From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 034A3370ADF; Wed, 16 Sep 2026 14:04:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789567486; cv=none; b=DE+WQWJruGycAbRhDFf/NQlcCG/baBS5eWg7U9haT7YE//3Q/gvjoHnT0B1xzhHK8DBhLURmxf8cHrHKB8EI4vW4qcBGuIr7RdUyPWFBYNmZPZZ1H8sciVnh79089fl6EHbEkXA/z9KuuUmjxmsSlYK1sRtw1qw+Fq1o/GUoo8Q= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789567486; c=relaxed/simple; bh=4p4hgcvw6kWcyC6EnxN9LbmyJCJrpBQ7Z3d+76JOY14=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=YqGGp5oYOPnCKqWn+Il049s6QV4oa0YTDWAjdyDLiZil6NgcwUZjsG+2yIAI6XC78nTyi+QD+ewG/jAa/sOMfzvhbldIoph6dMA0exFgn/Q4yKyfZ3wA0yMxxQ7pfhX6Zt/JuG6eOJSarbIQOyffsOdcl4+Jp9j2nIOZHxkGdqs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=QEqrNXj4; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="QEqrNXj4" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C72A01F000FF; Wed, 16 Sep 2026 14:04:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789567484; bh=4p4hgcvw6kWcyC6EnxN9LbmyJCJrpBQ7Z3d+76JOY14=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=QEqrNXj4hIJ+yI04UbRRbzBwkfAPGXGTc0IPJzRUfJ08hVbqxoA11qyOaeocRMZze QMDTNlNgZ7H/6jCbW4jc7XIIj+3crpYh6RQPGu/2+kV+9chxN+NMfi19lT+PZsz3q6 kJeTiFOZocvpahWB6/2aLwybCEhF1VgXISs4r9MysIyyIWac/3X2Q1aqa9WzRyv759 cq+oXi0EGQRTc0SkQkEwyDO6JX4YcPiIFG/z5UYYYaSOeB4TcDU3wzHNgcPxPEuoeH jyMHgQXRuDCjNHXLen/ynlZVk+jaxndcRdCxn72EKgpqHgdOxG8Z/1xMe2pcVmDJv5 uz3X+qN5sZ83w== Date: Wed, 16 Sep 2026 15:04:30 +0100 From: "Lorenzo Stoakes (ARM)" To: Kees Cook Cc: Linus Torvalds , Nathan Chancellor , Nicolas Schier , Nick Desaulniers , Bill Wendling , Justin Stitt , Masahiro Yamada , Alexey Gladkov , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexandre Ghiti , Arnd Bergmann , Catalin Marinas , Will Deacon , Mark Rutland , Ard Biesheuvel , Ilias Apalodimas , Josh Poimboeuf , Peter Zijlstra , Miguel Ojeda , Boqun Feng , Gary Guo , =?utf-8?B?QmrDtnJu?= Roy Baron , Benno Lossin , Andreas Hindborg , Alice Ryhl , Trevor Gross , Danilo Krummrich , Daniel Almeida , Tamir Duberstein , Alexandre Courbot , Onur =?utf-8?B?w5Z6a2Fu?= , Jonathan Corbet , Randy Dunlap , "Gustavo A. R. Silva" , linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, llvm@lists.linux.dev, linux-riscv@lists.infradead.org, linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-efi@vger.kernel.org, rust-for-linux@vger.kernel.org, linux-doc@vger.kernel.org, Jens Axboe , linux-hardening@vger.kernel.org Subject: Re: [PATCH v2 20/21] kbuild: build rust crates in parallel with the rest of the build Message-ID: References: <20260914-build-speedup-v2-0-39817ec5db23@kernel.org> <20260914-build-speedup-v2-20-39817ec5db23@kernel.org> <202609141133.7CA979C89@keescook> <202609150951.73C4F16EFB@keescook> 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=us-ascii Content-Disposition: inline In-Reply-To: <202609150951.73C4F16EFB@keescook> On Tue, Sep 15, 2026 at 09:52:01AM -0700, Kees Cook wrote: > On Tue, Sep 15, 2026 at 12:58:10PM +0100, Lorenzo Stoakes (ARM) wrote: > > Since this _still_ gives you a significant speed up on bigger boxes, I think > > it's fine as-is. > > > > The LLM says a fix for this would need significant work - a cross-instance lock > > and an on-demand rust/ build. So I think best as a follow-up? > > Sure! And I defer to the Rust folks on all of this. I just wanted to Yes indeed as do I :) I _think_ this change should be a lot more viable than the -Zthreads one though :) > note the possibly unintended behavioral change there. Thanks for > examining it! No worries! > > -- > Kees Cook -- Cheers, Lorenzo