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 4C0A553D0CE for ; Tue, 8 Sep 2026 12:42:31 +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=1788871352; cv=none; b=UBd+teO+9y0aVRWRNWU89QTgD7Ph2rB9EdJtgWy39ya7mvfpTMjblPYXIiD0Bz4rAfGHNg//zKqbruqlWkVV1ZTaBmBdOr/oP0dMYY5ZgKCP1mfzQ1bt/2Qt+ovrdlcULoOaEbTBbHD6hdsvEoXl/5KqawYkzb/HJSkUfoI+S54= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788871352; c=relaxed/simple; bh=KEJoMC1Qi+8T7N+BJf99nyPvPkDgOR2zUMOhqLIa5WU=; h=From:Subject:To:Cc:In-Reply-To:References:Content-Type:Date: Message-Id; b=eyQkR9pZPqgLM8bRTpuAi6mRhywWl1ld67jfT8fxiDjVy1jKlQWefk2wRBLxHxeIauP+zVwaXkCxoHfP37Op/H9LZIetbkYfh4H+ryWupUcVoh4qUU0o1kEUtZdguwPmVNrgX6foE2p4VoNopqygJWZtdde8DL+B5WuWEjcopI4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=HRC7sJum; 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="HRC7sJum" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BF59A1F00A3A; Tue, 8 Sep 2026 12:42:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788871351; bh=KEJoMC1Qi+8T7N+BJf99nyPvPkDgOR2zUMOhqLIa5WU=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=HRC7sJumUILIngPhlVAzs3gfx+jMaprDWkf+nlF7eiTy+dKCQrhMCUHvFEXVYxq+P 7fzQDyne+p8JT7DWBSr6agsAVbNSPIQjaPg52e2qedSxfi0phr/YIScIeVMEfpCeqJ ZdBgm8fs8jQV9pMf62PazO9knXq8zTFH+CUeX6nWn9twWSh9/FvgGWSXX11reBPmxD TrWZ2lMkh4Ft/0lYdcsWGaUfLDdPHX5dBImCXHvWONuR0uIWQ5GwBqjzvwmUBq96X0 azZ2zOnZCb4oE2a7PaBWLBvonVC5gaEmcFEjoXxJoChb64Kwr3zB8RXcdzM4wDs9gV rcJCgKy7bbN/Q== From: sashiko-bot@kernel.org Subject: Re: [PATCH v2 03/12] mm: enable MMU_GATHER_RCU_TABLE_FREE for MMU riscv Reply-To: sashiko-reviews@lists.linux.dev To: =?utf-8?b?TG9yZW56byBTdG9ha2VzIChBUk0p?= Cc: "Heiko Carstens" , "Vasily Gorbik" , "Alexander Gordeev" , linux-s390@vger.kernel.org, "Christian Borntraeger" In-Reply-To: <20260908-rcu-pagetable-freeing-v2-3-1f60b64e878e@kernel.org> References: <20260908-rcu-pagetable-freeing-v2-0-1f60b64e878e@kernel.org> <20260908-rcu-pagetable-freeing-v2-3-1f60b64e878e@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Tue, 08 Sep 2026 12:42:30 +0000 Message-Id: <20260908124230.BF59A1F00A3A@smtp.kernel.org> Precedence: bulk X-Mailing-List: linux-s390@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: > Currently riscv gates MMU_GATHER_RCU_TABLE_FREE on CONFIG_SMP and > CONFIG_MMU. >=20 > Commit 69be3fb111e7 ("riscv: enable MMU_GATHER_RCU_TABLE_FREE for SMP && > MMU") enabled CONFIG_MMU_GATHER_RCU_TABLE_FREE for CONFIG_SMP, CONFIG_MMU > riscv builds. >=20 > This is expressly for the safety of GUP-fast walkers (CONFIG_HAVE_GUP_FAST > is enabled if CONFIG_MMU is enabled). >=20 > Naturally a single core system does not encounter issues with software pa= ge > table walkers being correctly synchronised across cores, as there is only= a > single core. >=20 > However, CONFIG_PREEMPT_RCU is still available on a riscv UP system, so f= or > a future RCU-only page table walker, this guarantee is required to prevent > concurrent page table teardown. >=20 > All page table freeing is already done via tlb_remove_ptdesc() so the > conditions of CONFIG_MMU_GATHER_RCU_TABLE_FREE are already met. >=20 > This forms part of an overall effort to switch every architecture to this > mode. >=20 > Signed-off-by: Lorenzo Stoakes (ARM) Sashiko has reviewed this patch and found no issues. It looks great! --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20260908-rcu-pageta= ble-freeing-v2-0-1f60b64e878e@kernel.org?part=3D3