From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 10285CD343F for ; Mon, 18 May 2026 19:53:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=947SOLNtyKjftx3F/FZ7uNcrN3ZeuC/GABDa4a4xvv4=; b=WMiFbnOzhtUZMPknjxXgqLKU5P AIrSEu0/K7fcL9oX1XbxgUAlg77C82VGh5axFxG+/9fEYUOHkld5rJeQ7g36RMCFCmUp4FEwSqO8g b63n2/UNuqOZPF6WbJ6KCCyfk5NLriD6qLpJnxaN7MNwKvGwFjOkhC5jQT8Z6I16XtKEJN3vM++u8 PVOtGbeOYxvdf0fCUacgxmz73AVCHhWPXL5xpqnYKFviy5CAEox8SEQ2pNmsFJgphmN28LSN4rgRK 9xgFrr3AQtzZUc5bavgIFKTujclxkHlOhd+MQKUAet2QpNqkL8vP+3tXJskOFj+eee0rs1FaU4043 rQ5SLbMw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wP41y-0000000Go95-0BfJ; Mon, 18 May 2026 19:53:38 +0000 Received: from sea.source.kernel.org ([2600:3c0a:e001:78e:0:1991:8:25]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1wP41v-0000000Go8e-3SY5 for linux-arm-kernel@lists.infradead.org; Mon, 18 May 2026 19:53:36 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id 5A661419B5; Mon, 18 May 2026 19:53:35 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 245BFC2BCC6; Mon, 18 May 2026 19:53:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1779134015; bh=nZ0D31rkJ58LmFaS2W1jBidt3T9eg8DSZrXA9r0f9Ac=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=O7U/5SfC8PP4wcXOspJBnyLZb8fjuk1HP3PEPyF0HIn2Ol0sAqvYeirvFb76FXTEV 7bP5b9jtSmSp0lbLozkGPZzV2ePN+x3oKsnbmcjC3dGCgssQwrpbZEcc4f+Yrh9Zua DriwYDD0PKgwef2oYAWjf8kFFx4pIo645Am5zxDzXKIwL0mUfQWQn+WqmrU6EUuGMC 4oHyw0BCaJQeh3JHzSX28eKEPukAnj95j2ZxM40kb+iIrvhAqcNHOH2uXrsebtcEn+ cLD/nrjnJYs4zdQz08NAjMpyWK/YGQqSjN2NP8c+cBNlGfIOS3hLZ4dA+dGnlzn/sI j6XR/xgodjqmA== Date: Mon, 18 May 2026 09:53:34 -1000 From: Tejun Heo To: "David Hildenbrand (Arm)" Cc: David Vernet , Andrea Righi , Changwoo Min , Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , Martin KaFai Lau , Kumar Kartikeya Dwivedi , Catalin Marinas , Will Deacon , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , Andrew Morton , Mike Rapoport , Emil Tsalapatis , sched-ext@lists.linux.dev, bpf@vger.kernel.org, x86@kernel.org, linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/8] mm: Add ptep_try_install() for lockless empty-slot installs Message-ID: References: <20260517211232.1670594-1-tj@kernel.org> <20260517211232.1670594-2-tj@kernel.org> <9ba50fd2-077e-4291-9276-9adb18186873@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <9ba50fd2-077e-4291-9276-9adb18186873@kernel.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260518_125335_881086_747AD6A3 X-CRM114-Status: GOOD ( 11.73 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hello, On Mon, May 18, 2026 at 10:06:29AM +0200, David Hildenbrand (Arm) wrote: > On 5/17/26 23:12, Tejun Heo wrote: > > +static inline bool ptep_try_install(pte_t *ptep, pte_t new_pte) > > +{ > > + return false; > > +} > > +#endif > > Ehm, what? > > This is a very, very, very bad generic idea/interface. > > On which ptes is this supposed to be used? User ptes or kernel ptes? > > Surely we don't want this on user ptes. Yeah, this is only for the BPF arena PTEs which are already managed in their own way. I'd be happy to place / gate it however appropriate. Thanks. -- tejun