRJc2HSY9SmI62BQYDDKjeXD+Ix8bYaC91onrCyoO+Wyt/pscLImPT3c8th61Hgq206K2yVIbRGiIy2AQwri9/jk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1737467811; c=relaxed/simple; bh=MqI6lrWOZQoTFNws7n2UwUgsmLRqEZNZodv6GljplcY=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=s0RNozjaB5DNC6/HxZmZVm8JMA7guwHGdhwoqM3d1yeJXguuzs7EnomVIb/Q8IIvmMTQX1bs4IlQNc1RGky9pfrL9LSZaPmPOTBsP9C92VYHI+SLqN9Ba8wnes77+IZY62K0cNoHcE4qcAnJGDYkle8GP8aePN+r8YaDiPfhWoY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=isvlPBsQ; 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="isvlPBsQ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 13D92C4CEDF; Tue, 21 Jan 2025 13:56:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1737467810; bh=MqI6lrWOZQoTFNws7n2UwUgsmLRqEZNZodv6GljplcY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=isvlPBsQ7TrI9disQI4ep5AL0JttTMJYCjeOXU0i2Ch/ZJhKtfxYn7noZla1QkDqv en2cxtzrpb+ySn8gOB8ZoZV2S+K1n5H3W3i1NokW2jFX5MYZAQKEGHyjcd+04RPzL6 fTPenbokZbubnqvnOZIUv59tCiByEKKxVUoJRCVR2ClnBGXpdDVbmRMbF5RR0kls7U 7c4EikX8Q0rBg27nmXW8SWsbwke1FjZREhy6DgcwG1U+Sf6B+2s64Bk1dTdAxFB7Uo aEgg3mljv5NxhaLk6HLG7ru2QC2RXk1FcHRWMYbZ4w1F80Cti9sUorhTjzrFo4+wEW S4aA+5YxpaHVg== Date: Tue, 21 Jan 2025 14:56:47 +0100 From: Frederic Weisbecker To: Valentin Schneider Cc: linux-kernel@vger.kernel.org, x86@kernel.org, virtualization@lists.linux.dev, linux-arm-kernel@lists.infradead.org, loongarch@lists.linux.dev, linux-riscv@lists.infradead.org, linux-perf-users@vger.kernel.org, xen-devel@lists.xenproject.org, kvm@vger.kernel.org, linux-arch@vger.kernel.org, rcu@vger.kernel.org, linux-hardening@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, bpf@vger.kernel.org, bcm-kernel-feedback-list@broadcom.com, "Paul E . McKenney" , Juergen Gross , Ajay Kaher , Alexey Makhalov , Russell King , Catalin Marinas , Will Deacon , Huacai Chen , WANG Xuerui , Paul Walmsley , Palmer Dabbelt , Albert Ou , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "H. Peter Anvin" , Peter Zijlstra , Arnaldo Carvalho de Melo , Namhyung Kim , Mark Rutland , Alexander Shishkin , Jiri Olsa , Ian Rogers , Adrian Hunter , "Liang, Kan" , Boris Ostrovsky , Josh Poimboeuf , Pawan Gupta , Sean Christopherson , Paolo Bonzini , Andy Lutomirski , Arnd Bergmann , Jason Baron , Steven Rostedt , Ard Biesheuvel , Neeraj Upadhyay , Joel Fernandes , Josh Triplett , Boqun Feng , Uladzislau Rezki , Mathieu Desnoyers , Lai Jiangshan , Zqiang , Juri Lelli , Clark Williams , Yair Podemsky , Tomas Glozar , Vincent Guittot , Dietmar Eggemann , Ben Segall , Mel Gorman , Kees Cook , Andrew Morton , Christoph Hellwig , Shuah Khan , Sami Tolvanen , Miguel Ojeda , Alice Ryhl , "Mike Rapoport (Microsoft)" , Samuel Holland , Rong Xu , Nicolas Saenz Julienne , Geert Uytterhoeven , Yosry Ahmed , "Kirill A. Shutemov" , "Masami Hiramatsu (Google)" , Jinghao Jia , Luis Chamberlain , Randy Dunlap , Tiezhu Yang Subject: Re: [PATCH v4 03/30] rcu: Add a small-width RCU watching counter debug option Message-ID: References: <20250114175143.81438-1-vschneid@redhat.com> <20250114175143.81438-4-vschneid@redhat.com> Precedence: bulk X-Mailing-List: linux-arch@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20250114175143.81438-4-vschneid@redhat.com> Le Tue, Jan 14, 2025 at 06:51:16PM +0100, Valentin Schneider a écrit : > A later commit will reduce the size of the RCU watching counter to free up > some bits for another purpose. Paul suggested adding a config option to > test the extreme case where the counter is reduced to its minimum usable > width for rcutorture to poke at, so do that. > > Make it only configurable under RCU_EXPERT. While at it, add a comment to > explain the layout of context_tracking->state. > > Link: http://lore.kernel.org/r/4c2cb573-168f-4806-b1d9-164e8276e66a@paulmck-laptop > Suggested-by: Paul E. McKenney > Signed-off-by: Valentin Schneider > Reviewed-by: Paul E. McKenney Reviewed-by: Frederic Weisbecker